Validation of oscillometric blood pressure measuring devices : a case study of the BpTRUtm

Hypertension is one of the most common reasons why North Americans visit a physician's office and its measurement technique has been reasonably standard since the earliest accepted description of an indirect method of measuring blood pressure by Riva Rocci in 1896. Korotkoff later modified the traditional sphygmomanometer in 1905. However, since then the mercury sphygmomanometer has become not only the gold standard, but also an essential diagnostic tool in everyday medical care. Recently however, there has been growing concern over the accuracy of the measurements obtained and the potential biohazard with standard mercury sphygmomanometers. Many cities and countries in Europe and North America, are in the process of phasing them out. Newer instruments such as the auscultatory aneroid, and the automated electronic devices of which the majority are of the oscillometric type, are beginning to appear. All new devices have the option of undergoing a validation process to assess the accuracy according to the relevant governing bodies. The BpTRU™ is an automated oscillometric electronic blood pressure device developed by VSM Medtech Ltd of Vancouver. Connected in parallel by means of a T-tube, to the current gold standard mercury sphygmomanometer, allowed blood pressures to be measured simultaneously. Two observers blinded from each other and the device, recorded blood pressures individually. The mean observer average was compared to the device mean blood pressures for agreement. This was done according to the American National Standard for Electronic or Automated Sphygmomanometers-1992 and the British Hypertension Society protocol-1993. The validation process was initially conducted in adults and agreement was within the above standards. However the device tended to underestimate at higher systolic blood pressures, so the algorithm was modified and the device re-validated using embedded raw data. After running the validation study in children, which again satisfied the above criteria, the raw data was combined in a final study. The BpTRU™ is the only automated blood pressure measuring device that has been independently validated and has attained a high level of accuracy over this broad age and blood pressure range.Medicine, Faculty ofAnesthesiology, Pharmacology and Therapeutics, Department ofGraduat