만성기침환자에서 비강최대흡기유속 측정의 의의

Clinical Significance of Nasal Peak Inspiratory Flow Rate in Patients with Chronic Cough

연구배경 : 만성기침환자에 있어서 비폐색과 같은 주관적인 상기도 증상을 객관적인 지표로 나타내어 비교할 수 있게 하기 위해, 최근 비교적 높은 재현성을 보이는 것으로 보고된 비강최대흡기유속을 측정하여 만성기침환자들에서 비폐색을 객관적으로 측정해보고자 하였다. 방 법 : 정상인 7명에서 하루 2회씩 3일 동안 휴대용 폐활량 측정기를 이용하여 비강최대흡기유속과 폐기능검사를 시행하였다. 이들 7명을 포함한 총 32명의 정상인들과 만성기침환자 32명을 선별하여 최초 첫 방문 시에 비강최대흡기유속과 폐기능검사를 시행하였다. 결 과 : 정상인 7명에 대해서는 비교적 일관된 비강최대흡기 유속과 $FEV_1$ 및 FVC를 얻을 수 있었다. 만성기침환자는 남자 14명, 여자 18명으로 총 32명이었으며 나이는 $41.4{\pm}15.9$세였으며, 정상인은 남자 22명, 여자 10명으로 총 32명이었으며 나이는 $39.8{\pm}18.6$세였다. 만성기침환자군과 정상인군 사이의 연령 및 폐기능검사 상의 차이는 없었다. 만성기침환자들에서 비강최대흡기유속은 $2.25{\pm}0.68\;L/sec$, 정상인들에서는 $2.75{\pm}1.00\;L/sec$로 만성기침환자에서 의미 있게 낮았다(p=0.02). 만성기침환자들 중, 후비루종후군환자들이 27명으로 가장 많았으며, 비강최대흡기유속은 $2.18{\pm}0.66\;L/sec$로 정상인 $2.75{\pm}1.00\;L/sec$ 보다 더욱 의미 있게 낮았다(p=0.006). 결 론 : 비강최대흡기유속은 만성기침환자들에 있어서 주관적인 비폐색 증상을 객관적으로 보여주는 지표이다. 비강최대흡기유속은 비교적 재현성 있는 지표이며, 정상인에 비해서 만성기침환자, 특히 원인 질환이 후비루 증후군인 환자들에서 특히 감소되었다. 하지만, 양군간의 값이 중복되는 범위가 많아서 진단 및 감별진단의 지표로서의 가치는 좀 더 많은 대상에 대한 연구에 의하여 확인되어야 할 것으로 생각된다.

Background : The upper respiratory tract is the primary target organ of various airborne pollutants and is easily accessible part of the respiratory tract, and also is the predominant structure where chronic cough originates. The nasal peak inspiratory flow(PIFn), which is the peak inspiratory flow via nose with nasal mask and spirometry, could be a reliable parameter of nasal obstruction. The validity of PIFn has been evaluated in several studies by assessing the correlation between PIFn measurements and other parameters of nasal air flow. This study was designed to show the reproducibility of PIFn, the difference of PIFn between patients with chronic cough and normal subjects, and the usefulness of PIFn in the evaluation of nasal obstruction in patients with chronic cough. Methods : PIFn was measured by spirometry with nasal mask, twice a day for 3 consecutive days in 7 young normal subjects to evaluate validity of the test. In 32 patients with chronic cough and 25 age-matched normal subjects, PIFn and pulmonary function test($FEV_1$, $FEV_1%$ pred, FVC, and FVC% pred) were measured at first visiting. Results : Values of PIFn, $FEV_1$, and FVC were nearly constant in 7 young normal adults. Patients with chronic cough were 32 (14 males and 18 females) and the mean age was $41.4{\pm}15.9$ years. Normal subjects were 32(22 males and 10 females) and the mean age was $39.8{\pm}18.6$ years. There was no significant difference of age and pulmonary function test between patients with chronic cough and normal subjects(p<0.05). The PIFn values in patients with chronic cough was significantly lower than those of normal subjects($2.25{\pm}0.68\;L/sec$ vs. $2.75{\pm}1.00\;L/sec$ ; p=0.02). The postnasal drip syndrome(PNDS) comprised the majority of patients with chronic cough(27). The PIFn in patients with PNDS was significantly lower than that of normal subjects (mean$\pm$SD ; $2.18{\pm}0.66$ vs. $2.75{\pm}1.00\;L/sec$, p=0.006). Conclusion : There was a significant difference of PIFn between patients with chronic cough and normal subjects. Among the patients with chronic cough, patients with PNDS showed the most significant difference with normal subjects in PIFn. The PIFn could be a useful parameter of nasal obstruction in patients with chronic cough, especially in patients with PNDS.