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

Background: For a majority of patients undergoing anaesthesia for general surgery, mean arterial pressure (MAP) is only measured intermittently by arm cuff oscillometry (MAPiNIAP). In contrast, the Nexfin(®) device provides continuous non-invasive measurement of MAP (MAPcNIAP) using a finger cuff. We explored the agreement of MAPcNIAP and MAPiNIAP with the gold standard: continuous invasive MAP measurement by placement of a radial artery catheter (MAPinvasive).

Methods: In a total of 120 patients undergoing elective general surgery and clinically requiring MAPinvasive measurement, MAPiNIAP and MAPcNIAP were measured in a 30 min time period at an arbitrary moment during surgery with stable haemodynamics. MAPiNIAP was measured every 5 min.

Results: Data from 112 patients were analysed. Compared with MAPinvasive, modified Bland-Altman analysis revealed a bias (sd) of 2 (9) mm Hg for MAPcNIAP and -2 (12) mm Hg for MAPiNIAP. Percentage errors for MAPcNIAP and MAPiNIAP were 22% and 32%, respectively.

Conclusions: 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.

Clinical Trial Registration: NCT 01362335 (clinicaltrials.gov).