Pneumatic tourniquet versus no tourniquet in transfemoral amputation - a study protocol for a randomized controlled trial

Background: Lower extremity amputation patients represent a frail group with extensive comorbidity. Transfemoral amputation is a high-risk procedure with 37-50% risk of mortality in the first year. Substantial blood loss during surgery increases the risk of anemic complications and death for these already weakened patients. The use of tourniquet during surgery may reduce blood loss, the need for blood transfusions, the related complications as well as the length of the surgery. However the use of tourniquet may be related to impaired wound healing and hence the use should be investigated in a randomized controlled trial. The primary aim of this study is to investigate the total blood loss and secondary to investigate differences in complications after transfemoral amputation between patients operated with or without tourniquet. Methods: The total blood loss is calculated using Nadlers approach. Based on data from a pilot series, the sample size was calculated to 124, allocated 1:1 in two groups of 62 participants to ensure detection of at least 200 mL difference in the total blood loss. The primary outcome is the total blood loss. Secondary outcomes are blood transfusions, duration of surgery, length of hospital stay and risk of complications within 90 days (re-admissions, re-operations and mortality). Explorative outcomes are 1 year mortality and re-operation risk. Further explorative outcomes are postoperative quality of life (questionnaire EQ-5D-5L) and evaluation of number of prosthesis users including evaluation of prosthesis-specific function measured 3, 6, and 12 months postoperatively. Discussion: The possibility to enhance patient safety is highly relevant and this trial will provide data for evidence based recommendations of best practice in amputation surgery.