Does Bilevel Noninvasive Ventilation Have a Bronchodilating Effect and Alter Respiratory Mechanics in Asthmatic Individuals After Bronchoprovocation? Randomized, Crossover Study.

Background: Noninvasive ventilation (NIV) has an additional important effect that does not occur with medicinal therapy: a reduction in the work of breathing. Understanding the mechanical effects of these therapies is of considerable importance and can affect clinical decision making. Objective: Evaluate the effects of NIV compared to albuterol on lung function and respiratory mechanics in asthmatic adolescents and young adults after bronchoprovocation and determine the effects of a hypertonic saline solution on lung function respiratory mechanics. Methods: A randomized crossover study was conducted involving individuals with a diagnosis of asthma. Evaluations were performed with optoelectronic plethysmography (OEP) and spirometry at baseline, after the bronchial provocation test with 4.5% saline solution and after the intervention. The order of the procedures (bilevel NIV and albuterol) was randomized, with the participants crossing over to the other treatment after a 1-week washout period. Inspiratory positive airway pressure (IPAP) 12 and expiratory positive airway pressure (EPAP) 8 cmH2O were set for 10 minutes and the dose of albuterol was 400 µg. Results: Forty individuals were included in the study (mean age: 21.6 ± 4 years; 24 females). The recovery of FEV1% was 87.9% (80.8 ± 35 to 101.1 ± 46.1, p < 0.05) after NIV and 95.9% (84.4 ± 42.4 to 110.3 ± 44.3, p < 0.05) after albuterol. Inspiratory capacity (IC; L) reduced 12% to 15% after bronchoprovocation, with 100% recovery using NIV (2.1 ± 0.7 to 2.42.4 ± 0.6, p < 0.05) and 107.6% using albuterol (2.2 ± 0.8 to 2.8 ± 1.1, p < 0.05). Regarding OEP variables, tidal volume had greater participation in the thoracic compartment. NIV led to an increase in minute volume and a return to the baseline value, which did not occur with albuterol. Conclusion: NIV recovered FEV1 and improves signs of hyperinflation by improving IC. Bronchoprovocation with a hypertonic solution reduced FEV1 by 20% and reduced IC. NIV led to a faster recovery of minute volume and reduced the contraction velocity of the muscles of the rib cage compared to albuterol, although the effects on lung function were less intense.

Can a physical activity similar to activities of daily living cause dynamic hyperinflation and change the thoracoabdominal configuration in patients with chronic obstructive pulmonary disease?

Introduction: COPD is characterized by the ventilatory limitation, with reduction of the inspiratory reserve volume and dynamic hyperinflation (DH), which changes the configuration of the thoracic compartment, resulting in a disadvantage in respiratory muscle kinetics, and reduced functional capacity. The optoelectronic plethysmography (OEP) has been used to monitor changes in thoracoabdominal mobility. The Glittre-ADL test is a short battery of functional tests that simulate activities of daily living. In mild and moderate COPD, the effect of Glittre-ADL on thoracoabdominal kinetics and DH is understudied. Objective: The aim of our study was to evaluate the acute effects of the Glittre-ADL test on lung function and thoracoabdominal mobility using OEP in patients with mild and moderate COPD. Materials and methods: Twenty-five male and female patients between 45 and 80 years of age with COPD were submitted to the exercises that simulated Glittre-ADL test. Spirometry and OEP were performed before and after the test. Results: After the Glittre test, increases were found in EV (p=0.005), percentage of contribution of the abdominal compartment (p=0.054) and expiratory reserve volume (ERV) (p=0.006) and reductions were found in the contribution of the upper thoracic compartment (p=0.008) and inspiratory capacity (IC) (p=0.040). Conclusion: The acute effect of ADL was a change in thoracoabdominal kinetics, especially the percentage of contribution of the abdominal compartment, as demonstrated by OEP. These findings, together with the reduction in IC and increase in ERV, after the Glittre-ADL test suggest the occurrence of DH, even in patients with mild to moderate COPD according to the GOLD classification.