|EVIDENCE BASED DATA
|Year : 2007 | Volume
| Issue : 2 | Page : 153
Regional anaesthesia versus general anaesthesia: Is there an impact on outcome after major surgery?
M.D., FICS, FAMS, Sr.Prof. and Head, Department of Anaesthesiology, R.N.T.Medical College, Udaipur, India
|Date of Web Publication||20-Mar-2010|
M.D., FICS, FAMS, Sr.Prof. and Head, Department of Anaesthesiology, R.N.T.Medical College, Udaipur
Source of Support: None, Conflict of Interest: None
BEARs are the summary of the evidences pertaining to a specific clinical dilemma encountered in the day
today anaesthetic practice. They are not the systematic reviews but rather contain the best evidence (highest level)
available to any practicing anaesthesiologist. The search strategies adopted will not be discussed in detail.
|How to cite this article:|
Bajaj P. Regional anaesthesia versus general anaesthesia: Is there an impact on outcome after major surgery?. Indian J Anaesth 2007;51:153
|How to cite this URL:|
Bajaj P. Regional anaesthesia versus general anaesthesia: Is there an impact on outcome after major surgery?. Indian J Anaesth [serial online] 2007 [cited 2020 Feb 17];51:153. Available from: http://www.ijaweb.org/text.asp?2007/51/2/153/61136
The ability of neuraxial blockade, by either epidural or spinal analgesia, to provide excellent analgesia and to suppress some aspects of the stress response to surgery was established in the late 1970s. By 1982 Kehlet was suggesting that the neuroendocrine changes in surgery were detrimental and that obtunding or abolishing these changes could improve outcome.  In other words, the hormonal and metabolic responses to surgery were an epiphenomenon and no longer necessary for survival in modern surgical practice but may instead be associated with major morbidity and even mortality. This persuasive hypothesis, although without scientific foundation, stimulated considerable research in the succeeding years. Some early small studies supported the notion that regional anaesthesia (RA) improved morbidity and mortality. For example, in 1987 Yeager et al.  found a statistically significant improvement in mortality and morbidity in high - risk patients undergoing major surgery who received epidural anaesthesia and analgesia.
An authoritative review of the role of epidural anaesthesia and analgesia in determining postoperative outcome was published in 1995.  The authors concluded that the ability of epidural analgesia to alter clinical outcome was unproven. There was, however, some evidence to suggest that perioperative coagulability was decreased with epidural analgesia with a resultant decreased incidence of arterial and venous thromboses. Additionally, there were short-term improvements in gastrointestinal motility (time to pass flatus), but it was unclear whether these benefits would be translated into more rapid functional recovery. Otherwise, evidence for clinically important improvements in morbidity involving other organ systems was insufficient to draw conclusions. Furthermore, they concluded that more studies were needed to determine if a relationship exists between the stress response and postoperative morbidity before the importance of decreasing the stress response with RA can be determined.
| Meta - Analyses|| |
Many anaesthesiologists hold the view that neuraxial blockade improves respiratory function after abdominal and thoracic surgery and so results in fewer pulmonary complications. Support for this opinion was provided in 1998 by a meta-analysis of randomized controlled trials examining the effects of RA on postoperative pulmonary function  . However, there were no differences, clinical or statistical, in surrogate measures of respiratory function such as forced expiratory volume in 1 s, functional vital capacity, or peak expiratory flow rate, suggesting that these measurements are of little use as predictors, or determinants, of postoperative pulmonary morbidity. The results of this review indicated that postoperative epidural analgesia decreased pulmonary complications but that other regional techniques, such as intrapleural block and intercostal nerve block, were ineffective. It is notable that the main conclusions were based on a small number of studies with few patients (total, 200-250).
| Recent Randomized Controlled Trials|| |
Randomized controlled trials comparing RA with GA for major surgery have failed to demonstrate any useful effect of RA on outcome. A study conducted in United States Veterans Affairs hospitals compared GA intraoperatively and parenteral opioids postoperatively with epidural bupivacaine analgesia and light GA intraoperatively and epidural morphine postoperatively in 1021 patients undergoing intraabdominal aortic, gastric, biliary, or colonic surgery.  Overall, there was no significant difference in the incidence of death and major complications for up to 30 days after surgery between the groups. The RA group had better pain relief than the GA group and had needed significantly less postoperative analgesia. Subgroup analysis found that for aortic surgery the epidural group had fewer (P<0.01) major complications (cardiovascular complications, respiratory failure, and stroke), but the number of deaths was similar in both groups and there was no difference in duration of hospital stay. The overall mortality rate from aortic surgery was low (9 of 374 patients). These effects were not found in the other surgical groups.
The MASTER Anaesthesia Trial (Multicenter Australian Study of Epidural Anaesthesia) chose deliberately to study high-risk patients.  The investigators argued that the failure to demonstrate an effect of RA in previous studies may have been the result of a lack of major postoperative complications in relatively healthy patients. Nine hundred and fifteen patients undergoing major abdominal surgery with one or more defined comorbid states were randomly assigned to intraoperative epidural anaesthesia with GA and postoperative epidural analgesia for 72 h or a control group of GA and postoperative opioids for analgesia. The co-morbid states were : morbid obesity, diabetes mellitus, chronic renal failure, respiratory insufficiency, cardiac failure, recent acute myocardial infarction, exertional angina, myocardial ischemia, and severe hepatocellular disease. Epidural analgesia resulted in lower pain scores in the first three postoperative days. However, there was no difference in the 30 day mortality rate between the groups and only one major postoperative complication, respiratory failure, occurred less frequently in the RA group (23%) than in the GA group (30%) (P=0.02). The authors concluded that most major postoperative complications in high-risk patients undergoing major abdominal surgery are not decreased by the use of combined epidural and GA and postoperative epidural analgesia for 72 h.
A secondary subgroup analysis of the same data set was published in 2003 and found no difference in outcome between RA and GA in subgroups at increased risk of pulmonary or cardiac complication, or undergoing aortic surgery  . No differences were found in duration of hospital stay or intensive therapy unit stay. There was no relationship between frequency of use of epidural analgesia in routine practice outside the trial and benefit from RA in the trial. There was no indication that perioperative epidural analgesia significantly influenced serious morbidity and mortality after major abdominal surgery.
| Present position|| |
Although there is some evidence from meta-analyses that there may be benefits from RA on postoperative pulmonary complications, postoperative myocardial infarction, and even mortality, these have mostly not been confirmed by recent randomized controlled trials. These trials have been criticized in terms of their protocol design, evolution and timeliness, and statistical analysis.  Nevertheless, in most instances the management of epidural anaesthesia and analgesia reflected common clinical practice but not necessarily best practice. The lack of generalizability of results derived from complex, highly labor-intensive studies advocated by enthusiasts or RA is a major handicap to their widespread clinical acceptance.
Could the results derived from meta-analyses be misleading?
Anaesthetic and surgical practices evolve continuously with many small changes occurring concurrently. These include : new shorter-acting drugs, new monitoring standards, routine thromboprophylaxis, patient-care pathways with enhanced recovery, better preoperative assessment and optimization and rapid mobilization. Specific changes in neuraxial blockade have been much less pronounced in the past 25 yr. It is therefore possible that recent improvements in GA have been sufficient to catch up to the standards set by RA in the 1980s and early 1990s.
| Bottom line|| |
The supposition that RA decreases morbidity and mortality after major surgery remains unproven. Epidural analgesia provides excellent pain relief after surgery, which alone is sufficient to justify its use. The exhortation of de leon-Casasola in a recent editorial in Anesthesia& Analgesia  "do not throw away the Tuohy needles and epidural catheters just yet" must be based on the quality of analgesia rather than improved outcome.
| References|| |
|1.||Kehlet H. The modifying effect of general and regional anaesthesia on the endocrine-metabolic response to surgery. Reg Anesth 1982; 7: S38-48. |
|2.||Yeager MP, Glass DD, Neff RK, Brinck-Johnsen T. Epidural anesthesia and analgesia in high - risk surgical patients. Anesthesiology 1987; 66: 729-36. [PUBMED] [FULLTEXT] |
|3.||Liu, S, Carpenter RL, Neal JM. Epidural anesthesia and analgesia. Anesthesiology 1995; 82: 1474-506. |
|4.||Ballantyne JC, Carr DB, deFerranti S et al. The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. Anesth Analg 1998; 86: 598-612. |
|5.||Park WY, Thompson JS, Lee KK. Effect of epidural anesthesia and analgesia on perioperative outcome: a randomized, controlled Veterans Affairs cooperative study. Ann Surg 2001; 234: 560-71. [PUBMED] [FULLTEXT] |
|6.||Rigg JRA, Jamrozik K, Myles PS. Epidural anaesthesia and analgesia and outcome of major surgery: a randomized trial. Lancet 2002; 359: 1276-82. |
|7.||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. |
|8.||De Leon-Casasola OA. When it comes to outcome, we need to define what a perioperative epidural technique is. Anesth Analg 2003; 96: 315-18. [PUBMED] [FULLTEXT] |