Bittner H B, Kendall S W, Chen E P, Craig D, Van Trigt P
Department of General and Cardiothoracic Surgery, Duke University Medical Center, Durham, NC 27710, USA.
Chest. 1995 Nov;108(5):1358-63. doi: 10.1378/chest.108.5.1358.
Deterioration of donor lung function contributes to the shortage of donor organs and early postoperative failure after transplantation. A decrease in donor pulmonary function is associated with opacification of lung fields on radiographs, rendering the lungs unsuitable for transplantation, which may be related to the effects of brain death (BD) on pulmonary hemodynamics. Twenty mongrel canines (25.5 +/- 0.7 kg) underwent 20 BD experiments using a previously validated BD organ donor model. An ultrasonic flowmeter was applied on the pulmonary artery and micromanometers were inserted into the right ventricle, pulmonary artery, and left atrium to measure, which allowed the hemodynamic assessment and impedance profile analysis of the pulmonary vasculature by Fourier transformation. Characteristic impedance (Zo) was compared with input resistance (RIN) and with calculated pulmonary vascular resistance (PVR), the conventional index. Right ventricular hydraulic power was analyzed and divided in its components oscillatory and steady power. The results are expressed as means and SEM (analysis of variance, paired two-tailed t tests). Cushing reflex, hemodynamic response, and diabetes insipidus were consistent findings following BD. PVR, Zo, and RIN decreased significantly (p < 0.05) from 367 +/- 40 dyne.s.cm-5, 226 +/- 13 dyne.s.cm-5, and 771 +/- 52 dyne.s.cm-5 to 261 +/- 25 dyne.s.cm-5, 159 +/- 10 dyne.s.cm-5, and 651 +/- 69 dyne.s.cm-5 6 h after BD. Pulmonary artery blood flow increased significantly from 1,499 +/- 107 mL/min to 2,064 +/- 209 mL/min (p < 0.05) after BD. Hydraulic power increased from 69 +/- 6 mW to 104 +/- 13 mW (p < 0.05) and the oscillatory power to steady power ratio of 33%/67% changed to 23%/77% following BD. Extravascular pulmonary water content increased significantly by 10% after BD. BD causes a significant change in pulmonary vascular hemodynamics. The decrease in impedance and right ventricular afterload may lead to significant pulmonary overflow injury and edema. The increase in steady power represents an important reserve of the right ventricle to sustain pulmonary blood flow following BD.
供体肺功能恶化导致供体器官短缺以及移植后早期手术失败。供体肺功能下降与胸部X光片上肺野的模糊化有关，使得肺部不适合用于移植，这可能与脑死亡（BD）对肺血流动力学的影响有关。二十只杂种犬（25.5±0.7千克）使用先前验证过的BD器官供体模型进行了20次BD实验。在肺动脉上应用超声流量计，并将微压计插入右心室、肺动脉和左心房进行测量，通过傅里叶变换对肺血管系统进行血流动力学评估和阻抗剖面分析。将特征阻抗（Zo）与输入电阻（RIN）以及计算得出的肺血管阻力（PVR，传统指标）进行比较。分析右心室水力功率并将其分为振荡功率和稳定功率成分。结果以均值和标准误表示（方差分析，配对双尾t检验）。BD后库欣反射、血流动力学反应和尿崩症是一致的发现。BD后6小时，PVR、Zo和RIN显著降低（p<0.05），从367±40达因·秒·厘米⁻⁵、226±13达因·秒·厘米⁻⁵和771±52达因·秒·厘米⁻⁵降至261±25达因·秒·厘米⁻⁵、159±10达因·秒·厘米⁻⁵和651±69达因·秒·厘米⁻⁵。BD后肺动脉血流量从1499±107毫升/分钟显著增加至2064±209毫升/分钟（p<0.05）。水力功率从69±6毫瓦增加至104±13毫瓦（p<0.05），BD后振荡功率与稳定功率之比从33%/67%变为23%/77%。BD后肺血管外含水量显著增加10%。BD导致肺血管血流动力学发生显著变化。阻抗和右心室后负荷的降低可能导致显著的肺充血性损伤和水肿。稳定功率的增加代表了右心室在BD后维持肺血流的重要储备。
