Need for Re-validation of Automated Blood Pressure Devices for use in Unstable Conditions

The current validation of non-invasive blood pressure (NIBP) device is performed under resting conditon. However, NIBPs are often used without giving much consideration about the measurement conditions. This study aimed to provide scientific data on the use of BP devices in unstable conditions. BP measurements were performed on 20 healthy subjects under both resting and regular deep breathing conditions. During the measurement the oscillometric cuff pressure waveforms were recorded digitally. They were then regenerated by a specially designed BP simulator and presented to two clinically validated hospital grade automatic NIBP devices to obtain automated BPs. Automated BPs obtained from the two conditions were finally compared between the two devices. Under resting condition, there was no significant difference in both automated SBP and DBP between the two devices. However, under regular deep breathing condition, significant SBP and DBP differences were observed between the two devices ( both P<0.01; mean +/- SD: 118.8 +/- 10.6 vs 115.1 +/- 11.6 mmHg for SBP; 68.5 +/- 8.6 vs 65.3 +/- 8.9 mmHg for DBP). For the effect of deep breathing on BP measurement, significant SBP decrease was observed only from device 2 (P<0.05, with a mean difference +/- SD of 3.8 +/- 6.2 mmHg), indicating inconsistent measurements between the two devices under unstable conditions. Our results provide scientific evidence that automated BP devices can be used only under the condition for which the validation was performed.