ChronicPseudomonas aeruginosaInfection and Respiratory Muscle Impairment in Cystic Fibrosis

Abstract

BACKGROUND: Chronic infection with Pseudomonas aeruginosa in patients with cystic fibrosis (CF) is associated with increased morbidity. Chronic infection can cause limb and respiratory muscle compromise. Respiratory muscle function can be assessed via maximal inspiratory pressure (P Imax ), maximal expiratory pressure (P Emax ), and the pressure-time index of the respiratory muscles (PTI mus ). We studied the effect of chronic P. aeruginosa infection on respiratory muscle function in patients with CF. METHODS: This cross-sectional study assessed P Imax , P Emax , PTI mus , FEV 1 , FVC, maximum expiratory flow during the middle half of the FVC maneuver, body mass index, and upper arm muscle area in 122 subjects with CF, in 4 subgroups matched for age and sex at different stages of P. aeruginosa infection, according to the Leeds criteria. We compared respiratory muscle function in the subgroups according to P. aeruginosa infection state. RESULTS: Median P Imax was significantly lower in CF subjects with chronic P. aeruginosa infection (P Imax ‫؍‬ 62 cm H 2 O), compared to subjects who were never infected (P Imax ‫؍‬ 86 cm H 2 O, P ‫؍‬ .02), free of infection (P Imax ‫؍‬ 74 cm H 2 O, P ‫؍‬ .01), or intermittently infected (P Imax ‫؍‬ 72 cm H 2 O, P ‫؍‬ .02). Median PTI mus was significantly increased in CF subjects with chronic P. aeruginosa infection (PTI mus ‫؍‬ .142), compared to subjects who were free of infection (PTI mus ‫؍‬ .102, P ‫؍‬ .006). Median upper-arm muscle area was significantly lower in CF subjects with chronic P. aeruginosa infection (upper-arm muscle area ‫؍‬ 2,219 mm 2 ), compared to subjects who were never infected (2,754 mm 2 , P ‫؍‬ .03), free of infection (2,678 mm 2 , P ‫؍‬ .01), or intermittently infected (2,603 mm 2 , P ‫؍‬ .04). Multivariate logistic regression revealed P. aeruginosa state of infection as a significant determinant of PTI mus (P ‫؍‬ .03) independently of sex, upper-arm muscle area, and FEV 1 . CON-CLUSIONS: CF subjects with chronic P. aeruginosa infection exhibited impaired respiratory muscle function and decreased inspiratory muscle strength, and chronic P. aeruginosa infection independently impacts respiratory muscle function in subjects with CF.

Impact of <b><i>Pseudomonas aeruginosa</i></b> Infection on Respiratory Muscle Function in Adult Cystic Fibrosis Patients

“…Importantly, an animal study showed that CF mice with sustained infection with P. aeruginosa had a reduced diaphragmatic force-generating capacity [9]. Furthermore, a detailed study on the impact of P. aeruginosa infection on respiratory mechanics in adolescent CF patients clearly showed that P. aeruginosa infection can indeed have an independent effect on respiratory muscle function [7]. …”

“…Despite the link between P. aeruginosa infection and respiratory disturbances, respiratory mechanics are rarely investigated in CF patients. In general, the load imposed on the respiratory muscles, respiratory muscle efficiency, and respiratory muscle strength are all key factors in determining respiratory mechanics [7]. In particular, the impact of P. aeruginosa infection on respiratory mechanics is not fully understood, but it is suggested to be clinically important, since chronic infection has been shown to impair respiratory muscle function [8].…”

Inspiratory Muscle Strength and Endurance in Children and Adolescents with Cystic Fibrosis

“…13 Once infection is established, there is an accelerated decline in lung function, quality of life, and survival. 14,15 Furthermore, chronic P. aeruginosa infection has been related to decreased maximum inspiratory pressure (P Imax ) and is probably an independent predictor of respiratory muscle compromise in cystic fibrosis, 16 although its relation to muscle endurance remains unclear.…”

Effect of abdominal muscle training on respiratory muscle strength and forced expiratory flows in sedentary, healthy adolescents

“…13 On their side, Gollee et al observed that superficial abdominal muscle functional stimulation increased PCF and tidal volume in tetraplegic subjects. 21 The linear regression analysis done in our study estimated that per every cmH 2 each other. In biomechanical terms, during cough mechanism, expiratory muscles play a critical role both during relaxation in the inspiratory phase and during isometric contraction in the compression phase, which allows raising intraabdominal pressure up to 300 mmHg.…”