RESUMO
Pulseoximetry is widely used in the critical care setting, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO[2] [pulseoximetry oxygen saturation] in intensive care unit after cardiac surgery. Our objective was to compare pulseoximetry with arterial oxygen saturation [SaO[2]] during clinical routine in such patients, and to examine the effect of mild acidosis on this relationship. In an observational prospective study 80 patients were evaluated in intensive care unit after cardiac surgery. SPO[2] was recorded and compared with SaO[2] obtained by blood gas analysis. One or serial arterial blood gas analyses [ABGs] were performed via a radial artery line while a reliable pulseoximeter signal was present. One hundred thirty seven samples were collected and for each blood gas analyses, SaO[2] and SPO[2] we recorded. O[2] saturation as a marker of peripheral perfusion was measured by Pulseoximetry [SPO[2]]. The mean difference between arterial oxygen saturation and pulseoximetry oxygen saturation was 0.12% +/- 1.6%. A total of 137 paired readings demonstrated good correlation [r=0.754; P<0.0001] between changes in SPO[2] and those in SaO[2] in samples with normal hemoglobin. Also in forty seven samples with mild acidosis, paired readings demonstrated good correlation [r=0.799; P<0.0001] and the mean difference between SaO[2] and SPO[2] was 0.05% +/- 1.5%.Data showed that in patients with stable hemodynamic and good signal quality, changes in pulseoximetry oxygen saturation reliably predict equivalent changes in arterial oxygen saturation. Mild acidosis doesn't alter the relation between SPO[2] and SaO[2] to any clinically important extent. In conclusion, the pulse oximeter is useful to monitor oxygen saturation in patients with stable hemodynamic.