INTERVENTIONS TO PROMOTE VENTILATOR WEANING

描述(改编自《调查者摘要》)：断奶 危重病患者从机械通气(MV)到自主呼吸 呼吸机(SPV)仍然是护理的一个重大挑战。它是 据估计，9%-37%的机械通气患者在 血流动力学不稳定引起的从MV到SPV的即刻转变 由先前存在的左心功能不全引起。这项研究的目的是 研究优化心肺(CP)血流动力学变化的干预措施 与从MV到SPV的即时转换相关联，同时比较 常用模式(T形件、持续正压和压力 支持)在有心脏和无心脏受试者中的自发通风 失败了。具体目标是：1)比较预压的效果 速尿利尿前后的正常血容量和高血容量 大鼠从MV到SPV(T段、CPAP和PS)过渡过程中CP血流动力学的研究 正常犬(GI)和心力衰竭(GII)犬(GII)。2)比较 硝普钠降低后负荷前后脑性瘫痪的血流动力学 在Gi和Gii从MV到SPV(T段、CPAP和PS)的过渡过程中 犬科动物。3)确定脑性瘫痪患者的血流动力学改变是否与 利尿或后负荷前后从MV到SPV的转换 心率反映的自主神经系统张力降低 GI和GII犬种的变异性。样本将由116只狗组成 随机分配到GI或GII。GII犬将接受心脏起搏器 心动过速慢性充血性心动过速起搏7周 心力衰竭。在麻醉下，受试者将接受状态检测 ART生物技术包括右室射血分数肺 动脉导管和米氏微压计压力导管测量正确 心功能和电导导管及Miller微量压力计 压力导管连续测量左心功能。数据 将采用重复测量多变量方差分析进行分析。这个 这项研究的结果将为优化方法提供洞察力 心血管功能与自发性运动方式的选择 基于心血管状态的通风，稍后可以在 人体随机对照试验。

DESCRIPTION (As Adapted from the Investigator's Abstract): Weaning the critically ill patient from mechanical ventilation (MV) to spontaneous ventilation (SpV) continues to be a significant challenge for nursing. It is estimated that 9-37% of mechanically ventilated patients have difficulty with the immediate transition from MV to SpV due to hemodynamic instability caused by pre-existing left ventricular dysfunction. The purpose of this study is to examine interventions to optimize the cardiopulmonary (CP) hemodynamic changes associated with the immediate transition from MV to SpV while comparing commonly used modes (t-piece, continuous positive airway press and pressure support) of spontaneous ventilation in canine subjects with and without heart failure. The specific aims are: 1) to compare the effects of preload at normovolemia and hypervolemia prior to and following diuresis with furosemide on CP hemodynamics during the transition from MV to SpV (T-piece, CPAP & PS) in normal canines (GI) and in heart failure (paced) canines (GII). 2) to compare CP hemodynamics prior to and following afterload reduction with nitroprusside during the transition from MV to SpV (T-piece, CPAP & PS) in GI and GII canines. 3) to determine whether CP hemodynamic changes associated with the transition from MV to SpV prior to and following diuresis or afterload reduction alter autonomic nervous system tone as reflected by heart rate variability in GI ad GII canines. The sample will consist of 116 canines randomly assigned to GI or GII. The GII canines will undergo pacemaker insertion and pacing for 7 weeks to produce a tachycardic chronic congestive heart failure. Under anesthesia, he subjects will be instrumented with state of the art biotechnology including a right ventricular ejection fraction pulmonary artery catheter and a Millar micromanometer pressure catheter to measure right ventricular function and a conductance catheter and Miller micromanometer pressure catheter to measure left ventricular function continuously. The data will be analyzed using repeated measures multivariate analysis of variance. The results of this study will provide insight into methods of optimizing cardiovascular function and the selection of an appropriate mode of spontaneous ventilation based on cardiovascular status that can be later tested in a randomized controlled trial in humans.