IN VIVO ASSESSMENT OF RADIOLABELED AEROSOL DURING NONINVASIVE VENTILATION IN STABLE COPD: A RANDOMIZED CROSSOVER CLINICAL TRIAL
IN VIVO ASSESSMENT OF RADIOLABELED AEROSOL DURING NONINVASIVE VENTILATION IN STABLE COPD: A RANDOMIZED CROSSOVER CLINICAL TRIAL
Background: Beneficial effects from noninvasive ventilation (NIV) in acute COPD are well-established, but couple to nebulization is still challenging. Aim: To compare radioaerosol pulmonary deposition and radioaerosol mass balance in the different compartments (pulmonary and extrapulmonary) using vibrating mesh nebulizer (VMN) and jet nebulizer (JN) coupled to NIV.Methods: It was a crossover study involving 9 stable moderate to severe COPD randomly allocated for both phases of the study: Phase 1(NIV+MN,n=9) and phase 2(NIV+JN,n=9). Bronchodilators were delivered during NIV using a facemask (pressures of 12 cmH2O and 5 cmH2O - inspiratory and expiratory, respectively). Radioactivity counts were performed using a gamma camera and regions of interest(ROIs) were delimited. We determine aerosol mass balance from the lungs, upper airways, stomach, nebulizer, circuit, inspiratory and expiratory filters, and mask as a percentage.
Inclusion Criteria:
Inclusion criteria were considered as follows: moderate to severe stable COPD (50% ≤ FEV1 < 80% from predicted values or 30% ≤ FEV1 < 50% from predicted values)(4); none exacerbation in the last six months; age between 18 - 60 years; both sexes; no smoking history; able to understand verbal commands, and consent to participate in this protocol.
Exclusion Criteria:
Presence of dyspnea; cardiopulmonary diseases (chronic obstructive pulmonary disease, pneumonia, cardiac failure, myocardial infarction, pneumothorax); hyperthermia; hemodynamic instability (heart rate > 150 bpm and systolic blood pressure < 90 mmHg); arrhythmia absence; pregnancy; and contraindications for use of NIV (29).