Home measurement of oxygen saturation during sleep in patients with cystic fibrosis

Feasibility and reproducibility of home measurement of arterial oxygen saturation (Sa O 2) were evaluated in 14 clinically stable patients with cystic fibrosis (CF). Changes in Sa Sa O 2 during sleep were compared to the clinical status and pulmonary function while awake to identify predictors of nocturnal oxyhemoglobin desaturation. Each patient was assessed by clinical score, spirometry, and arterial blood gas analysis within 72 hours of the overnight study. Eight patients were studied on more than one occasion to assess dependence of Sa O 2, on position and reproducibility of overnight studies. A pulse oximeter stored up to 8 hours of nocturnal Sa O 2 measurements in its memory. Off‐line analysis of trend data provided the proportion of sleep with Sa O 2 <90% and <85%. We found that patients with daytime Pa O 2 <60 mm Hg spent >80% of their sleep with Sa O 2 <90%, while those with Pa O 2 >70 mm Hg spent <20% of the night with Sa O 2 <90%. Patients with daytime Pa O 2 of 67–70 mm Hg were desaturated to less than 90%, from 0 to 98% of the night. No consistent body position dependence of daytime Sa O 2 was found. Home measurement of Sa O 2 during sleep was reproducible, with a difference on two repeat occasions of 4% ± 2 (mean ± SEM) for %time with Sa O 2 <90% and 3% ± 2 for %time with Sa O 2 <85%. The severity of hemoglobin desaturation during sleep could not be reliably predicted from clinical scores or awake pulmonary function. Thus, monitoring of nocturnal Sa O 2 is needed to evaluate the extent of desaturation in these patients. Pediatr Pilmonol. 1989; 7:29–34.