Does Bilevel Noninvasive Ventilation Have a Bronchodilating Effect and Alter Respiratory Mechanics in Asthmatic...

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. 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. 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. 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. 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.