Usefulness of pulse oximetry in thoracic surgery

: Saturation of hemoglobin in arterial blood was simultaneously measured by co-oximetry (SaO2) and by pulse oximetry (SpO2) in 228 samples from 42 patients undergoing general anesthesia for thoracic surgery. Data was referred to SaO2 obtained with arterial catheterization. We found a significant correlation (r: 0.949 and p less than 0.001) and the mean differences were 0.77 +/- 1.84. The correlation between PaO2 and the difference among both methods was significantly negative (r: -0.20; p less than 0.001). Although there was a significant correlation, the method loses reliability and accuracy in patients with hypoxemia. In these patients oximetric values are slightly lower than those obtained with arterial cannulation. We emphasize the clinical usefulness of this technique since it is instantaneous and allowed immediate therapeutic actions.