How important is the recommended slow cuff pressure deflation rate for blood pressure measurement?

Cuff pressure deflation rate influences blood pressure (BP) measurement. However, there is little quantitative clinical evidence on its effect. Oscillometric pulses recorded from 75 subjects at the recommended deflation rate of 2-3 mmHg per second were analyzed. Some pulses were removed to realize six faster rates (2-7 times faster than the original). Systolic, diastolic, and mean arterial blood pressures (SBP, DBP, MAP) were determined from the original and six reconstructed oscillometric waveforms. Manual measurement was based on the appearance of oscillometric pulse peaks, and automatic measurement on two model envelopes (linear and polynomial) fitted to the sequence of oscillometric pulse amplitudes. The effects of deflation rate on BP determination and within-subject BP variability were analyzed. For SBP and DBP determined from the manual measurement, different deflation rates resulted in significant changes (both p < 0.001). However, for SBP, DBP, and MAP determined from the automatic linear and polynomial model techniques, there was no deflation rate effect (all p > 0.3). Faster deflation increased the within-subject BP variability (all p < 0.001). In conclusion, for the manual technique accurate BP measurement could be achieved only with the recommended slow deflation rate, and for the automatic model-based techniques, the deflation rate had little effect.