RESUMO
In newborn and premature infants whose lung immaturity entails a limited capacity for O2 detoxification, the use of supplemental oxygen should be continuously and non-invasively monitored. Pulse oximetry and transcutaneous O2 monitoring are the systems most used in the NICU. Major limitations of pulse oximetry are motion artifact, sensitivity to excessive light, cutaneous hypoperfusion, hypothermia, venous congestion, arterio-venous shunting, strong skin pigmentation, anemia and high percentage of abnormal hemoglobin. Alarm habituation is a further major risk. New oxymeters show less motion, artifact and higher accuracy during low oxygen saturation. The accuracy during high oxygen saturation is very dependent on the specific oxymeter model used. Transcutaneous O2 monitoring is usually combined with transcutaneous PCO2 monitoring, hence enabling evaluation of oxygenation as well as ventilation. A major risk of this method is related to the heated electrode sensor, which can induce skin burns. A combined ear sensor for pulse oximetry and PCO2 monitoring seems promising.