Validity, tolerability, and feasibility of automated arterial occlusion pressure across body positions

Objective To evaluate the validity, safety, and feasibility of automated algorithm-based arterial occlusion pressure (AOP) measurement compared to pulsed wave Doppler ultrasound across supine, seated, and standing positions.Approach This two-phase sequential study enrolled healthy adults. In Phase One (n=46), AOP was measured using both automated and Doppler ultrasound methods at three body positions in randomized order. Validity was assessed using intraclass correlation coefficients (ICC), Bland-Altman analysis, and proportional bias testing. Safety was evaluated through measurement duration and pain perception. Feasibility was assessed by the first-attempt success rate. In Phase Two (n=15), a post hoc study examined whether averaging two automated measurements improved accuracy in supine position.Main results Automated algorithm-based AOP measurement demonstrated good agreement withDoppler ultrasound in supine (ICC=0.76), seated (ICC=0.87), and standing (ICC=0.83) positions. However, 95% limits of agreement ranged from -38 to +48 mmHg across positions. A significant negative proportional bias was observed in supine (p=0.031), indicating underestimation at higher AOP values. Automated measurements required significantly longer duration than Doppler across all positions (p<0.001). Pain perception was comparable between methods. First-attempt success rate was significantly lower for automated measurement in standing compared to Doppler method (87% vs. 100%, p=0.041). In Phase Two, 73% of participants demonstrated improved accuracy when averaging two automated measurements.Significance Automated algorithm-based arterial occlusion pressure (AOP) assessment demonstrates acceptable validity and safety when performed in seated and standing positions, supporting its use for individualized pressure prescription in these postures. However, clinicians and practitioners should exercise caution when determining AOP in the supine position, as proportional bias and reduced agreement with Doppler ultrasound may result in underestimation at higher AOP values. When measuring AOP in standing positions, providing external support (e.g., upper limb support on a stable surface) to reduce lower limb muscle activation may improve first-attempt success rates.