조절된 천식 소아에서 약제 중단 후 외래용 간이 폐활량계를 이용하여 정기적으로 평가한 기도가역성 지표의 변화: 예비 연구 = Changes in the Indices of Bronchial Reversibility Assessed by the Office Spirometry and Their Relationship to Asthma Symptoms after Discontinuing Controller Medication in Children with Controlled Asthma: Pilot Study

다국어 초록 (Multilingual Abstract)

Purpose:It is important to assess the level of control in asthmatic children who were well-controlled and thus discontinued controller medications. Office spirometry has been regarded to provide objective measures. We aimed to see time changes in lung function indices measured by the office spirometry and their relationship to clues for asthma exacerbation after discontinuation of controller medications.
Methods:As a pilot study, a total of 20 well-controlled children with persistent asthma were included. After discontinuing controller medications, each made follow-up visits at the 2nd, 6th, and 12th week. At each visit, spirometric values before and after bronchodilators were evaluated by the office-based spirometer. Time changes and their relationship to clues for asthma exacerbation were assessed.
Results:Among 20 children, 13 (65%) were successfully followed-up for 12 weeks with asthma kept stable. They presented similar spirometric values (forced expiratory volume in 1 second [FEV1], peak expiratory flow rate [PEFR], bronchodilator responses [BDRs] based on the FEV1 and PEFR) across all time-points. No differences in spirometric values were found between those who were stable and those who exhibited clues for asthma exacerbation. BDRs calculated from FEV1 values (BDRFEV1) correlated well with those calculated from PEFR values (BDRPEFR).
Conclusion:When controller medications were discontinued in children with well-controlled asthma, many of them were able to maintain the stable condition. Since the spirometric measures including BDR failed to differentiate clues for asthma exacerbation, the usefulness of office spirometry needs to be reevaluated by the larger population of children with controlled asthma after discontinuing medications.

국문 초록 (Abstract)

목적:잘 조절된 천식 소아에서 조절 약제의 사용 중단 후, 폐 기능 지표를 외래용 간이 폐활량계로 측정하여 그 변화 양상을 관찰하고 호흡기 증상 악화 여부와의 연관성을 평가하였다.
방법:예비 연구로서 서울대학교병원 소아청소년과에 내원하여 지속성 천식으로 확진 받고 조절제를 사용 중인 학동기 소아로, 3개월 이상 잘 조절된 상태가 유지되는 소아 20명을 대상으로 조절제를 중단하고 12주 동안 추적 관찰 하였다. 조절제 중단 당일, 2주, 6주, 12주 차에 외래에 내원하여 천식 조절 상태에 대한 설문과 이학적 검진을 시행하고, 휴대용 폐활량계로 기관지 확장제 흡입 전후의 폐 기능 지표를 측정하여 그 추이를 관찰하고 임상 소견과의 연관성을 평가하였다.
결과:총 13명(65%)의 소아가 조절 상태를 유지한 채 추적 관찰을 완료하였는데, 이들에서 기관지 확장제 반응(BDRFEV1, BDRPEFR)은 방문 시기별 차이를 보이지 않았다. 또한 각 관찰 시기별로 천식 증상을 보였거나 천명음을 청진할 수 있었던 증상 악화군과 나머지 안정군은 기관지 확장제 반응 뿐 아니라 폐 기능 검사 지표 (FEV1, PEFR)에 있어 차이를 보이지 않았다. 한편 모든 측정 시점에서 측정된 BDRFEV1과 BDRPEFR은 동일 소아에서 반복 측정된 영향을 보정하여 산출 시, 좋은 상관 관계를 보였다.
결론:잘 조절된 천식 소아에서 조절제 사용 중단 시 다수에서 천식 악화는 관찰되지 않았으나, 외래용 간이 폐활량계를 이용하여 평가한 폐 기능 지표가 호흡기 증상 악화에 따라 차이가 있음을 규명할 수는 없었다. 따라서 약제 중단 후 천식 상태의 평가에서 외래용 간이 폐활량계의 유용성에 대해서는 향후 보다 큰 규모의 후속 연구가 필요할 것으로 생각된다.

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