Non-invasive oscillometric versus invasive arterial blood pressure measurements in critically ill patients: A post hoc analysis of a prospective observational study

Purpose: The aimwas to compare non-invasive blood pressuremeasurementswith invasive blood pressure measurements in critically ill patients. Methods: Non-invasive blood pressure was measured via automated brachial cuff oscillometry, and simultaneously the radial arterial catheter-derived measurement was recorded as part of a prospective observational study. Measurements of systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) were compared using Bland-Altman and error grid analyses. Results: Paired measurements of blood pressurewere available for 736 patients. Observedmean difference (+/- SD, 95% limits of agreement) between oscillometrically and invasively measured blood pressure was 0.8 mmHg (+/- 15.7 mmHg, -30.2 to 31.7 mmHg) for SAP, -2.9 mmHg (+/- 11.0 mmHg, -24.5 to 18.6 mmHg) for DAP, and -1.0 mmHg (+/- 10.2 mmHg, -21.0 to 18.9 mmHg) for MAP. Error grid analysis showed that the proportions of measurements in risk zones A to E were 78.3%, 20.7%, 1.0%, 0%, and 0.1% for MAP. Conclusion: Non-invasive blood pressure measurements using brachial cuff oscillometry showed large limits of agreement compared to invasivemeasurements in critically ill patients. Error grid analysis showed that measurement differences between oscillometry and the arterial catheter would potentially have triggered at least lowrisk treatment decisions in one in five patients. (c) 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).