Protective effect of extracorporeal membrane pulmonary oxygenation combined with cardiopulmonary resuscitation on post-resuscitation lung injury

BACKGROUND: Cardiac arrest(CA) is a critical condition that is a concern to healthcare workers. Comparative studies on extracorporeal cardiopulmonary resuscitation(ECPR) and conventional cardiopulmonary resuscitation(CCPR) technologies have shown that ECPR is superior to CCPR. However, there is a lack of studies that compare the protective effects of these two resuscitative methods on organs. Therefore, we aim to perform experiments in swine models of ventricular fibrillation-induced CA to study whether the early application of ECPR has advantages over CCPR in the lung injury and to explore the protective mechanism of ECPR on the post-resuscitation pulmonary injury.METHODS: Sixteen male swine were randomized to CCPR(CCPR;n=8;CCPR alone) and ECPR(ECPR;n=8;extracorporeal membrane oxygenation with CCPR) groups, with the restoration of spontaneous circulation at 6 hours as an endpoint. RESULTS: For the two groups, the survival rates between the two groups were not statistically significant(P>0.05), the blood and lung biomarkers were statistically significant(P<0.05), and the extravascular lung water and pulmonary vascular permeability index were statistically significant(P<0.01). Compared with the ECPR group, electron microscopy revealed mostly vacuolated intracellular alveolar type II lamellar bodies and a fuzzy lamellar structure with widening and blurring of the blood-gas barrier in the CCPR group.CONCLUSIONS: ECPR may have pulmonary protective effects, possibly related to the regulation of alveolar surface-active proteins and mitigated oxidative stress response postresuscitation.

Extracorporeal Membrane Oxygenation Improving Survival and Alleviating Kidney Injury in a Swine Model of Cardiac Arrest Compared to Conventional Cardiopulmonary Resuscitation

Background： Acute kidney injury （AKI） frequently occurs in cardiopulmonary resuscitation patients. Studies comparing the effects of extracorporeal membrane oxygenation （ECMO） with conventional cardiopuhnonary resuscitation （CCPR） on AKI were rare. This study aimed to compare the effects of ECMO with those of CCPR on survival rate and AKI and explore the underlying mechanisms in a swine model of cardiac arrest （CA）. Methods： Sixteen male pigs were treated with ventricular fibrillation to establish CA model and then underwent CCPR （CCPR group, n = 8） or ECMO during cardiopulmonary resuscitation （ECPR group, n = 8）. The study endpoints were 6 h after return of spontaneous circulation （ROSC） or death. Serum and urine samples were collected at baseline and during the 6 h after ROSC. The biomarkers of AKI were detected by enzyme-linked immunosorbent assay. The apoptosis of renal tubular epithelial cells was discovered by transmission electron microscope （TEM） and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Apoptosis-related genes were detected by immune-staining and Western blotting. Data were compared by Student＇s t-test. Results： All pigs in ECPR group were successfully resuscitated with a higher 6-h survival rate （8/8） compared to CCPR group （6/8）. The expressions ofAKl biomarkers including neutrophil gelatinase-associated lipocalin （NGAL）, tissue inhibitor ofmetalloproteinase2 （TIMP2）, insulin-like growth factor-binding protein 7 （IGFBP7）, liver fatty acid-binding protein （LFABP）, and kidney injury molecule l （Kim-1） were all increased along with the time after ROSC in both groups and lower in ECPR group compared with CCPR group. Especially, products of urinary T1MP and IGFBP levels （TIMP＊IGFBP） were significantly lower at ROSC4 （0.58 ± 0.10 ng^2/ml^2 vs. 1.18 ± 0.38 ng^2/ml^2, t = 4.33, P =0.003） and ROSC6 （1.79 ±0.45 ng2^/ml^2 vs. 3.00 ±0.44 ng^2/ml^2, t = 5.49, P 〈 0.001）; urinary LFABP was significantly lower at ROSC6 （0.74 ± 0.06 pg/ml vs. 0.85 4±0.11 pg/ml, t = 2.41, P = 0.033）; and urinary Kim-1 was significantly lower at ROSC4 （0.66 ± 0.09 pg/ml vs. 0.83 ± 0.06 pg/ml, t = 3.99, P = 0.002） and ROSC6 （0.73 ± 0.12 pg/ml vs. 0.89 ± 0.08 pg/ml, t = 2.82, P = 0.016）. Under light microscope and TEM, the morphological injures in renal tissues were found to be improved in ECPR group. Moreover, apoptosis was also alleviated in ECPR group. Conclusions： Compared with CCPR, ECMO improves survival rate and alleviates AKI in a swine model of CA. The mechanism of which might be via downregulating AKI biomarkers and apoptosis in kidney.