Study Objective: To evaluate the influence of nasal oxygen (O2) administration on the duration of
arterial oxygen saturation (SpO2) ≥95% during simulated difficult laryngoscopy in obese patients.
Design: Prospective, randomized, controlled trial.
Setting: University hospital.
Patients: 30 obese men undergoing general anesthesia.
Interventions: After thorough preoxygenation, and using total intravenous anesthesia, simulated
difficult laryngoscopy was performed, with half the patients receiving additional nasal O2 during apnea.
Measurements: Duration of SpO2 ≥95% was measured up to a maximum of 6 minutes. Lowest SpO2
values and time to regain 100% SpO2 (resaturation time) also were recorded.
Main Results: Nasal O2
administration was associated with significant prolongation of SpO2 ≥95%
time (5.29 ± 1.02 vs. 3.49 ± 1.33 min, mean ± SD), a significant increase in patients with SpO2 ≥95%
apnea at 6 minutes (8 vs. one pt), and significantly higher minimum SpO2 (94.3 ± 4.4% vs. 87.7 ±
9.3%). Resaturation times were no different between the groups.
Conclusions: Nasal O2 administration is associated with significant increases in frequency and
duration of SpO2 ≥95%, and higher minimum SpO2 during prolonged laryngoscopy in obese patients.