Influence of arrhythmias on accuracy of non-invasive blood pressure monitors.

PURPOSE

To compare the accuracy of non-invasive blood pressure (NIBP) monitors in response to common cardiac arrhythmias.

METHODS

Simulated signals of normal sinus rhythm (NSR), premature ventricular contractions (PVCs), atrial fibrillation (AF) and missed beats (MB) were generated from a Cufflink (Dynatech Nevada) NIBP simulator. Using these signals, the Critikon 1846SX (C1846), Critikon 845xt (C845). Critikon Vital Signs (CVIT), and Hewlett Packard M1008a (HP1008) were studied at a standard dynamic blood pressure of 120/90/80 mmHg, in order to compare monitor accuracy and signal response times.

RESULTS

The C845 monitors most closely estimated a simulated SBP of 120 mmHg, although SBP was greater during PVCs and AF than NSR (P < 0.05). The Critikon 1846, Critikon Vital Signs, and Hewlett Packard systematically underestimated SBP during these arrhythmias, but variability was modest, as reflected by small coefficients of variation (< 2% for SBP) with all monitor types. In general, MAP and DBP were less sensitive to the effects of these arrhythmias. Finally, missed beats prolonged signal response times with all four monitor types (P < 0.05), whereas PVCs and AF did not alter this parameter.

CONCLUSIONS

This study demonstrates the extent to which the accuracy of NIBP monitors is altered by common cardiac arrhythmias. Differences in the electromechanical characteristics of these devices may help to explain the observed similarities and discrepancies.