Blood Pressure Response To The Presence Of A Physician During Blood Pressure Measurement

Objective: Automated blood pressure (BP) measurement has attracted attention since the SPRINT study had been published. It can be measured either with (attended) or without the presence of the staff (unattended). Although it is well known that attended measurements are higher, studies that quantify the effect in well defined conditions are scarce. Design and method: We performed a study on 38 stable treated hypertensive subjects, mean age 66.5 ± 8.1 years, 45% males. Two sets of BP measurement, attended and unattended, were done with the Omron 907 device in a random order; each set consisted of three measurements separated by a one-minute interval. During attended BP measurements, a physician unknown to the patient was present. The physician was either in close (n = 22) or loose (n = 16) contact with the subject. During the close contact, the physician placed the stethoscope to the cubita as if he measured BP with auscultatory method so that the distance from the patient was standardized but all the measurements were oscillometric. With the loose contact, the physician was sitting in the room at a two-meter distance from the patient. Results: Means of three BP attended and unattended measurements were 129.3/73.5 mm Hg and 123.7/70.3 mm Hg, respectively, difference: 6.1 ± 7.6/3.2 ± 5.1 mm Hg, p < 0.0004. The difference was higher with close contact (8.2/4.3 mm Hg, p = 0.0023) than with loose contact (3.2/1.7, p = 0.16). Predictors of BP increase during attended measurements were studied in a multivariate linear regression. While no factor was associated with systolic BP increase, diastolic BP increase was positively related to smoking (p = 0,028) and negatively to the room temperature (p = 0,018). Conclusions: Our study shows that circumstances under which BP is measured are crucial even in the subjects treated for hypertension for a long time. The BP reaction is higher when the physician is close to the patient, imitating auscultatory measurement.