Perez C A, Bui K C, Bustorff-Silva J, Atkinson J B
Division of Pediatric Surgery, UCLA School of Medicine, Los Angeles, CA, USA.
Crit Care Med. 2000 Mar;28(3):774-81. doi: 10.1097/00003246-200003000-00028.
To study changes in PaCO2 and PaO2 during intratracheal pulmonary ventilation (ITPV) and hybrid intratracheal pulmonary ventilation (h-ITPV) compared with conventional mechanical ventilation (CMV) in a rabbit model of respiratory failure, and to define the technique of h-ITPV that combines conventional mechanical ventilation and ITPV.
Prospective, interventional study.
Twelve adult New Zealand White rabbits.
Surfactant deficiency was induced by saline lavage, and rabbits were randomized to either ITPV or h-ITPV. The study consisted of four phases: phase 0, CMV after saline lavage, ventilator rate 30 breaths/min; phase I, ITPV or h-ITPV initiated at the same pressure and rate as in phase 0; phase II, ITPV or 1.0 L/min h-ITPV bias flow, with peak inspiratory pressure (PIP) decreased and ventilator rate increased to achieve the lowest tidal volume while maintaining adequate gas exchange; and phase III, animals returned to CMV.
In phase I, no difference in PaCO2 was observed between ITPV, h-ITPV, or CMV. There was a decrease in PaO2 when switching from CMV to ITPV but not to h-ITPV. In phase II, it was possible to decrease PIP (average of 37% for ITPV and 36% for h-ITPV) and tidal volume (average of 64% for ITPV and 53% for h-ITPV) without compromising gas exchange (p < .05). Oxygenation tended to improve from phase 0 to the end of phase II. In phase III, PaCO2 increased (average of 71% for ITPV and 79% for h-ITPV) and pH decreased (p < .05). Normocapnia was achieved using significantly higher PIP and tidal volume, compared with phase 0 (p < .05).
ITPV and h-ITPV can effectively ventilate and oxygenate rabbits with surfactant-deficient lungs at tidal volumes and therefore pressures lower than required with CMV. Maximum benefit appears to occur at high ventilator rates. These findings suggest that both modes of ventilation may represent powerful new tools in the management of patients with acute respiratory failure. (Crit Care Med 2000; 28:774-781)
在呼吸衰竭兔模型中，研究气管内肺通气（ITPV）和混合气管内肺通气（h - ITPV）与传统机械通气（CMV）相比时动脉血二氧化碳分压（PaCO₂）和动脉血氧分压（PaO₂）的变化，并确定结合传统机械通气和ITPV的h - ITPV技术。
前瞻性干预研究。
12只成年新西兰白兔。
通过盐水灌洗诱导表面活性物质缺乏，将兔子随机分为ITPV组或h - ITPV组。研究包括四个阶段：0期，盐水灌洗后CMV，通气频率30次/分钟；I期，以与0期相同的压力和频率启动ITPV或h - ITPV；II期，ITPV或1.0 L/分钟的h - ITPV偏流，降低吸气峰压（PIP）并增加通气频率以在维持足够气体交换的同时实现最低潮气量；III期，动物恢复至CMV。
在I期，ITPV、h - ITPV或CMV之间未观察到PaCO₂差异。从CMV转换为ITPV时PaO₂降低，但转换为h - ITPV时未降低。在II期，可以降低PIP（ITPV平均降低37%，h - ITPV平均降低36%）和潮气量（ITPV平均降低64%，h - ITPV平均降低53%），而不影响气体交换（p < 0.05）。从0期到II期末氧合趋于改善。在III期，PaCO₂升高（ITPV平均升高71%，h - ITPV平均升高79%）且pH降低（p < 0.05）。与0期相比，使用显著更高的PIP和潮气量才能实现正常碳酸血症（p < 0.05）。
ITPV和h - ITPV能够以低于CMV所需的潮气量及相应压力有效地为表面活性物质缺乏的兔肺进行通气和氧合。在高通气频率时似乎能获得最大益处。这些发现表明这两种通气模式可能是治疗急性呼吸衰竭患者的有力新工具。（《危重病医学》2000年；28：774 - 781）
