高海拔是否會增加氣胸發生的機率Bullous lung disease (EUROPEAN RESPIRATORY JOURNAL Eur Respir J 2007; 29: 770–792)
Bullous lung disease (EUROPEAN RESPIRATORY JOURNAL Eur Respir J 2007; 29: 770–792)
九位肺水泡(說氣泡似乎更好)疾病患者, 在快速減壓至模擬海拔 13110 公尺的狀態, 肺表面的氣泡只有一例變大, 而且無氣胸發生
六名慢性阻塞性肺病 COPD 患者, 在每分鐘 304公尺減壓速率, 模擬海拔 5488 公尺的氣壓, X光檢查沒有發現水泡擴張, 或氣胸.
四名 COPD患者, 已經有空氣滯留問題, 在模擬海拔至 5488 公尺狀態, 沒有發現肺部功能惡化, 或氣胸.
電腦斷層檢查更詳細的發現, 水泡也許會擴大, 但確實沒有氣胸產生
為何沒有氣胸發生呢?? 原因不明. 也許是肺部水泡疾病的氣泡, 跟呼吸道有相通, 使壓力得以平衡, 此外, 爬山的氣壓變化, 比潛水來的少, 所以肺部水泡和正常肺泡的壓力差比較小.
An important issue in the COPD patient with severe bullous disease is whether the decrease in ambient pressure at altitude might lead to bullae expansion and pneumothorax. The available literature suggests that this concern may be unwarranted. PARKER and STONEHILL [90] studied nine non-COPD patients with blebs or pulmonary cysts and found that upon rapid decompression to a simulated altitude of 13,110 m, the size of the bleb or cyst increased in only one patient and there were no pneumothoraces. TOMASHEFSKI et al. [91] brought six COPD patients with blebs and bullae to a simulated altitude of 5,488 m at a rate of 304 m?min-1 and found no radiographic evidence of bullae distention or pneumothoraces. Finally, YANDA and HERSCHENSOHN [92] took four patients with COPD and evidence of air-trapping to a simulated altitude of 5,488 m and did not find evidence of worsening pulmonary function or pneumothorax. While computed tomography (CT) scanning might provide more accurate assessment of bullae size compared to the conventional radiography used in these studies, the absence of pneumothoraces in these studies is reassuring. The reason for the absence of pneumothoraces in patients with bullous disease has not been elucidated. Bullae may communicate with the airways to a greater extent than expected, allowing for pressure equalisation. In addition, the pressure changes with ascent to altitude (,50 kPa) are less than those seen with scuba diving (200–300 kPa) and, as a result, the pressure gradient for bullae expansion and rupture is much lower.
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