Is there a correlation between clinical factors and nocturnal oximetry in cystic fibrosis children?

Abstract

Introduction Cystic Fibrosis (CF) patients develop sleep hypoxemia and hypercapnia in the course of disease.The magnitude of nocturnal oxygen desaturation (NOD) may correlate with the severity of lung disease and the development of pulmonary hypertension.In children studies are scarce and controversial.Aim: to identify predictive factors of NOD using nocturnal Oxygen Desaturation Index (ODI) and its association with clinical severity in CF children. Materials and methods Twenty-four CF patients were included, January 2012 to June 2013.Clinical files were reviewed and data about nutritional status (BMI z -score), hospitalizations, bacterial isolates and pattern, and X-ray imaging findings were collected.Patients underwent a nocturnal pulse oximetry and ODI was classified as normal ( Results Twenty-four patients, median age 12.5 years (min7; max 18), twelve (50%) are homozygous for delF508.Twelve (50%) patients had nocturnal hypoxemia, either mild (6;50%), moderate (3;25%) or severe (3;25%).Twenty-two patients (92%) had bacterial isolates, sixteen (67%) of which were chronic.Seven patients (29%) had been hospitalized during the period of study.None children had a normal imaging and sixteen (67%) had bronchiectasis.No correlation was found between ODI and number of hospitalizations, total number and chronic isolates, microorganisms identified, BMI z-score and imaging changes.After ODI severity stratification, a significant correlation was found between moderate ODI and number of chronic isolates ( ρ = 0.999, p = 0.021).Although non significant, we found a moderate correlation between mild ODI and total number of isolates ( ρ = 0.639, p = 0.172) and isolation of MRSA ( ρ = 0.644, p = 0.150), moderate ODI and isolation of MRSA ( ρ = 0.866, p = 0.333) and severe ODI and isolation of B. cepacia ( ρ = 0.866, p = 0.333). Conclusion We couldn’t find a correlation between ODI and clinical severity.The only factor that showed a strong and statistically significant ODI correlation was the number of chronic bacterial isolations in the moderate ODI group.The small number of patients may explain some of the non-significant correlations, further and larger studies in children are needed. Acknowledgements - Dr. Rita Jotta – Patients and their families.