To test the hypothesis that the overall incidence of chest tubes insertion for pneumothoraces in pediatric ARDS patients has decreased with protective lung strategy (PLS) during mechanical ventilation (MV) while the incidence of chest tubes insertion for pleural effusions has increased.
We retrospectively reviewed charts of pediatric ARDS patients who required a minimum PEEP level of 8 cm of water. Data of patients treated in our PICU during years 1992 –1993 (pre-PLS) were compared with those of years 2000-2003 (post-PLS). Pre-PLS was defined as a period during which unlimited peak airway pressures (PIP) were allowed during MV and the tidal volumes used were ranging between 10 ml/kg and 20 ml/kg. Post-PLS was characterized by MV with smaller tidal volumes (6-10 ml/kg) and by PIP values not exceeding 40 cm of water.
Twenty seven patients were studied in the pre-PLS period and 59 patients in the post-PLS period. The incidences of chest tubes insertion was 55% (15 out of 27) and 19% (11 out of 59), respectively (p<0.05). In the pre-PLS period, 14 out of the 15 chest tubes (93%) were inserted for pnemothoraces evacuation and 1 (7%) for evacuation of pleural effusion. In the post-PLS period 5 of the chest tubes (45%) were for pnumothoraces and 6 (55%) for pleural effusion (p<0.05).
The overall incidences of tube thoracostomy for pneumothoraces and for pleural effusions with PLS implementation has significantly decreased and increased, respectively.
Our study supports the clinical theory that the ‘Starling resistor’ principles for pressure relationship within lung units could explain why the high pre-PLS airway pressures could prevent pulmonary exudates (effusions) but not pneumothoraces and vice versa.
Michael Miller, None.