A survey of nocturnal hypoxaemia and health related quality of life in patients with cryptogenic fibrosing alveolitis

Background-A survey of overnight oximetry was conducted to estimate the pre valence of nocturnal hypoxaemia in patients with cryptogenic fibrosing alve olitis and to establish whether nocturnal hypoxaemia is related to quality of life. Methods-All patients with cryptogenic fibrosing alveolitis attending Nottin gham City Hospital were invited to enter the study. Spirometric measurement s and capillary blood gas tensions were obtained and overnight oxygen satur ation was recorded at home. Quality of life was assessed using the Short Fo rm-36, Chronic Respiratory Questionnaire, Hospital Anxiety Depression Scale , and Ep-worth Sleepiness Score questionnaires. Results-Sixty seven eligible patients were identified and 50 agreed to ente r the study, although two were subsequently excluded because they already u sed oxygen overnight. In the remaining 48 the mean (SD) overnight oxygen sa turation (Sao,) was 92.5 (4.3)% and the median number of dips greater than 4% per hour was 2.3 (interquartile range 1.5-5.3). Daytime oxygen level pre dicted mean overnight Sao, (1.94%/kPa, 95% CI 1.22 to 2.66, p <0.001) but p ercentage predicted forced vital capacity (FVC) did not (0.018%/% predicted FVC, 95% CI -0.04 to 0.08, p=0.5). Nocturnal hypoxaemia was associated wit h decreased energy levels and impaired daytime social and physical function ing, and these effects were independent of FVC. Conclusions-Nocturnal hypoxaemia is common in patients with cryptogenic fib rosing alveolitis and may have an impact on health related quality of life.