Tag Archives: research

The “Top 10” Regional Anesthesia Articles of 2016

I was recently asked to provide a list of my “Top 10” regional anesthesia research articles from 2016 and not to include my own. So for what it’s worth (not much!), I’m sharing them below in no particular order.

In my humble opinion, these articles from 2016 have already influenced my clinical practice, taught me to look at something differently, or made me think of a new research question.

Trends in the Use of Regional Anesthesia: Neuraxial and Peripheral Nerve Blocks. Reg Anesth Pain Med. 2016 Jan-Feb;41(1):43-9. doi: 10.1097/AAP.0000000000000342.

The Second American Society of Regional Anesthesia and Pain Medicine Evidence-Based Medicine Assessment of Ultrasound-Guided Regional Anesthesia: Executive Summary. Reg Anesth Pain Med. 2016 Mar-Apr;41(2):181-94. doi: 10.1097/AAP.0000000000000331.

Teaching ultrasound-guided regional anesthesia remotely: a feasibility study. Acta Anaesthesiol Scand. 2016 Aug;60(7):995-1002. doi: 10.1111/aas.12695.

Paravertebral block versus thoracic epidural for patients undergoing thoracotomy. Cochrane Database Syst Rev. 2016 Feb 21;2:CD009121. doi: 10.1002/14651858.CD009121.pub2.

Perineural versus intravenous dexamethasone as adjuncts to local anaesthetic brachial plexus block for shoulder surgery. Anaesthesia. 2016 Apr;71(4):380-8. doi: 10.1111/anae.13409.

Continuous Popliteal Sciatic Blocks: Does Varying Perineural Catheter Location Relative to the Sciatic Bifurcation Influence Block Effects? A Dual-Center, Randomized, Subject-Masked, Controlled Clinical Trial. Anesth Analg. 2016 May;122(5):1689-95. doi: 10.1213/ANE.0000000000001211.

A randomised controlled trial comparing meat-based with human cadaveric models for teaching ultrasound-guided regional anaesthesia. Anaesthesia. 2016 Aug;71(8):921-9. doi: 10.1111/anae.13446.

Adductor Canal Block Provides Noninferior Analgesia and Superior Quadriceps Strength Compared with Femoral Nerve Block in Anterior Cruciate Ligament Reconstruction. Anesthesiology. 2016 May;124(5):1053-64. doi: 10.1097/ALN.0000000000001045.

A radiologic and anatomic assessment of injectate spread following transmuscular quadratus lumborum block in cadavers. Anaesthesia. 2017 Jan;72(1):73-79. doi: 10.1111/anae.13647.

Regional Nerve Blocks Improve Pain and Functional Outcomes in Hip Fracture: A Randomized Controlled Trial. J Am Geriatr Soc. 2016 Dec;64(12):2433-2439. doi: 10.1111/jgs.14386.

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Tips for Reading a Clinical Research Article

paper stackIt is getting more and more difficult to keep up with newly published articles even just in one medical subspecialty.  With so much to read, from background articles for research papers to articles for journal club to manuscript assignments as a peer reviewer, it is important to be efficient and attack every scientific article or manuscript strategically.

Clinical research is my focus area, but the following updated tips for interpreting a journal article may apply to other areas of research as well.

Background:  Do the authors summarize previously published studies leading up to the present study?  What don’t we already know about this topic?

  1. Do the authors do a good job justifying the reason for the study?  This should not be lengthy if there is clearly a need for the study.
  2. Do the authors present a hypothesis?  What is it?
  3. What is the primary aim/objective of the study?  Do the authors specific secondary aims/objectives?

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

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

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

Cross-sectional (“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:  Gold standard for clinical research–may be observational or interventional/experimental.  Check if the study is prospectively registered (e.g., clinicaltrials.gov) because most journals expect this.

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 (“clinical trial”)

  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)?  This should be centered around the primary outcome.
  5. What are the study groups?  Are the groups independent or related?
  6. Is there a control group such as a 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 define 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:  I personally tend to skip the discussion section of the paper at first and come up with my own conclusions based on the study results; then I read what the authors have to say later.

  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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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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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.

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).

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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