Time course and recovery of arterial blood gases during exacerbations in adults with Cystic Fibrosis

IntroductionHypoxia and hypercapnia are closely linked to morbidity and mortality in patients with Cystic Fibrosis (CF). The aims of this study were to describe the changes in blood gases during and following an acute pulmonary exacerbation in adults with CF.MethodsWe performed a prospective observational study of patients with CF admitted for management of an acute exacerbation. Blood gas and spirometric analysis was performed on admission, throughout the treatment period, and 31 days after discharge (day 45).ResultsAt presentation, eight of nineteen patients had evidence of either hypoxia (PaO₂ < 8 kPa) and/or hypercapnia (PaCO₂ > 6.6 kPa). Blood gas parameters stabilized following two weeks of intravenous antibiotic therapy, with little difference evident in between treatment completion and subsequent review following discharge. Hypercapnia reversed in three patients, with persistent hypercapnia evident in two patients.ConclusionIn our study group, hypoxemia and hypercapnia were frequently observed at presentation of the acute exacerbation. Blood gases stabilized following two weeks of intravenous antibiotic therapy, with arterial PCO₂ one month following hospital discharge generally similar to that at time of discharge.