Comparison of continuous non-invasive finger arterial pressure monitoring with conventional intermittent automated arm arterial pressure measurement in patients under general anaesthesia

Abstract

For a majority of patients undergoing anaesthesia for general surgery, mean arterial pressure (MAP) is only measured intermittently by arm cuff oscillometry (MAP_iNIAP). In contrast, the Nexfin^® device provides continuous non-invasive measurement of MAP (MAP_cNIAP) using a finger cuff. We explored the agreement of MAP_cNIAP and MAP_iNIAP with the gold standard: continuous invasive MAP measurement by placement of a radial artery catheter (MAP_invasive). In a total of 120 patients undergoing elective general surgery and clinically requiring MAP_invasive measurement, MAP_iNIAP and MAP_cNIAP were measured in a 30 min time period at an arbitrary moment during surgery with stable haemodynamics. MAP_iNIAP was measured every 5 min. Data from 112 patients were analysed. Compared with MAP_invasive, modified Bland–Altman analysis revealed a bias (sd) of 2 (9) mm Hg for MAP_cNIAP and −2 (12) mm Hg for MAP_iNIAP. Percentage errors for MAP_cNIAP and MAP_iNIAP were 22% and 32%, respectively. In a haemodynamically stable phase in patients undergoing general anaesthesia, the agreement with invasive MAP of continuous non-invasive measurement using a finger cuff was not inferior to the agreement of intermittent arm cuff oscillometry. Continuous measurements using a finger cuff can interchangeably be used as an alternative for intermittent arm cuff oscillometry in haemodynamically stable patients, with the advantage of beat-to-beat haemodynamic monitoring. NCT 01362335 (clinicaltrials.gov).