From Korotkoff and Marey to automatic non-invasive oscillometric blood pressure measurement: does easiness come with reliability?

Abstract

The auscultatory technique remains the point of reference for the validation of non-invasive blood pressure measurement devices, although the exact origin of the Korotkoff sounds is still debated and comparison with intra-arterial measurement shows limits and pitfalls. Automatic oscillometric devices are now widely used by nurses, physicians, and patients. However, many available devices have not been duly validated. Moreover, they calculate systolic and diastolic blood pressures using undisclosed algorithms. Therefore, these devices are not interchangeable, and their reliability may be questionable in some clinical situations. Nevertheless, oscillometry is increasingly used, beside NIBP, for the assessment of central blood pressure and systemic arterial wall stiffness. Awareness of its limits and causes of error is all the more necessary.

Perioperative Quality Initiative consensus statement on the physiology of arterial blood pressure control in perioperative medicine

“…The pressure level at which the rate of increase is maximal defines MAP; a proprietary algorithm uses this value to estimate systolic and diastolic blood pressure. 45 Absolute arterial pressure, differences in arterial pressure between left and right arms, variability between different devices/manufacturers, cuff size, posture, environment, and ambient temperature may all adversely affect accuracy. 45 Failing to take these limitations into account may lead to iatrogenic harm when single or intermittent measurements shape clinical decisions.…”

A convenient method to verify the accuracy of oscillometric blood pressure monitors by the auscultatory method: A smartphone‐based app

“…Although most oscillometric devices show good agreement with reference to the auscultatory method based on Korotkoff sounds in a vast majority of cases, agreement is remarkably poor in some cases and seems to be related to the shape of the oscillometric waveform . The reliability of oscillometric blood pressure measurement is especially questionable in pregnant women, children, and the elderly and may also be questioned in some clinical situations, especially when BP is either very low or very high, when patients have increased arterial wall stiffness, or when there is an arrhythmia…”

Blood pressure measurement by oscillometric and auscultatory methods in normotensive pregnant women

“…Despite the increasing availability of automatic devices to measure BP by patients and professionals and the increased number of validated devices, many researchers are concerned about their indiscriminate use (15)(16)(17) .…”

“…Oscillometric devices may perform unreliable BP measurements when used in special groups (diabetic, pregnant, elderly, and arrhythmia patients), since the oscillometric waveform does not present a pattern in all population groups, and may be affected by age and arterial compliance. Therefore, oscillometric devices must be validated independently (11,15) .…”