The effect of hyperoxia on disordered breathing during recovery from general anesthesia: A single-blinded, crossover, non-randomized -controlled, trial.

OBJECTIVE

While supplemental O2 corrects hypoxemia and promotes respiratory stability during sleep, its effect on post-anesthesia ventilation is unknown. Using home sleep apnea testing (HSAT) equipment, we previously found that hyperoxia improved obstructed breathing in post-anesthesia patients by primarily reducing desaturation-based hypopnea events. This trial tested the hypothesis that hyperoxia will improve disordered breathing during recovery from anesthesia, independent of oxygenation-based scoring criteria.

DESIGN

Single-blinded, non-randomized-controlled, crossover trial.

SETTING

University hospital.

PATIENTS: 10 patients undergoing robotic-assisted laparoscopic nephrectomy.

MEASUREMENTS: All patients underwent a HSAT recording during two 40-min-long interventions when inhalation of an O2/air mixture targeted an SpO2 > 96 % (Liberal O2), or an SpO2 90-94 % (Conservative O2). Continuous transcutaneous (TcPCO2) and intermittent arterial (PaCO2) measurements of CO2 were performed. Apnea/hypopnea index (AHIflow) was measured using standard criteria, except hypopneas were defined solely by standard airflow reduction without requiring associated desaturation or arousal. StanpumpR was utilized to simulate analgesic effect of administered opioids, expressed as percentage of minimum effective analgesic concentration (MEAC), which was then used to adjust the comparison between the two interventions.

MAIN

RESULTS

AHIflow decreased significantly from 36 ± 23 (mean ± Std) events per hour during Conservative O2, to 25 ± 17 in the Liberal O2 session (paired t-test, P = 0.0069 adjusted for the area under the MEAC-time curve). Pairwise comparisons did not show any significant difference in the TcPCO2 or PaCO2 levels between the two treatment sessions, while the percentage of time spent with TcPCO2 > 45 mmHg was also comparable between the two interventions.

CONCLUSIONS

Oxygenation-independent assessment showed that hyperoxia improved disordered breathing immediately following anesthesia, primarily by decreasing the number of hypopneas.

TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05922020.