Evaluating Tourniquet Efficacy Comparing Exsanguination Techniques for the Upper Extremity.

Tourniquets have been used in the medical setting for centuries and have become the gold standard when preparing patients for surgery, particularly in orthopaedic surgery. Upper extremity tourniquet use improves intraoperative visibility and identification of anatomy. It also decreases blood loss intraoperatively and improves the safety of orthopaedic procedures. Despite the widespread use of tourniquets and differing methods of limb exsanguination, little research has been done quantifying its efficacy. The purpose of this study was to compare gravity exsanguination to Esmarch exsanguination of the upper extremity prior to tourniquet inflation in a large patient sample. A plethysmographic method based on water displacement served as a surrogate for the blood volume exsanguinated. Control measurements of water displacement were obtained from both upper extremities without tourniquet inflation. Water displacement was then measured with both gravity and Esmarch exsanguination techniques. Gender, handedness, height, weight, body mass index, and age were recorded for volunteers and used as covariates. Change in mean water displacement from control (un-exsanguinated) arm and gravity alone measurement was 37.2 ml. Change in mean water displacement between control arm and mean Esmarch measurement was 56.3 ml. Exsanguination using Esmarch compared to gravity alone resulted in a 51.2% increase in blood removal. Only age had a significant interaction effect for the Esmarch method. Analysis revealed that age accounted for 21.4% of all variance in blood exsanguinated using the Esmarch method when compared to the control group. The Esmarch technique was more efficacious for all demographics measured, but most efficacious in subjects who were older than 40 years. This data reaffirms that gravity exsanguination is more efficacious than no tourniquet use at all, and that the Esmarch technique is more efficacious than gravity. To our knowledge, this study is the most robust of its kind to critically and objectively compare upper extremity exsanguination methods and overall tourniquet use by age and supports the common practice of Esmarch exsanguination in orthopaedic extremity surgery.