Study objectives: Investigating the effect of low-volume pressure-limited ventilation and repeated prone positioning on the short-term course and outcome in patients with severe ARDS.
Setting: Level 1 trauma center of a university hospital.
Patients: Twenty-five patients suffering from ARDS with a lung injury score (LIS) ≥2.5 admitted consecutively to our ICU from January 1992 to December 1994.
Methods: Mechanical ventilation with peak inspiratory pressure limitation to 35 mbar, irrespective of hypercapnia and prone positioning to achieve adequate oxygenation.
Scoring and measurements: Patient assessment with LIS, APACHE (acute physiology and chronic health evaluation) II score, injury severity score, and multiple organ failure score. Blood gas analyses and estimation of static compliance were repeated at least every 4 h during the treatment period. PaO2/FIO2 (fraction of inspired oxygen) ratio, alveolo-arterial oxygen difference, and intrapulmonary shunt were calculated according to standard equations. The best values taken from each 4-h period during the investigation were used to evaluate the best possible performance of the lung within this interval and to investigate the entire course.
Results: Mean predicted mortality based on the APACHE II score was 35.4±15.2%. Three of the 25 patients (12%) died. However, none was related to respiratory failure. No pneumothorax occurred. Sixteen patients, lacking any contraindication for prone positioning, responded positively to this change in position, each to a different individual degree.
Conclusion: We assume that our low mortality in patients with severe ARDS might be due mainly to low-volume pressure-limited ventilation and prone positioning. This simple strategy seems to allow successful treatment for patients with severe ARDS.