A Comparison and Validation of Predicted Continuous Positive Airway Pressure Formulas vs Autotitration

ABSTRACT

Background: Continuous positive airway pressure (CPAP) is the treatment of obstructive sleep apnea (OSA). The CPAP pressure is generally estimated by manual titration or an auto-CPAP device. An alternative method involves the use of the predictive equation. There is limited study available for the Indian population. Objectives: To compare CPAP pressure obtained by mathematical formulas with auto-CPAP titration and formulation, a preliminary predictive equation from derived data to be validated with titrated CPAP. Methods and materials A retrospective observational study was performed in 130 patients in Department of Pulmonary Medicine of our institute from April 2019 to July 2021. Detailed history, anthropometric parameters, whole-night level-II polysomnography (PSG), and CPAP titration were performed. Stepwise linear regression was applied to establish predictive equation. This equation results were compared with available other equations and autotitrated readings. Results: The mean (SD) of age, BMI, neck girth, Epworth score, lowest SPO2 (%), and AHI was 56.72 (11.31), 33.87 (6.43), 39.7 (4.46), 17.75 (3.18), 84.65 (8.44), and 48.75 (21.09), respectively, with male杅emale ratio of 32. Mild, moderate, and severe OSA were 7 (5.4%), 18 (13.8%), and 105 (80.8%), respectively. Continuous positive airway pressure obtained from equations was in the range of 7.40�.95 cm H2O. Obtained readings by equations showed a comparable correlation with CPAP-titrated results (p <0.001). Conclusion: The optimum titration pressure correlates with pressure derived from the predictive equation that is predicted average therapeutic CPAP pressure = 3.98 + 0.065 (ODI) + (AHI) + 0.018 (nadir SPO2) - 0.013 (NC).