Effect of Pneumatic Tourniquet on Muscle Oxygen Tension

Tourniquet use in upper limb surgery

Tourniquets are compressive devices that occlude venous and arterial blood flow to limbs and are commonly used in upper limb surgery. With the potential risk of complications, there is some debate as to whether tourniquets should continue to be routinely used. In this review, we first look at the different designs, principles, and practical considerations associated with the use of tourniquets in the upper limb. The modern pneumatic tourniquet has many design features that enhance its safety profile. Current literature suggests that the risk of tourniquet-related complications can be significantly reduced by selecting cuff inflation pressures based on the limb occlusion pressure, and by a better understanding of the actual level of pressure within the soft tissue, and the effects of cuff width and contour. The evidence behind tourniquet time, placement, and limb exsanguination is also discussed as well as special considerations in patients with diabetes mellitus, hypertension, vascular calcification, sickle cell disease and obesity. We also provide an evidence-based review of the variety of local and systemic complications that may arise from the use of upper limb tourniquets including pain, leakage, and nerve, muscle, and skin injuries. The evidence in the literature suggests that upper limb tourniquets are beneficial in promoting optimum surgical conditions and modern tourniquet use is associated with a low rate of adverse events. With the improvement in knowledge and technology, the incidence of adverse events should continue to decrease. We recommend the use of tourniquets in upper limb surgery where no contraindications exist.

The arterial tourniquet: pathophysiological consequences and anaesthetic implications

The arterial tourniquet is widely used in upper and lower extremity surgery and in intravenous regional anaesthesia. The local and systemic physiological effects and the anaesthetic implications are reviewed. Localised complications result from either tissue compression beneath the cuff or tissue ischaemia distal to the tourniquet. Systemic effects are related to the inflation or deflation of the tourniquet. Safe working guidelines for the application of an arterial tourniquet have not been clearly defined.

Surgical hemostasis by pneumatic ankle tourniquet during 3027 podiatric operations

A retrospective study was performed at the Denver Doctors Hospitals in which 3818 surgical cases on the foot and/or ankle were reviewed over a 4-year period from July 1986 through May 1990. From the 3027 ankle tourniquet cases reviewed, it was determined that pneumatic ankle tourniquets are safe and effective in providing hemostasis during foot surgery. There were five postoperative complications noted with ankle cuffs, with post-tourniquet syndrome being the most common (three cases). Over the 4-year period, ankle tourniquets failed a total of 50 times, a 1.8% failure rate (0.25% failure rate in the last 17 months). The most common pressure setting used for ankle cuffs was 325 mm. Hg (400 mm. Hg for thigh cuffs). Tourniquet ischemia lasted from 4 to 139 min.; the most common duration of ischemia noted for ankle tourniquets was 30 to 60 min. (60 to 90 min. for thigh tourniquets). A review of the potential complications associated with tourniquets, as well as safeguards, recommendations, and contraindications are presented.

Effects of prolonged tourniquet ischaemia and short-term venous stasis on plasma endothelin-1 levels in man

In vitro studies have indicated increased endothelial release of endothelin during tissue and cellular hypoxia. Therefore, we studied the effect of tourniquet ischaemia and venous stasis on plasma endothelin-1 (ET-1) levels in humans in vivo. The effect of hypoxia on plasma ET-1 levels in 16 patients subjected to an orthopaedic operation and six healthy volunteers was studied by (a) tourniquet ischaemia, in which a limb is totally emptied of blood and kept ischaemic by means of a pneumatic tourniquet, and (b) venous stasis in an upper arm. The mean (SEM) basal plasma ET-1 concentration in the patients subjected to tourniquet ischaemia of a lower limb was 4.1 (1.0) pg ml-1. No significant change in plasma ET-1 levels during or after tourniquet ischaemia was found. The mean (SEM) plasma ET-1 concentration in six healthy subjects prior to venous occlusion in the right upper arm was 3.3 (0.7) and 2.7 (0.3) pg ml-1 in the right and left arm, respectively. A significant increase in plasma ET-1 concentration after 20 min was observed in the arm subjected to venous stasis, but not in the other, control, arm. Mean arterial blood pressure did not change significantly. Local tissue hypoxia may not be an important stimulus for ET-1 release in humans in vivo, whereas short-term venous occlusion in an upper arm leads to local release of ET-1 by an as yet unknown mechanism.

The effect of tourniquet pressure on muscle function

The adverse effects of excessive tourniquet pressure on underlying muscle were studied using a cat model. A direct effect of the magnitude of tourniquet pressure on the degree of muscle disability was observed. The effect of direct pressure on the muscle may contribute to the postoperative weakness seen in the quadriceps muscle. Our data, in conjunction with the results of other studies that correlate certain tourniquet times and pressures with potential adverse effects, suggest that the selection of an appropriate tourniquet pressure and duration will minimize the development of clinically significant complications.

Isolated contracture of the abductor digiti minimi

A case of isolated contracture of an intrinsic hand muscle, the abductor digiti minimi, after the use of an upper extremity tourniquet is reported. Six cadaver specimens were studied after latex arterial injection. We present an anatomic study and pathomechanical analysis, along with a review of the literature on tourniquet-associated injuries.

Extracellular potassium concentration and membrane potential in rabbit gastrocnemius muscle during tourniquet ischemia

The relationship between the extracellular potassium concentration (K+ e.c.) and the resting membrane potential (MP) of the gastrocnemius muscle was studied in the anesthetized rabbit during a 3-h period of hindleg ischemia and a subsequent 1.5-h period of resumed flow. The K+ e.c. was measured on the skeletal muscle surface, using a potassium selective electrode. The MP was recorded with conventional microelectrodes. Small biopsies were taken and analysed for content of ATP and lactate. The lactate content increased fourfold during the ischemic period, but returned to normal values after reflow. No significant changes occurred in the ATP content during the period of the experiment. K+ e.c. increased from 3.6 +/- 0.2 to 16.1 +/- 0.7 mmol/l, and the MP decreased from -90.2 +/- 0.6 to -58.5 +/- 1.9 mV during the 3-h period of ischemia. After release of the tourniquet there was an initial rapid decrease in K+ e.c. to 7.8 +/- 0.9 mmol/l during the first 15 min of resumed flow, followed by a slower decrease. The MP increased linearly during the first hour of resumed flow and both variables returned to near normal values 1.5 h after releasing the tourniquet.

The effect of tourniquet ischaemia on intact, tenotomized and motor nerve injured human hand muscles

Ultrastructural examination of the intrinsic hand muscles was performed on young healthy patients undergoing reconstructive operation following tendon or nerve lesions. The muscle specimens were taken at the start and then every fifteen to twenty minutes until the end of the tourniquet ischaemia. The authors have not found any morphological alterations following the use of a tourniquet up to two hours in either the intact or previously injured muscles.