Are nocturnal hypoxemia and hypercapnia associated with desaturation immediately after adenotonsillectomy?

Background: Children who undergo adenotonsillectomy for sleep-disordered breathing frequently have postoperative oxygen desaturations. Nocturnal hypoxia has been shown to predict postoperative respiratory complications; however, other gas exchange abnormalities detected on polysomnography (PSG) have not been evaluated.

Aim: We sought to determine whether hypercapnia seen on preoperative nocturnal PSG can predict postoperative hypoxemia.

Methods: We conducted a retrospective review of 319 children who underwent polysomnography before adenotonsillectomy. Saturation levels were recorded for at least 2 h postoperatively, and the primary outcome was desaturation (<90%).

Results: The median patient age was 5 years (range, 5 months-17 years). Patients who desaturated postoperatively had higher median peak endtidal CO2 (EtCO2 ) levels (55.5 vs 52 mmHg; P = 0.02), lower saturation nadirs (80.5% vs 88%; P = 0.048), and were younger (2 vs 6 years; P < 0.001) than those without desaturation. Age was significantly correlated with peak EtCO2 (r = -0.16), respiratory disturbance index (RDI; r = -0.23), and oxygen saturation nadir (r = 0.25; all P < 0.01). In unadjusted analysis, age <3 years compared to ≥9 years (odds ratio [OR] = 10.09; 95% confidence interval [CI] = 2.13-96.26), peak EtCO2  > 55 mmHg (OR = 3.38; 95% CI = 1.21-9.47), and RDI ≥ 10 (OR = 2.89; 95% CI = 1.05-8.42) were associated with increased odds of desaturation. Multivariable logistic regression on age, race, sex, peak EtCO2 , RDI, opioid use, and saturation nadir showed that only age was significantly associated with postoperative desaturation. Patients 0-2 years old were 10.43 (95% CI = 1.89-110.9) times more likely to have desaturation than patients 9-17 years old.

Conclusion: Patients <3 years of age are most likely to have postoperative hypoxemia after adenotonsillectomy. Gas exchange abnormalities did not correlate with postoperative desaturations, although age and peak EtCO2 did strongly correlate.