A systematic review of variability and reliability of manual and automated blood pressure readings

Aims and objectives: To compare the accuracy and appropriateness of auscultatory (manual) and oscillometric (automated) devices for measuring blood pressure in clinical settings.

Background: Accurate measurement of blood pressure is integral to early recognition of deterioration in the condition of a patient. Despite recommendations regarding the use of auscultatory devices in situations where treatment decisions are made dependent on blood readings, the use of automated machines is becoming common practice.

Design: Systematic review.

Methods: A search of the Medline, CINAHLPlus and The Cochrane Library databases was undertaken for papers published in English between January 1997-May 2009. Sixteen studies were identified that fulfilled the inclusion criteria. After quality assessment, all were included in the review. Results are presented in tabular and narrative form.

Results: In 10 of the studies reviewed, the authors came to the conclusion that oscillometric devices were less accurate than auscultatory devices. However, in most cases the oscillometric device appears sufficiently accurate for clinical use, the exceptions being use with hypertensive patients, patients with arrhythmia and after trauma. Only two studies assessed the comparative accuracy of aneroid devices, and these indicated that they were more accurate than oscillometric devices, but the differences were not clinically important.

Conclusions: There are situations where the substitution of oscillometric for auscultatory devices could have particularly serious repercussions for the patient, such as when the patient is either hypertensive or hypotensive. However, further research is required on the use of aneroid sphygmomanometers as a replacement for mercury devices.

Relevance to clinical practice: Practitioners should be made aware of the need to use auscultatory devices in specific circumstances, such as in management of hypertension, after the patient has experienced trauma or where there is significant potential for deterioration in the patient's condition.