Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
Crit Care. 2009;13(1):R17. doi: 10.1186/cc7716. Epub 2009 Feb 11.
Interventional lung assist (ILA), based on the use of a pumpless extracorporeal membrane oxygenator, facilitates carbon dioxide (CO2) elimination in acute respiratory distress syndrome (ARDS). It is unclear whether an ILA system should be clamped during cardiopulmonary resuscitation (CPR) in patients with ARDS or not. The aim of our study was to test the effects of an ILA on haemodynamics and gas exchange during CPR on animals with ARDS and to establish whether the ILA should be kept open or clamped under these circumstances.
The study was designed to be prospective and experimental. The experiments were performed on 12 anaesthetised and mechanically ventilated pigs (weighing 41 to 58 kg). One femoral artery and one femoral vein were cannulated and connected to an ILA. ARDS was induced by repeated bronchoalveolar lavage. An indwelling pacemaker was used to initiate ventricular fibrillation and chest compressions were immediately started and continued for 30 minutes. In six animals, the ILA was kept open and in the other six it was clamped.
Systolic and mean arterial pressures did not differ significantly between the groups. With the ILA open mean +/- standard deviation systolic blood pressures were 89 +/- 26 mmHg at 5 minutes, 71 +/- 28 mmHg at 10 minutes, 63 +/- 33 mmHg at 20 minutes and 83 +/- 23 mmHg at 30 minutes. The clamped ILA system resulted in systolic pressures of 77 +/- 30 mmHg, 90 +/- 23 mmHg, 72 +/- 11 mmHg and 72 +/- 22 mmHg, respectively. In the group with the ILA system open, arterial partial pressure of CO2 was significantly lower after 10, 20 and 30 minutes of CPR and arterial partial pressure of oxygen was higher 20 minutes after the onset of CPR (191 +/- 140 mmHg versus 57 +/- 14 mmHg). End-tidal partial pressure of CO2 decreased from 46 +/- 23 Torr (ILA open) and 37 +/- 9 Torr (ILA clamped) before intervention to 8 +/- 5 Torr and 8 +/- 10 Torr, respectively, in both groups after 30 minutes of CPR.
Our results indicate that in an animal model of ARDS, blood pressures were not impaired by keeping the ILA system open during CPR compared with the immediate clamping of the ILA with the onset of CPR. The effect of ILA on gas exchange implied a beneficial effect.
基于无泵型体外膜肺氧合器的使用，介入性肺辅助（ILA）有助于急性呼吸窘迫综合征（ARDS）中二氧化碳（CO2）的排出。在 ARDS 患者中，心肺复苏（CPR）期间是否应夹住 ILA 系统尚不清楚。我们的研究目的是测试 ILA 在 ARDS 动物的 CPR 期间对血液动力学和气体交换的影响，并确定在这些情况下是否应保持 ILA 打开或夹住。
该研究旨在进行前瞻性和实验性研究。实验在 12 只麻醉和机械通气的猪（体重 41 至 58 公斤）上进行。一条股动脉和一条股静脉被插管并连接到 ILA。通过反复支气管肺泡灌洗诱导 ARDS。使用内置起搏器引发心室颤动，立即开始并持续 30 分钟进行胸部按压。在 6 只动物中，保持 ILA 打开，在另外 6 只动物中夹住 ILA。
两组的收缩压和平均动脉压没有显著差异。ILA 打开时，平均 +/- 标准差收缩压在 5 分钟时为 89 +/- 26 mmHg，在 10 分钟时为 71 +/- 28 mmHg，在 20 分钟时为 63 +/- 33 mmHg，在 30 分钟时为 83 +/- 23 mmHg。夹闭的 ILA 系统分别导致收缩压为 77 +/- 30 mmHg、90 +/- 23 mmHg、72 +/- 11 mmHg 和 72 +/- 22 mmHg。在 ILA 系统打开的组中，CPR 后 10、20 和 30 分钟时动脉血二氧化碳分压显著降低，CPR 后 20 分钟时动脉血氧分压升高（191 +/- 140 mmHg 对 57 +/- 14 mmHg）。在 CPR 后 30 分钟，两组的呼气末二氧化碳分压从干预前的 46 +/- 23 Torr（ILA 打开）和 37 +/- 9 Torr（ILA 夹闭）分别降至 8 +/- 5 Torr 和 8 +/- 10 Torr。
我们的结果表明，在 ARDS 动物模型中，与 CPR 开始时立即夹闭 ILA 相比，在 CPR 期间保持 ILA 系统打开不会损害血压。ILA 对气体交换的影响表明存在有益的影响。
