Tight application of a surgical tourniquet prior to inflation increases venous pressure in the upper limb; Potentially resulting in increased blood loss and poorer visibility.

Background: Tourniquets are commonly used in extremity surgery to help provide a bloodless operative field to improve visibility and reduce length of procedures. With the development of WALANT (wide awake, local anaesthetic, no tourniquet) techniques, many surgeons undertake surgery without tourniquet inflation. The correct technique of pneumatic tourniquet application is poorly understood by healthcare staff. The application of a tight tourniquet when applied for optional use or use for only a portion of a procedure, rather than for inflation throughout can cause venous engorgement of an extremity leading to increased blood loss and reduced operative field visualisation thereby discouraging surgeons from persevering with WALANT strategies.

Aim: To determine the effect of tourniquet application tension on limb volume prior to skin incision.

Methods: 30 volunteers had the volume of their non-dominant forearm measured post-inflation of a surgical tourniquet using two different application techniques. Tight application was defined as the tourniquet fastened using a dynamometer to a tension of 100 N. Loose application was defined as the tourniquet fastened using a dynamometer to a tension of 50 N. The tourniquet was then inflated to 200 mmHg after both application techniques. Exsanguination was performed by elevation of the arm for 1 min prior to tourniquet inflation. At 5 min the forearm volume was measured using a volume displacement technique.

Results: 93 % of participants (28/30) had a higher volume of water displaced when the tourniquet was applied tightly. The mean difference between the loose and tight applications was 30.06 mls.

Conclusion: The increase in volume in tightly applied tourniquets is believed to result from increased intravascular volume. This increase in blood volume can lead to increased intra-operative blood loss and poor intra-operative visualisation when operating without tourniquet inflation. Loose application of the tourniquet pre-inflation appears to prevent sequestration of venous blood in the limb, therefore decreasing operative blood loss and improving view for operating.

Level of evidence: Level 1; Symptom Prevalence Study.