Chest Physiotherapy in Cystic Fibrosis: Improved Tolerance With Nasal Pressure Support Ventilation

Abstract

ABSTRACT. Objective. Chest physiotherapy (CPT) is an integral part of the treatment of patients with cystic fibrosis (CF). CPT imposes additional respiratory work that may carry a risk of respiratory muscle fatigue. Inspiratory pressure support ventilation (PSV) is a new mode of ventilatory assistance designed to maintain a constant preset positive airway pressure during spontaneous inspiration with the goal of decreasing the patient's inspiratory work. The aim of our study was 1) to evaluate respiratory muscle fatigue and oxygen desaturation during CPT and 2) to determine whether noninvasive PSV can relieve these potential adverse effects of CPT.Methods. Sixteen CF patients in stable condition with a mean age of 13 ؎ 4 years participated to the study. For CPT, we used the forced expiratory technique (FET), which consisted of one or more slow active expirations starting near the total lung capacity (TLC) and ending near the residual volume. After each expiration, the child was asked to perform a slow, nonmaximal, diaphragmatic inspiration. After one to four forced breathing cycles, the child was asked to cough and to expectorate. A typical 20-minute CPT session consisted of 10 to 15 FET maneuvers separated by rest periods of 10 to 20 breathing cycles each. During the study, each patient received two CPT sessions in random order on two different days, at the same time of day, with the same physiotherapist. During one of these two sessions, PSV was provided throughout the session (PSV session) via a nasal mask using the pressure support generator ARM25 designed for acute patients (TAEMA, Antony, France). The control session was performed with no nasal mask or PSV. Both CPT sessions were performed without supplemental oxygen. Lung function and maximal inspiratory pressures (PImax) and expiratory pressures (PEmax) were recorded before and after each CPT session.Results. Mean lung function parameters were comparable before the PSV and the control sessions. Baseline pulse oximetry (SpO 2 ) was significantly correlated with the baseline vital capacity (% predicted) and forced expiratory volume in 1 second (FEV 1 ) (% predicted). PSV was associated with an increase in tidal volume (Vt) from 0.42 ؎ 0.01 liters to 1.0 ؎ 0.02 liters. Respiratory rate was significantly lower during PSV. SpO 2 between the FET maneuvers was significantly higher during PSV as compared with the control session. SpO 2 decreases after FET were significantly larger during the control session (nadir: 91.8 ؎ 0.7%) than during the PSV session (93.8 ؎ 0.6%). Maximal pressures decreased during the control session (from 71.9 ؎ 6.1 to 60.9 ؎ 5.3 cmH 2 O, and from 85.3 ؎ 7.9 to 77.5 ؎ 4.8 cmH 2 O, for PImax and PEmax, respectively) and increased during the PSV session (from 71.6 ؎ 8.6 to 83.9 ؎ 8.7 cmH 2 O, and from 80.4 ؎ 7.8 to 88.0 ؎ 7.4 cmH 2 O, for PImax and PEmax, respectively). The decrease in PEmax was significantly correlated with the severity of bronchial obstruction as evaluated based on baseline FEV 1 (% predicted). Forced expiratory flows did...

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

“…3,4,28,29 Dunnink et al 4 suggest that the increased work of breathing due to airway obstruction could cause an effect of conditioning the respiratory muscles. On the contrary, some studies 5,12,30,31 showed a reduction of respiratory muscle strength, associating this finding with hyperinflation and malnutrition. Furthermore, Dassios et al 32 showed that maximum respiratory pressures were significantly diminished in subjects with no severe lung disease; however, no correlation between P Imax and BMI was found.…”

Noninvasive Ventilation Coupled With Nebulization During Asthma Crises: A Randomized Controlled Trial

“…In regions with mild to severe obstruction, increased velocity and turbulent flows seem to promote deposition through the impaction mechanism, resulting in a concentration of radio-aerosol in "hot spots" near the obstructed areas. 33 The radio-aerosol penetration index was higher in the central regions of the lungs in both groups, thereby reducing the percentage that reached the intermediate and peripheral regions. Fauroux et al 33 found a higher radioaerosol penetration index in the NIV ϩ nebulizer group, but the comparison of those data to our results is limited, as the patients assessed in the Fauroux et al study had cystic fibrosis, and the obstruction measured by the spirometry differed from those patients with asthma.…”

“…Previous studies described similar results, with flow values of around 40 L/min contributing to less peripheral deposition. 18,33 The analysis of deposition in the vertical differences revealed greater deposition in the middle third in comparison to the upper and lower thirds, and in the lower third, in comparison to the upper third, in both lungs. However, no difference in radio-aerosol counts was detected between the upper and lower thirds of the left lung in the control group.…”

“…Higher flows could lead to greater aerosol impaction in the upper and central airways, as turbulent flows produce strong inertial forces that impact aerosols in the proximal airways. [31][32][33] Inspiratory flow and V T were monitored during inhalation, and an increase in these variables was observed in the NIV ϩ nebulizer group, when compared to the control group. Both groups had an inspiratory flow above 30 L/min, favoring greater penetration of radio-aerosol in the central airways.…”

Equações internacionais superestimam a força muscular ventilatória em crianças e adolescentes com fibrose cística

“…Some papers report that hyperinflation combined with malnutrition may be a factor predisposing to ventilatory muscle weakening 4,6,7 . On the other hand, chronic cough and increase in ventilatory effort seem to favor muscle strength 5,8 .…”