Cerebral Oximetry Monitoring with Near Infrared Spectroscopy Detects Alterations in Oxygenation Before Pulse Oximetry

Background: The monitoring of oxygenation may be imperative to ensure patient safety and optimal outcome. We anecdotally noted that monitoring cerebral oxygenation (rSO2) using near infrared spectroscopy may provide an earlier warning of changes in oxygenation than pulse oximetry.

Methods: Patients scheduled for airway laser surgery requiring intermittent periods of apnea were monitored with both a cerebral oximeter and a pulse oximeter. Following inhalational induction and endotracheal intubation, anesthesia was maintained with propofol. After 3 minutes of ventilation with 100% oxygen, the endotracheal tube was removed and laser surgery performed on the airway during apnea. The time for a 5% and a 10% decrease in the cerebral oximeter and the pulse oximeter was noted.

Results: The study cohort included 10 infants and children ranging in age from 1 month to 7 years. The time for a 5% decrease of the rSO2 was 94 + 8 seconds versus 146 + 49 seconds for a 5% decrease of the SaO 2 (P < .0001). During all 42 episodes of apnea, the rSO2 decreased by 5% before the SaO2 had decreased by 5%. When the SaO2 had decreased by 5% (down to 95% from the starting value of 100%), the rSO2 had decreased by 16 + 4%. The time for a 10% decrease of the rSO2 was 138 + 29 seconds versus 189 + 64 seconds for a 10% decrease of the SaO2 (P = .0009). In all 42 cases, the rSO2 decreased by 10% before the SaO2.

Conclusions: Cerebral oxygenation monitoring using near infrared spectroscopy detects changes in oxygenation earlier than standard pulse oximetry.