Deep breathing and awake apnoea in a patient who had recurrent hypoxaemia and hypercapnia without sleep apnoea

Abstract

aaPrimary alveolar hypoventilation is characterized by alveolar hypoventilation in the absence of mechanical hypoventilation [1]. In most patients, hypoventilation is more severe during sleep, and apneic periods are common [2][3][4]. Some patients with primary alveolar hypoventilation have no demonstrable ventilatory response to hypoxia during wakefulness [2,3]. In general, a patient who shows hypoxaemia with hypercapnia during wakefulness is prone to show a further deterioration in blood gases during sleep. We report on a patient who showed central apnoeas with sighs during wakefulness with hypoxaemia and hypercapnia. He had no abnormal breathing during sleep and had normal lung function and normal ventilatory responses to hypoxia and hypercapnia. Administration of a respiratory stimulant (acetazolamide) eliminated apnoeas between sighs, and the patient's hypoxaemia and hypercapnia improved. Case reportA 21 yr old male with dyspnoea was admitted to the Hospital of Chest Disease Research Institute, Kyoto University because of recurrent hypoxaemia with hypercapnia over a 3-month period (arterial oxygen tension (Pa,O 2 ) 9.2 (1.6 SD) kPa, 95% confidence intervals (CI) (7.9-10.5); arterial carbon dioxide tension (Pa,CO 2 ) 6.3 (0.3) kPa (6.0-6.5); pH 7.387 (0.014) (7.376-7.399); n=8) ( fig. 1). The patient was 165 cm tall, and his weight was 60 kg. The patient sighed irregularly at 10-50 s intervals. Medical staff, including physicians, psychoneurologists and nurses, did not find any evidence of a psychiatric problem. The patient had not been exposed to any known toxins, and had not taken any drugs, other than smoking 20 cigarettes·day -1 . The patient's heart size and functional assessment by echocardiography were normal. Despite hypercapnia, he was suspected to have a pulmonary embolism, as evidenced by recurrent hypoxaemia. The patient's pulmonary scintigram, however, was normal, and his pulmonary function was also normal (% vital capacity, 127%; forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) ratio, 82%; % diffusing capacity, 112%). He was suspected to have a central nervous system abnormality, possibly multiple sclerosis, because his symptoms and arterial blood gas data fluctuated considerably ( fig. 1) . MagneticDeep breathing and awake apnoea in a patient who had recurrent hypoxaemia and hypercapnia without sleep apnoea. K. Chin, Y. Oku, K. Nishimura, M. Ohi. ©ERS Journals Ltd 1998. ABSTRACT: A 21 yr old with deep breathing and awake apnoea, who had recurrent hypoxaemia and hypercapnia without sleep apnoea, was presented. Although the organic abnormality responsible for the breathing disturbance was not found, administration of acetazolamide facilitated several breaths between sighs, and the patient's hypoxaemia with hypercapnia improved.Some patients who have abnormalities in the cortical control of breathing that cannot be detected by present methods of examination may experience some improvement in breathing with the administration of chemical stimulants such as acetazolamide. E...