ACCURACY OF OSCILLOMETRIC BLOOD-PRESSURE MONITORING IN PREGNANCY AND PREECLAMPSIA

Objective To assess the accuracy of the Omron HEM 705 CP oscillometric device for the measurement of blood pressure in pregnancy and pre-ecl ampsia. Setting Two teaching hospitals. Participants Eighty-five pregn ant women with a wide range of blood pressures, and 43 women with pree clampsia. Methods Evaluation was carried out according to the British Hypertension Society protocol, incorporating criteria of the Associati on for the Advancement of Medical Instrumentation (AAMI). Results Mean differences (device minus observer) for systolic blood pressure were -0.9 mmHg (SD 10) in normal pregnancy, and -2 mmHg (SD 10) in the wome n with pre-eclampsia. For diastolic blood pressure, Korotkoff phase V, the differences were -1.5 mmHg (SD 10), and -8 mmHg (SD 8) respective ly; i.e. the device consistently under-read the diastolic blood pressu re in pre-eclamptic women by a mean of 8 mmHg when compared with conve ntional sphygmomanometry. Korotkoff phase TV could not be accurately r eproduced. According to the British Hypertension Society grading crite ria, the device reached a 'B' grading in the 85 pregnant women. In pre -eclampsia only a 'C' grade was reached for systolic blood pressure, a nd 'D' grade for diastolic blood pressure. Accuracy criteria stipulate d by the AAMI were not met in any situation. Conclusion The Omron HEM 705 CP does not reach acceptable accuracy criteria for blood pressure measurement when compared with trained observers in women with pre-ecl ampsia, as judged by the British Hypertension Society Protocol. It als o failed to meet the AAMI criteria, although the methodology stipulate d by the AAMI may not be applicable to a pregnancy population.