0671. Extended extracorporeal lung support in a porcine acute lung injury model. Feasibility and preliminary data
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KeywordsLung Injury Acute Lung Injury Extracorporeal Membrane Oxygenation ECMO Circuit Saline Lavage
During the last years there has been a renewed interest in using extracorporeal membrane oxygenation (ECMO) to treat severe ARDS. ECMO may correct hypoxemia but may also aid in protecting the lungs . However, there is scarce data about the optimal way to ventilate the lungs during ECMO. Experimental models of acute lung injury with ECMO are usually too short.
To develop an extended severe ARDS model supported with ECMO suitable to assess the impact of different ventilatory strategies during ECMO.
Eighteen domestic pigs (27-35 kg) were anesthetized, mechanically ventilated (Vt 10 ml/kg, PEEP 5, O2 1.0) and invasively monitored. Thereafter they were randomized into 3 groups: sham, lung injury, and lung injury + ECMO. SHAM animals were ventilated for 24 hours with standard ventilation (Vt 10 ml/kg, PEEP 5, FiO2 1.0 and RR adjusted to keep PaCO2 30 to 50 mmHg) and then euthanized. In the other groups lung injury was induced by saline lavages (30 ml/kg per lavage) performed repeatedly in both supine and prone position until PaO2/FiO2 dropped below 250. They were then subjected to a 2-hour injurious ventilation with PCV, PEEP = 0,Pinsp = 40 cmH2O, RR = 10/min, I:E = 1:1, one hour in prone and the other in supine. After completing lung injury (time 0) animals were subjected to 24 hours of standard ventilation. In the ECMO group, animals were immediately connected to a saline primed-MEDOS Hilite ECMO circuit by inserting a AVALON 23F double-lumen cannula through the external jugular vein. Blood flow was set at 60-70% of cardiac output. Respiratory and hemodynamic data, as well as plasma and BAL samples were collected at times 0,3, 6, 12, 18 and 24h. After euthanizing animals at time 24h tissue samples were extracted from the lungs.
An extended lung injury model supported with ECMO is feasible. The two-hit model produced a steady compromise in compliance despite partial recovery of hypoxemia.
CONICYT, Fondecyt 1130428