Beneficial effects of chest tube drainage of pleural effusion in acute respiratory failure refractory to positive end-expiratory pressure ventilation.

BACKGROUND: As part of an ongoing prospective evaluation of the response of acute respiratory failure (ARF) to ventilation with titrated amounts of positive end-expiratory pressure (PEEP), a subset of patients with a poor response to the initial application of PEEP and radiographic evidence of pleural effusion was identified. The effusion(s) were treated by tube thoracostomy (TT) to test the hypothesis that drainage would have a favorable effect on oxygenation and compliance in critically ill patients with substantial pulmonary dysfunction.

METHODS: Consecutive patients with ARF underwent a titrated progressive application of PEEP if arterial oxygen saturation was less than 90% on fraction of inspired oxygen less than 0.5. One or two thoracostomy tubes (TT) were placed afterward in patients with radiologic evidence of effusion who had a poor response to PEEP therapy. The lung injury score (LIS), PaO2:FiO2 (P:F), peak airway pressure, dynamic compliance, and TT output were recorded. Changes over time were analyzed by one-way analysis of variance with repeated measures.

RESULTS: Nineteen of 199 patients needed TT. LIS was 3.0 +/- 0.1. Maximum PEEP was 16.6 +/ 1.0 cm H2O. TT drainage was 863 +/- 164 ml in the first 8 hours. Mortality was 63% (12 of 19) but only 41% (74 of 180) in the patients who did not require TT (p = 0.11). TT improved oxygenation and compliance immediately after insertion in 17 of 19 patients, and P:F remained statistically higher (245 +/- 29 versus 151 +/- 13, p < 0.01) 24 hours after TT drainage. There was no correlation between the volume of fluid removed and P:F either immediately (R2, 0.16) or 24 hours after TT (R2, 0.07).

CONCLUSIONS: Drainage of pleural fluid resulted in a significant improvement in oxygenation in ARF patients with pleural effusions who were refractory to treatment with mechanical ventilation and PEEP. TT represents a simple and safe alternative for aggressive management of selected patients, obviating the inherent risk of pneumothorax with thoracentesis and possibly avoiding the need for more complex forms of support in this critically ill patient population.