Outcome and characteristics of infants with acute viral bronchiolitis submitted to mechanical ventilation in a Brazilian pediatric intensive care.

Bueno, Fernanda Umpierre; Piva, Jefferson Pedro; Garcia, Pedro Celiny Ramos; Lago, Patrícia Miranda; Einloft, Paulo Roberto

OBJECTIVE To describe the characteristics and the outcome of infants with acute viral bronchiolitis submitted to mechanical ventilation. METHODS We performed a retrospective study enrolling all infants (less than 12 months old) admitted with the diagnosis of acute viral bronchiolitis and submitted to mechanical ventilation in an university affiliated Brazilian pediatric intensive care unit between March, 2004 and September, 2006 (3 consecutives winters). The mechanical ventilation parameters' employed on 1st, 2nd, 3rd, 7th day and before extubation were evaluated as well as the evolution (mortality rate, presence of acute respiratory distress syndrome and the prevalence of complications). The groups were compared using the Student t test, the Mann-Whitney U test and the Chi-square test. RESULTS Fifty-nine infants were included (3.8 ± 2.7 months old, 59% male), with 9.0 ± 9.4 days on mechanical ventilation. Prior mechanical ventilation, non invasive ventilation was instituted in 71% of children. Anemia was observed in 78% of the sample. In 51 infants (86.5%) the lower airway obstructive pattern was maintained up to tracheal extubation with a nil mortality and low prevalence of pneumothorax (7.8%). Acute respiratory distress syndrome occurred in 8 infants (13.5%), with higher mortality and a higher prevalence of pneumothorax (62.5%). CONCLUSIONS The declining mortality in acute viral bronchiolitis is observed even in non developed regions, involving children with high rates of anemia and premature labor. The low mortality is associated with the maintenance of the lower airway obstructive pattern during the period on mechanical ventilation. The development of acute respiratory distress syndrome is associated with increased mortality and higher prevalence of complications, representing the actual challenge in the management of children with severe acute viral bronchiolitis.