During proportional assist ventilation (PAV), the ventilator pressure is servocontrolled throughout each spontaneous inspiration such that it instantaneously increases in proportion to the airflow (resistive unloading...
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During proportional assist ventilation (PAV), the ventilator pressure is servocontrolled throughout each spontaneous inspiration such that it instantaneously increases in proportion to the airflow (resistive unloading mode), or inspired volume (resistive unloading mode), or both (combined unloading mode). The PAV pressure changes are generated in a closed-loop feedback circuitry commonly using a pneumotachographic signal. In neonates, however, a pneumotachograph increases dead space ventilation, and its signal may include a substantial endotracheal tube leak component. We hypothesized that respiratory inductive during proportional assist ventilation (PAV), the ventilator pressure is servocontrolled throughout each spontaneous inspiration such that it instantaneously increases in proportion to the airflow (resistive unloading mode), or inspired volume (elastic unloading mode), or both (combined unloading mode). The PAV pressure changes are generated in a closed-loop feedback circuitry commonly using a pneumotachographic signal. In neonates, however, a pneumotachograph increases dead space ventilation, and its signal may include a substantial endotracheal tube leak component. We hypothesized that respiratory inductive plethysmography (RIP) can replace pneumotachography to drive the ventilator during PAV without untoward effects on ventilation or respiratory gas exchange. Ten piglets and five rabbits were supported for 10-min (normal lungs) or 20-min (meconium injured lungs) periods by each of the three PAV modes. In each mode, three test periods were applied in random order with the ventilator driven by the pneumotachograph signal, or the RIP abdominal band signal, or the RIP sum signal of rib cage and abdomen. Interchanging the three input signals did not affect the plethysmography (RIP) can replace pneumotachography to drive the ventilator during PAV without untoward effects on ventilation or respiratory gas exchange. Ten piglets and five rabbits were supported for
目的:分析肝移植术后持续性血小板减少的危险因素,探索减少该疾病发生的有效治疗手段。方法:回顾性分析在浙江大学医学院附属第一医院肝胆胰外科2009年1月—2012年6月期间接受肝移植手术并符合纳入标准的128例患者资料,对移植前脾脏体积、术前门静脉直径、术前胃左静脉直径、术前和术后血小板、术前和术后白细胞、术前总胆红素水平及终末期肝病模型评分等指标进行统计分析,筛选术后持续性血小板减少的独立危险因素。并且对在2012—2013年期间部分术前存在危险因素的患者行肝移植同期脾动脉缩窄术,分析其术后持续性血小板减少的发生率。结果:患者肝移植术前脾脏体积大于500 ml ( P=0.012, OR=2.789,95%可信区间:1.249~6.227)以及门静脉直径大于15 mm ( P =0.017, OR=3.124,95%可信区间:1.230~7.933)为术后持续性血小板减少的独立危险因素。行肝移植同期脾动脉缩窄术的6例患者中仅1例(16.7%)在术后表现为持续性血小板减少,而对照组48例中32例(66.7%)术后存在持续性血小板减少,两者间差异有统计学意义( P<0.05)。结论:患者肝移植术前脾脏体积大于500 ml以及门静脉直径大于15 mm可以作为肝移植术后持续性血小板减少的独立危险因素。肝移植手术同期行脾动脉缩窄术以控制脾脏体积作为肝移植术后持续性血小板减少的预防方法具有一定的临床效果。
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