Objective: To assess the effect of mechanical ventilation on prone position for the treatment of acute respiratory distress syndrome (ARDS) originating from pulmonary disease and extra-pulmonary disease.
Methods: From January 2001 to February 2004 in intensive care unit (ICU), 42 patients with ARDS were divided into pulmonary disease group and extra-pulmonary disease group. All the patients were mechanically ventilated on prone position. Arterial blood gases, respiratory rate (RR), fraction of inspired oxygen (FiO(2)), pulmonary compliance (C), tidal volume (V(T)), airway resistance (Raw) were measured before prone position and 2 hours and 4 hours after prone position. Lung-CT was measured in supine position and prone position.
Results: When patients were turned to prone position, SaO(2) and RR were decreased markedly in two groups. V(T) was increased in extra-pulmonary disease groups compared with pulmonary disease group at the same time. Oxygen index, hemoglobin oxygen saturation and Raw were increased markedly when patients were turned to prone position, and oxygen index of pulmonary disease group was higher than that of extra-pulmonary disease group at the same time. No change was found in blood pH and partial pressure of carbon dioxide in artery (PaCO(2)), but oxygenation was improved markedly in two groups. The effective rate of improved oxygenation was 65% in pulmonary disease group and 68% in extrapulmonary disease group, but no significant difference was found. Lung CT revealed that when the patients were in prone position, the degree of lung infiltration in the dorsal part of lung decreased while that in the ventral part increased.
Conclusion: Oxygenation is improved markedly in prone position in two groups. Mechanical ventilation on prone position was an effective method in the treatment of ARDS patients.