Non-invasive blood pressure monitoring with an oscillometric brachial cuff: impact of arrhythmia.

Arrhythmia-induced beat-to-beat variability of blood pressure (BP) is deemed to hinder the reliability of non-invasive oscillometric measurements (NIBP) but few data support this belief. We assessed the impact of arrhythmia on a NIBP device never tested for this purpose. We compared, in intensive care unit patients with and without arrhythmia, the agreement between three pairs of NIBP (Infinity™ Delta monitor, Dräger medical systems) and invasive readings. For systolic, diastolic and mean BP, the mean bias between NIBP and invasive measurements was not higher, in 89 patients with arrhythmia, than that observed in 127 patients with regular rhythm (p = 0.93 for mean BP). Averaging three measurements overcame the higher within-subject variability of NIBP measurements during arrhythmia, and yielded similar agreement between the two techniques in patients with arrhythmia and with regular rhythm. The international organization for standardization criteria (mean bias < 5 and SD < 8 mmHg) were satisfied neither during arrhythmia nor during regular rhythm: for mean BP, mean bias of - 8.0 ± 6.5 and - 7.5 ± 6.1 mmHg, respectively. The detection of hypotension (systolic invasive BP < 90 mmHg or mean invasive BP < 65 mmHg) or hypertension (systolic invasive BP > 140 mmHg) by NIBP was similar during arrhythmia and regular rhythm [areas under the receiver operating characteristic curves (AUCROC) of 0.88-0.92, p > 0.13]. The detection of a 10% increase in mean invasive BP after cardiovascular intervention was also associated with similar AUCROCs between the two groups. Provided that triplicates are averaged, the agreement between NIBP measured with the tested device and invasive measurements was not worse during arrhythmia than during regular rhythm.

Blood pressure monitoring during arrhythmia: agreement between automated brachial cuff and intra-arterial measurements.

BACKGROUND: Since arrhythmia induces irregular pulse waves, it is widely considered to cause flawed oscillometric brachial cuff measurements of blood pressure (BP). However, strong data are lacking. We assessed whether the agreement of oscillometric measurements with intra-arterial measurements is worse during arrhythmia than during regular rhythm. METHODS: Among patients of three intensive care units (ICUs), a prospective comparison of three pairs of intra-arterial and oscillometric BP readings was performed among patients with arrhythmia and an arterial line already present. After each inclusion in the arrhythmia group, one patient with regular rhythm was included as a control. International Organization for Standardization (ISO) standard validation required a mean bias <5 (sd 8) mm Hg. RESULTS: In 135 patients with arrhythmia, the agreement between oscillometric and intra-arterial measurements of systolic, diastolic and mean BP was similar to that observed in 136 patients with regular rhythm: for mean BP, similar mean bias [-0.1 (sd 5.2) and 1.9 (sd 5.9) mm Hg]. In both groups, the ISO standard was satisfied for mean and diastolic BP, but not for systolic BP (sd >10 mm Hg) in our ICU population. The ability of oscillometry to detect hypotension (systolic BP <90 mm Hg or mean BP <65 mm Hg), response to therapy (>10% increase in mean BP after cardiovascular intervention) and hypertension (systolic BP >140 mm Hg) was good and similar during arrhythmia and regular rhythm (respective areas under the receiver operating characteristic curves ranging from 0.89 to 0.96, arrhythmia vs regular rhythm between-group comparisons all associated with P>0.3). CONCLUSIONS: Contrary to widespread belief, arrhythmia did not cause flawed automated brachial cuff measurements.