Jornal Brasileiro de Pneumologia (Dec 2010)
Temperatura do ar exalado, um novo biomarcador no controle da asma: um estudo piloto Exhaled breath temperature, a new biomarker in asthma control: a pilot study
Abstract
OBJETIVO: Avaliar se a temperatura do ar exalado (TAE), medida por um método não invasivo, é efetiva no monitoramento de pacientes com asma não controlada. MÉTODOS: Estudo piloto com nove pacientes (sete mulheres e dois homens; média de idade: 39 anos) com diagnóstico de asma por pelo menos um ano e sem uso de tratamento de manutenção por pelo menos três meses antes do início do estudo. Na primeira visita, os pacientes foram submetidos à espirometria e à medida da TAE. Todos os pacientes foram orientados a iniciar tratamento com budesonida/formoterol (200/6 µg) inalatório a cada 12 h por seis semanas. Além disso, os pacientes com asma grave (VEF1 OBJECTIVE: To evaluate whether the exhaled breath temperature (EBT), measured by a noninvasive method, is an effective means of monitoring patients with uncontrolled asthma. METHODS: A pilot study comprising nine patients (seven women and two men; mean age: 39 years) diagnosed with asthma at least one year prior to the beginning of the study and not having been under maintenance therapy for the last three months. In the first visit, the patients underwent spirometry and measurement of EBT. The patients were then instructed to use inhaled budesonide/formoterol (200/6 µg) every 12 h for six weeks. In addition, the patients with severe asthma (FEV1 < 60% of predicted) were instructed to use oral prednisolone (40 mg/day) for five days. After six weeks, the patients underwent the same tests. RESULTS: All of the patients reported an improvement in the symptoms of asthma, as confirmed by a statistically significant increase in FEV1 from the first to the second visit (mean, 56.1% vs. 88.7% of predicted; p < 0.05). Five patients used oral prednisolone for the first five days of the treatment period. Six patients used additional doses of inhaled budesonide/formoterol (mean duration, 2.5 weeks). The EBT decreased significantly from the first to the second visit (mean EBT: 35.1ºC vs. 34.1ºC; p < 0.05). CONCLUSIONS: Uncontrolled asthma, especially during exacerbations, is followed by an increase in EBT, which decreases after appropriate asthma control, as demonstrated by an increase in FEV1 and an improvement of the reported symptoms. These preliminary results suggest that EBT can be used as a parameter for the assessment of asthma control.
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