1040 Sleep Hypoventilation with Daytime Eucapnia in COPD May Predict Hypercapnia During Exacerbation

Abstract

Abstract Introduction Patients with severe Chronic Obstructive Pulmonary Disease (COPD) are known to be at risk for nocturnal hypoventilation1. We present a case of patient with severe COPD with near normalization of PaCO2 levels after exacerbation but persistent nocturnal hypoventilation. Report of case(s) 71-year-old woman with COPD Group 4D, on home oxygen, was seen in pulmonary clinic after two hospitalizations for hypercapnic respiratory failure, PcO2 >100 mm Hg requiring acute Noninvasive ventilation (NIV) support. Three weeks after discharge, ABG improved to 7.39/49/140 on 32% Fio2, preventing her from qualifying for long-term home NIV. Sleep study was negative for sleep apnea but showed hypoventilation during sleep. Wake supine transcutaneous CO2 was 45-47 mmHg, increasing to 51-55 mmHg during sleep, worse with supplemental oxygen to 66-67 mm. Conclusion Chronic hypercapnia is a poor prognostic indicator in COPD4. In patients with persistent hypercapnia following COPD exacerbation, NIV prolongs time to re-admission or death within 12 months2. Blunting of chemoreceptor response has been noted in hypercapnic patients3, possibly causing subsequent daytime hypercapnia and overt respiratory failure. However, nocturnal hypercapnia is present in some patients and may be a risk factor for profound, life-threatening hypercapnia during exacerbation. Future studies are needed to better phenotype patients such as ours who may be seemingly eucapnic in between exacerbations, but markedly hypercapnic during exacerbation, to determine if there is benefit in treating these patients with NIV as well. Support (if any) 1. The American Academy of Sleep Medicine Task Force. Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. Report of American Academy of Sleep Medicine Task Force. Sleep 1999:22:667-689 2. Murphy PB, Rehal S, Arbane G, Bourke S, Calverley PMA, Crook AM, et al. Effect of home noninvasive ventilation with oxygen therapy vs oxygen therapy alone on hospital readmission or death after an acute COPD exacerbation: a randomized clinical trial. JAMA. 2017:317:2177 3. Scano G,Spinelli A, Duranti R, et al. Carbon dioxide responsiveness in COPD patients with and without chronic hypercapnia. Eur Respir J 1995:8:78-85 4. Cooper CB, Waterhouse J, Howard P. Twelve-year clinical study of patients with hypoxic co pulmonale given long term domiciliary oxygen therapy. Thorax 1987:42:105-110