비대칭 폐 유순도 모델에서 기도 폐쇄가 환기의 분배에 미치는 영향

Abstract

Background: Unilateral lung hyperinflation occurring in obstructive lung disease with asymmetric lung compliance leads to acute vital instabilities. Unilateral lung hyperinflation is mainly due to dynamic hyperinflation, which can be affected by compliance, tidal volume, airway resistance and respiration rate changes. Methods: The model was made by using two test lungs, each named lung1 and lung2. To make asymmetric lung compliance, two groups were set by manipulating lung1 compliance as ARDS lung (ARDS group) and COPD lung (COPD group), while fixating lung2 compliance as normal lung. In addition, control group with symmetric compliance of normal lung was set, resulting in total 3 groups. Respiratory variables were measured above (proximal measurement) and below (distal measurement) the model's trachea. The model was mechanically ventilated, while airway diameter was changed from 3 to 8 mm serially by 1 mm interval. Results: PEEP had statistically significant increase below ID 5 mm, and also had statistically significant increase throughout airway diameter change in COPD group versus control group and ARDS group. was similar to in most of the group at distal measurement, but approached to value of 1 in distal measurement of COPD group at ID 3, 4 mm. Conclusions: Ventilatory distribution was proportionate to lung compliance. PEEP was statistically increased when airway cross sectional area decreased to 7.1 cm2 (ID 3 mm) in ARDS group and 19.6 cm2 (ID 5 mm) in control, COPD group. COPD group alone showed statistically significant PEEP. Adequate limitation of flow and inspiratory pause may ameliorate uneven ventilatory distribution.

Key Words: asymmetric compliance, unilateral lung hyperinflation, distribution of ventilation, PEEP, airway obstruction