University of California San Francisco Flight Attendants Medical Research Institute Center of Excellence, San Francisco, California, United States of America.
PLoS One. 2012;7(4):e34393. doi: 10.1371/journal.pone.0034393. Epub 2012 Apr 6.
Flight attendants who worked on commercial aircraft before the smoking ban in flights (pre-ban FAs) were exposed to high levels of secondhand smoke (SHS). We previously showed never-smoking pre-ban FAs to have reduced diffusing capacity (Dco) at rest.
To determine whether pre-ban FAs increase their Dco and pulmonary blood flow (Qc) during exercise, we administered a symptom-limited supine-posture progressively increasing cycle exercise test to determine the maximum work (watts) and oxygen uptake (VO2) achieved by FAs. After 30 min rest, we then measured Dco and Qc at 20, 40, 60, and 80 percent of maximum observed work.
The FAs with abnormal resting Dco achieved a lower level of maximum predicted work and VO2 compared to those with normal resting Dco (mean±SEM; 88.7±2.9 vs. 102.5±3.1%predicted VO2; p = 0.001). Exercise limitation was associated with the FAs' FEV(1) (r = 0.33; p = 0.003). The Dco increased less with exercise in those with abnormal resting Dco (mean±SEM: 1.36±0.16 vs. 1.90±0.16 ml/min/mmHg per 20% increase in predicted watts; p = 0.020), and amongst all FAs, the increase with exercise seemed to be incrementally lower in those with lower resting Dco. Exercise-induced increase in Qc was not different in the two groups. However, the FAs with abnormal resting Dco had less augmentation of their Dco with increase in Qc during exercise (mean±SEM: 0.93±0.06 vs. 1.47±0.09 ml/min/mmHg per L/min; p<0.0001). The Dco during exercise was inversely associated with years of exposure to SHS in those FAs with ≥10 years of pre-ban experience (r = -0.32; p = 0.032).
This cohort of never-smoking FAs with SHS exposure showed exercise limitation based on their resting Dco. Those with lower resting Dco had reduced pulmonary capillary recruitment. Exposure to SHS in the aircraft cabin seemed to be a predictor for lower Dco during exercise.
在航班禁烟令实施前（禁烟令前）在商业航班上工作的空乘人员曾接触过高水平的二手烟（SHS）。我们之前曾表明，从不吸烟的禁烟令前空乘人员在休息时的弥散能力（Dco）降低。
为了确定禁烟令前的空乘人员在运动期间是否增加了 Dco 和肺血流量（Qc），我们对空乘人员进行了一项症状限制的仰卧位逐渐增加的循环运动测试，以确定他们实现的最大工作量（瓦特）和氧气摄取量（VO2）。休息 30 分钟后，我们在最大观察到的工作量的 20%、40%、60%和 80%时测量 Dco 和 Qc。
与休息时 Dco 正常的空乘人员相比，休息时 Dco 异常的空乘人员达到的最大预测工作量和 VO2 水平较低（平均值±SEM；88.7±2.9%与 102.5±3.1%预测 VO2；p=0.001）。运动受限与空乘人员的 FEV（1）有关（r=0.33；p=0.003）。休息时 Dco 异常的空乘人员在运动时 Dco 的增加较少（平均值±SEM：1.36±0.16 与 1.90±0.16 ml/min/mmHg 每 20%增加预测瓦特；p=0.020），而且在所有空乘人员中，休息时 Dco 较低的人，运动时的增加似乎逐渐较低。两组间运动诱导的 Qc 增加无差异。然而，休息时 Dco 异常的空乘人员在运动时，随着 Qc 的增加，Dco 的增加幅度较小（平均值±SEM：0.93±0.06 与 1.47±0.09 ml/min/mmHg 每 L/min；p<0.0001）。在禁烟令前经验≥10 年的空乘人员中，运动时的 Dco 与 SHS 暴露量呈负相关（r=-0.32；p=0.032）。
本队列从不吸烟的空乘人员因 SHS 暴露而出现运动受限，基于他们的休息时 Dco。休息时 Dco 较低的人肺毛细血管募集减少。在飞机机舱内接触 SHS 似乎是运动时 Dco 降低的一个预测因素。
