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 TOP Article #1 appraised Structured abstractArticle #2 appraisedStructured abstractCommentary by S. GanapathyReferencesCommentary by C.J.L. McCartney,...References |
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Structured abstract |
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TOPArticle #1 appraisedStructured abstractArticle #2 appraisedStructured abstractCommentary by S. GanapathyReferencesCommentary by C.J.L. McCartney,...References |
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Design: Multicenter, randomized, unblinded trial.
Setting: Fifteen hospitals of the US Department of Veterans Affairs.
Patients: Two thousand seven hundred and thirty-one patients undergoing abdominal aortic, gastric, biliary, or colon surgery were screened. Exclusion criteria included age < 21 yr; female gender; American Society of Anesthesiologists physical status class I, II, or V; mental confusion; emergency surgery; myocardial infarction within the past six months; abdominal procedure within the past three months; previous aortic surgery; use of chemotherapeutic or immunosuppressive drugs (other than steroids); tracheostomy or endotracheal intubation; contraindications to any study drug or technique; insistence of surgeon or anesthesiologist on a particular anesthetic; or participation in another study. Of the 1,371 eligible patients, 1,021 consented to participate. After randomization, 37 patients (25 in the epidural group; 12 in the systemic group) were excluded due to surgical cancellation or patient withdrawal. Eleven patients did not complete the 30-day follow-up.
Intervention: Five hundred and fourteen patients were allocated to receive lumbar or thoracic epidural anesthesia using 0.5% bupivicaine with epinephrine plus balanced general anesthesia (nitrous oxide, isoflurane, fentanyl, vecuronium) and postoperative epidural morphine 3 to 6 mg every 12 to 24 hr. Five hundred and seven patients were allocated to receive a thiopental or midazolam/fentanyl induction plus balanced general anesthesia (as described above) and postoperative intramuscular or intravenous morphine or meperidine.
Main outcomes: The primary outcome was the combined endpoint of 30-day all-cause mortality, myocardial infarction, congestive heart failure, ventricular tachyarrhythmia, complete atrioventricular block, severe hypotension, cardiac arrest, pulmonary embolism, respiratory failure, stroke, and renal failure. The secondary outcomes were angina, respiratory depression, pneumonia, sepsis, gastrointestinal bleeding, epidural hematoma, and reoperation. Postoperative pain at rest, physical mobilization, and lengths of intensive care unit (ICU) and hospital stay were evaluated also.
Main results: Analysis was intention-to-treat. Clinical characteristics, indicators of surgical severity, and surgical complexity were similar. Mean duration of epidural analgesia was 55.2 hr. The two groups did not have any significant differences in the frequencies of primary or secondary outcomes, the average postoperative physical performance scores, or lengths of ICU or hospital stay. Visual analogue pain scores were lower in the epidural group (P 
0.03) on postoperative days one, three, and seven. Subgroup analysis showed statistically significant reductions in the frequency of the primary outcome, respiratory failure, and stroke in patients undergoing abdominal aortic surgery in the epidural group (Table
).
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Funding: US Department of Veterans Affairs Cooperative Studies Program, Veterans Health Administration.
Correspondence: Dr. Jon S. Thompson, University of Nebraska Medical Center, Department of Surgery, 983280 Nebraska Medical Center, Omaha, NE 68198-3280, USA. E-mail: jthompso{at}unmc.edu
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Article #2 appraised |
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TOPArticle #1 appraisedStructured abstractArticle #2 appraisedStructured abstractCommentary by S. GanapathyReferencesCommentary by C.J.L. McCartney,...References |
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Structured abstract |
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TOPArticle #1 appraisedStructured abstractArticle #2 appraisedStructured abstractCommentary by S. GanapathyReferencesCommentary by C.J.L. McCartney,...References |
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Design: Multicenter, randomized trial. Outcome adjudicators were blinded.
Setting: Twenty-five hospitals in Australia, Hong Kong, Malaysia, Saudi Arabia, Singapore, and Thailand.
Patients: Patients were eligible if they were undergoing elective, non-laparoscopic abdominal or esophageal operations lasting more than one hour, and were 
18 yr old with morbid obesity, diabetes mellitus, chronic renal failure, respiratory insufficiency, major hepatocellular disease, or cardiac disease within the past two years, or 75 yr old with two or more risk factors (significant respiratory disease, cardiac dysrhythmia, hypertension, moderate obesity, frailty, or myocardial infarction). Patients with contraindications to epidural use were excluded.
Intervention: Four hundred and sixty-one patients were allocated to receive lumbar or thoracic epidural anesthesia using local anesthetic with or without opioids plus balanced general anesthesia and postoperative 72-hr continuous epidural analgesia with bupivacaine or ropivacaine, with or without meperidine or fentanyl. Four hundred and fifty-four patients were allocated to receive balanced general anesthesia and postoperative intravenous opioids. After randomization, 27 patients were excluded due to surgical cancellation or ineligible procedure, leaving 447 and 441 patients in the epidural and systemic groups respectively.
Main outcomes: The primary outcome was the combined endpoint of 30-day all-cause mortality and major postoperative complications (myocardial infarction, angina, congestive heart failure, cardiac shock, ventricular or supraventricular tachyarrhythmia, complete atrioventricular block, respiratory failure, gastrointestinal failure, hepatic failure, pancreatic failure, renal failure, hematological failure, and major inflammatory complications [infection, pneumonia, or sepsis]). Postoperative pain at rest and after coughing were also assessed.
Main results: Analysis was intention-to-treat. Frequencies of preoperative risk factors were similar in the two groups. Mean duration of epidural analgesia was 73.6 hr. There was no significant difference in the frequency of the primary outcome. Visual analogue pain scores were significantly lower in the epidural group at rest on postoperative day one (P = 0.0002) and after coughing on postoperative days one to three (P 0.0007). Epidural/general anesthesia and epidural analgesia reduced the frequency of respiratory failure compared to general anesthesia and systemic analgesia (Table
). Twenty-nine patients (6.5%) in the epidural group did not receive an epidural; nineteen patients (4.3%) in the systemic group received epidural analgesia. "As treated" analysis yielded similar results to the intention-to-treat analysis.
Conclusion: Overall, epidural/general anesthesia and epidural analgesia does not reduce 30-day mortality or major morbidity but does provide better pain control than general anesthesia and systemic analgesia.
Funding: The Australian and New Zealand College of Anaesthetists, the Health Department of Western Australia, and the National Health and Medical Research Council.
Correspondence: Dr. John Rigg, Office of Safety and Quality, St John of God Health Care, 175 Cambridge Street, Subiaco, WA 6008, Australia. E-mail: john.rigg{at}sjog.org.au
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Commentary by S. Ganapathy |
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TOPArticle #1 appraisedStructured abstractArticle #2 appraisedStructured abstractCommentary by S. GanapathyReferencesCommentary by C.J.L. McCartney,...References |
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The study by Park and colleagues used intraoperative lumbar or thoracic epidural local anesthetic without narcotics for abdominal surgery followed by postoperative analgesia with epidural narcotics. There are two fundamental problems with the intervention. First, the benefits of epidural analgesia following abdominal surgery are seen only with local anesthetics administered via the thoracic epidural route.3 Second, epidural opioids alone or lumbar epidural local anesthetics have not been efficacious in reducing postoperative complications.3 Thus, the intervention in Park‘s study may not have been optimal. In spite of this limitation, patients receiving an epidural in the aortic surgery subgroup were less likely to experience one or more primary endpoints (P < 0.01), or cardiovascular (P = 0.03), cerebrovascular (P = 0.03), or pulmonary (P < 0.01) complications. The discussants of this paper clearly bring out some of the pitfalls with this study.
The study by Rigg and colleagues is more robust with regards to its design, clinical applicability, sample size, and population. Other than a reduction in the rate of respiratory failure, they did not demonstrate any advantage to thoracic epidural analgesia. Their finding reiterates the observation made by Norris et al. in aortic surgery..4
In both studies, the primary analysis was "intention-to-treat". Although this provides an estimate of effectiveness of the intervention, crossover of patients from one group to the other may compromise detection of efficacy. An "as treated" analysis might be more appropriate. Crossover rates in Park‘s and Rigg‘s studies were 7.8% and 5.4% respectively. The "as treated" analyses confirmed the results found with "intention-to-treat".
Finally, I firmly believe epidural analgesia is not a cure for preexisting morbidity that contributes to postoperative complications. One cannot reduce death from severe coronary artery disease with a short-term intervention.
For now, I will tell my patients that thoracic epidural analgesia provides them with excellent analgesia with activity, reduces respiratory complications, and provides questionable benefits with other outcomes. Will I continue to use it? You bet.
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References |
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TOPArticle #1 appraisedStructured abstractArticle #2 appraisedStructured abstractCommentary by S. GanapathyReferencesCommentary by C.J.L. McCartney,...References |
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2 Rodgers A, Walker N, Schug S, et al. Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: results from overview of randomised trials. BMJ 2000; 321: 1493–7.
3 Liu S, Carpenter RL, Neal JM. Epidural anesthesia and analgesia. Their role in postoperative outcome. Anesthesiology 1995; 82: 1474–1506.[Medline]
4 Norris EJ, Beattie C, Perler BA, et al. Double-masked randomized trial comparing alternate combinations of intraoperative anesthesia and postoperative analgesia in abdominal aortic surgery. Anesthesiology 2001; 95: 1054–67.[Medline]
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Commentary by C.J.L. McCartney, W.S. Beattie, and V.W.S. Chan |
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TOPArticle #1 appraisedStructured abstractArticle #2 appraisedStructured abstractCommentary by S. GanapathyReferencesCommentary by C.J.L. McCartney,...References |
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The recently published MASTER Trial and Veterans Affairs study,2,3 both large randomized controlled outcome studies (915 and 1,021 patients respectively), failed to demonstrate reduction in major morbidity and mortality up to 30 days postoperatively in patients who had epidural anesthesia and analgesia. However, both studies lacked adequate sample size and power to demonstrate a difference in overall mortality or cardiac morbidity between epidural and systemic treatments. To demonstrate a 30% reduction in myocardial infarction, as suggested by Rodgers et al.,1 a study with a 5% type I error rate and 80% power would require at least 9,500 patients. In addition, in the MASTER trial, nearly 50% of patients in the epidural group were not fully compliant with the study protocol and thoracic epidural was not mandatory. Two recent meta-analyses have demonstrated that only thoracic, and not lumbar, epidural analgesia can reduce the incidence of mortality1 or perioperative myocardial infarction.4
Despite a lack of power, both studies demonstrate several advantages of the use of epidural techniques. Superior postoperative analgesia was evident in both studies despite epidural opioids alone being used in the Veteran Affairs study. The MASTER Trial demonstrated a significant reduction in respiratory failure (30.2% vs 23.3%, P = 0.02) in all patients who had epidural techniques. The Veterans Affairs study showed significantly fewer patients experiencing one or more primary postoperative complications (40 events vs 70 events, P < 0.01) in the epidural group following abdominal aortic surgery. These included lower incidences of respiratory failure and cardiovascular morbidity with the epidural technique. Importantly, both studies found significant clinical benefits of the epidural technique with no increase in adverse effects or complications.
Good quality pain relief aside, recent studies also show improved postoperative exercise tolerance, quality of life, and return of gastrointestinal function as other benefits of epidural analgesia.5 Unquestionably, evidence today supports the routine use of postoperative epidural analgesia in high risk surgical patients. However, as physicians, we must constantly remind ourselves that proper epidural catheter management goes beyond consideration of technique or site of catheter insertion. Furthermore, epidural analgesia is only one of many perioperative factors that can affect patient outcome.
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References |
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TOPArticle #1 appraisedStructured abstractArticle #2 appraisedStructured abstractCommentary by S. GanapathyReferencesCommentary by C.J.L. McCartney,...References |
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2 Rigg JR, Jamrozik K, Myles PS, et al.; MASTER Anaesthesia Trial Study Group. Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. Lancet 2002; 359: 1276–82.[Medline]
3 Park WY, Thompson JS, Lee KK, and the Department of Veterans Affairs Cooperative Study #345 Study Group. Effect of epidural anesthesia and analgesia on perioperative outcome: a randomized, controlled Veterans Affairs cooperative study. Ann Surg 2001; 234: 560–9.[Medline]
4 Beattie WS, Badner NH, Choi P. Epidural analgesia reduces postoperative myocardial infarction: a meta-analysis. Anesth Analg 2001; 93: 853–8.
5 Carli F, Mayo N, Klubien K, Schricker T, Trudel J, Belliveau P. Epidural analgesia enhances functional exercise capacity and health-related quality of life after colonic surgery: results of a randomized trial. Anesthesiology 2002; 97: 540–9.[Medline]
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