Blood pressure determination by traditionally trained personnel is less reliable and tends to underestimate the severity of moderate to severe hypertension.

OBJECTIVE: Blood pressure determined by nurses has been observed to be unreliable. This study was conducted to compare the reliability of blood pressure measurements performed by traditionally trained nurses with those performed by a well-trained nurse and by an automatic device.
METHODS: Hypertensive patients in an outpatient clinic were studied. Each individual was subjected to three blood pressure measurements: the first one was performed by the traditionally trained nurse on duty at the time of study (TT nurse BP), the second one by a specifically trained nurse (ST nurse BP), both using sphygmomanometer; and the third one was done using Omron HEM-907 (digital BP).
RESULTS: A total of 907 participants were enrolled. More than 99% of both systolic and diastolic TT nurse BP ended with zero, demonstrating that they had terminal digit preference. ST nurse BP was in better agreement with digital blood pressure measurement than with TT nurse BP. The number of differences of < or =5 mmHg between ST nurse BP and digital blood pressure measurement was approximately 60% for both systolic and diastolic blood pressure. Overall, traditionally trained nurses overestimated, rather than underestimated, blood pressure. However, systolic blood pressure underestimation was extremely prominent in participants with moderate to severe hypertension. Systolic blood pressure underestimation of >5 mmHg was as high as 57.5% by traditionally trained nurses versus 33.8% by the automatic device, indicating that traditionally trained nurses tended to underestimate blood pressure in participants with more severe hypertension.