Neuraxial anaesthesia for surgical correction of arterial vascular obstruction in the lower limbs   

Atherosclerosis is a chronic inflammatory process that is responsible for reduced blood flow to some parts of the body, including the lower limbs. People who do not receive adequate treatment can lose their lower limbs. Bypassing arterial vascular obstruction in the legs is a surgical procedure that improves blood flow to reduce leg pain and sometimes to improve function. The mortality rate can be 10.5% after acute occlusion of an arterial blood vessel. The surgical procedure can improve outcomes when performed up to 12 hours after symptoms are first noted. Usually the procedure is performed with the patient unconscious and under general anaesthesia or awake but with legs numbed by neuraxial anaesthesia. Neuraxial anaesthesia may be administered as an injection of local anaesthetic around the spinal cord either in the back (spinal anaesthetic) or in the area where the nerves from the legs come together (epidural anaesthesia). A combination of general and neuraxial anaesthesia can be used. Other types of anaesthesia are used less often. At present, no single guideline shows why one anaesthetic technique is better than another. This systematic review is important because review authors assessed the risk of important outcomes after lower-limb revascularization with the participant under neuraxial or general anaesthesia. They performed this systematic review to answer a single research question: What are the rates of death and major complications with spinal and epidural anaesthesia as compared with other types of anaesthesia for lower-limb revascularization? In this second update of the Cochrane review, we searched the databases until April 2013 but found no new studies. The total number of participants in the four included studies was 696, of whom 417 received neuraxial anaesthesia and 279 received general anaesthesia. No evidence revealed differences in postoperative risk of death, myocardial infarction or leg amputation between the two types of anaesthetic. The risk of pneumonia was 9% after neuraxial anaesthesia and 20% after general anaesthesia. Evidence was insufficient to show the effects of neuraxial anaesthesia compared with other types of anaesthesia on cerebral stroke, duration of hospital stay, postoperative cognitive dysfunction, complications in the anaesthetic recovery room and transfusion requirements. No data described nerve dysfunction, postoperative wound infection, patient satisfaction, postoperative pain score, claudication distance and pain at rest. One study recruited more than 50% of all reported cases.This systematic review shows that neuraxial anaesthesia may reduce the risk of pneumonia after lower-limb revascularization, but evidence is insufficient to support other benefits or harms. 

Authors' conclusions: 

Available evidence from included trials that compared neuraxial anaesthesia with general anaesthesia was insufficient to rule out clinically important differences for most clinical outcomes. Neuraxial anaesthesia may reduce pneumonia. No conclusions can be drawn with regard to mortality, myocardial infarction and rate of lower-limb amputation, or less common outcomes.

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Background: 

Lower-limb revascularization is a surgical procedure that is performed to restore an adequate blood supply to the limbs. Lower-limb revascularization surgery is used to reduce pain and sometimes to improve lower-limb function. Neuraxial anaesthesia is an anaesthetic technique that uses local anaesthetics next to the spinal cord to block nerve function. Neuraxial anaesthesia may lead to improved survival. This systematic review was originally published in 2010 and was first updated in 2011 and again in 2013.

Objectives: 

To determine the rates of death and major complications associated with spinal and epidural anaesthesia as compared with other types of anaesthesia for lower-limb revascularization in patients aged 18 years or older who are affected by obstruction of lower-limb vessels.

Search strategy: 

The original review was published in 2010 and was based on a search until June 2008. In 2011 we reran the search until February 2011 and updated the review. For this second updated version of the review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, CINAHL and Web of Science from 2011 to April 2013.

Selection criteria: 

We included randomized controlled trials comparing neuraxial anaesthesia (spinal or epidural anaesthesia) versus other types of anaesthesia in adults (18 years or older) with arterial vascular obstruction undergoing lower-limb revascularization surgery.

Data collection and analysis: 

Two review authors independently performed data extraction and assessed trial quality. We pooled the data on mortality, myocardial infarction, lower-limb amputation and pneumonia. We summarized dichotomous data as odds ratio (OR) with 95% confidence interval (CI) using a random-effects model.

Main results: 

In this updated version of the review, we found no new studies that met our inclusion criteria. We included in this review four studies that compared neuraxial anaesthesia with general anaesthesia. The total number of participants was 696, of whom 417 were allocated to neuraxial anaesthesia and 279 to general anaesthesia. Participants allocated to neuraxial anaesthesia had a mean age of 67 years, and 59% were men. Participants allocated to general anaesthesia had a mean age of 67 years, and 66% were men. Four studies had an unclear risk of bias. No difference was observed between participants allocated to neuraxial or general anaesthesia in mortality rate (OR 0.89, 95% CI 0.38 to 2.07; 696 participants; four trials), myocardial infarction (OR 1.23, 95% CI 0.56 to 2.70; 696 participants; four trials), and lower-limb amputation (OR 0.84, 95% CI 0.38 to 1.84; 465 participants; three trials). Pneumonia was less common after neuraxial anaesthesia than after general anaesthesia (OR 0.37, 95% CI 0.15 to 0.89; 201 participants; two trials). Evidence was insufficient for cerebral stroke, duration of hospital stay, postoperative cognitive dysfunction, complications in the anaesthetic recovery room and transfusion requirements. No data described nerve dysfunction, postoperative wound infection, patient satisfaction, postoperative pain score, claudication distance and pain at rest.

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