Accuracy of plethysmography derived blood pressure -A prospective observational study

The initial appearance of the plethysmograph waveform can serve as an early indicator of systolic blood pressure (SBP) when a non-invasive blood pressure (NIBP) cuff is deflated after being inflated beyond the point of detectable pulsatile blood flow in the downstream limb, provided both the pulse oximeter and the NIBP cuff are applied on the same limb. This approach can be helpful for quickly estimating SBP even before it is formally displayed on the monitor. In the operating room, several factors particularly motion artifacts such as shivering, patient movement, or positional changes can affect the accuracy of the final NIBP reading. Therefore, the reappearance of the plethysmograph waveform on the pulse oximeter, when both devices are used on the same limb, can provide a rapid and practical indication of blood pressure, especially in situations requiring prompt clinical response. This study aims to assess the accuracy of measuring systolic BP by correlating it with the NIBP cuff pressure at the moment the plethysmograph waveform reappears on the pulse oximeter.