Accuracy of radial arterial pressure measurement during surgery under controlled hypotension

Background: Radial arterial pressure underestimates the pressure in the aorta in several clinical situations. A central-to-radial pressure gradient was attributed to intense vasodilation. The aim of this study was to evaluate the accuracy of radial pressure monitoring during controlled hypotension achieved with profound arterial vasodilation. Methods: Ten patients with ASA physical status 1 and 11 undergoing maxillofacial surgery under general anesthesia were enrolled in this prospective study. Radial and femoral arteries were cannulated and connected to a pressure monitoring system. Controlled hypotension was achieved with an infusion of nicardipine titrated to maintain MAP between 50 and 60 mmHg. Simultaneous radial and femoral systolic, mean and diastolic arterial pressures were recorded before, during and after controlled hypotension. Results were expressed as mean +/- SD. Concomitant radial and femoral pressures were compared by a paired Student's test, P < 0.05 being significant. Results: In all, 150 sets of arterial pressures measurement were obtained. There were no statistically significant differences between radial and femoral arterial pressures measured before, during or after controlled hypotension. Conclusion: Radial arterial pressure is an accurate measure of central arterial pressure during controlled hypotension achieved with arterial vasodflation.