Accuracy of non-invasive and minimally invasive hemodynamic monitoring: where do we stand?

One of the most important variables for patient assessment in the intensive care unit (ICU), hospital, or clinic is the ability to measure vital signs accurately. Among these vital signs, blood pressure and cardiac function serve as important markers of cardiovascular system, thus having reliable methods of measurement play a vital role. Blood pressure correlates directly with the cardiac and vascular function and it can be used to assess the cardiac output. Blood pressure fluctuations can lead to devastating outcomes if not controlled well. Hypotension has been linked to postoperative ischemic stroke, myocardial injury, and acute kidney injury (1,2). In a recent cohort study of intraoperative blood pressures, when the mean arterial blood pressure was less than 55 mmHg, even if for a short time, it was associated with development of acute kidney injury and myocardial injury (3). It has been demonstrated that mortality risk was increased by 1.036 times per minute of systolic blood pressure less than 80 mmHg (4). In a recent study by Mascha et al., researchers were able to show that variability in mean arterial pressure independent of time-weighted average of the mean arterial pressure, was associated with 30-day post-operative mortality in patients who underwent noncardiac surgery (5). Intraoperative systolic blood pressure variability in patients who underwent aortocoronary bypass surgery has been shown to result in increased 30-day postoperative mortality, which directly correlated with the amount of time per minute outside of the target blood pressure range (6). As a result, management of blood pressure is beneficial for increasing long term benefits and decreasing morality