[Residual hypoxemia during titration with self-adjusting CPAP at home in patients without prior adaptation]

Introduction: Self-adjusting titration (APAP) at home is accepted to define therapeutic pressure (CPAPT). The APAP device report may be insufficient to ensure adequate therapeutic response in all patients. There is no consensus on the use of oximetry during APAP titration.

Objective: To evaluate the prevalence and magnitude of residual hypoxemia (RH) in titration with APAP not monitored at home and to identify related variables.

Materials and methods: Retrospective study based on APAP titrations with coupled oximetry, arterial blood gases and spirometry test. A T90 > 10% of the night was considered significant RH. Predictors of HR were identified by logistic regression (RL).

Results: 116 cases were included. 41% in the group with RH. These were older (66.7 vs. 59.6 years, p: 0.02), lower absolute FEV1 (2.17 vs. 2.57 liters, p: 0.06), lower absolute FVC (2.9 vs. 3.3 liters, p: 0.02) and lower basal PO2 (77.3 vs. 84.2 mmHg, p: 0.04). The titration period reached 3.6 ± 1 nights, average adherence of 374 ± 88.4 minutes/night; CPAPT (cm H2O): 9.4 ± 1.8, AHIr; 3.1 ± 3.2 ev/h and leaks (liters/min): 19.7 ± 11.2. Multiple logistic regression identified age > 66 years as a predictor of RH (OR 3.32, 95% CI 1.43 - 7.69, p: 0.005) and FEV1 < 1.76 liters (OR 3.29 – IC95% 1.27 – 8.53, p: 0.0139).

Conclusions: Incompletely corrected nocturnal oximetry was observed in a significant proportion of patients with APAP. Age over 66 years and absolute FEV1 < 1.76 liters were correlated with residual hypoxemia.