Introduction: No clear understanding exists about the course of a patient’s blood pressure (BP) during an emergency department (ED) visit. Prior investigations have demonstrated that BP can be reduced by removing patients from treatment areas or by placing patients supine and observing them for several hours. However, modern EDs are chaotic and noisy places where patients and their families wait for long periods in an unfamiliar environment. We sought to determine the stability of repeated BP measurements in the ED environment.

Methods: A prospective study was performed at an urban ED. Research assistants trained and certified in BP measurement obtained sequential manual BPs and heart rates on a convenience sample of 76 patients, beginning with the patient arrival in the ED. Patients were observed through their stay for up to 2 hours, and BP was measured at 10-minute intervals. Data analysis with SAS PROC MIXED (SAS Institute, Cary, North Carolina) for regression models with correlated data determined the shape of the curve as BP changed over time. Patients were grouped on the basis of their presenting BP as normal (less than 140/90), elevated (140–160/90–100), or severely elevated (greater than 160/100) for the regression analysis.

Results: A statistically significant downward trend in systolic and diastolic BP was observed only for those patients presenting with severely elevated BPs (ie, greater than 160/100).

Conclusion: We demonstrate a statistically significant decline in systolic and diastolic BP over time spent in the ED only for patients with severely elevated presenting BPs. [West J Emerg Med. 2011;12(4):421–425.]