Treatment Effects on Carbon Dioxide Retention in Patients With Obstructive Sleep Apnea-Hypopnea Syndrome

• Published in: Chest Vol. 119; no. 6; pp. 1814 - 1819
• Main Authors: Han, Fang, Chen, Erzhang, Wei, Hailing, He, Quanying, Ding, Dongjie, Strohl, Kingman P.
• Format: Journal Article
• Language: English
• Published: Northbrook, IL Elsevier Inc 01.06.2001; American College of Chest Physicians
• Subjects: Adult; Biological and medical sciences; Body mass index; Carbon Dioxide - metabolism; Chemoreceptor Cells - physiopathology; CO2 retention; Electromyography; Eye movements; Female; Humans; Hypoventilation; Hypoxia; Hypoxia - physiopathology; Male; Medical sciences; Middle Aged; Neuromuscular diseases; Obesity; Obesity - complications; obstructive sleep apnea-hypopnea syndrome; Oxygen saturation; Patients; Pneumology; Positive-Pressure Respiration; respiratory control; Respiratory system : syndromes and miscellaneous diseases; Retention; Sleep - physiology; Sleep apnea; Sleep Apnea, Obstructive - physiopathology; Sleep Apnea, Obstructive - therapy; Sleep disorders; respiratory control; SIT90; obstructive sleep apnea-hypopnea syndrome; AHI; CPAP; MAHT; V˙e; ESS; P0.1; NREM; CO2 retention; TST; Sao2; OSAHS; SL; MSao2; REM; BMI; Human; Hypercapnia; Sleep apnea syndrome; Oxygen; Prognosis; Treatment; Respiratory disease; Follow up study; Carbon dioxide; Hypoxia
• ISSN: 0012-3692; 1931-3543
• DOI: 10.1378/chest.119.6.1814

This study was designed to examine respiratory control in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS), with or without CO2 retention. We recruited 10 body mass index-matched, apnea-hypopnea index-matched, age-matched, and lung function-matched OSAHS patients, according to their awake Paco2. Five patients were hypercapnic (Paco2, ≥ 45 mm Hg), and five patients were eucapnic. Hypoxic responses (the ratio of the change in minute ventilation [Δ V˙e] to the change in arterial oxygen saturation[ΔSao2] and the ratio of the change in mouth occlusion pressure over the first 100 ms of inspiration against an occluded airway [ΔP0.1] to Δ Sao2) and hypercapnic responses (Δ V˙e/ΔPco2 ratio andΔP0.1/ΔPco2 ratio) were testedduring wakefulness before treatment in all 10 patients, and before and during treatment (at 2, 4, and 6 weeks) with pressure support in the hypercapnic group. Hypercapnic patients had lower mean (± SD)Δ V˙e/Δ Sao2 ratio than eucapnic patients (−0.17 ± 0.04 vs −0.34 ± 0.04 L /min/% Sao2, respectively), lower meanΔP0.1/Δ Sao2 ratio(−0.04 ± 0.02 vs −0.14 ± 0.03 cm H2O/% Sao2, respectively), and lower ΔP0.1/ΔPco2 ratio(0.23 ± 0.1 vs 0.49 ± 0.1 cm H2O/mm Hg, respectively)[p < 0.05]. After receiving noninvasive ventilation treatment, the hypercapnic and hypoxic responses of the hypercapnic patients increased. At 4 to 6 weeks, values for both responses had increased to within the normal range and Paco2 had fallen to< 45 mm Hg, while weight was unchanged. Depressed chemoresponsiveness plays a role that is independent of obesity in the development of CO2 retention in some OSAHS patients, and it may be a response to sleep-disordered breathing.