Role Of Lateral Position Ventilation In Patients With ARDS Originating From Pulmonary Disease And Extra-pulmonary Disease

Objective:To assess the effects of lateral position ventilation for treatment of acute respiratory distress syndrome (ARDS) originating from pulmonary disease and extra-pulmonary disease. Methods:Twenty-three patients with ARDS were divided into pulmonary disease group and extra-pulmonary disease group. All patients were mechanically ventilated Supine position, lateral position and supine position were successively adopted in each patient and each position continued for 1 h. Functional residual capacity (FRC), peak inspiratory pressure (PIP), plateau airway pressure (Pplat), airway resistance (Raw), static pulmonary compliance (Cst), heart rate (HR), cardiac index (CI),mean artery pressure (MAP) and arterial blood gas were measured at the end of each epoch. Results:(1) The change of gas exchanges:When patients were turned to lateral position, Arterial oxygenation index (PaO2/FiO2) and partial pressure of arterial oxygen (PaO2) increased (P<0.05) and increased after resumed supine ventilation (P<0.05). Compared with initial supine ventilation, PaO2/FiO2 and PaO2 increased greatly after resumed supine ventilation (P<0.01). PaO2 was increased in extra-pulmonary disease group compared with pulmonary disease group at the same time. If a 10 mmHg increase was regarded as the standard of treatment effectiveness, then the effective rate in the extra-pulmonary disease group was 72% and in the pulmonary disease group was 33%, the difference being significant (P<0.05). (2) The change of lung volume:FRC increased after lateral ventilation (P<0.05) and decreased after resumed supine ventilation (P< 0.05). Compared with initial supine ventilation, there was no significant difference in FRC after resumed supine ventilation (P>0.05). FRC was increased in pulmonary disease group compared with extra-pulmonary disease group, the difference being significant (P <0.05). (3) The change of lung mechanics:There were no significant differences in PIP, Pm, Raw, Cst after change of positions (P>0.05 for all). (4) The change of hemodynamics: There were no significant differences in HR and MAP after change of positions (P>0.05 for all). Conclusion:Increased FRC and improved oxygenation markedly in lateral position ventilation in two groups; the outcome of the patients with ARDS needs further investigation.