Serum myoglobin following tourniquet release under anaesthesia.

Serum myoglobin concentrations were studied in 34 patients during tendon and nerve reconstruction operations that required the application of a pneumatic limb tourniquet. Seventeen patients received general anaesthesia without the use of suxamethonium, while the remaining 17 were given suxamethonium as part of the anaesthetic technique. Tourniquet times of up to 2.5 h were associated with negligible myoglobin release, but the use of suxamethonium administration resulted in a rise of serum myoglobin in some subjects, reaching a maximum of 300 micrograms litre-1 20-40 min after induction. No rise in serum myoglobin occurred in any patient following deflation of the tourniquet. Three of the four patients who required a re-application of the tourniquet (after a short reperfusion time) had rises of serum myoglobin up to 120 micrograms litre-1 following the second deflation. Pneumatic tourniquets appear to cause no detectable ischaemic damage for up to 2.5 h, with or without prior use of suxamethonium. Re-application after only a short period of reperfusion may be inadvisable.