To the Editor:
The recent MASTER trial (1,2) concluded that “most adverse morbid outcomes in high-risk patients undergoing major abdominal surgery are not reduced by the use of combined epidural and general anesthesia and postoperative epidural analgesia.” The authors reported that their findings were similar to the equivocal results from a recent randomized trial that also included about 1,000 participants (3) However, the VACS trial did not report any confidence intervals for their main outcomes, making it difficult to assess the range of plausible effects or their consistency with past evidence (4) With only about 40 deaths and up to a few dozen major endpoints in both the MASTER and VACS trials, the confidence intervals are wide and compatible with benefits seen in a previous overview (5). Rigg et al. (1) note that “there is more agreement…than may seem apparent.” Lack of evidence of effect should not be interpreted as evidence of lack of effect. This is particularly so when trials involve only a few dozen events. In this setting, the most reliable assessments are obtained from trial overviews. A basic update of some major outcomes in our previous overview (see Table 1) still indicates thatregional anesthesia provides important improvements in major postoperative complications.
1. Rigg JRA, Jamrozik K, Myles PS, et al. Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. Lancet 2002; 359: 1276–82.
2. Peyton PJ, Myles PS, Silbert BS, et al. Perioperative epidural analgesia and outcome after major abdominal surgery in high risk patients. Anesth Analg 2003; 96: 548–54.
3. Park YW, Thompson JS, Lee KK, et al. Effect of epidural anesthesia and analgesia on perioperative outcome: a randomized, controlled veterans affairs cooperative study. Ann Surg, 2001; 234: 560–71.
4. Gardner MJ. Altman DG. Confidence intervals rather than P values: estimation rather than hypothesis testing. Br Med J (Clin Res Ed) 1986; 292: 746–50.
5. 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. Br Med J 2000; 321: 1493–7.