The effect of torso elevation on minimum effective continuous positive airway pressure for treatment of obstructive sleep apnea

Abstract

Continuous positive airway pressure (CPAP) is considered the gold standard treatment of obstructive sleep apnea (OSA). However, it can be a challenge in some patients to find an effective CPAP setting that is well tolerated. A lower CPAP setting may improve patient tolerance of the treatment. The objective of this study was to evaluate the effect of approximately 30° torso elevation on minimum effective CPAP for the treatment of OSA. A retrospective chart review was performed to determine the effective CPAP setting required to treat OSA in patients who underwent CPAP titration with torso elevation using a wedge cushion, after having failed during the same titration study to achieve therapeutic results at CPAP of 20cm H2O without torso elevation. Thirty-nine patients who underwent CPAP titration with and without torso elevation utilizing a wedge cushion had statistically significant lowering of the minimum effective CPAP setting with torso elevation, with a mean CPAP reduction of 4.7 (p< 0.001) compared to ineffective treatment at CPAP of 20cm H2O without torso elevation. Apnea hypopnea index (AHI), respiratory disturbance index (RDI), and lowest oxygen saturation (SpO2) were all improved with torso elevation, with a mean AHI difference of 4.4 (p= 0.03), mean RDI difference of 14.2 (p= 0.001), and mean SpO2 difference of 5.9% (p= 0.002). Age and BMI were inversely correlated, and gender had no correlation with therapeutic CPAP settings with use of torso elevation. Torso elevation of approximately 30° resulted in effective CPAP treatment at settings significantly lower than 20cm H2O in all reviewed OSA patients, who had been ineffectively treated without torso elevation at the maximum tested setting of 20cm H2O. This intervention may be a useful adjunct during in-lab titration studies for patients who are not effectively treated at or cannot tolerate high CPAP settings.