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

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.