Background
Each year, millions of people worldwide are affected by blockages of their arteries that require amputations. A large volume of blood can be lost during this surgery, which can lead to complications including death. Treating patients with blood transfusions has risks. Tourniquets are devices that squeeze the leg above where it is due to be amputated, and can be used during amputation to reduce blood loss and the need for blood transfusions. Although they are considered to be safe during the surgical replacement of knee joints, their use among people with blockages in their blood vessels undergoing amputation remains controversial. Healthcare professionals worry about tourniquets causing damage to patient's skin, muscles, and blood vessels during the operation, which could reduce the blood supply to the stump and thereby affect wound healing.
This review searched for studies that looked at whether tourniquet use in people undergoing amputation due to blockages in their blood vessels is safe and effective in reducing complications such as blood loss during surgery, fall in blood counts, need for blood transfusions, wound healing, and need for repeat amputation surgery.
Study characteristics and key results
We searched medical databases to find relevant studies that compared the use of tourniquets to no tourniquets in people undergoing amputation due to blockages in their blood vessels. We identified one randomised controlled trial (a type of study where participants are randomly assigned to one of two or more treatment groups) conducted in the UK. Sixty-four people undergoing amputation below the knee for severe blockages of their arteries were assigned to either tourniquet or no tourniquet. The study assessed blood loss during surgery, change in blood count, blood transfusion requirement, wound healing, and revision surgery. The results suggested that the use of a tourniquet during an amputation below the knee halved blood loss during surgery and reduced fall in blood counts and need for blood transfusions. However, there was no effect on wound healing, need for repeat amputation surgery, or other complications following the surgery including death.
Certainty of the evidence
Because we found only one small study at high risk of bias in some areas, we have low confidence in the evidence for the use of tourniquets in people undergoing amputation.
Conclusions
When tourniquets are used during amputation in the setting of blocked arteries, they appear to reduce blood loss during surgery as well as the need for blood transfusion. However, the evidence comes from one small study, and further high-quality studies are needed to help doctors decide about the use of tourniquets in these patients.
This review identified only one small historical RCT evaluating tourniquet use in MLLA. Tourniquets appeared to reduce intraoperative blood loss, drop in haemoglobin, and blood transfusion requirements following transtibial amputations for people with PAD. However, it is unclear whether tourniquets affect wound healing, stump revision rates, postoperative complications, or mortality. High-certainty evidence is required to inform clinical decision-making for the use of tourniquets in these patients.
At least 7000 major lower limb amputations (MLLAs) are performed in the UK each year, 80% of which are due to peripheral arterial disease (PAD). Intraoperative blood loss can have a deleterious effect on patient outcomes, and its replacement with transfused blood is not without risk. Tourniquets can be used in lower limb surgical procedures to provide a bloodless surgical field, minimise intraoperative blood loss, and reduce perioperative blood transfusion requirements. Although their safety has been demonstrated in certain orthopaedic operations, their use among people with PAD undergoing MLLA remains controversial. Many clinicians are concerned about tourniquets potentially compromising perfusion of the stump and thereby impacting wound healing through direct tissue injury, damage to the arterial supply of the wound, or both.
To assess the safety and effectiveness of tourniquet use in people undergoing MLLA for complications of PAD, specifically with regard to intraoperative blood loss, change in haemoglobin levels, transfusion rates, wound healing, need for revision surgery, and postoperative complications including mortality.
We searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers from inception to 17 May 2022.
We included randomised controlled trials (RCTs) comparing tourniquet use to no tourniquet use among people with PAD undergoing MLLA.
We used standard Cochrane methods. Primary outcomes were intraoperative blood loss, fall in haemoglobin levels, and perioperative blood transfusion requirement. Secondary outcomes were primary wound-healing rates, stump revision rates, other postoperative complications defined as per Clavien‐Dindo classification, and postoperative mortality at 30 days and at maximal follow-up. We used GRADE to assess the certainty of evidence for each outcome.
One RCT met our inclusion criteria, which was a prospective randomised blinded controlled trial conducted in Sheffield, UK in 2006. In total 64 participants undergoing transtibial amputation for non-reconstructable PAD were randomised to either tourniquet or no tourniquet to assess for intraoperative blood loss, fall in haemoglobin, transfusion requirement, wound healing, stump breakdown and revision. Ten participants were excluded postrandomisation (five from the tourniquet group and five from the no tourniquet group). The reported median volume of intraoperative blood loss was significantly less in the tourniquet group (255 mL (interquartile range (IQR) 150 to 572.5 mL))) compared to the control group (550 mL (IQR 255 to 1050 mL)) (P = 0.014). There was a significantly lower median drop in haemoglobin concentration in the tourniquet group (1.0 g/dL (IQR 0.6 to 2.4 g/dL)) compared to the control group (1.8 g/dL (IRQ 0 to 1.2 g/dL)) (P = 0.035). There was a significantly lower perioperative blood transfusion requirement in the tourniquet group (8 participants, 32%) compared to the control group (14 participants, 48%) (P = 0.047). There were no clear differences in wound breakdown, stump revision, primary wound healing at six weeks, postoperative complications (myocardial infarction, cardiac arrhythmias, pulmonary oedema), and death between groups. We assessed the one included study as at low risk of bias for sequence generation and blinding of outcome assessors; high risk of bias for incomplete outcome data and selective outcome reporting; and unclear risk of bias for allocation concealment, blinding of participants and personnel, and other sources of bias. We assessed the certainty of the evidence as low or very low due to risk of bias, small sample size, and the study being insufficiently powered for most outcomes.