Efeito imediato da pressão positiva continua nas vias aereas não invasiva no volume pulmonar expiratorio final de pacientes com doença pulmonar obstrutiva cronica / Immediate effects of non invasive continuous positive airway pressure in end-expiratory lung volume in chronic obstructive pulmonary disease patients

AUTOR(ES)

Silvia Maria de Toledo Piza Soares

DATA DE PUBLICAÇÃO

2007

RESUMO

Bachground: Flow limitation and dynamic hyperinflation are common findings in COPD patients. Inspiratory capacity (IC) has been proposed as a simple method to assess changes in end-expiratory lung volume (EEL V) and lung hyperinflation. However, few studies verified if the application of continuous positive airway pressure (CP AP) could decrease lung hyperinflation. Objective: To assess the immediate effect of the CP AP in EEL V in stable COPD patients. Method: Prospective study of 21 stable COPD patients, age 63 + ou - 9 years, with forced expiratory volume in first second (FEV1) of 40.7 + ou - 11.7%, who were submitted to the gradual test of CP AP (4, 7 and 11 CmH20 - Drãger - SA VINA ventilator). The IC was measured by spirometry, before and after each CP AP leveI. In patients in whom all three CP AP levels resulted in a decreased IC, an additional CP AP test at 2 cmH20 was conducted. For each patient, a "best" CPAP leveI was defined as the one associated with the greater IC observed. This "best" CP AP leveI was then applied during 10 min and subsequent spirometry was performed. Results: During the gradual test of CP AP, 6 patients (non responder group) did not present any improvement of the IC. When the "best" CPAP was then applied in these cases, a significant worsening of the IC was observed of 83.7 + ou -19.4% to 74 + ou - 22.8% (p = 0.0341). In 15 patients (responder group), the IC increased significantly ITom 68.6 + ou - 17.9% to 75.3 + ou - 18.0% (p = 0.0002). The. slow vital capacity was the only other spirometric parameter that also increased post "best" CP AP in the responder group (240 mL, 7.4% of the predicted value, p <0.01). No significant differences in IC were observed after "best" CP AP in patients with expiratory flow limitation (IC pre CP AP 80% of predicted value). However, the patients with pulmonary emphysema and IC

ASSUNTO(S)

doenças pulmonares ventilação mecanica mechanical ventilation spirometry espirometria pulmonary diseases

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