Interventions to reduce tourniquet-related ischaemic damage in orthopaedic surgery: a qualitative systematic review of randomised trials.

Ischaemia of the extremity from the use of a tourniquet and the subsequent reperfusion contribute to the release of reactive oxygen species. This release may result in injury to remote organs. We performed a qualitative systematic review exploring the interventions used to prevent tourniquet-related oxidative damage in adults undergoing orthopaedic surgery, and the possible relationship between biochemical oxidative stress markers and postoperative clinical outcomes. Seventeen randomised controlled studies were included in the qualitative synthesis. Most trials were of low methodological quality and only two studies reported postoperative clinical outcomes. Nine studies tested anaesthetics (propofol, dexmedetomidine, ketamine, and spinal anaesthesia); four studies tested antioxidants (N-acetyl-cysteine, vitamin C, and mannitol); and four studies tested ischaemic pre-conditioning. Fifteen studies showed a significant reduction in biochemical oxidative stress markers. We conclude that propofol and ischaemic pre-conditioning, in particular, appear to show some benefit at reducing oxidative stress following operations under tourniquet; the correlation between a reduction in oxidative stress and postoperative clinical outcomes should be further investigated in the future.