Development and initial evaluation of novel tourniquet apparatus for improved safety through optimization of tourniquet inflation time

Abstract

Current clinical practice for reducing tourniquet inflation time by applying a cuff and only inflating it when necessary, can introduce a hazard of venous congestion if the cuff is applied tightly. Venous congestion is associated with risks such as limb swelling, excess blood loss, thrombosis, and hemorrhagic infiltration of nerves. Clinical feedback and results of a conducted survey indicate that venous congestion due to improper cuff application is common, and likely related to variations in training or experience of the applicator, cuff design, and the inaccurate and subjective methods for assessing proper cuff snugness. Therefore, a novel self-loosening tourniquet cuff was developed to reduce the risk of venous congestion by ensuring proper and consistent application snugness, facilitating the optimization of tourniquet time by enabling a cuff to be applied safely and remain uninflated until necessary. After development, a pilot clinical study was conducted to evaluate the cuff’s efficacy in reducing venous congestion caused by tight application when compared to a standard cuff and a no-cuff control. A published air plethysmography method was adapted to characterize changes in limb volume indicative of venous congestion in ten healthy subjects (5 male, 5 female; 36.4 ± 10.7 years). The no-cuff control showed no increase in plethysmography pressure above the baseline. The greatest pressures above the baseline were reduced by 20.98 ± 3.55mmHg (83.7%), when comparing the standard cuff (25.07 ± 3.41mmHg) to the self-loosening cuff (4.09 ± 1.00mmHg). Regardless of the cuff application tightness, the novel cuff significantly reduced the change in pressure (4.09mmHg) indicative of venous congestion, while achieving a consistent snugness (±1.00mmHg). These results indicate that the self-loosening tourniquet cuff can reduce the risk of venous congestion and improve cuff application consistency, enabling the optimization of tourniquet time by enabling a cuff to be applied and safely remain uninflated until needed.