Prediction of ventilation weaning outcome: children are not little adults

In this issue of Critical Care, Leclerc and colleagues [1] report on whether mechanical ventilation weaning predictors proposed by the Task Force of the American College of Chest Physicians (ACCP) are useful to predict weaning outcome in children. Determination of predictors of weaning from mechanical ventilation in children is important, not only to reduce the risk of re-intubation and avoid delaying weaning resulting in longer paediatric intensive care unit (PICU) stay, but also to provide clearer weaning guidelines, especially as there is an increasing trend for weaning and extubation to be carried out by nursing staff. In addition, unsuccessful extubation increases both morbidity and mortality. Kurachek et al. [2] found that PICU patients failing extubation had longer length of PICU stay (17 versus 7 days), and a significantly higher mortality (4% versus 0.8%).In adult intensive care, there are established indices predicting the outcome of trials of weaning from mechanical ventilation, such as the rapid shallow breathing index [3]. These were established to identify the earliest time that a patient can resume spontaneous breathing [3] and they also appear to apply if performed immediately pre-extubation [4]. Major efforts have been made to identify parameters that can predict extubation failure in children, but a clearly defined set of risk factors has not yet been established. Leclerc et al. [1] also found that the ACCP adult criteria were poor predictors of weaning outcome in children.There are several possible reasons for this discrepancy between adult and paediatric studies. In the adult studies, the length of mechanical ventilation and failed weaning rate are higher than in children, thus possibly allowing identification of risk factors using smaller numbers of patients. In the adult studies, the median length of ventilation was 8 to 11 days [3,4], and weaning failure rates were 40% [3]. In paediatric studies, the length of mechanical ventilation is general