Air leaks from the respiratory tract in mechanically ventilated children with severe respiratory disease.

Our objectives were to evaluate the frequency of air leaks (AL) from the respiratory tract (pneumothorax, pneumomediastinum, pneumoperitoneum, subcutaneous emphysema) in critically ill children on mechanical ventilation (MV) for severe respiratory diseases, and to examine whether AL could be correlated with specific clinical events or ventilator settings. The study constitutes a retrospective cohort of 80 consecutive critically ill children receiving MV for severe respiratory diseases between 1986 and 1993. Patients (mean age 2.9 +/- 0.6 years, 49 males and 31 females), were admitted to the Pediatric Intensive Care Unit (PICU) with acute respiratory syndrome (ARDS) (27%), asthma (15%), bronchiolitis (10%), pneumonia (21%), pulmonary congenital diseases (9%), or foreign body aspiration (18%). Patients were divided into two groups; those with AL (n=22) and those without air-leaks (non-AL) (n = 58). Air leaks developed in 22 of 80 patients or in 27.5%. Survival was significantly lower in the AL group, compared to the non-AL group (41% vs. 76%, P < 0.01). The odds ratio that a patient with multiple organ system failure (MOSF) or infection would develop AL was 2.96 and 2.19, respectively. Candida and Pseudomonas species were recovered with significantly higher frequency in the AL group compared with the non-AL group (P < 0.025). There was a strong positive correlation between the incidence of AL and high ventilatory pressures (PIP 36 vs. 29.7 cm H(2)O, P < 0.001), or large tidal volumes (V(T) 12 vs. 9 mL/kg, P < 0.05), suggesting that large volumes might elicit injury to the pulmonary epithelium. Multiple logistic regression analysis showed that only V(T) was independently associated with the development of AL in children with primary severe respiratory disease (r(2) = -0.38, P = 0.01). In conclusion, MV will produce AL, particularly when high peak airway pressures (barotrauma) or large tidal volumes (volotrauma) are delivered by the ventilator. Sepsis, MOSF, and lung superinfection with Pseudomonas or Candida species may be also important factors in the development of AL in critically ill children.