RESUMO
We compared the ability of automated non-invasive intermittent oscillometric blood pressure monitoring with a new device, CNAP(TM) (continuous non-invasive arterial pressure) to provide a new blood pressure reading in each 1-min interval between spinal anaesthesia and delivery during caesarean section. We also compared the accuracy of continuous non-invasive arterial pressure readings with non-invasive blood pressure measurements before spinal anaesthesia. Fifty-nine women participated. The non-invasive and continuous non-invasive monitors displayed new blood pressure readings in a mean of 82% (11%) and 83% (13%) (p = 0.97) of the one-minute intervals between spinal anaesthesia and delivery, respectively. Continuous non-invasive arterial pressure was more likely to fail on two or more consecutive minutes (p=0.001). From the pre-spinal readings, the mean bias, defined as non-invasive-continuous non-invasive arterial pressure, and limits of agreement (±2SD mean bias) for systolic, diastolic and mean blood pressure respectively were +1.3 (±26.0), -2.9 (±21.8) and +2.6 (±20.4) mmHg. The new monitor has disadvantages compared with conventional non-invasive intermittent blood pressure monitoring.