Accuracy and clinical performance of a continuous intra-arterial blood-gas monitoring system during thoracoscopic surgery

Accuracy and performance of the only currently available intra-arterial blood-gas monitoring system (Paratrend 7, PT7) were assessed in 23 patients during thoracoscopic surgery using one-lung ventilation. Over a wide range of values for arterial Po-2 (6.1-61.1 kPa), Pco(2) (4.1-9.5 kPa) and pH (7.19-7.50), 138 arterial blood-gas values obtained by PT7 were compared with corresponding in vitro laboratory blood-gas measurements. We found good clinical performance with the PT7 and good agreement between PT7 values and in vitro measurements for arterial Po-2 (bias (1.96 SD)=0.38 (9.52) kPa), Pco(2) (0.31 (0.76) kPa) and pH (-0.017 (0.065)). Also, the bias for sequential changes between two consecutive times was not significantly different from the ideal value of 0. We conclude that the PT7 is helpful in monitoring patients during thoracoscopy.