Effect of anaesthetic technique on mortality following major lower extremity amputation: a propensity score‐matched observational study

Abstract

SummaryWe investigated whether the type of anaesthesia affects mortality and length of stay after non-traumatic major lower extremity amputations. A total of 1365 eligible patients who were operated on between 2002 and 2010 were included in the final analysis. Propensity score matching was used to produce 475 matched pairs of patients undergoing operation with either general or regional anaesthesia. We found that 30-day mortality was significantly greater in the general anaesthesia group compared with the regional anaesthesia group, with an odds ratio (95% CI) of 1.5 (1.0-2.3) in the total matched population and 4.2 (1.3-13.4) in a high-risk subgroup. The median (IQR [range]) length of postoperative hospital stay was significantly less in the patients of the high-risk subgroup who had general anaesthesia at 15 (7-21 [1-101]) days compared with 25 days (10-37 [0-78]) for those who had regional anaesthesia (p = 0.027). The results of our study suggest that 30-day mortality is significantly higher in patients undergoing major lower extremity amputations under general anaesthesia compared with regional anaesthesia. The choice of an appropriate anaesthetic technique is usually made by the anaesthesiologist after taking into account the patient's medical condition, operative factors, surgical requirements, skills of the anaesthesiologist and the preferences of the patient. Many of these decisions are based on previous experience and expert opinion. The fact that the anaesthetic technique can have repercussions beyond the traditional peri-operative period is only now being realised [1]. This new realisation has made intra-operative anaesthetic choice even more complex, requiring a more robust level of evidence to guide decision making than just expert opinion alone.The effect of anaesthetic technique on postoperative mortality has been studied in the past in various types of surgery [2,3], but the heterogeneity of the surgical population makes generalisations about the effect of anaesthesia on mortality inappropriate.Patients undergoing non-traumatic major lower extremity amputation (MLEA) are known to have a large number of comorbidities and an associated 30-day mortality ranging between 8% and 32% [4][5][6][7][8]. Cardiovascular complications make up the most common cause of postoperative mortality among these patients [7,9]. Although there is some evidence indicating that 612 Anaesthesia

Factors Affecting Post-Operative Mortality Rate after Major Lower Extremity Amputations in a Tertiary Institution in Singapore

“…[1][2][3][4][5][6][7] Patient's pre-operative condition, including their ASA status, presence of septic shock and site of amputation undertaken are significant predictors of post-operative in hospital mortality rate and ICU admission rate. Patients with pre-operative septic shock, ASA 4 status and undergoing AKA should be regarding as high risk group, and appropriate level of intra-operative monitoring and post-operative disposition should be arranged.…”

“…One large scale retrospective study showed that 30-day mortality is significantly higher in patients undergoing MLEA under general anaesthesia compared with regional anaesthesia with an odds ratio of 1.5. 7 However when further subgroup analyses was done for patients that underwent knee amputation surgery under peripheral nerve block alone, the authors was unable to detect any significant difference of the effect of anaesthesia on 30-day mortality rate.…”

“…One study found that the type of anaesthetic (neuraxialvs general) was not associated with survival when corrected for other variables, 12 while other studies show that avoiding general anaesthesia in favour of regional anaesthesia may improve post-operative outcomes in non-traumatic MLEA surgeries. 7,16 However, all these studies did not distinguish between central neuraxial block and peripheral nerve block in the group analysed under regional anaesthesia. One large scale retrospective study showed that 30-day mortality is significantly higher in patients undergoing MLEA under general anaesthesia compared with regional anaesthesia with an odds ratio of 1.5.…”

“…[1][2][3][4][5][6][7] With the increasing incidence of diabetes mellitus in Asia, the incidence of MLEA surgeries is set to increase over the next few years [8][9][10] as diabetes is one of the major risk factors for critical limb ischaemia and lower limb amputation surgeries. 10 It is important to identify factors that affects outcome in this group of patients.…”

“…Studies have found the 30-day mortality rate for this group of patients to be ranging from 7-23%. [1][2][3][4][5][6][7] Patients undergoing these operations often have significant multiple comorbidities 4 and pre-operative hemodynamic disturbances, putting them at high risk both for surgery and for the further hemodynamic changes associated with anaesthesia. Most studies evaluating factors associated with peri-operative mortality rates in this group of patients are conducted in Caucasian populations, [3][4][5][6] and we find a lack of similar studies evaluating these factors in the Asian population.…”