Anesthesiology, Medical Education, Outcomes Research, Pain Medicine, Patient Safety, Regional Anesthesiology, Uncategorized

Ultrasound in Regional Anesthesia: What is the Evidence?

Medical scannerThe use of ultrasound guidance in the practice of regional anesthesia arguably began in the late 1980s (1), although ultrasound Doppler technology was used to direct needle insertion for peripheral nerve blockade in the 1970s (2). This past decade has seen a rapid increase in practical applications and clinical research in the field of ultrasound-guided regional anesthesia (UGRA), and the American Society of Regional Anesthesia and Pain Medicine (ASRA) and European Society of Regional Anesthesia have even published joint committee guidelines for training in this discipline (3).

Given the rapid adoption of UGRA, evidence to support this practice was initially limited; however, many studies have emerged in an attempt to define the role of ultrasound. In 2010, ASRA published a series of important articles which distill the body of evidence related to UGRA up to that time point (4-13). Additional studies have been completed and published since 2010 and will be included in an update that should be published in the next year.

Ultrasound Guidance for Extremity Peripheral Nerve Blocks

The 2010 ASRA systematic reviews covering this subject include 24 RCTs which compare ultrasound guidance to an alternative nerve localization technique for either upper or lower extremity peripheral nerve blockade (5). For both upper and lower extremity blocks, the majority of studies report faster block onset when ultrasound is employed (5,6,11), although 5 of 15 studies in the upper extremity and 2 of 5 studies in the lower extremity fail to find a difference in onset time (5). There is evidence to support a decrease in procedural time when ultrasound is used for upper and lower extremity blocks (6-11); however, set-up time and pre-scanning with ultrasound are not consistently measured or reported. In terms of block quality, lower extremity studies are more likely to report an advantage with ultrasound than upper extremity studies; only 4 of 16 upper extremity studies show improvement with ultrasound, and these studies use nerve stimulation or transarterial injection as the comparator (5). When a fixed time point is used for assessing block success, ultrasound use is more likely to show an advantage although the definitions of successful block vary widely (6,11). Only one study in the upper extremity shows a difference in block duration in favor of ultrasound while all other RCTs do not demonstrate a difference (5). For femoral and subgluteal sciatic nerve blocks, ultrasound use decreases the minimum effective anesthesia volume to achieve a successful block in 50% of patients (11).

Ultrasound for Continuous Peripheral Nerve Blocks

Although many large case series describing ultrasound-guided techniques for continuous peripheral nerve block (CPNB) performance have been published, there are relatively-fewer RCTs comparing ultrasound to other nerve localization techniques for CPNB. When an exclusively ultrasound-guided technique is compared to a stimulating catheter technique, procedural duration is shorter with ultrasound at four distinct insertion sites (14-17) with less procedure-related pain for lower extremity catheters (14,16) and fewer inadvertent vascular punctures for femoral and infraclavicular catheters (14,15). Most studies report similar analgesia and other acute pain outcomes from catheters placed with ultrasound when compared to other methods (18-20), with the exception of one study involving popliteal-sciatic catheters which suggests that stimulating catheters may provide an analgesic advantage although successful placement occurs less often (21).

Ultrasound for Truncal and Neuraxial Blocks

To date, RCTs comparing ultrasound guidance to traditional techniques for paravertebral blockade or transversus abdominis plane (TAP) blocks have yet to be reported. For both of these procedures, the 2010 ASRA systematic review recommends the use of ultrasound although this recommendation is based on case series data only (4). In one study comparing ultrasound-guided TAP to conventional ilioinguinal/iliohypogastric nerve blocks for inguinal hernia repair, subjects who received ultrasound-guided TAP blocks reported lower pain scores for the first 24 hours (22). Ultrasound-guidance and the landmark-based technique for ilioinguinal/iliohypogastric nerve blocks have been compared in children with the ultrasound-guided technique resulting in decreased need for systemic analgesic supplementation (23). For neuraxial blocks, there is evidence to support ultrasound scanning prior to employing conventional neuraxial block techniques rather than relying solely on surface landmarks (10), especially in patients with challenging anatomy (24).

Ultrasound for Regional Anesthesia in Special Populations

Ultrasound-guided techniques for peripheral (25) and neuraxial (26) blocks in children have been described previously. The 2010 ASRA evidence-based review on ultrasound for pediatric regional anesthesia included 6 RCTs involving peripheral nerve blocks and one randomized trial in neuraxial blockade in addition to case series of >10 patients (12). In this population, ultrasound may improve the speed of block onset and duration of analgesia, increase success rates for truncal blocks compared to blind techniques, and reduce the volume of local anesthetic required (12). In obese patients, ultrasound may play a role in identifying target peripheral and neuraxial structures as well as real-time procedural performance (27). When performing CPNB in obese patients, procedural time is not prolonged compared to non-obese patients when as long as ultrasound is used (28).

#Ultrasound has been shown to decrease serious complications related to nerve blocks.

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MedianIn summary, there is sufficient evidence to support the use of ultrasound guidance for peripheral nerve blockade based on short-term outcomes, and the results of a large prospective registry study suggest that ultrasound may decrease in the risk of local anesthetic systemic toxicity (29). Additional prospective studies are needed to further define the role of ultrasound in neuraxial blockade, long-term patient outcomes, and advantages in special populations.

References

  1. Ting PL, Sivagnanaratnam V: Ultrasonographic study of the spread of local anaesthetic during axillary brachial plexus block. Br J Anaesth 1989; 63: 326-9
  2. la Grange P, Foster PA, Pretorius LK: Application of the Doppler ultrasound bloodflow detector in supraclavicular brachial plexus block. Br J Anaesth 1978; 50: 965-7
  3. Sites BD, Chan VW, Neal JM, Weller R, Grau T, Koscielniak-Nielsen ZJ, Ivani G: The American Society of Regional Anesthesia and Pain Medicine and the European Society Of Regional Anaesthesia and Pain Therapy Joint Committee recommendations for education and training in ultrasound-guided regional anesthesia. Reg Anesth Pain Med 2009; 34: 40-6
  4. Abrahams MS, Horn JL, Noles LM, Aziz MF: Evidence-based medicine: ultrasound guidance for truncal blocks. Reg Anesth Pain Med 2010; 35: S36-42
  5. Liu SS, Ngeow J, John RS: Evidence basis for ultrasound-guided block characteristics: onset, quality, and duration. Reg Anesth Pain Med 2010; 35: S26-35
  6. McCartney CJ, Lin L, Shastri U: Evidence basis for the use of ultrasound for upper-extremity blocks. Reg Anesth Pain Med 2010; 35: S10-5
  7. Narouze SN: Ultrasound-guided interventional procedures in pain management: Evidence-based medicine. Reg Anesth Pain Med 2010; 35: S55-8
  8. Neal JM: Ultrasound-guided regional anesthesia and patient safety: An evidence-based analysis. Reg Anesth Pain Med 2010; 35: S59-67
  9. Neal JM, Brull R, Chan VW, Grant SA, Horn JL, Liu SS, McCartney CJ, Narouze SN, Perlas A, Salinas FV, Sites BD, Tsui BC: The ASRA evidence-based medicine assessment of ultrasound-guided regional anesthesia and pain medicine: Executive summary. Reg Anesth Pain Med 2010; 35: S1-9
  10. Perlas A: Evidence for the use of ultrasound in neuraxial blocks. Reg Anesth Pain Med 2010; 35: S43-6
  11. Salinas FV: Ultrasound and review of evidence for lower extremity peripheral nerve blocks. Reg Anesth Pain Med 2010; 35: S16-25
  12. Tsui BC, Pillay JJ: Evidence-based medicine: Assessment of ultrasound imaging for regional anesthesia in infants, children, and adolescents. Reg Anesth Pain Med 2010; 35: S47-54
  13. Jadad AR, Moore RA, Carroll D, Jenkinson C, Reynolds DJ, Gavaghan DJ, McQuay HJ: Assessing the quality of reports of randomized clinical trials: is blinding necessary? Control Clin Trials 1996; 17: 1-12
  14. Mariano ER, Cheng GS, Choy LP, Loland VJ, Bellars RH, Sandhu NS, Bishop ML, Lee DK, Maldonado RC, Ilfeld BM: Electrical stimulation versus ultrasound guidance for popliteal-sciatic perineural catheter insertion: a randomized controlled trial. Reg Anesth Pain Med 2009; 34: 480-5
  15. Mariano ER, Loland VJ, Bellars RH, Sandhu NS, Bishop ML, Abrams RA, Meunier MJ, Maldonado RC, Ferguson EJ, Ilfeld BM: Ultrasound guidance versus electrical stimulation for infraclavicular brachial plexus perineural catheter insertion. J Ultrasound Med 2009; 28: 1211-8
  16. Mariano ER, Loland VJ, Sandhu NS, Bellars RH, Bishop ML, Afra R, Ball ST, Meyer RS, Maldonado RC, Ilfeld BM: Ultrasound guidance versus electrical stimulation for femoral perineural catheter insertion. J Ultrasound Med 2009; 28: 1453-60
  17. Mariano ER, Loland VJ, Sandhu NS, Bellars RH, Bishop ML, Meunier MJ, Afra R, Ferguson EJ, Ilfeld BM: A trainee-based randomized comparison of stimulating interscalene perineural catheters with a new technique using ultrasound guidance alone. J Ultrasound Med 2010; 29: 329-336
  18. Ilfeld BM: Continuous peripheral nerve blocks: a review of the published evidence. Anesth Analg 2011; 113: 904-25
  19. Fredrickson MJ, Danesh-Clough TK: Ambulatory continuous femoral analgesia for major knee surgery: a randomised study of ultrasound-guided femoral catheter placement. Anaesth Intensive Care 2009; 37: 758-66
  20. Choi S, Brull R: Is ultrasound guidance advantageous for interventional pain management? A review of acute pain outcomes. Anesth Analg 2011; 113: 596-604
  21. Mariano ER, Loland VJ, Sandhu NS, Bishop ML, Lee DK, Schwartz AK, Girard PJ, Ferguson EJ, Ilfeld BM: Comparative efficacy of ultrasound-guided and stimulating popliteal-sciatic perineural catheters for postoperative analgesia. Can J Anaesth 2010; 57: 919-926
  22. Aveline C, Le Hetet H, Le Roux A, Vautier P, Cognet F, Vinet E, Tison C, Bonnet F: Comparison between ultrasound-guided transversus abdominis plane and conventional ilioinguinal/iliohypogastric nerve blocks for day-case open inguinal hernia repair. Br J Anaesth 2011; 106: 380-6
  23. Willschke H, Marhofer P, Bosenberg A, Johnston S, Wanzel O, Cox SG, Sitzwohl C, Kapral S: Ultrasonography for ilioinguinal/iliohypogastric nerve blocks in children. Br J Anaesth 2005; 95: 226-30
  24. Chin KJ, Perlas A, Chan V, Brown-Shreves D, Koshkin A, Vaishnav V: Ultrasound imaging facilitates spinal anesthesia in adults with difficult surface anatomic landmarks. Anesthesiology 2011; 115: 94-101
  25. Tsui B, Suresh S: Ultrasound imaging for regional anesthesia in infants, children, and adolescents: a review of current literature and its application in the practice of extremity and trunk blocks. Anesthesiology 2010; 112: 473-92
  26. Tsui BC, Suresh S: Ultrasound imaging for regional anesthesia in infants, children, and adolescents: a review of current literature and its application in the practice of neuraxial blocks. Anesthesiology 2010; 112: 719-28
  27. Brodsky JB, Mariano ER: Regional anaesthesia in the obese patient: lost landmarks and evolving ultrasound guidance. Best Pract Res Clin Anaesthesiol 2011; 25: 61-72
  28. Mariano ER, Brodsky JB: Comparison of procedural times for ultrasound-guided perineural catheter insertion in obese and nonobese patients. J Ultrasound Med 2011; 30: 1357-61
  29. Barrington MJ, Kluger R: Ultrasound guidance reduces the risk of local anesthetic systemic toxicity following peripheral nerve blockade. Reg Anesth Pain Med 2013; 38: 289-297

 

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Hints for Anesthesiology Residency Applicants

Job-InterviewThis post is co-authored by Dr. Kyle Harrison (@KyleHarrisonMD) and has also been featured on CSA Online First.

So, you’ve finished your third year of medical school and have decided that you want to be an anesthesiologist. In our completely biased opinion, you are making the right choice and, at the end of your residency training, you will be in a unique position to enhance the experience and improve the outcomes of patients undergoing surgery and invasive procedures. However, securing a coveted slot in an anesthesiology residency in the United States has never been more competitive. In the many years that we have spent as faculty in academic anesthesiology departments, we have learned a few things about the application process. Our views are our own and do not reflect the official views of any anesthesiology residency program with which we have been affiliated. The following are some (hopefully helpful) answers to common questions that we have been asked over the years.

Congratulations on choosing #anesthesiology! Some tips on applying for residency.

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How High Do My USMLE Score and GPA Have to Be?
Competitive scores are essential. We can’t quote you a number because they vary year to year and program to program, but the trend is only increasing. All medical students, regardless of school, applying in anesthesiology must do well on the USMLE. Think about it — this is the only equalizing factor between schools that teach differently or have different reputations. Having a great score doesn’t guarantee you admission, but if your scores are not competitive, you will have an uphill battle to get a residency slot at a top program. The value of the standardized test score in learning is often debated in academia; however, no one will argue against the conclusion that previous success on standardized tests usually predicts future success on standardized tests. Residency training is demanding. Programs want their residents 100 percent committed and not worrying too much about how they will perform on their annual in-training exams and eventual certification exam.

Do I Need to Have Research Experience?
No program will ever discourage applicants with research experience from applying; we would say that it is not required but is recommended. Don’t do it for the sake of doing it, but definitely do it if you can find a project that you are passionate about. While research in anesthesiology or pain makes sense (shows academic interest in the chosen field), it can really be in any area. It is more impressive to be involved in a project (big or small), see it through, and maybe even present at a meeting or publish in a journal, than to just say you did “research.” If you do list research on your application or curriculum, make sure you can talk about the project, your specific role, and what you learned from it; you will be asked. If you are not interested in research, then consider focusing on another aspect of extracurricular life such as community service.

What Should Be on My List of Extracurricular Activities?
If there is something about you that is really different, it’s helpful to mention it. Again, the application process isn’t perfect, but the file you submit is all the information program coordinators and directors have. If you have done something special — climbed Mt. Everest, set up HIV clinics in Africa, won Olympic medals, had a previous career — or do something noteworthy, such as volunteer extensively in your community, play an instrument, or dance professionally, mention those things. Yes, we have actually seen these applicants (and interviewed them of course)! Selection committee members often apply the “3 a.m. call rule” when reviewing an applicant. This is: Would you like to be on call in the middle of the night with this person? Applicants viewed as hardworking, clinically competent, and interesting to talk to should result in a solid “yes.” If you just like to run in your free time, mentioning that probably doesn’t make a huge difference in the application.

Do I Need to Do an Anesthesiology Rotation?
You should do an anesthesiology rotation at your local institution at the very least. Programs want to know if you understand what you’re getting yourself into. And it does make a difference how well you did on the rotation. Many students approach their anesthesiology rotation as the “intubation and IV insertion” rotation. Most anesthesiologists like us are passionate about their specialty, and the specialty itself in rapidly evolving (familiarize yourself with the Perioperative Surgical Home model). Trust us — we can tell when a student is genuinely interested in anesthesiology, or not. In our experience, medical students who stand out pay attention to what is going on in the perioperative period, anticipate events, know how to be helpful, get involved with the entire patient care episode (starting with the preoperative evaluation, through giving report to the nurse in the recovery room, and even including postoperative follow-up). It is never impressive to see a medical student standing around looking bored. There is always something to do — for example, when a patient arrives in the OR, you can start applying monitors without prompting, or help with positioning. Residents and staff anesthesiologists recognize these things and reward you by getting you more involved with patient care, including procedures.

Who Should Write My Letters of Recommendation?
The dean’s letter is the big one and counts the most. The form of the dean’s letter is usually standardized, so residency program directors have to weed through all the verbiage to get the information they want. It helps when the dean’s letter includes the student’s rank and any special merits (e.g., AOA). Additional letters should be written by faculty members who really know you and can provide helpful content — research mentor, career advisor, staff physician with whom you have worked closely. It doesn’t add strength to an application to have a lot of generic letters (quality over quantity); three strong letters are better than two strong plus three average letters, since the strong letters may get lost in the sea of information in the applicant’s file.

interview-panel-ace

What Else Can I Do to Improve My Chances?
Unfortunately there are no guarantees. The “gatekeeper” is the initial electronic application. With anesthesiology departments receiving hundreds of applications each year, most will sound exactly the same. “I love pharmacology and physiology” (while possibly true for some) only takes you so far. Something unique about the applicant has to come through the pages. Excellent grades and USMLE scores, strong dean’s letter and other recommendations, personal experiences, prior careers, other degrees, thought-provoking research, a list of activities, and a unique personal statement — anything that sets you apart from the pack can make a difference!

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Personalized Medicine: What it Means to be a Physician Anesthesiologist

This post has also been featured on KevinMD.com.

I wear a lot of hats in my job. Though I’m a physician who specializes in the practice of anesthesiology, I don’t spend all day every day at the head of an operating room table.

Team Photo 2Many days I spend in an administrative leadership role or conducting research studies. These functions support the best interests of my patients as well as the science and practice of anesthesiology. On my “clinical” days that I spend in hands-on patient care, I provide anesthesia for patients who undergo surgery and other invasive procedures. I also treat acute pain as a consultant. Some of my colleagues in anesthesiology specialize in chronic pain or critical care medicine.

As a medical student, I had a hard time at first understanding what the physician anesthesiologist does. I saw monitors, complicated equipment, and technical procedures that involved a lot of needles. Thankfully, I worked with resident and attending anesthesiologists who inspired me to pursue this specialty.

Anesthesiology is at the same time incredibly cerebral and extremely physical.

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Anesthesiology is a unique field within medicine. It is at the same time incredibly cerebral and extremely physical. For example, the physician anesthesiologist must be ready to diagnose heart or lung problems that may complicate the patient’s surgery, and decide which medications are appropriate.

BefoAnesthesiologist-4re administering a medication, it’s not enough just to understand the complex pharmacologic effects of the drug and determine the right dose. The anesthesiologist also has to know how to dilute and prepare the drug, the appropriate route for the medication, which other medications are and are not compatible, and how to program the infusion device. In addition, an anesthesiologist has to be technically skilled at finding veins—sometimes in the hand or arm, sometimes leading centrally to the heart—in order to give the medication in the first place.

The job of the physician anesthesiologist is deeply personal.

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I am always aware of the trust that patients and their families give me, a total stranger, and I work hard to earn that trust throughout the perioperative period. The job of the physician anesthesiologist is deeply personal. In the operating room, I care for the most vulnerable of patients—those who, while under anesthesia, cannot care for themselves.

– I constantly listen to the sounds of their hearts.
– I breathe for them when they are unable.
– I keep them warm in the cold operating room.
– I provide the fluids that their bodies need.
– I pad their arms and legs and other pressure points.
– I watch the operation step by step, anticipating and responding.
– I learn from their bodies’ response to anesthesia to give the right amount.
– I prevent and relieve their pain.
– I protect them from dangers of which they are unaware.

I have heard people, my colleagues included, compare physician anesthesiologists to pilots. No one claps when the plane lands, just as no one expects any less than a perfect uncomplicated anesthetic every time. We physician anesthesiologists draw great personal satisfaction from doing what we do, and from providing a unique type of personalized medicine. Our patients and their families depend on us to be at our best, always.

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Pay for Performance in Perioperative Pain Management

Costs RocketWe have all heard the “doom and gloom” statistics about rising health care spending, and maybe even some of them have begun to sink in since the roll-out of the Affordable Care Act.

For many reasons, the federal government is working to curb health care expenditures, but many of the processes currently attributed to “Obamacare” have been in the works for a long time.  As an example, the Medicare Modernization Act of 2003 introduced the Inpatient Prospective Payment System; this system encouraged participating hospitals to voluntarily report performance data to avoid payment reductions.  The Deficit Reduction Act of 2005 went further by mandating the development of what we now know as pay-for-performance or value-based purchasing (used interchangeably).

In 2012, the Institute of Medicine published “Best Care at Lower Cost:  the Path to Continuously Learning Health Care in America.”  In this report, recommendation 9 refers to performance transparency:  making data related to “quality, prices and cost, and outcomes of care” available to consumers.

VBPWhat does this mean?  Value-based purchasing in health care is supposed to reward better value, patient outcomes, and innovations – instead of just volume of services (read more).  It is funded by participating institutions based on withholding a set percentage (1.25% currently) of their estimated annual Diagnosis-Related Group (DRG) payments from Center for Medicare and Medicaid Services (CMS).  The percentage is increasing every year and will be 2% by 2017.

VBP2For FY2014, the elements of value-based purchasing have been updated to include the Clinical Process of Care Domain, Patient Experience of Care Domain, and a new Outcomes Domain.  The amount that each of these domains contributes to the eventual DRG payment return at the end of the year is 45%, 30%, and 25%, respectively.  Scores in each domain are calculated based on an institution’s improvement compared to its own historical performance and a comparison against national benchmarks (read more).

The Patient Experience Domain is assessed using the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey.  HCAHPS consists of 32 questions, publicly reports its results 4 times a year on http://www.hospitalcompare.hhs.gov, and contains 7 questions that directly or indirectly relate to pain.  For details, please see my previous post “Why We Need Acute Pain Medicine Specialists.”

How do we as anesthesiologists address the need for acute pain medicine physicians and have a positive impact on the patient experience?  We can take the lead in developing multimodal perioperative pain management protocols (1).  For total joint arthroplasty, many of these protocols emphasize opioid-sparing regional anesthesia techniques such as peripheral nerve blocks (PNB) and perineural catheters.  These techniques decrease patients’ reliance on opioids for postoperative pain management and are also associated with fewer opioid-related side effects, better sleep, and higher satisfaction (2).  In addition, greater selectivity in the PNB technique included in a multimodal protocol may even lead to greater functional achievements for total knee arthroplasty (TKA) patients which generates additional value (3).  For more information about TKA perioperative pain management and improving rehabilitation outcomes, please see my previous post “Regional Anesthesia & Rehabilitation Outcomes after Knee Replacement.”

Anesthesiologists can also add value through cost savings for the hospital.  More effective pain management can prevent inadvertent admissions or readmissions due to pain.  In addition, an effective multimodal analgesic protocol can directly or indirectly prevent hospital-acquired conditions (HACs).  HACs are considered by CMS to be “never events” and supposedly preventable (4); hospitals reporting HACs as secondary diagnoses are not entitled to CMS payments for related care.  Examples of HACs include:  urinary and vascular catheter-related infections, surgical site infections, DVT/PE, pressure ulcers, and inpatient falls leading to injury.

Fall riskThere remains substantial controversy related to the potential association between regional anesthesia and inpatient falls (5, 6).  We do know that falls, when they occur, are associated with worse outcomes for patients and higher resource utilization (7) and that falls may occur in lower extremity joint replacement patients with or without PNB (8).  For these reasons, these patients should always be treated as high fall risk, and anesthesiologists can take the lead in developing fall prevention education and fall reduction programs to keep them safe.

In summary, pay for performance in perioperative pain management is already here.  The HCAHPS survey assesses the Patient Experience Domain and can be heavily influenced by the effectiveness of pain management.  There are clear opportunities for anesthesiologists to take an active role in adding value and minimizing risks for surgical patients in the perioperative period.

References:

  1. Hebl JR, Kopp SL, Ali MH, Horlocker TT, Dilger JA, Lennon RL, Williams BA, Hanssen AD, Pagnano MW. A comprehensive anesthesia protocol that emphasizes peripheral nerve blockade for total knee and total hip arthroplasty. J Bone Joint Surg Am 2005;87 Suppl 2:63-70.
  2. Ilfeld BM. Continuous peripheral nerve blocks: a review of the published evidence. Anesth Analg 2011;113:904-25.
  3. Mudumbai SC, Kim TE, Howard SK, Workman JJ, Giori N, Woolson S, Ganaway T, King R, Mariano ER. Continuous Adductor Canal Blocks Are Superior to Continuous Femoral Nerve Blocks in Promoting Early Ambulation After TKA. Clinical orthopaedics and related research 2014;472:1377-83.
  4. Hospital-acquired condition (HAC) in acute inpatient payment system (IPPS) hospitals. http://www.cms.gov/Medicare/Medicare-Fee-for-Service-Payment/HospitalAcqCond/Downloads/HACFactsheet.pdf
  5. Ilfeld BM, Duke KB, Donohue MC. The association between lower extremity continuous peripheral nerve blocks and patient falls after knee and hip arthroplasty. Anesth Analg 2010;111:1552-4.
  6. Memtsoudis SG, Danninger T, Rasul R, Poeran J, Gerner P, Stundner O, Mariano ER, Mazumdar M. Inpatient falls after total knee arthroplasty: the role of anesthesia type and peripheral nerve blocks. Anesthesiology 2014;120:551-63.
  7. Memtsoudis SG, Dy CJ, Ma Y, Chiu YL, Della Valle AG, Mazumdar M. In-hospital patient falls after total joint arthroplasty: incidence, demographics, and risk factors in the United States. The Journal of arthroplasty 2012;27:823-8 e1.
  8. Johnson RL, Kopp SL, Hebl JR, Erwin PJ, Mantilla CB. Falls and major orthopaedic surgery with peripheral nerve blockade: a systematic review and meta-analysis. Br J Anaesth 2013;110:518-28.

 

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Time to Rethink Preoperative Preparation

Anesthesia1The concept of preoperative preparation for patients scheduled for surgery requiring anesthesia is not a new one.  In fact, the idea goes back to Dr. Albert Lee’s description in 1949 (1, 2).  Dr. Lee had observed in his day that patients commonly presented for surgery in various states of poor health; it seemed to make more sense to see these patients before surgery to identify areas of concern early and optimize patients’ conditions they went under the knife.

The model of a stand-alone preoperative evaluation clinic, often run by anesthesiology staff, with a “one stop shop” model for patients’ interviews and examinations, testing, education, and referrals really did not take off until the 1990s (3).  This patient-centered care model was intended to improve efficiency by decreasing the run-around that many patients encountered, but it also saved money for the institution by reducing the ordering of unnecessary tests (4) and decreasing day-of-surgery cancellations (4, 5).

Current State
Current State

In the present state (assuming an ACO or HMO model), patients are referred to the surgeon by the primary care physician for evaluation of a problem that may be amenable to surgical correction.  If the surgeon deems the patient a surgical candidate, the patient may receive a scheduled date for surgery and then may be referred to the anesthesiology preoperative evaluation clinic (“preop clinic”) for further work-up.  During this encounter, the provider in the preop clinic may request a variety of tests based on the planned surgery and the patient’s comorbid conditions in order to make appropriate recommendations regarding perioperative management to minimize risks.  The American Society of Anesthesiologists (ASA) has published a recent (2012) practice advisory for preanesthesia evaluation to guide this process.

“Clearance” for #surgery was novel once. Time to try something new.

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Unfortunately, after nearly 2 decades of employing this model, day of surgery cancellations still occur at various rates around the world.  Some of the reasons are related to factors that preop clinics were meant to avoid:  inadequate preoperative work-up or change in medical condition (6).  Other reasons are patient-driven:  patients’ not showing up (7) or patients’ changing their minds about having surgery (8).  Although not all of these issues are easily solved, it does make me wonder–perhaps it is time for us to rethink the process of preparing patients for surgery.

In our current state, a patient may hypothetically be scheduled for surgery in 8 weeks, a date agreed upon by the patient and surgeon based on available dates.  Even if a preop clinic visit takes place the same day as the surgery clinic visit, this only allows 2 months to optimize a patient’s chronic medical conditions (e.g., hypertension, diabetes, coronary artery disease) that took years to develop.  Imagine if the timeline was even shorter, like 3 weeks.  Add to this time pressure the tremendous physiologic stress that surgery and the subsequent rehabilitation put on the body, and it is not difficult to see why patients can still be cancelled on the day of surgery when they present with abnormal vital signs or test results, making the risks seem too high.  We would not expect ourselves to run a marathon without adequate training and preparation on short notice–why would we do this to our patients having elective surgery?

Future State
Future State

How can we improve preoperative preparation?  I think it still starts with the primary care physician.  With advances in technology such as telemedicine and e-consults (or low-tech phone calls), we have ways to create a direct interface between primary care physicians and anesthesiologists to discuss advanced preparation of patients who may undergo elective surgical procedures.

Advances in technology should drive improvement in preoperative preparation.

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This coordinated care model is consistent with ASA’s Perioperative Surgical Home.  Early consultation may involve assessment of a patient’s risks and benefits from the procedure, consideration of alternative treatments, and development of a plan to optimize the patient’s comorbid conditions, medication management, and nutrition.  Strong for Surgery is a program that provides patients and clinicians useful checklists based on best-available evidence to guide early preoperative preparation related to smoking cessation, nutrition, glycemic control, and medication management.  For elective surgery, the decision when to refer the patient to a surgeon can be made jointly by the primary care physician and anesthesiologist.  Prior to surgery, the preop clinic visit should still take place, but the focus no longer needs to be on information-gathering and ordering a battery of tests; rather, the goals should be to review pertinent instructions, preview the perioperative experience for patients, and address any logistical or scheduling issues raised by patients to prevent their not showing up or changing their minds at the last minute.  Let’s get started.

For more information, check out this brilliant and inspiring video from the Royal College of Anaesthetists “Perioperative Medicine:  the Pathway to Better Surgical Care.”

REFERENCES

  1. Lee JA. The anaesthetic out-patient clinic. Anaesthesia. 1949 Oct;4(4):169-74.

  2. Yen C, Tsai M, Macario A. Preoperative evaluation clinics. Curr Opin Anaesthesiol. 2010 Apr;23(2):167-72.

  3. Fischer SP. Cost-effective preoperative evaluation and testing. Chest. 1999 May;115(5 Suppl):96S-100S.

  4. Fischer SP. Development and effectiveness of an anesthesia preoperative evaluation clinic in a teaching hospital. Anesthesiology. 1996 Jul;85(1):196-206.

  5. Ferschl MB, Tung A, Sweitzer B, Huo D, Glick DB. Preoperative clinic visits reduce operating room cancellations and delays. Anesthesiology. 2005 Oct;103(4):855-9.

  6. Xue W, Yan Z, Barnett R, Fleisher L, Liu R. Dynamics of Elective Case Cancellation for Inpatient and Outpatient in an Academic Center. J Anesth Clin Res. 2013 May 1;4(5):314.

  7. Kumar R, Gandhi R. Reasons for cancellation of operation on the day of intended surgery in a multidisciplinary 500 bedded hospital. J Anaesthesiol Clin Pharmacol. 2012 Jan;28(1):66-9.

  8. Caesar U, Karlsson J, Olsson LE, Samuelsson K, Hansson-Olofsson E. Incidence and root causes of cancellations for elective orthopaedic procedures: a single center experience of 17,625 consecutive cases. Patient Saf Surg. 2014 Jun 2;8:24.

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Anesthesiology, Healthcare, Medical Education, Pain Medicine, Regional Anesthesiology

Why We Need Acute Pain Medicine Specialists

Not all pain is the same.

Chronic #pain can be palliated. Acute pain must be stamped out.

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PainChronic pain can be palliated, but “acute” pain (new onset, often with an identifiable cause) must be stamped out. This requires a systems-based approach led by physicians dedicated to understanding acute pain pathophysiology and investigating new ways to treat it. The solution is definitely not giving more and more opioids.

As our understanding of pain mechanisms has evolved, select physicians have developed a special focus on pain in the acute injury/illness and perioperative settings that has led to the rapid advancement of systemic and site-specific interventions to effectively manage this type of pain. Acute pain medicine involves the routine use of multiple modalities concurrently (i.e., multimodal analgesia) in the in-hospital setting to reduce the intensity of acute pain and minimize the development of debilitating persistent pain, a problem that can result from even common surgical procedures or trauma. Unfortunately, the need for specialists in acute pain medicine is increasing.

The need for physicians who specialize in acute #pain medicine is increasing.

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In December of 2013, I submitted a 161 page letter to the Accreditation Council for Graduate Medical Education (ACGME) requesting that regional anesthesiology and acute pain medicine be considered for fellowship accreditation with the help of my fellowship director colleagues. The Board of Directors of the ACGME informed me this past fall (2014) that they have approved our fellowship to be the next accredited subspecialty within anesthesiology.

Wait – don’t we already have a fellowship program in pain medicine? Yes we do, and this one year post-residency program does include the “Acute Pain Inpatient Experience.” However, this requirement may be satisfied by documented involvement with a minimum of only 50 new patients and is not the primary emphasis of fellowship training in the specialty. Pain medicine is a board-certified subspecialty of anesthesiology, physical medicine and rehabilitation, and psychiatry and neurology; graduates from any of these residency programs can apply to the one year program. In a recent survey study of practicing pain physicians in the United States with added qualification in pain management according to the American Board of Medical Specialties (ABMS), the great majority (83.7%) of respondents defined their practices as following “chronic pain patients longitudinally” (1).

There is clearly room and a need for a subspecialty training program in acute pain medicine that can focus on improving the in-hospital pain experience. Such a program should advance, in a positive and value-added fashion, the present continuum of training in pain medicine.

HCAHPS Pain QuestionsThe Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey is administered to a random sample of patients who have received inpatient care and receive government insurance through Center for Medicare and Medicaid Services (CMS). The survey consists of 32 questions and is intended to assess the “patient experience of care” domain in the value-based purchasing program. A hospital’s survey scores are publicly disclosed and make up 30% of the formula used to determine how much of its diagnosis-related group payment withholding will be paid by CMS at the end of each year. Of the 32 questions, 7 directly or indirectly relate to in-hospital pain management.

Why should acute pain medicine be a subspecialty of anesthesiology? Anesthesiology is a hospital-based medical specialty, and anesthesiologists are physicians who focus on the prevention and treatment of pain for their patients who undergo surgery, suffer trauma, or present for childbirth on a daily basis. For more details on the role of the anesthesiologist, please see “Physicians specializing in the patient experience.” Further, history supports the evolution of acute pain medicine through anesthesiology. The concept of an anesthesiology-led acute pain management service was described first in 1988 (2), but arguably the techniques employed in modern acute pain medicine and regional anesthesiology date back to Gaston Labat’s publication of Regional Anesthesia: its Technic and Clinical Application in 1922, with advancement and refinement of this subspecialty in the 1960s and 1970s (3-7).

By the time they complete the core residency in anesthesiology today, not all trainees have gained sufficient clinical experience to provide optimal care for the complete spectrum of issues experienced by patients suffering from acutely painful conditions, including the ability to reliably provide advanced interventional techniques proven to be effective in managing pain in the acute setting (8-12). We need physician leaders who can run acute pain medicine teams and design systems to provide individualized, comprehensive, and timely pain management for both medical and surgical patients in the hospital, expeditiously managing requests for assistance when pain intensity levels exceed those set forth in quality standards, or to prevent pain intensity from reaching such levels. The mission statement for the Acute Pain Medicine Special Interest Group within the American Academy of Pain Medicine provides additional justification.

In a survey of fellowship graduates and academic chairs published in 2005, 61 of 132 of academic chairs responded (46%), noting that future staffing models for their department will likely include an average of 2 additional faculty trained in regional anesthesiology and acute pain medicine (13).

Currently, there are over 60 institutions in the United States and Canada that list themselves as having non-accredited fellowship training programs focused on regional anesthesiology and acute pain medicine on the ASRA website. Since 2002, the group of regional anesthesiology and acute pain medicine fellowship directors has been meeting twice yearly at the ASRA Spring Annual Meeting and ASA Annual Meeting which takes place in the fall. Despite not being an ACGME-accredited fellowship, this group, recognizing the lack of formalized training guidelines, voluntarily began to develop such guidelines as the foundation for subspecialty fellowship training in existing and future programs. These guidelines were originally published in Regional Anesthesia and Pain Medicine in 2005 (14), then were subsequently reviewed, revised, and published as the 2nd edition in 2011 (15), and have been recently updated again (16).

As with other subspecialties, acute pain medicine has emerged due to the need for trained specialists—in this case, those who understand the complicated, multi-faceted disease processes of acute pain, and its potential continuity with chronic pain, and can apply appropriate medical and interventional treatment in a timely fashion. The fellowship-trained regional anesthesiologist and acute pain medicine specialist must be capable of collaborating with other healthcare providers in anesthesiology, surgery, medicine, nursing, pharmacy, physical therapy, and more to establish multidisciplinary programs that add value and improve patient care in the hospital setting and beyond.

REFERENCES

  1. Breuer B, Pappagallo M, Tai JY, Portenoy RK: U.S. board-certified pain physician practices: uniformity and census data of their locations. J Pain 2007; 8: 244-50
  2. Ready LB, Oden R, Chadwick HS, Benedetti C, Rooke GA, Caplan R, Wild LM: Development of an anesthesiology-based postoperative pain management service. Anesthesiology 1988; 68: 100-6
  3. Winnie AP, Ramamurthy S, Durrani Z: The inguinal paravascular technic of lumbar plexus anesthesia: the “3-in-1 block”. Anesth Analg 1973; 52: 989-96
  4. Winnie AP, Collins VJ: The Subclavian Perivascular Technique of Brachial Plexus Anesthesia. Anesthesiology 1964; 25: 353-63
  5. Raj PP, Montgomery SJ, Nettles D, Jenkins MT: Infraclavicular brachial plexus block–a new approach. Anesth Analg 1973; 52: 897-904
  6. Raj PP, Parks RI, Watson TD, Jenkins MT: A new single-position supine approach to sciatic-femoral nerve block. Anesth Analg 1975; 54: 489-93
  7. Raj PP, Rosenblatt R, Miller J, Katz RL, Carden E: Dynamics of local-anesthetic compounds in regional anesthesia. Anesth Analg 1977; 56: 110-7
  8. Buvanendran A, Kroin JS: Multimodal analgesia for controlling acute postoperative pain. Curr Opin Anaesthesiol 2009; 22: 588-93
  9. Hebl JR, Dilger JA, Byer DE, Kopp SL, Stevens SR, Pagnano MW, Hanssen AD, Horlocker TT: A pre-emptive multimodal pathway featuring peripheral nerve block improves perioperative outcomes after major orthopedic surgery. Reg Anesth Pain Med 2008; 33: 510-7
  10. Jin F, Chung F: Multimodal analgesia for postoperative pain control. J Clin Anesth 2001; 13: 524-39
  11. Kehlet H, Dahl JB: The value of “multimodal” or “balanced analgesia” in postoperative pain treatment. Anesth Analg 1993; 77: 1048-56
  12. Young A, Buvanendran A: Recent advances in multimodal analgesia. Anesthesiol Clin 2012; 30: 91-100
  13. Neal JM, Kopacz DJ, Liguori GA, Beckman JD, Hargett MJ: The training and careers of regional anesthesia fellows–1983-2002. Reg Anesth Pain Med 2005; 30: 226-32
  14. Hargett MJ, Beckman JD, Liguori GA, Neal JM: Guidelines for regional anesthesia fellowship training. Reg Anesth Pain Med 2005; 30: 218-25
  15. Guidelines for fellowship training in Regional Anesthesiology and Acute Pain Medicine: Second Edition, 2010. Reg Anesth Pain Med 2011; 36: 282-8
  16. Guidelines for fellowship training in Regional Anesthesiology and Acute Pain Medicine: Third Edition, 2014. Reg Anesth Pain Med 2015; 40: 213-7

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CME, Medical Education, Pain Medicine

ASRA Comes to San Francisco!

GGB
Golden Gate Bridge

This year’s American Society of Regional Anesthesia and Pain Medicine’s 13th Annual Fall Pain Medicine meeting happens to be in my “neck of the woods”—one of the greatest cities in the world—San Francisco, California.  Here are a few things you may or may not have known about San Francisco.

San Francisco is the biggest little city.  At just under 47 square miles and with more than 200,000 inhabitants, San Francisco is second only to New York City in terms of population density.  Despite its relatively small size, “the City” (as we suburbanites refer to it) consists of many small neighborhoods, each with its own charm and character:  Union Square, the Financial District, Pacific Heights, the Marina, Haight-Ashbury, Chinatown, Little Italy, Nob Hill, Russian Hill, SoMa (South of Market), the Fillmore, Japantown, Mission District, Noe Valley, Twin Peaks, Castro, Sunset, Tenderloin, and others.  For this reason, San Francisco may arguably be the only option for die-hard New Yorkers who wish to relocate away from snow.

Chinatown
Chinatown

Even though it doesn’t snow, San Francisco weather is incredibly unpredictable, even when going from one side of the city to the other.  “The coldest winter I ever spent was a summer in San Francisco,” a quote often mistakenly attributed to Mark Twain (no one really knows who actually said it), is nevertheless often true.  Here in the San Francisco Bay Area, our local meteorologists provide daily forecasts for each of the region’s microclimates.  The western side of the City along California’s coast is regularly plagued with fog while the eastern side of the City tends to be sunny most days of the year.  It’s always a good idea to check the microclimate forecast before heading over to see the Golden Gate Bridge just in case it happens to be shrouded in fog.  Also, average July temperatures in the City range in the 50s-60s Fahrenheit (no different than average November temperatures), so summer tourists often contribute to the local economy by buying “SF” logo sweatshirts for their walk across the City’s most famous bridge.

Ferry Bldg
Ferry Building

San Francisco is very family-friendly.  If you’re debating whether or not to make a family trip out of the Fall Pain Meeting, my advice is to do it.  Right around the conference hotel, the Hyatt Regency San Francisco, there are a number of attractions and events worth checking out.  Every Saturday there is a huge farmers market at the Ferry Building across the street from the hotel.  As you probably figured out, from the Ferry Building you can also take a ferry ride to a number of other destinations in the Bay Area (I recommend Sausalito, a short trip that takes you past Alcatraz).  For kids, there are 3 parks within walking distance, the San Francisco Railway Museum, Exploratorium, and the cable car turnabout at Powell and Market Street; trips to Fisherman’s Wharf or the aquarium are a short taxi or cable car ride away.  In addition, runners will love running up and down the Embarcadero which gives you a view of the Bay Bridge and takes you past the City’s many piers; shoppers will be in heaven; and foodies have an impossible decision to make when choosing the location for every meal (try Slanted Door at the Ferry Building at least once).

Enough about San Francisco—you’ll have to see it for yourself.  To register for the Fall Pain Medicine meeting, visit http://www.asrameetings.com/. For an overview of scheduled events in the words of meeting Chair, Dr. David Provenzano, see the August 2014 issue of ASRA News.  This issue also includes fantastic original content covering the topics of digital subtraction angiography, pain outcomes, ASRA’s first entry into the app market, and much more!

 

Related Posts:

Anesthesiology, Healthcare, Knee Replacement, Medical Education, Outcomes Research, Pain Medicine, Patient Safety, Regional Anesthesiology

Regional Anesthesia & Rehabilitation Outcomes after Knee Replacement

kneeAmong Medicare beneficiaries in the United States, the number of primary total knee arthroplasty (TKA) procedures from 1991 to 2010 increased by 161.5% (1). Postoperative pain remains one of patients’ top concerns when undergoing elective surgery (2) and can limit patients’ functional ability in the early postoperative period (3). Providing effective perioperative pain control has potential longer-term implications since early rehabilitation may lead to improvements in functional outcomes later on (4). With the ability to select specific targets for local anesthetic injection and infusion, regional anesthesia techniques, neuraxial and peripheral, are commonly included in the perioperative analgesic protocol for joint arthroplasty patients (5-11). While the data supporting the analgesic efficacy of regional anesthesia techniques in this setting are strongly positive, studies attempting to attribute functional outcome benefits to regional anesthesia demonstrate mixed results.

The main challenge in assessing functional outcomes following joint replacement is the selection of outcomes; these can be divided into performance-based outcomes and self-reported outcomes (12, 13). Performance-based outcomes are measurable and arguably more objective, although often subject to effort. Examples of these outcomes and their units of measure include joint range of motion in degrees (e.g., flexion, extension, rotation); timed walking tests in meters (e.g., 6 minute walking test [6MWT], 2 minute walking test [2MWT]); muscle strength in units of force using a dynamometer (e.g., maximum voluntary isometric contraction [MVIC]); and timed up-and-go (TUG) in minutes (12, 13). Self-reported outcomes are typically survey-based; examples include the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), Knee Society Score, and Lower Extremity Functional Scale (12, 13). Since patient perception of successful rehabilitation is an important factor, self-reported outcomes should be reported with performance-based outcomes (12). Another important challenge when measuring and comparing functional outcomes is that clinical pathways for joint arthroplasty that integrate pain management (including regional analgesia), physical therapy, nursing, and surgical care are often specific to individual institutions, and institutions may vary with respect to rehabilitation goals and the timeline to achieve them.

Epidural Analgesia

Epidural analgesia has been used for perioperative pain management in joint replacement patients since at least the 1980s (14, 15). In 1987, Raj and colleagues compared postoperative systemic opioid analgesia to continuous epidural analgesia (bupivacaine 0.25% at 6-15 ml/hr) for TKA patients in a prospective non-randomized study (14). Although pain scores were lower in the epidural group, not surprisingly a high proportion of these patients experienced complete motor block of the lower extremities; although the authors mention “rigorous passive exercises,” specific rehabilitation outcomes were not reported (14). Later studies have reported functional benefits associated with continuous epidural analgesia, such as shorter time to achieve ambulation distance and range of motion goals, when compared to parenteral opioids alone (16). At institutions where continuous epidural analgesia is currently employed as part of a multimodal analgesic protocol, very low doses of local anesthetic (e.g., 0.06% bupivacaine) in combination with opioid are used in order to minimize motor block (17).

Peripheral Nerve Blocks

The innervation of the knee is complex and involves contributions from both the lumbar and sacral plexuses. While epidural analgesia is effective, it is also associated with clinically-significant side effects (e.g., nausea/vomiting and motor block of the non-operative limb) (5, 18) and the potential for neuraxial hematoma in patients on pharmacologic thromboprophylaxis (19). Thus, peripheral nerve block options, either single-injection or continuous infusions, have been explored for postoperative pain management.

Two early studies by Capdevila (6) and Singelyn (20) have shown continuous femoral nerve block (FNB) to provide comparable analgesia and physical therapy outcome achievement with fewer side effects when compared to epidural analgesia. Both of these studies also demonstrated shorter hospital length of stay for the regional anesthesia groups compared to an opioid-only group (6, 20), but hospitalization duration for these studies was, on average, greater than what has been reported in other studies (21). Triple-masked, placebo-controlled randomized clinical trials have shown that CPNB can shorten the time to achieve discharge criteria, including 100 m ambulation distance, for TKA (10, 22) and total hip arthroplasty (THA) (9) patients, but actual hospital duration was similar in these studies.

One of the interesting findings from the Singelyn study was that regional anesthesia patients maintained a knee flexion advantage over the opioid-only group at 6 week follow-up (20); although this advantage did not remain at 3 months, this finding supported the potential for long-term functional improvement resulting from effective pain management and early rehabilitation in the immediate perioperative period (4). In a randomized comparison of continuous FNB to local infiltration analgesia (LIA) for TKA, the FNB group spent more time out of bed walking; at 6 weeks, the FNB group showed more improvement in performance-based (6MWT) and self-reported functional outcome assessments (23). In contrast, the one year follow-up studies of randomized clinical trial subjects (9, 10, 22) using self-reported outcome measures for functional status (WOMAC) did not show long-term improvement associated with regional anesthesia techniques (24-27).

The rehabilitation outcome measured in the immediate postoperative period that correlates best with long-term functional improvement is not yet established. Ambulation distance is often measured by physical therapists and included in discharge criteria (9, 10, 22). For institutions that emphasize ambulation in their clinical pathway for lower extremity joint arthroplasty, a major concern raised with regard to FNBs is the potential association with increased fall risk (28, 29) although a recent large database study disputes this finding. In-hospital falls can lead to prolonged hospital stays with higher costs and are associated with more frequent postoperative complications, including serious organ system dysfunction and death (30). With currently-available local anesthetic solutions and typical doses, perineural infusion does produce clinically-significant quadriceps weakness when administered near the femoral nerve or lumbar plexus (31, 32). Since the local anesthetics themselves cannot select sensory over motor nerves( 33), anesthesiologists have started exploring alternate nerve block locations to minimize the risk of motor block and maximize patient rehabilitation.

From Workman JJ, et al. Presented at 2013 ASRA Spring Annual Meeting
From Workman JJ, et al. Presented at 2013 ASRA Spring Annual Meeting

For TKA, a more distal nerve block location in the adductor canal can provide effective analgesia postoperatively (34) and has been shown to better preserve quadriceps strength compared to a FNB in both volunteers (35) and clinical patients (11). Regional analgesic techniques are only one part of the overall pain management plan. While they are often included in multimodal analgesic protocols along with non-steroidal anti-inflammatory drugs (NSAIDs), acetaminophen, and low-dose opioids (36), there is a growing body of evidence to support the adductor canal block as the regional analgesic technique of choice for promoting postoperative ambulation within a clinical pathway (37, 38).

For patient information with answers to frequently-asked questions about regional anesthesia, please see “Regional Anesthesia FAQs.”

References

  1. Cram P, Lu X, Kates SL, Singh JA, Li Y, Wolf BR. Total knee arthroplasty volume, utilization, and outcomes among Medicare beneficiaries, 1991-2010. JAMA. Sep 26 2012;308(12):1227-1236.
  2. Macario A, Weinger M, Carney S, Kim A. Which clinical anesthesia outcomes are important to avoid? The perspective of patients. Anesth Analg. Sep 1999;89(3):652-658.
  3. Holm B, Kristensen MT, Myhrmann L, et al. The role of pain for early rehabilitation in fast track total knee arthroplasty. Disability and rehabilitation. 2010;32(4):300-306.
  4. Munin MC, Rudy TE, Glynn NW, Crossett LS, Rubash HE. Early inpatient rehabilitation after elective hip and knee arthroplasty. JAMA. Mar 18 1998;279(11):847-852.
  5. Barrington MJ, Olive D, Low K, Scott DA, Brittain J, Choong P. Continuous femoral nerve blockade or epidural analgesia after total knee replacement: a prospective randomized controlled trial. Anesth Analg. Dec 2005;101(6):1824-1829.
  6. Capdevila X, Barthelet Y, Biboulet P, Ryckwaert Y, Rubenovitch J, d’Athis F. Effects of perioperative analgesic technique on the surgical outcome and duration of rehabilitation after major knee surgery. Anesthesiology. Jul 1999;91(1):8-15.
  7. Chelly JE, Greger J, Gebhard R, et al. Continuous femoral blocks improve recovery and outcome of patients undergoing total knee arthroplasty. J Arthroplasty. Jun 2001;16(4):436-445.
  8. Hebl JR, Dilger JA, Byer DE, et al. A pre-emptive multimodal pathway featuring peripheral nerve block improves perioperative outcomes after major orthopedic surgery. Reg Anesth Pain Med. Nov-Dec 2008;33(6):510-517.
  9. Ilfeld BM, Ball ST, Gearen PF, et al. Ambulatory continuous posterior lumbar plexus nerve blocks after hip arthroplasty: a dual-center, randomized, triple-masked, placebo-controlled trial. Anesthesiology. Sep 2008;109(3):491-501.
  10. Ilfeld BM, Le LT, Meyer RS, et al. Ambulatory continuous femoral nerve blocks decrease time to discharge readiness after tricompartment total knee arthroplasty: a randomized, triple-masked, placebo-controlled study. Anesthesiology. Apr 2008;108(4):703-713.
  11. Jaeger P, Zaric D, Fomsgaard JS, et al. Adductor canal block versus femoral nerve block for analgesia after total knee arthroplasty: a randomized, double-blind study. Reg Anesth Pain Med. Nov-Dec 2013;38(6):526-532.
  12. Choi S, Trang A, McCartney CJ. Reporting functional outcome after knee arthroplasty and regional anesthesia: a methodological primer. Reg Anesth Pain Med. Jul-Aug 2013;38(4):340-349.
  13. Bernucci F, Carli F. Functional outcome after major orthopedic surgery: the role of regional anesthesia redefined. Curr Opin Anaesthesiol. Oct 2012;25(5):621-628.
  14. Raj PP, Knarr DC, Vigdorth E, et al. Comparison of continuous epidural infusion of a local anesthetic and administration of systemic narcotics in the management of pain after total knee replacement surgery. Anesth Analg. May 1987;66(5):401-406.
  15. Pettine KA, Wedel DJ, Cabanela ME, Weeks JL. The use of epidural bupivacaine following total knee arthroplasty. Orthopaedic review. Aug 1989;18(8):894-901.
  16. Mahoney OM, Noble PC, Davidson J, Tullos HS. The effect of continuous epidural analgesia on postoperative pain, rehabilitation, and duration of hospitalization in total knee arthroplasty. Clin Orthop Relat Res. Nov 1990(260):30-37.
  17. YaDeau JT, Cahill JB, Zawadsky MW, et al. The effects of femoral nerve blockade in conjunction with epidural analgesia after total knee arthroplasty. Anesth Analg. Sep 2005;101(3):891-895, table of contents.
  18. Zaric D, Boysen K, Christiansen C, Christiansen J, Stephensen S, Christensen B. A comparison of epidural analgesia with combined continuous femoral-sciatic nerve blocks after total knee replacement. Anesth Analg. Apr 2006;102(4):1240-1246.
  19. Horlocker TT, Wedel DJ, Rowlingson JC, et al. Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine Evidence-Based Guidelines (Third Edition). Reg Anesth Pain Med. Jan-Feb 2010;35(1):64-101.
  20. Singelyn FJ, Deyaert M, Joris D, Pendeville E, Gouverneur JM. Effects of intravenous patient-controlled analgesia with morphine, continuous epidural analgesia, and continuous three-in-one block on postoperative pain and knee rehabilitation after unilateral total knee arthroplasty. Anesth Analg. Jul 1998;87(1):88-92.
  21. Salinas FV, Liu SS, Mulroy MF. The effect of single-injection femoral nerve block versus continuous femoral nerve block after total knee arthroplasty on hospital length of stay and long-term functional recovery within an established clinical pathway. Anesth Analg. Apr 2006;102(4):1234-1239.
  22. Ilfeld BM, Mariano ER, Girard PJ, et al. A multicenter, randomized, triple-masked, placebo-controlled trial of the effect of ambulatory continuous femoral nerve blocks on discharge-readiness following total knee arthroplasty in patients on general orthopaedic wards. Pain. Sep 2010;150(3):477-484.
  23. Carli F, Clemente A, Asenjo JF, et al. Analgesia and functional outcome after total knee arthroplasty: periarticular infiltration vs continuous femoral nerve block. Br J Anaesth. Aug 2010;105(2):185-195.
  24. Ilfeld BM, Shuster JJ, Theriaque DW, et al. Long-term pain, stiffness, and functional disability after total knee arthroplasty with and without an extended ambulatory continuous femoral nerve block: a prospective, 1-year follow-up of a multicenter, randomized, triple-masked, placebo-controlled trial. Reg Anesth Pain Med. Mar-Apr 2011;36(2):116-120.
  25. Morin AM, Kratz CD, Eberhart LH, et al. Postoperative analgesia and functional recovery after total-knee replacement: comparison of a continuous posterior lumbar plexus (psoas compartment) block, a continuous femoral nerve block, and the combination of a continuous femoral and sciatic nerve block. Reg Anesth Pain Med. Sep-Oct 2005;30(5):434-445.
  26. Ilfeld BM, Ball ST, Gearen PF, et al. Health-related quality of life after hip arthroplasty with and without an extended-duration continuous posterior lumbar plexus nerve block: a prospective, 1-year follow-up of a randomized, triple-masked, placebo-controlled study. Anesth Analg. Aug 2009;109(2):586-591.
  27. Ilfeld BM, Meyer RS, Le LT, et al. Health-related quality of life after tricompartment knee arthroplasty with and without an extended-duration continuous femoral nerve block: a prospective, 1-year follow-up of a randomized, triple-masked, placebo-controlled study. Anesth Analg. Apr 2009;108(4):1320-1325.
  28. Feibel RJ, Dervin GF, Kim PR, Beaule PE. Major complications associated with femoral nerve catheters for knee arthroplasty: a word of caution. J Arthroplasty. Sep 2009;24(6 Suppl):132-137.
  29. Ilfeld BM, Duke KB, Donohue MC. The association between lower extremity continuous peripheral nerve blocks and patient falls after knee and hip arthroplasty. Anesth Analg. Dec 2010;111(6):1552-1554.
  30. Memtsoudis SG, Dy CJ, Ma Y, Chiu YL, Della Valle AG, Mazumdar M. In-hospital patient falls after total joint arthroplasty: incidence, demographics, and risk factors in the United States. J Arthroplasty. Jun 2012;27(6):823-828 e821.
  31. Charous MT, Madison SJ, Suresh PJ, et al. Continuous femoral nerve blocks: varying local anesthetic delivery method (bolus versus basal) to minimize quadriceps motor block while maintaining sensory block. Anesthesiology. Oct 2011;115(4):774-781.
  32. Ilfeld BM, Moeller LK, Mariano ER, et al. Continuous peripheral nerve blocks: is local anesthetic dose the only factor, or do concentration and volume influence infusion effects as well? Anesthesiology. Feb 2010;112(2):347-354.
  33. Ilfeld BM, Yaksh TL. The end of postoperative pain–a fast-approaching possibility? And, if so, will we be ready? Reg Anesth Pain Med. Mar-Apr 2009;34(2):85-87.
  34. Lund J, Jenstrup MT, Jaeger P, Sorensen AM, Dahl JB. Continuous adductor-canal-blockade for adjuvant post-operative analgesia after major knee surgery: preliminary results. Acta Anaesthesiol Scand. Jan 2011;55(1):14-19.
  35. Jaeger P, Nielsen ZJ, Henningsen MH, Hilsted KL, Mathiesen O, Dahl JB. Adductor Canal Block versus Femoral Nerve Block and Quadriceps Strength: A Randomized, Double-blind, Placebo-controlled, Crossover Study in Healthy Volunteers. Anesthesiology. Feb 2013;118(2):409-415.
  36. Practice guidelines for acute pain management in the perioperative setting: an updated report by the American Society of Anesthesiologists Task Force on Acute Pain Management. Anesthesiology. Feb 2012;116(2):248-273.
  37. Perlas A, Kirkham KR, Billing R, et al. The impact of analgesic modality on early ambulation following total knee arthroplasty. Reg Anesth Pain Med. Jul-Aug 2013;38(4):334-339.
  38. Mudumbai SC, Kim TE, Howard SK, et al. Continuous adductor canal blocks are superior to continuous femoral nerve blocks in promoting early ambulation after TKA. Clin Orthop Relat Res. 2014 May;472(5):1377-83.

 

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Healthcare, Outcomes Research, Patient Safety, Regional Anesthesiology

Anesthesiology and Perioperative Outcomes Research: Where Should We Focus?

Since 2012, the American Society of Anesthesiologists has promoted the Perioperative Surgical Home model in which anesthesiologists function as leaders in the coordination of perioperative care for surgical patients to improve outcomes (1,2). While anesthesiologists globally have had similar interests over the years, the unifying challenge continues to be the selection of outcomes and demonstration of improvement due to the anesthesiologist’s role and/or choice of anesthetic or analgesic technique. Since the types of outcomes and frequency of occurrence vary widely, a comprehensive discussion of perioperative outcomes is beyond the scope of this summary. Therefore, this review will focus on select anesthesiologist-driven factors related to acute pain management and anesthetic technique on perioperative outcomes and potential research directions.

Rare Outcomes and Big Data

For anesthesiologists, avoiding adverse events of the lowest frequency (death, recall, and nerve injury) receives highest priority with death ranking first among complications to avoid (3). Studies involving rare outcomes, positive or negative, will invariably require accumulation of “big data.” Such studies must either involve multiple institutions over a long study period (if prospective) or access data involving a large cohort of patients for retrospective studies; these study designs involving longitudinal data may also require advanced statistical methods (4). For example, Memtsoudis and colleagues sought to evaluate postoperative morbidity and mortality for lower extremity joint arthroplasty patients in a recent study (5). They utilized a large nationwide administrative database maintained by Premier Perspective, Inc. (Charlotte, NC, USA); the study data were gathered from 382,236 patients in approximately 400 acute care hospitals throughout the United States over 4 years (5). Other retrospective cohort studies comparing the occurrence of perioperative complications such as surgical site infections, cardiopulmonary morbidity, and mortality have used the American College of Surgeons National Surgical Quality Improvement Project (NSQIP) (6-8). NSQIP originally started within the Veterans Health Administration (VHA) system in the 1980s with a small sample of hospitals; this project, which included public reporting of outcomes data, eventually expanded to include all VHA surgical facilities and others outside the VHA system (9). Multi-center prospective registries such as the SOS Regional Anesthesia Hotline (10, 11) and AURORA (12, 13) have been developed for outcomes research and have reported the occurrence rates of rare complications related to regional anesthesia. The disadvantages to these data-driven studies include lack or randomization introducing potential bias, missing or incorrectly coded data, inability to draw conclusions regarding causation, and restrictions to access such as information security issues and/or cost (e.g., the Premier database). However, these retrospective cohort database studies may offer large samples sizes and administrative data from actual “real world” patients over a longer period of time and may identify important associations that influence clinical practice and generate hypotheses for future prospective studies.

Anesthesia Type and Perioperative Mortality

Based on the study by Memtsoudis and colleagues, overall 30-day mortality for lower extremity arthroplasty patients is lower for patients who receive neuraxial and combined neuraxial-general anesthesia compared to general anesthesia alone (5). In most categories, the rates of occurrence of in-hospital complications are also lower for the neuraxial and combined neuraxial-general anesthesia groups vs. the general anesthesia group, and transfusion requirements are lowest for the neuraxial group compared to all other groups (5). Studies using NSQIP have reported no difference in 30-day mortality for carotid endarterectomy patients associated with anesthetic technique although regional anesthesia patients are more likely to have a shorter operative time and next-day discharge (8); similarly, there is no difference in 30-day mortality for endovascular aortic aneurysm repair although general anesthesia patients are more likely to have longer length of stay and pulmonary complications (14).

Perioperative Analgesia and Cancer Recurrence

In a relatively-small matched retrospective study, Exadaktylos and colleagues have reported lower rates of recurrence and metastasis for breast cancer surgery patients who receive paravertebral analgesia vs. conventional systemic opioids (15). Although the exact mechanism was not well-understood at that time (regional anesthesia vs. reduction in the use of anesthetic agents and opioids), clinical and basic science research in this area has grown rapidly and has demonstrated mixed results. A follow-up study involving 503 patients who underwent abdominal surgery for cancer and were previously enrolled in a large multi-center clinical trial (16) and a retrospective database study of 424 colorectal cancer patients who underwent laparoscopic resection (17) have not shown a difference in recurrence-free survival or mortality. A recent meta-analysis including 14 prospective and retrospective studies involving cancer patients (colorectal, ovarian, breast, prostate, and hepatocellular) demonstrates a positive association between epidural analgesia and overall survival but no difference in recurrence-free survival compared to general anesthesia with opioid analgesia (18).

Analgesic Technique and Persistent Postsurgical Pain

Chronic pain may develop after many common operations including breast surgery, hernia repair, thoracic surgery, and amputation and is associated with severe acute pain in the postoperative period (19). While regional analgesic techniques are effective for acute pain management, currently-available data are inconclusive with regard to their ability to prevent the development of persistent postsurgical pain (20-22). There is an opportunity to use larger databases to investigate this issue further.

Ultrasound and Patient Safety

In 2010, the American Society of Regional Anesthesia and Pain Medicine published a series of articles presenting the evidence basis for ultrasound in regional anesthesia (23). According to the article focused on patient safety, evidence at the time suggested that ultrasound may decrease the incidence of minor adverse events (e.g., hemidiaphragmatic paresis from interscalene block or inadvertent vascular puncture), but serious complications such as local anesthetic systemic toxicity (LAST) and nerve injury did not occur at different rates based on the nerve localization technique (24). Since then, a large prospective multi-center registry study has shown that the use of ultrasound in regional anesthesia does reduce the incidence of LAST compared to traditional techniques (13). Similar methodology may be applied to other rare complications associated with anesthetic interventions.

Perioperative Medicine and Health Care Costs

Approximately 31% of costs related to inpatient perioperative care is attributable to the ward admission (25). Anesthesiologists as perioperative physicians have an opportunity to influence the cost of surgical care by decreasing hospital length of stay through effective pain management and by developing coordinated multi-disciplinary clinical pathways (26, 27).

REFERENCES

  1. Vetter TR, Goeddel LA, Boudreaux AM, Hunt TR, Jones KA, Pittet JF. The Perioperative Surgical Home: how can it make the case so everyone wins? BMC anesthesiology. 2013;13:6.
  2. Vetter TR, Ivankova NV, Goeddel LA, McGwin G, Jr., Pittet JF. An Analysis of Methodologies That Can Be Used to Validate if a Perioperative Surgical Home Improves the Patient-centeredness, Evidence-based Practice, Quality, Safety, and Value of Patient Care. Anesthesiology. Dec 2013;119(6):1261-1274.
  3. Macario A, Weinger M, Truong P, Lee M. Which clinical anesthesia outcomes are both common and important to avoid? The perspective of a panel of expert anesthesiologists. Anesth Analg. May 1999;88(5):1085-1091.
  4. Ma Y, Mazumdar M, Memtsoudis SG. Beyond repeated-measures analysis of variance: advanced statistical methods for the analysis of longitudinal data in anesthesia research. Reg Anesth Pain Med. Jan-Feb 2012;37(1):99-105.
  5. Memtsoudis SG, Sun X, Chiu YL, et al. Perioperative comparative effectiveness of anesthetic technique in orthopedic patients. Anesthesiology. May 2013;118(5):1046-1058.
  6. Liu J, Ma C, Elkassabany N, Fleisher LA, Neuman MD. Neuraxial anesthesia decreases postoperative systemic infection risk compared with general anesthesia in knee arthroplasty. Anesth Analg. Oct 2013;117(4):1010-1016.
  7. Radcliff TA, Henderson WG, Stoner TJ, Khuri SF, Dohm M, Hutt E. Patient risk factors, operative care, and outcomes among older community-dwelling male veterans with hip fracture. J Bone Joint Surg Am. Jan 2008;90(1):34-42.
  8. Schechter MA, Shortell CK, Scarborough JE. Regional versus general anesthesia for carotid endarterectomy: the American College of Surgeons National Surgical Quality Improvement Program perspective. Surgery. Sep 2012;152(3):309-314.
  9. Ingraham AM, Richards KE, Hall BL, Ko CY. Quality improvement in surgery: the American College of Surgeons National Surgical Quality Improvement Program approach. Advances in surgery. 2010;44:251-267.
  10. Auroy Y, Benhamou D, Bargues L, et al. Major complications of regional anesthesia in France: The SOS Regional Anesthesia Hotline Service. Anesthesiology. Nov 2002;97(5):1274-1280.
  11. Auroy Y, Narchi P, Messiah A, Litt L, Rouvier B, Samii K. Serious complications related to regional anesthesia: results of a prospective survey in France. Anesthesiology. Sep 1997;87(3):479-486.
  12. Barrington MJ, Watts SA, Gledhill SR, et al. Preliminary results of the Australasian Regional Anaesthesia Collaboration: a prospective audit of more than 7000 peripheral nerve and plexus blocks for neurologic and other complications. Reg Anesth Pain Med. Nov-Dec 2009;34(6):534-541.
  13. Barrington MJ, Kluger R. Ultrasound guidance reduces the risk of local anesthetic systemic toxicity following peripheral nerve blockade. Reg Anesth Pain Med. Jul-Aug 2013;38(4):289-297.
  14. Edwards MS, Andrews JS, Edwards AF, et al. Results of endovascular aortic aneurysm repair with general, regional, and local/monitored anesthesia care in the American College of Surgeons National Surgical Quality Improvement Program database. J Vasc Surg. Nov 2011;54(5):1273-1282.
  15. Exadaktylos AK, Buggy DJ, Moriarty DC, Mascha E, Sessler DI. Can anesthetic technique for primary breast cancer surgery affect recurrence or metastasis? Anesthesiology. Oct 2006;105(4):660-664.
  16. Myles PS, Peyton P, Silbert B, Hunt J, Rigg JR, Sessler DI. Perioperative epidural analgesia for major abdominal surgery for cancer and recurrence-free survival: randomised trial. BMJ. 2011;342:d1491.
  17. Day A, Smith R, Jourdan I, Fawcett W, Scott M, Rockall T. Retrospective analysis of the effect of postoperative analgesia on survival in patients after laparoscopic resection of colorectal cancer. Br J Anaesth. Aug 2012;109(2):185-190.
  18. Chen WK, Miao CH. The effect of anesthetic technique on survival in human cancers: a meta-analysis of retrospective and prospective studies. PloS one. 2013;8(2):e56540.
  19. Kehlet H, Jensen TS, Woolf CJ. Persistent postsurgical pain: risk factors and prevention. Lancet. May 13 2006;367(9522):1618-1625.
  20. Kairaluoma PM, Bachmann MS, Rosenberg PH, Pere PJ. Preincisional paravertebral block reduces the prevalence of chronic pain after breast surgery. Anesth Analg. Sep 2006;103(3):703-708.
  21. Schnabel A, Reichl SU, Kranke P, Pogatzki-Zahn EM, Zahn PK. Efficacy and safety of paravertebral blocks in breast surgery: a meta-analysis of randomized controlled trials. Br J Anaesth. Dec 2010;105(6):842-852.
  22. Wildgaard K, Ravn J, Kehlet H. Chronic post-thoracotomy pain: a critical review of pathogenic mechanisms and strategies for prevention. Eur J Cardiothorac Surg. Jul 2009;36(1):170-180.
  23. Neal JM, Brull R, Chan VW, et al. The ASRA evidence-based medicine assessment of ultrasound-guided regional anesthesia and pain medicine: Executive summary. Reg Anesth Pain Med. Mar-Apr 2010;35(2 Suppl):S1-9.
  24. Neal JM. Ultrasound-guided regional anesthesia and patient safety: An evidence-based analysis. Reg Anesth Pain Med. Mar-Apr 2010;35(2 Suppl):S59-67.
  25. Macario A, Vitez TS, Dunn B, McDonald T. Where are the costs in perioperative care? Analysis of hospital costs and charges for inpatient surgical care. Anesthesiology. Dec 1995;83(6):1138-1144.
  26. Ilfeld BM, Mariano ER, Williams BA, Woodard JN, Macario A. Hospitalization costs of total knee arthroplasty with a continuous femoral nerve block provided only in the hospital versus on an ambulatory basis: a retrospective, case-control, cost-minimization analysis. Reg Anesth Pain Med. Jan-Feb 2007;32(1):46-54.
  27. Jakobsen DH, Sonne E, Andreasen J, Kehlet H. Convalescence after colonic surgery with fast-track vs conventional care. Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland. Oct 2006;8(8):683-687.

 

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Medical Education

More Journal Club, Less Book Report

ArticleWhen I hear clinical research articles presented for Journal Club, the presentations are sometimes very dry and remind me of book reports–just regurgitating statements made by the authors of the article.  In reality, Journal Club should offer a “deep dive” into study design and scientific methodology.

Journal Club should offer a “deep dive” into study design & methodology. #research #meded

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In the following outline, I suggest a format for evaluating clinical research articles layer by layer.  This can be used by the presenter as well as the discussion moderator to promote a more interactive Journal Club.  Coincidentally, the same format can also be used by journal reviewers and editors when reviewing submitted manuscripts (in other words–this is how I review manuscripts).

Here are some tips for presenting your next #research article for journal club. #meded

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Background:  Provide a brief synopsis of preliminary studies cited in the introduction leading up to the present study.

  1. Is the present study justified?  (Should not be lengthy if there is clearly a need for the study)
  2. Do the authors present a hypothesis or hypotheses?
  3. What is the primary aim/objective of the study?  Secondary aims/objectives?

Study Design:  Do the authors explicitly state the design used in the present study?  If so, what is it?

Retrospective (aka “case-control”):  Starts with the outcome then looks back in time for exposure to risk factors or intervention

  1. Can calculate odds ratios to estimate relative risk.
  2. Cannot calculate risk/incidence (not prospective).

Cross-sectional (aka “prevalence study”):  Takes a snapshot of risk factors and outcome of interest at one point in time or over a specific period of time

  1. Can calculate prevalence.
  2. Cannot calculate risk/incidence (not longitudinal).

Prospective (aka “cohort”):  Gold standard for clinical research–may be observational or interventional/experimental (Is it prospectively registered?  Check clinicaltrials.gov)

  • Observational (cohort study)
  1. May or may not have a designated control group (can start with defined group and risk factors are discovered over time such as the Framingham Study).
  2. Can calculate incidence and relative risk for certain risk factors.
  3. Identify causal associations.
  • Interventional/Experimental
  1. What is the intervention or experiment?
  2. Is there blinding?  If so, who is blinded:  single, double, or triple (statistician blinded)?
  3. Are the groups randomized?  How is this performed?
  4. Is there a sample size estimate and what is it based on (alpha and beta error, population mean and SD, expected effect size)?
  5. What are the study groups?  Are the groups independent or related?
  6. Is there a control group–placebo (for efficacy studies) or active comparator (standard of care)?

Measurements:  How are the outcome variables operationalized?  Check the validity, precision, and accuracy of the measurement tools (e.g., survey or measurement scale).

  1. Validity:  Has the tool been used before?  Is it reliable?  Does the tool make sense (face validity)?  Is the tool designed to measure the outcome of interest (construct validity)?
  2. Precision:  Does the tool hit the target?
  3. Accuracy:  Are the results reproducible?

Analysis:  What statistical tests are used and are they appropriate?  How do the authors determine statistical significance (p-value or confidence intervals)?  How are the results presented in the paper and are they clear?

  1. Categorical variables with independent groups:  1 outcome and 2 groups = Chi square test (exact tests are used when n<5 in any field); multiple outcomes or multiple groups = Kruskal Wallis (with one-way ANOVA and post-hoc multiple comparisons test (e.g., Tukey-Kramer).
  2. Continuous variables with independent groups:  1 outcome and 2 groups = Student’s t test (if normal distribution) or Mann-Whitney U test (if distribution not normal); multiple outcomes or multiple groups = ANOVA with post-hoc multiple comparisons testing; multiple outcomes and multiple groups = linear regression.
  3. Continuous variables with related groups:  paired t test or repeated-measures ANOVA depending on the number of outcomes and groups.
  4. Are the results statistically significant?  Clinically significant?
  5. Do the results make sense?

Conclusions:  Skip the discussion section of the paper at first and come up with your own conclusions based on the study results; then read what the authors have to say.

  1. Did the authors succeed in proving what they set out to prove?
  2. Read the discussion section.  Do you agree with the authors’ conclusions?
  3. What are possible future studies based on the results of the present study and how would you design the next study?

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Edward R. Mariano, MD, MAS, FASA, FASRA is a physician specializing in anesthesiology, professor, husband, and father working to improve pain control, outcomes, and the overall experience for patients having surgery