Postoperative Oxygen Therapy in Patients With OSA: A Randomized Controlled Trial.

BACKGROUND: Surgical patients with OSA are at increased risk for perioperative complications. Postoperative supplemental oxygen is commonly used, but it may contribute to respiratory depression in patients with OSA receiving opioids. The objective of the study is to investigate the effect of postoperative supplemental oxygen on arterial oxygen saturation (Sao2 ), sleep respiratory events, and CO2 level in patients with untreated OSA.

METHODS: Consented patients with an apnea hypopnea index (AHI) > 5 events per hour on a preoperative polysomnography were randomized (1:1) to oxygen (O2 group) or no oxygen (control group). The O2 group received oxygen at 3 L/min via nasal prongs for three postoperative nights. The primary outcomes were polysomnographic parameters measuring Sao2 , sleep respiratory events, and Pco2 measured by transcutaneous CO2 monitor (Ptc CO2 ) on nights 1 through 3. The intention-to-treat and per protocol analysis were completed.

RESULTS: There were 123 patients randomized (O2 group: n = 62; control group: n = 61). On night 3, the O2 vs control group had a higher average Sao2 (95.2% ± 3% vs 91.4% ± 4%, respectively; P < .001) and lower oxygen desaturation index (median, 2.3; 25th-75th percentile, 0.2-13.8 vs median, 18.5; 25th-75th percentile, 8.2-45.9 events per hour, respectively; P < .0001). The O2 group had a decreased AHI (median, 8.0; 25th-75th percentile, 2.1-19.9 vs median, 15.6; 25th-75th percentile, 9.5-45.8, respectively; P = .016), hypopnea index (P < .001), and central apnea index (P = .026) and a shortened longest apnea hypopnea duration (P = .002). Although time percentage with Ptc CO2  ≥ 55 mm Hg ≥ 10% on postoperative night 1, 2, or 3 was found in 11.4% patients, there was no difference in Ptc CO2 between the groups.

CONCLUSIONS: Postoperative supplemental oxygen was found to improve oxygenation and decrease the AHI without increasing the duration of apnea-hypopnea event or Ptc CO2 level. A small number of patients had significant CO2 retention while receiving supplemental oxygen.

TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01552304; URL: www.clinicaltrials.gov.