Nasal high-flow oxygen therapy system for improving sleep-related hypoventilation in chronic obstructive pulmonary disease: a case report

INTRODUCTION Sleep-related hypoventilation should be considered in patients with chronic obstructive pulmonary disease, because appropriate respiratory management during sleep is important for preventing elevation of PaCO2 levels. A nasal high-flow oxygen therapy system using a special nasal cannula can deliver suitably heated and humidified oxygen at up to 60 L/min. Since the oxygen concentration remains a constant independent of minute ventilation, this system is particularly useful in patients with chronic obstructive pulmonary disease who have hypercapnia. This is the first report of sleep-related hypoventilation with chronic obstructive pulmonary disease improving using a nasal high-flow oxygen therapy system. CASE PRESENTATION We report the case of a 73-year-old Japanese female who started noninvasive positive-pressure ventilation for acute exacerbation of chronic obstructive pulmonary disease and CO2 narcosis due to respiratory infection. Since she became agitated as her level of consciousness improved, she was switched to a nasal high-flow oxygen therapy system. When a repeat polysomnography was performed while using the nasal high-flow oxygen therapy system, the Apnea Hypopnea Index was 3.7 times/h, her mean SpO2 had increased from 89 to 93%, percentage time with SpO2 ≤ 90% had decreased dramatically from 30.8 to 2.5%, and sleep stage 4 was now detected for 38.5 minutes. As these findings indicated marked improvements in sleep-related hypoventilation, nasal high-flow oxygen therapy was continued at home. She has since experienced no recurrences of CO2 narcosis and has been able to continue home treatment. CONCLUSIONS Use of a nasal high-flow oxygen therapy system proved effective in delivering a prescribed concentration of oxygen from the time of acute exacerbation until returning home in a patient with chronic obstructive pulmonary disease, dementia and sleep-related hypoventilation. The nasal high-flow oxygen therapy system is currently used as a device to administer high concentrations of oxygen in many patients with type I respiratory failure, but may also be useful instead of a Venturi mask in patients like ours with type II respiratory failure, additionally providing some positive end-expiratory pressure.