(A74) Reducing the Potential for Tourniquet Associated Reperfusion Injury

Abstract

Background

Tourniquets have reappeared in the management of massive hemorrhage and as a tool to ameliorate the effects of reperfusion injury from limb entrapment or suspension trauma, while the patient is rescued to a safer environment. Strategies to minimize subsequent reperfusion injury were investigated in this prospective, randomized study.

Methods

In the safety of an operating theater, sixteen fit and healthy patients scheduled for repair of bimalleolar ankle fractures were randomized into two groups. In the standard release group (R, n1 = 6), the tourniquet was fully deflated at the end of surgery. In the staggered release group (SR, n2 = 10), the tourniquet was fully deflated for 30 seconds and subsequently re-inflated to 300mmHg. The procedure was repeated twice at three-minute intervals prior to full removal. Hemodynamic and blood biochemistry measurements were obtained from an indwelling arterial catheter immediately prior to initial tourniquet deflation and thereafter at 1, 4, 7 and 15 minutes.

Results

Serum Ca2 + concentrations were less in group R at 4 (1.027 ± 0.5 vs. 1.084 ± 0.07mmol/l, p = 0.046) and 7 minutes (1.045 ± 0.04 vs. 1.110 + /- 0.06mmol/l, p = 0.013). Serum lactate concentration was greater in group R compared to group SR at 1 (1.75 ± 0.19 vs. 1.33 ± 0.31mmol/l, p = 0.005) and 4 minutes (1.98 ± 0.23 vs. 1.48 ± 0.39mmol/l, p = 0.007), respectively. End-tidal CO2 was less in group SR compared to group R at 1 (4.82 ± 0.45 vs. 5.68 ± 0.26kPa, p = 0.0004) and 4 minutes (5.01 ± 0.59 vs. 5.68 ± 0.35kPa, p = 0.01), respectively. At 15 minutes, less hypotension and bradycardia was noted in group SR.

Conclusions

A staggered tourniquet release was associated with greater hemodynamic stability and reduced the rate of acute systemic metabolic changes associated with limb reperfusion. Re-application of a tourniquet seemed to halt further reperfusion, providing a window period for patient evaluation and management.