Pulse oximetry and finger blood pressure measurement during open-heart surgery

Pulse oximeter arterial hemoglobin oxygen saturation (SpO2) and finger arterial pressure (FINAP) were continuously monitored before, during, and after cardiopulmonary bypass in 15 male patients. SpO2 was monitored simultaneously with two pulse oximeters, a Nellcor N-100 and an Ohmeda Biox III. The readings obtained from the two pulse oximeters were compared with arterial blood measurements obtained using a CO-oximeter. FINAP was monitored by a prototype device (Finapres) based on the Penaz volume-clamp method. FINAP was correlated with intraarterial pressure (IAP). Both pulse oximeters functioned well before cardiopulmonary bypass. The correlations with CO-oximeter values were 0.927 for the N-100 and 0.921 for the Biox III. Immediately after the onset of cardiopulmonary bypass, the N-100 pulse oximeter stopped displaying values. The Biox III pulse oximeter continued to display values during the cardiopulmonary bypass period; the correlation with CO-oximeter values was 0.813. After cardiopulmonary bypass, the N-100 began displaying values in 2 to 10 minutes. After cardiopulmonary bypass the correlation with CO-oximeter values was 0.792 for the N-100 and 0.828 for the Biox III pulse oximeter. The Finapres finger blood pressure device functioned well in 13 of 15 patients before cardiopulmonary bypass. The mean bias +/- precision of FINAP-IAP for mean pressure was 8.3 +/- 10.2 mm Hg (SD) and the correlation coefficient was 0.814. During cardiopulmonary bypass, the Finapres device functioned well in 10 of 15 patients. The mean bias precision of FINAP-IAP, for mean pressure in these 10 patients was 6.6 +/- 8.7 mm Hg and the correlation coefficient was 0.902.(ABSTRACT TRUNCATED AT 250 WORDS)