Loer S A, Tarnow J
Department of Experimental Anesthesiology, Heinrich-Heine-University of Düsseldorf, Germany.
Crit Care Med. 1998 Dec;26(12):2037-41. doi: 10.1097/00003246-199812000-00037.
The density of perfluorocarbons is almost twice that of blood. Therefore, we hypothesized that partial liquid ventilation with these fluids markedly affects pulmonary hemodynamics and filtration coefficients. To test these hypotheses we studied pressure-flow relationships, vascular compliances, capillary pressures, and filtration coefficients in normal and perfluorocarbon-ventilated rabbit lungs.
Controlled animal study with an ex-vivo isolated lung preparation.
Research laboratory for experimental anesthesiology at the Heinrich-Heine-University of Düsseldorf.
Fourteen New Zealand White rabbits.
The lungs were perfused under zone 3 flow conditions with autologous blood at various flow rates (50 to 250 mL/min, closed circuit, roller pump, 37 degrees C) and ventilated with 5% CO2 in air (positive end-expiratory pressure: 2 cm H2O, tidal volume: 10 mL/kg, respiratory rate: 30 breaths/min) without (control group, n=7) and with (n=7) perfluorocarbon administered intratracheally (15 mL/kg).
Pulmonary arterial, left atrial, and airway pressures, as well as blood reservoir volume (reflecting changes in pulmonary blood volume) and lung weight, were measured continuously. Inconsistent with our hypothesis, we found no significant differences between both groups in the slopes and intercepts of the pressure-flow relationships. There were no significant differences in capillary pressures determined by double occlusion (6.7+/-1.2 vs. 6.3+/-1.3 cm H2O for control group, p=.53), vascular compliances (0.51+/-0.10 vs. 0.47+/-0.09 mL/cm H2O for control group, p=.38), and filtration coefficients (0.33+/-0.06 vs. 0.37+/-0.07 mL/min/mm Hg/100 g wet weight for control group, p=.80, Mann-Whitney).
Partial liquid ventilation with perfluorocarbons has no relevant effects on pulmonary filtration coefficients and global hemodynamic variables of isolated zone 3 lungs. These findings suggest that right ventricular afterload is not changed with partial liquid ventilation. It is likely, however, that intrapulmonary blood flow is redistributed toward less-dependent regions, although relevant global hemodynamic changes are absent during partial liquid ventilation.
全氟化碳的密度几乎是血液的两倍。因此，我们推测用这些液体进行部分液体通气会显著影响肺血流动力学和滤过系数。为验证这些假设，我们研究了正常和经全氟化碳通气的兔肺的压力-流量关系、血管顺应性、毛细血管压力和滤过系数。
采用离体肺制备的对照动物研究。
杜塞尔多夫海因里希-海涅大学实验麻醉学研究实验室。
14只新西兰白兔。
在区域3血流条件下，用自体血以不同流速（50至250毫升/分钟，闭路，滚压泵，37摄氏度）灌注肺，并分别在不通气（对照组，n = 7）和通气（n = 7）的情况下，以气管内注入全氟化碳（15毫升/千克）并同时用含5%二氧化碳的空气进行通气（呼气末正压：2厘米水柱，潮气量：10毫升/千克，呼吸频率：30次/分钟）。
持续测量肺动脉、左心房和气道压力，以及血容量（反映肺血容量变化）和肺重量。与我们的假设不符，我们发现两组在压力-流量关系的斜率和截距方面无显著差异。通过双阻断测定的毛细血管压力（对照组为6.7±1.2对6.3±1.3厘米水柱，p = 0.53）、血管顺应性（对照组为0.51±0.10对0.47±0.09毫升/厘米水柱，p = 0.38）和滤过系数（对照组为0.33±0.06对0.37±0.07毫升/分钟/毫米汞柱/100克湿重，p = 0.80，曼-惠特尼检验）均无显著差异。
用全氟化碳进行部分液体通气对离体区域3肺的肺滤过系数和整体血流动力学变量无相关影响。这些发现表明部分液体通气不会改变右心室后负荷。然而，尽管部分液体通气期间无相关的整体血流动力学变化，但肺内血流可能会重新分布至依赖性较小的区域。
