Abstract P491: Characterizing Agreement in Level of Inter-extremity Blood-Pressure Readings of Adults in the Emergency Department (CALIBRATE Study)

Abstract

Introduction: Inter-arm blood-pressure difference (IBPD) has been studied previously in multiple settings, but few reports are available from the Emergency department (ED) setting, where BP varies significantly due to acute medical conditions or stress from various factors. CALIBRATE aims to study the inter-arm blood pressure differences in the patients presenting to the ED in Qatar and to assess the IBPD distribution in this population. Methods: In sitting position, two consecutive BP measurements were obtained from the right and left arm for each participant using calibrated automated machines and appropriate cuff sizes. Considering the demographic mix of the population presenting to the ED, a 1:1 of male to female and 2:1 for GCC (Gulf Cooperation Council) to non-GCC recruitment strategy was predefined. The data were recorded using predefined data fields including patient demographics, past medical, social and family history. The continuous variables were reported as mean (SD) or median (IQR) based on the distribution of data. The data was analyzed using Stata MP 14.0 (College Station, Texas). Results: A total of 1800 patients were prospectively recruited from the ED. The mean age was 34 (10) years. The absolute systolic blood pressure (ΔSBP) difference between the right and left arm was same for the first (ΔSBP1) and the second reading (ΔSBP2), as 6 mmHg (3-10). The absolute average of ΔSBP1 and ΔSBP2 was 7 mmHg (4-10). The difference in SBP of less than 20 mmHg for IBP was seen in 95 th percentile of the population with single reading, whereas, with the average of two individual readings it was observed in 97 th percentile. No meaningful association could be detected between the significant IBPD and the study variables such as age, demographics, regions of interest and risk factors. Although, patients with diagnosed hypertension met the pre-defined criterion for significance, this difference was not clinically significant. There was no significant difference between IBPD noted for the Asia-pacific or Arab population. Conclusion: In population presenting to the ED, the IBPD of at least 20 mmHg reached at 95 th percentile validating the known significant difference. The utility of SBP difference can be improved further by taking the average of two individual readings.