3-minute central apneas: enhanced expiratory rebreathing space to the rescue

Abstract

This case report presents an atypical case of central sleep apnea treated with continuous positive airway pressure (CPAP), enhanced expiratory rebreathing space, and oxygen. A 69-year-old female with morbid obesity and congestive heart failure who previously failed multiple positive airway pressure modalities for presumed obstructive sleep apnea was referred for retitration with transcutaneous carbon dioxide monitoring. Titration with CPAP, bilevel positive airway pressure, and intelligent volume-assured pressure support resulted in 3- to 4-minute central apneas with an oxygen saturation nadir of 49% and an average transcutaneous carbon dioxide of 27 mmHg. Subsequent split-night polysomnography revealed central sleep apnea without obstructive sleep apnea. CPAP and adaptive servo-ventilation alone and CPAP with oxygen were inadequate. Addition of enhanced expiratory rebreathing space and oxygen supplementation to CPAP led to an improved Epworth Sleepiness Score (12 to 3), and overnight oximetry confirmed a satisfactory oxygen saturation nadir of 92%. This case highlights the use of transcutaneous carbon dioxide monitoring in the recognition of hypocapnic central sleep apnea leading to successful treatment with CPAP, enhanced expiratory rebreathing space, and oxygen.

Citation: Wojnowski K, Primera G, Johnson KG. 3-minute central apneas: enhanced expiratory rebreathing space to the rescue. J Clin Sleep Med. 2025;21(6): 1133-1137.

Keywords: EERS; central sleep apnea; enhanced expiratory rebreathing space; high loop gain; hypocapnia.