Baseline oxygen saturation predicts exercise desaturation below prescription threshold in patients with chronic obstructive pulmonary disease.

BACKGROUND: Recent studies of exercise-induced hypoxemia in patients with chronic obstructive pulmonary disease (COPD) have shown that oxygen supplementation during exertion increases exercise tolerance and alleviates dyspnea. Although measurements of forced expiratory volume in 1 second and diffusion capacity for carbon monoxide (DLCO) are known to predict exercise-induced desaturation in patients with COPD, baseline oxygen saturation has never been studied as a predictor of exercise-induced desaturation. METHODS: A retrospective analysis was performed of 100 consecutive patients with forced expiratory volume in 1 second-forced vital capacity ratio of 70% or less who underwent exercise testing for desaturation. Any desaturation to 88% or less with exercise was considered significant. Nineteen patients with total lung capacity of 80% or less were excluded to avoid evaluating those with combined obstructive and restrictive defects; 81 patients remained available for study. RESULTS: Nineteen (51%) of 37 patients with resting saturation of 95% or less desaturated with exercise as opposed to 7 (16%) of 44 with resting saturation of 96% or greater (P =.001). The sensitivity and the negative predictive value of baseline saturation of 95% or less as a screening test for exercise desaturation were 73% and 84%, respectively. If all patients with DLCO of 36% or less were excluded, 40 patients were left for study. Eight (40%) of 20 patients with baseline saturation of 95% or less compared with 0 of 20 with resting saturation of 96% or greater desaturated with exercise (P =.006). In this subset, the sensitivity and the negative predictive value of baseline saturation of 95% or less as a screening test for exercise desaturation both improved to 100%. CONCLUSIONS: In patients with COPD, baseline saturation of 95% or less is a good screening test for exercise desaturation, especially in patients with DLCO greater than 36%. This readily available office screening procedure merits further study in larger prospective patient cohorts.

Clarithromycin for safe and cost-effective reduction of cyclosporine doses in lung allograft recipients.

BACKGROUND: This study was done to analyze the economic effect of clarithromycin on the daily dosing of cyclosporine in lung transplantation. METHODS: Nine consecutive patients (mean age +/- SEM, 34.6 +/- 5.2 years) had transplantation from June 1995 to June 1996. Median follow-up time was 649 days (range, 431 to 799 days). Preoperative diagnoses were cystic fibrosis (n = 4), idiopathic pulmonary fibrosis (n = 2), emphysema, bronchiectasis, and obliterative bronchiolitis. Median time from transplantation to addition of clarithromycin to a standard immunosuppressive regimen was 86 days (range, 14 to 181 days). RESULTS: Baseline cyclosporine dose (9.9 +/- 2.2 mg/kg/day) was reduced to 5.8 +/- 1.0 mg/kg/day and 4.1 +/- 0.8 mg/kg/day at 1 month and 1 year, respectively, after initiation of clarithromycin therapy. Estimated annual savings were $3,400 per patient. There was no increase in infection or rejection episodes. CONCLUSIONS: Clarithromycin safely reduced the dose and cost of cyclosporine in this series.