Miedinger David, Bläuenstein Andrea, Wolf Nathalie, Frey Franz, Karli Christoph, Leuppi Jörg D
University Hospital, 4031 Basel, Switzerland.
J Asthma. 2010 Mar;47(2):178-84. doi: 10.3109/02770900903483782.
Breathing dry, cold air may cause bronchoconstriction in asthmatics working with self-contained breathing apparatus (SCBA). Air delivered by SCBA is cooler than ambient air. It is unclear whether a bronchial challenge test using mannitol (BCTM) can predict a fall in forced expiratory volume in one second (FEV(1)) during exercise with SCBA.
A prospective study of army recruits assigned to work with SCBA was carried out. Participants completed self-administered questionnaires on respiratory symptoms, BCTM, and measurement of exhaled nitric oxide. A subgroup of participants with a positive BCTM (BTCM+) and with negative BCTM underwent exercise test on bicycle ergometer (ET) while using SCBA.
One hundred and six recruits participated in this study. One hundred and two underwent BCTM and 28 ET. Nineteen out of 97 participants had a positive BCTM and 6 out of 27 had a positive ET. Seventeen out of 19 participants with a positive BCTM had current respiratory symptoms such as wheeze, cough, chest tightness, or dyspnea. Sensitivity, specificity, positive predictive value, and negative predictive value for a positive ET under SCBA were 100%, 64%, 43%, and 100% for the BCTM, respectively. BCTM-positive participants with respiratory symptoms had more physician consultations during MBT compared to BCTM-negative participants.
Despite medical evaluation and exclusion of asthmatics by a physician during conscription, a high proportion of recruits assigned to work with SCBA smoke, have respiratory symptoms, and have a positive BCTM suggesting current asthma. BCTM has a high sensitivity to predict a significant fall in FEV(1) after exercise with SCBA and participants with a positive BCTM tend to use more health care resources during basic military training. Recruits should be counseled about smoking cessation prior and during basic military training.
对于使用自给式呼吸器（SCBA）的哮喘患者而言，呼吸干燥、寒冷的空气可能会导致支气管收缩。SCBA输送的空气比周围空气温度低。目前尚不清楚使用甘露醇进行的支气管激发试验（BCTM）能否预测使用SCBA进行运动期间一秒用力呼气量（FEV₁）的下降情况。
对被分配使用SCBA工作的新兵进行了一项前瞻性研究。参与者完成了关于呼吸道症状、BCTM以及呼出一氧化氮测量的自我管理问卷。BCTM呈阳性（BTCM+）和BCTM呈阴性的参与者亚组在使用SCBA的同时在自行车测力计上进行运动测试（ET）。
106名新兵参与了本研究。102人接受了BCTM检查，28人接受了ET测试。97名参与者中有19人BCTM呈阳性，27名中有6人ET呈阳性。19名BCTM呈阳性的参与者中有17人目前有呼吸道症状，如喘息、咳嗽、胸闷或呼吸困难。在使用SCBA的情况下，BCTM对于ET呈阳性的敏感性、特异性、阳性预测值和阴性预测值分别为100%、64%、43%和100%。与BCTM呈阴性的参与者相比，有呼吸道症状的BCTM呈阳性参与者在军事基础训练期间看医生的次数更多。
尽管在征兵期间医生进行了医学评估并排除了哮喘患者，但被分配使用SCBA工作的新兵中仍有很大比例吸烟、有呼吸道症状且BCTM呈阳性，提示当前患有哮喘。BCTM对于预测使用SCBA运动后FEV₁的显著下降具有较高的敏感性，且BCTM呈阳性的参与者在基础军事训练期间往往会使用更多的医疗资源。应在基础军事训练之前及期间向新兵提供戒烟咨询。
