Riedel Thomas, Fraser John F, Dunster Kimble, Fitzgibbon John, Schibler Andreas
Paediatric Intensive Care Unit, The Children's Hospital, West Mead, New South Wales, Australia.
J Appl Physiol (1985). 2006 Sep;101(3):763-70. doi: 10.1152/japplphysiol.01635.2005. Epub 2006 Apr 20.
Smoke inhalation injuries are the leading cause of mortality from burn injury. Airway obstruction due to mucus plugging and bronchoconstriction can cause severe ventilation inhomogeneity and worsen hypoxia. Studies describing changes of viscoelastic characteristics of the lung after smoke inhalation are missing. We present results of a new smoke inhalation device in sheep and describe pathophysiological changes after smoke exposure. Fifteen female Merino ewes were anesthetized and intubated. Baseline data using electrical impedance tomography and multiple-breath inert-gas washout were obtained by measuring ventilation distribution, functional residual capacity, lung clearance index, dynamic compliance, and stress index. Ten sheep were exposed to standardized cotton smoke insufflations and five sheep to sham smoke insufflations. Measured carboxyhemoglobin before inhalation was 3.87 +/- 0.28% and 5 min after smoke was 61.5 +/- 2.1%, range 50-69.4% (P < 0.001). Two hours after smoke functional residual capacity decreased from 1,773 +/- 226 to 1,006 +/- 129 ml and lung clearance index increased from 10.4 +/- 0.4 to 14.2 +/- 0.9. Dynamic compliance decreased from 56.6 +/- 5.5 to 32.8 +/- 3.2 ml/cmH(2)O. Stress index increased from 0.994 +/- 0.009 to 1.081 +/- 0.011 (P < 0.01) (all means +/- SE, P < 0.05). Electrical impedance tomography showed a shift of ventilation from the dependent to the independent lung after smoke exposure. No significant change was seen in the sham group. Smoke inhalation caused immediate onset in pulmonary dysfunction and significant ventilation inhomogeneity. The smoke inhalation device as presented may be useful for interventional studies.
烟雾吸入性损伤是烧伤致死的主要原因。黏液堵塞和支气管收缩导致的气道阻塞可引起严重的通气不均一性并加重缺氧。目前尚无描述烟雾吸入后肺黏弹性特征变化的研究。我们展示了一种新型烟雾吸入装置在绵羊身上的实验结果，并描述了烟雾暴露后的病理生理变化。15只雌性美利奴母羊接受麻醉并插管。通过测量通气分布、功能残气量、肺清除指数、动态顺应性和应力指数，利用电阻抗断层成像和多次呼吸惰性气体洗脱技术获取基线数据。10只绵羊暴露于标准化的棉花烟雾吸入，5只绵羊进行假烟雾吸入。吸入前测得的碳氧血红蛋白为3.87±0.28%，烟雾吸入5分钟后为61.5±2.1%，范围为50 - 69.4%（P < 0.001）。烟雾吸入2小时后，功能残气量从1773±226毫升降至1006±129毫升，肺清除指数从10.4±0.4升至14.2±0.9。动态顺应性从56.6±5.5降至32.8±3.2毫升/厘米水柱。应力指数从0.994±0.009升至1.081±0.011（P < 0.01）（所有均值±标准误，P < 0.05）。电阻抗断层成像显示烟雾暴露后通气从下肺叶向上肺叶转移。假手术组未见明显变化。烟雾吸入导致立即出现肺功能障碍和明显的通气不均一性。所展示的烟雾吸入装置可能对介入研究有用。
