Theophylline toxicity in Thai children.

Theophylline is a useful drug in the treatment of respiratory diseases with bronchospasm but it has very narrow safety margin. The study was carried out in 44 admitted Thai children with plasma theophylline levels > 20 microg/ml to determine the association between blood levels and symptoms of theophylline toxicity. The prevalence of theophylline toxicity (plasma theophylline level > 20 microg/ml) in Thai children is about 11%. Thirty-four percent of the patients who had theophylline levels less than 30 microg/ml and 78% of those who had levels more than 30 microg/ml had symptoms of theophylline toxicity. The symptoms were related to the gastrointestinal tract (34%), cardiovascular system (18.2%), neurological system (6.8%) and metabolism (54.5%). The possible causes of theophylline toxicity were respiratory tract infection, theophylline overdosage, interaction with other drugs, impairment of liver function, congenital heart disease and theophylline usage in neonates. Theophylline is still a useful drug but should be used with caution. Theophylline levels should be checked in every child who receives theophylline.

PRISM score and factors predicting mortality of patients with respiratory failure in the pediatric intensive care unit.

A total of 96 patients with respiratory failure who required mechanical ventilation admitted to the PICU, Chulalongkorn Hospital from July 1998 to June 1999 were reviewed to evaluate the PRISM score for mortality prediction and to identify factors that might influence the outcome. The statistical difference in outcome between the 2 groups (survivors and non-survivors) were underlying diseases, age, maximum positive inspiratory pressure (PIP), maximum positive end expiratory pressure (PEEP), maximum fractional inspiratory oxygen (FiO2) and PRISM score (p < 0.05). However, based on the original logistic regression equation, the predicted mortality from PRISM score in our study was much lower than our actual mortality (2.4% vs 26.0%). The sensitivity and specificity of mortality predicted by PRISM score calculated at cut-off r = 0.0 (expected mortality = 50%) was 4 per cent and 97 per cent respectively. In conclusion, the original PRISM score underpredicted the mortality outcome in our patients with respiratory failure. This suggests that PRISM score is population dependent and should be modified before being used with our patients.