[Non-specific bronchoprovocation with metacholine in children before and during sugar cane burning in Catanduva-SP]

OBJECTIVE: Evaluate the influence of sugar cane burning on BHR of asthmatic and "normal" control children by metacholine bronchoprovocation tests; and verify if interferes in pulmonary function tests.METHODS: Twenty-two asthmatic children (A) aged from 7 to 14 years old, and twelve "normal" control children (C), aged from 8 to 13 years, were submitted to non-specific bronchoprovocation test with methacholine before and during the sugar cane burning. The metacholine concentrations used were 0.025; 0.25; 1.0; 2.5; 10.0; 25.0 mg/ml, and the results were expressed in PC(20) FEV1 (concentration of metacholine that induces a fall of 20% or more in the forced expiratory volume in the first second).RESULTS: The PC(20) average for asthmatic children was significantly lower than the control group, before (A= 3.68; C= 25.62 mg/ml) and during the burning (A= 4.11; C= 25.25 mg/ml) (p < 0.05). However, there were no significant differences, when compared in each group PC(20) values before and during burning. The same was observed regarding FEV1, forced vital capacity (FVC) and forced expiratory flux between 25 and 75% of FVC (FEF (25-75%)).CONCLUSIONS: It was not possible to demonstrate that cane plantation burning influences the BHR, and pulmonary functions tests of the studied children.