Validation of the Masimo O3™ regional oximetry device in pediatric patients undergoing cardiac surgery

We assessed the accuracy of Masimo O3 (TM) regional cerebral oxygen saturation (rSO(2)) readings by comparing them with reference values and evaluated the relationship between rSO(2) and somatic tissue oxygen saturation (StO(2)) in children undergoing cardiac surgery. After anesthesia induction, pediatric sensors were applied to the forehead and foot sole, and rSO(2) and StO(2) values were monitored continuously. Before cardiopulmonary bypass (CPB), F1O2 was set to 0.2, 0.5, and 0.8 serially every 15 min. After CPB, F1O2 was reversed. The reference values (SavO(2)) were calculated by combining arterial (SaO(2)) and central venous oxygen saturation (SavO(2)) readings from the arterial and central lines, respectively (0.7 x SaO(2) + 0.3 x SaO(2)). In total, 265 pairs of rSO(2)/StO(2) and SavO(2) from 49 patients were analyzed. The bias, standard deviation (SD), standard error (SE), and root mean squared error (RMSE) of rSO(2) were 2.6%, 4.5%, 0.3%, and 4.3%, respectively. The limits of agreement ranged from -6.3% to 11.6%. Trend accuracy analysis yielded a relative mean error of -1.4%, with an SD of 4.3%, SE of 0.2%, and RMSE of 3.9%. According to multiple linear regression analysis, the application of CPB, F1O2 , Hb level, and tip location of the central venous catheter influenced the bias (all P < 0.05). Furthermore, the correlation between rSO(2) and StO(2) was weak (r = 0.254). rSO(2) readings by the Masimo O3 (TM) device and pediatric sensor had good absolute and trending accuracies with respect to the calculated reference values in children undergoing cardiac surgery. rSO(2) and StO(2) cannot be used interchangeably.