Leddy J J, Roberts A, Moalem J, Curry T, Lundgren C E
Center for Research and Education in Special Environments, Department of Physiology and Biophysics, State University of New York at Buffalo, USA.
Undersea Hyperb Med. 2001 Summer;28(2):75-82.
Immersion induces air trapping in the lungs, as does asthma. Consequently, when using diving apparatus, asthmatics may face greater risk than non-asthmatics of pulmonary barotrauma (PBT) during ascent. We studied the pulmonary airflows and closing capacities (CC = closing volume + residual volume) in subjects with exercise-induced asthma (A, n = 12) and in healthy controls (C, n = 11) under four conditions: dry and immersed, both before and after exercise (treadmill running, non-immersed). Immersed, both C and A had significant and equivalent reductions in vital capacity, FEV1, FEV1/FVC, and FEF25%-75%. Post-exercise and immersed, pulmonary airflows deteriorated further in A but were better in C: FEV1 (A, 3.6 +/- 0.8 liter vs. 3.3 +/- 0.8 liter, P = 0.001; C, 3.9 +/- 0.5 liter vs. 4.1 +/- 0.6 liter, P = 0.006), FEF25-75% (A, 3.5 +/- 1.0 liter x s(-1) vs. 3.0 +/- 0.8 liter x s(-1). P < 0.05; C, 4.0 +/- 0.9 liter x s(-1) vs. 4.3 +/- 0.9 liter x s(-1), P < 0.05). Therefore, in contrast to C, A subjects had reduced pulmonary airflows during immersion after exercise. Furthermore, A subjects more often had no closing volume phase IV when immersed after exercise than C (P = 0.005). Interpreting the absence of phase IV as indicative of more air trapping in the asthmatics during immersion after exercise would be consistent with the reductions in airflow.
与哮喘一样，浸入水中会导致肺部气体潴留。因此，哮喘患者在使用潜水设备时，上升过程中发生肺气压伤（PBT）的风险可能比非哮喘患者更高。我们研究了运动诱发性哮喘患者（A组，n = 12）和健康对照者（C组，n = 11）在四种情况下的肺气流和闭合容量（CC = 闭合容积 + 残气量）：运动前和运动后（跑步机跑步，非浸入状态）的干燥和浸入状态。浸入水中时，C组和A组的肺活量、第一秒用力呼气容积（FEV1）、FEV1/用力肺活量（FVC）和25%-75%用力呼气流量（FEF25%-75%）均有显著且相当程度的降低。运动后浸入水中时，A组的肺气流进一步恶化，而C组则较好：FEV1（A组，3.6±0.8升对3.3±0.8升，P = 0.001；C组，3.9±0.5升对4.1±0.6升，P = 0.006），FEF25-75%（A组，3.5±1.0升·秒⁻¹对3.0±0.8升·秒⁻¹，P < 0.05；C组，4.0±0.9升·秒⁻¹对4.3±0.9升·秒⁻¹，P < 0.05）。因此，与C组相比，A组患者运动后浸入水中时肺气流降低。此外，运动后浸入水中时，A组患者比C组更常出现无闭合容积IV期（P = 0.）。将无IV期解释为运动后浸入水中时哮喘患者气体潴留更多，这与气流降低是一致的。
