Evaluation of clinical course in patients with eosinophilic bronchitis: A prospective follow up study / 천식및알레르기

BACKGROUND: Eosinophilic bronchitis (EB) presents as a chronic cough and sputum eosinophilia without airflow limitation and bronchial hyperreactivity. The long-term clinical courses remain unknown. OBJECTIVE AND METHOD: The aim of this study was to evaluate how frequently EB recurs and whether it develops into chronic airway obstruction. Cough severity, FEV1, PC20 methacholine and sputum eosinophil percentages were serially measured in 36 subjects for up to 48 months. RESULT: Five subjects developed recurrent episodes of EB (RG) between 4 to 6 months after the first episode of EB. Asthma developed in the 9th month of the study in one of these subjects and a progressive FEV1 reduction exceeding 20% was observed in two. Nineteen subjects had no recurrence of EB (NRG). However, sputum eosinophilia recurred between 4 and 24 months in 10 subjects of the NRG, though this was without cough or FEV1 reduction. The follow-up eosinophil percentages were significantly higher in the RG than NRG group with recurrent sputum eosinophilia. CONCLUSION: About 14% of EB cases experience repeated episodes of EB and in about 30%, the EB recurs as asymptomatic sputum eosinophilia. Moreover, the extent of sputum eosinophilia was found to be associated with the recurrence of eosinophilic bronchitis, which leads to an airflow rate deterioration. These results suggest that repeated episode of EB is a risk factor for the development of asthma or chronic airway obstruction.

Measurement of Ventilatory Threshold in the Patients with Chronic Airway Obstruction / 결핵

BACKGROUND: There are many suggested methods for the indirect determination of anaerobic threshold(AT) using the changes of ventilatory parameters in respones to ventilatory load accompanying the increase of blood lactic acid level during exercise and the threshold derived from them is called ventilatory threshold( VT). They include ventilatory equivalent method(VEM), End-tidal PO2 method(PETO2), V-slope method(VSM), and respiratory quotient method(RQ). But in the patients with chronic airway ohstruction(CAO), the AT determined by ventilatory methods may not reflect true AT because the patients with GAO show inadequate ventilatory response to the increase of blood lactic acid level during excercise. METHODS: For the investigation of detection rate and reliability of above four VT determination methods in the patients with GAO, we performed the symptom-limited and maximal incremental exercise test in 17 patients with GAO and 12 normal controls. The incremental workload was 10 W/min in GAO group and 25 W/min in control group. The reliability of VT in each group was investigated by the calculation of Spearman correlation coefficient. RESULTS: The detection rates of VT were 100% by RQ, 91.7% by both VEM and POETO2, and 83.3% by VSM in normal control group, while 94.1% by RQ, 64.7% by VEM and PETO2, and 83.3% by VSM in GAO group. Good correlations were noted among VEM, PETO2, and VSM except RQ in normal control group. But there was no significant correlation except between VEM and PETO2 in GAO group. CONCLUSIONS: RQ is very sensitive but crude and VEM is near similar to PETO2. The clinical usefulness of VT determined by ventilatory method might be limited in patients with severe GAO.