Objective: To assess and develop an accurate blood pressure measurement device for use in low resource settings and by untrained staff, according to the World Health Organisation guidelines.
Methods: Ninety-nine adults were recruited to validate the device according to the International Protocol of the European Society of Hypertension. All participants provided written informed consent. Patients with an arrhythmia or unclear Korotkoff sounds were excluded. Nine sequential same-arm measurements were taken from each participant alternating between the test device and mercury sphygmomanometry. Differences between the test device and observers were evaluated according to the criteria of the International Protocol and the Association for the Advancement of Medical Instrumentation.
Results: The device failed the first assessment of the oscillometric function and required modification to both the deflation rate and the algorithm to fulfil the International Protocol criteria. It then achieved an acceptable mean difference of -0.7 (4.7) mmHg for systolic and -2.0 (4.6) mmHg for diastolic pressure (oscillometric function) and -1.9 (3.8) mmHg and -0.9 (3.3) mmHg for systolic and diastolic pressures, respectively (auscultatory function).
Conclusion: The Microlife 3AS1-2 is a semi-automated upper arm device with features consistent with low resource requirements. We successfully developed this device for accurate blood pressure measurement in adults according to the International Protocol, through adjustment of the deflation rate and algorithm. The accuracy and user-friendly design of this low-cost device makes it a highly valuable monitor in clinical practice, particularly in low resource settings and for use by untrained staff.