United States Army Institute of Surgical Research, Pulmonary/Critical Care Service, Department of Medicine, Brooke Army Medical Center, Fort Sam Houston, TX, USA.
Crit Care Med. 2011 Oct;39(10):2314-21. doi: 10.1097/CCM.0b013e318225b5b3.
The role of airway pressure release ventilation in the management of early smoke inhalation injury has not been studied. We compared the effects of airway pressure release ventilation and conventional mechanical ventilation on oxygenation in a porcine model of acute respiratory distress syndrome induced by wood smoke inhalation.
Prospective animal study.
Government laboratory animal intensive care unit.
Thirty-three Yorkshire pigs.
Smoke inhalation injury.
Anesthetized female Yorkshire pigs (n = 33) inhaled room-temperature pine-bark smoke. Before injury, the pigs were randomized to receive conventional mechanical ventilation (n = 15) or airway pressure release ventilation (n = 12) for 48 hrs after smoke inhalation. As acute respiratory distress syndrome developed (PaO2/Fio2 ratio <200), plateau pressures were limited to <35 cm H2O. Six uninjured pigs received conventional mechanical ventilation for 48 hrs and served as time controls. Changes in PaO2/Fio2 ratio, tidal volume, respiratory rate, mean airway pressure, plateau pressure, and hemodynamic variables were recorded. Survival was assessed using Kaplan-Meier analysis. PaO2/Fio2 ratio was lower in airway pressure release ventilation vs. conventional mechanical ventilation pigs at 12, 18, and 24 hrs (p < .05) but not at 48 hrs. Tidal volumes were lower in conventional mechanical ventilation animals between 30 and 48 hrs post injury (p < .05). Respiratory rates were lower in airway pressure release ventilation at 24, 42, and 48 hrs (p < .05). Mean airway pressures were higher in airway pressure release ventilation animals between 6 and 48 hrs (p < .05). There was no difference in plateau pressures, hemodynamic variables, or survival between conventional mechanical ventilation and airway pressure release ventilation pigs.
In this model of acute respiratory distress syndrome caused by severe smoke inhalation in swine, airway pressure release ventilation-treated animals developed acute respiratory distress syndrome faster than conventional mechanical ventilation-treated animals, showing a lower PaO2/Fio2 ratio at 12, 18, and 24 hrs after injury. At other time points, PaO2/Fio2 ratio was not different between conventional mechanical ventilation and airway pressure release ventilation.
气道压力释放通气在早期烟雾吸入性损伤治疗中的作用尚未得到研究。我们比较了气道压力释放通气和常规机械通气对烟雾吸入性急性呼吸窘迫综合征猪模型的氧合作用。
前瞻性动物研究。
政府实验室动物重症监护病房。
33 头约克夏猪。
烟雾吸入损伤。
麻醉雌性约克夏猪（n = 33）吸入室温松节油烟雾。在损伤前，猪被随机分为常规机械通气组（n = 15）或气道压力释放通气组（n = 12），在烟雾吸入后 48 小时接受治疗。当急性呼吸窘迫综合征发生（PaO2/Fio2 比 <200）时，将平台压力限制在 <35 cm H2O。6 头未受伤的猪接受常规机械通气 48 小时，作为时间对照。记录 PaO2/Fio2 比、潮气量、呼吸频率、平均气道压、平台压和血流动力学变量的变化。采用 Kaplan-Meier 分析评估存活率。气道压力释放通气组的 PaO2/Fio2 比值在 12、18 和 24 小时（p <.05）时低于常规机械通气组，但在 48 小时时无差异。在损伤后 30 至 48 小时，常规机械通气动物的潮气量较低（p <.05）。在 24、42 和 48 小时，气道压力释放通气动物的呼吸频率较低（p <.05）。在 6 至 48 小时，气道压力释放通气动物的平均气道压较高（p <.05）。常规机械通气与气道压力释放通气猪的平台压、血流动力学变量和存活率无差异。
在本研究中，严重烟雾吸入性猪急性呼吸窘迫综合征模型中，气道压力释放通气治疗动物比常规机械通气治疗动物更快地发生急性呼吸窘迫综合征，在损伤后 12、18 和 24 小时时 PaO2/Fio2 比值较低。在其他时间点，常规机械通气和气道压力释放通气之间的 PaO2/Fio2 比值没有差异。
