Cavanagh K A, Hill H F, Wojciechowski W V, Parker J C
Department of Respiratory Care/Cardiopulmonary Sciences, University of South Alabama, Mobile, USA.
Crit Care Med. 1996 Feb;24(2):280-6. doi: 10.1097/00003246-199602000-00017.
To determine whether intubation and ventilation with either conventional mechanical ventilation or high-frequency jet ventilation, using dry or humidified gas, could induce regional tracheal ischemia and serve as a basis for the tracheal necrosis observed clinically during ventilation.
Prospective, multiple group, controlled experimental study.
Medical school research laboratory.
Twenty, 3- to 5-wk-old suckling pigs.
Anesthetized, closed-chest piglets were intubated and ventilated for 30 mins with conventional mechanical ventilation and then ventilated for 2 additional hrs with either conventional mechanical ventilation or high-frequency jet ventilation. Groups were also ventilated, using both modes of ventilation, with either 37 degrees C humidified gas or 25 degrees C dry gas.
Blood flow groups were compared during spontaneous breathing, conventional mechanical ventilation, high-frequency jet ventilation and both ventilation modes, using 37 degrees C humidified or 22 degrees C dry inspired gas. Groups were compared, using an analysis of variance with a Newman-Keul's post-test. Regional tracheal blood flow was measured, using radioactive microspheres. Cardiac output and organ blood flows were also monitored. Tracheal blood flow increased 10.3-fold within 30 mins after intubation, but there were no significant differences in regional or total tracheal blood flow between conventional mechanical ventilation and high-frequency jet ventilation, using 37 degrees C humidified gas. Tracheal blood flow was increased further using high-frequency jet ventilation and 25 degrees C dry gas but not conventional mechanical ventilation with dry gas. Although ventilation reduced cardiac output by approximately 30%, there were no significant differences in organ distribution between modes of ventilation.
Acute tracheal hyperemia occurred with intubation and ventilation with both conventional mechanical ventilation and high-frequency jet ventilation but no differences were observed between ventilation modes. Hyperemia was further increased with cool, dry inspired gas, using high-frequency jet ventilation but not conventional mechanical ventilation. Although acute tracheal ischemia was not produced by high-frequency jet ventilation or conventional mechanical ventilation, factors which alter the balance between arterial supply and metabolic demand or induce inflammation may contribute to the tracheal necrosis reported during sustained ventilation.
确定使用干燥或湿润气体，通过传统机械通气或高频喷射通气进行插管和通气是否会导致局部气管缺血，并作为通气期间临床上观察到的气管坏死的基础。
前瞻性、多组、对照实验研究。
医学院研究实验室。
20只3至5周龄的乳猪。
对麻醉的闭胸仔猪进行插管，先用传统机械通气通气30分钟，然后再用传统机械通气或高频喷射通气通气2小时。各小组还分别使用37℃湿润气体或25℃干燥气体，通过两种通气模式进行通气。
在自主呼吸、传统机械通气、高频喷射通气以及使用37℃湿润或22℃干燥吸入气体的两种通气模式期间，对血流组进行比较。使用方差分析和纽曼-库尔事后检验对各小组进行比较。使用放射性微球测量局部气管血流。还监测心输出量和器官血流。插管后30分钟内气管血流增加了10.3倍，但使用37℃湿润气体时，传统机械通气和高频喷射通气之间的局部或总气管血流无显著差异。使用高频喷射通气和25℃干燥气体时气管血流进一步增加，但使用干燥气体的传统机械通气未出现此情况。尽管通气使心输出量降低了约30%，但通气模式之间的器官分布无显著差异。
传统机械通气和高频喷射通气进行插管和通气时均出现急性气管充血，但通气模式之间未观察到差异。使用高频喷射通气而非传统机械通气时，凉爽、干燥的吸入气体会使充血进一步增加。尽管高频喷射通气或传统机械通气未导致急性气管缺血，但改变动脉供应与代谢需求之间平衡或诱发炎症的因素可能导致持续通气期间报告的气管坏死。
