1250 Blame it on the mask

Abstract

Introduction: Continuous positive airway pressure (CPAP) is considered the gold-standard treatment for obstructive sleep apnea (OSA). There are several different interfaces for CPAP including nasal pillows, nasal and full-face styles. Nasal pillows and masks can be used with a chin strap to prevent air leak through the mouth. Full-face interfaces tend to be more robust and may be preferred for higher pressures. Report of Case: We present a case of an 81-year old lady with a history of stroke, systemic hypertension, mild chronic obstructive pulmonary disease and depression. She had a history of snoring, worse on the back, snort arousals and witnessed apneas. She reported 3-4 awakenings secondary to nocturia. She felt unrefreshed upon awakening and took hourlong daytime naps. Physical examination revealed high blood pressure, body mass index of 18.99 kg/m2, Friedman class IV oropharynx, overbite and overjet. She underwent in-laboratory split-night polysomnography. The diagnostic study showed moderately severe OSA with an apnea-hypopnea index of 24 and respiratory disturbance index of 39 per hour, worse in rapid eye movement (REM) sleep and on the back, with an oxyhemoglobin saturation nadir of 83%. CPAP titration was conducted utilizing a full-face interface between 5 cm to 17 cm of water pressure. As the pressures were increased, obstructive sleep disordered breathing events worsened (see Figure). The patient was switched to a nasal mask with chin strap and the pressure was decreased gradually to 7 cm of water which eliminated most sleep disordered breathing events in REM supine sleep. A full-face interface can depress the lower jaw simulating a pseudo- retrognathic condition. This may be more pronounced in a frail person with already existing retrognathia. In such circumstances, increasing pressures to eliminate events could be counterproductive. Changing to a nasal pillow or nasal interface may result in optimal treatment of OSA at lower pressures. Conclusion: This case highlights one of the drawbacks of a full-face interface. Being cognizant of the relative merits and disadvantages associated with different CPAP interfaces may help sleep technologists and clinicians make appropriate choices for their patients on an individual basis and effectively treat their OSA.