Impact of Pseudomonas aeruginosa Infection on Respiratory Muscle Function in Adult Cystic Fibrosis Patients

Abstract

Background: Pseudomonas aeruginosa infection impairs respiratory muscle function in adolescents with cystic fibrosis, but its impact on adult patients has not been characterised.

Objectives: To investigate respiratory muscle function in adult cystic fibrosis patients according to P. aeruginosa status (repetitive samples over 12 months).

Methods: The pressure-time index of the respiratory muscles (PTImus), a measure of their efficiency, served as the primary outcome. In addition, respiratory load and maximal respiratory muscle strength were assessed.

Results: In 51 patients examined (65% female; median age 32 years, IQR 24-40), a median of 3.0 (IQR 2-4) different pathogens was found in each patient. The PTImus was 0.113 and 0.126 in Pseudomonas-positive (n = 33) and -negative (n = 18) patients, respectively (p = 0.53). Univariate analysis showed a lower PTImus in male than in female patients (p = 0.006). Respiratory muscle load and strength were otherwise comparable, with the exception of higher nasal sniff pressures in Pseudomonas-positive patients who were chronically infected (>50% of positive samples). Quality of Life (according to the Cystic Fibrosis Questionnaire-Revised) was higher if both respiratory load and the PTImus were low (high respiratory muscle efficiency).

Conclusions: Chronic P. aeruginosa infection does not influence respiratory muscle efficiency in adult cystic fibrosis patients with otherwise multiple co-infections. In addition, patients with reduced respiratory muscle efficiency had worse Quality of Life.