It's time to regulate - The importance of accurate surgical-grade tourniquet autoregulation in blood flow restriction exercise applications

Objective: Evaluate the efficacy of five common blood flow restriction (BFR) systems to accurately maintain and autoregulate BFR pressure in the tourniquet cuff near target pressure throughout exercise. Design: Randomised crossover design. Setting: Laboratory. Participants: 15 healthy individuals. Outcome measures: 1) Percentage of total BFR time that surgical -grade tourniquet autoregulation, defined as automatic and rapid self -regulation of cuff pressure to within +/- 15 mmHg of initial target pressure within 1 s in the presence of transient pressure changes associated with exercise, was provided; 2) pressure change in the BFR cuff throughout exercise, by comparing the initial target pressure to the measured pressure at completion of BFR exercise. Results: One BFR system could provide surgical -grade tourniquet autoregulation for the whole duration (100 +/- 0%) of the BFR exercise in all subjects. In two of the five BFR systems evaluated, measured cuff pressure at the end of exercise was not different (p < 0.05) to the initial target pressure. Conclusions: Surgical -grade tourniquet autoregulation is important to consistently and reliably apply a targeted BFR pressure stimulus. This may allow BFR methodology and protocols to be accurately implemented and controlled so that the results can be more meaningfully compared, leading to the potential optimization of applications.