Kidney Protection by Hypothermic Total Liquid Ventilation after Cardiac Arrest in Rabbits

Abstract

Total liquid ventilation (TLV) with perfluorocarbons has been shown to induce rapid protective cooling in animal models of myocardial ischemia and cardiac arrest, with improved neurological and cardiovascular outcomes after resuscitation. In this study, the authors hypothesized that hypothermic TLV can also limit kidney injury after cardiac arrest. Anesthetized rabbits were submitted to 15 min of untreated ventricular fibrillation. After resuscitation, three groups of eight rabbits each were studied such as (1) life support plus hypothermia (32°-33 °C) induced by cold TLV (TLV group), (2) life support without hypothermia (control group), and (3) Sham group (no cardiac arrest). Life support was continued for 6 h before euthanasia and kidney removal. Time to target esophageal temperature was less than 5 min in the TLV group. Hypothermia was accompanied by preserved renal function in the TLV group as compared with control group regarding numerous markers including creatinine blood levels (12 ± 1 vs. 16 ± 2 mg/l, respectively; mean ± SEM), urinary N-acetyl-β-(D)-glucosaminidase (1.70 ± 0.11 vs. 3.07 ± 0.10 U/mol of creatinine), γ-glutamyltransferase (8.36 ± 0.29 vs. 12.96 ± 0.44 U/mol of creatinine), or β2-microglobulin (0.44 ± 0.01 vs. 1.12 ± 0.04 U/mol of creatinine). Kidney lesions evaluated by electron microscopy and conventional histology were also attenuated in TLV versus control groups. The renal-protective effect of TLV was not related to differences in delayed inflammatory or immune renal responses because transcriptions of, for example, interferon-γ, tumor necrosis factor-α, interleukin-1β, monocyte chemoattractant protein-1, toll-like receptor-2, toll-like receptor-4, and vascular endothelial growth factor were similarly altered in TLV and control versus Sham. Ultrafast cooling with TLV is renal protective after cardiac arrest and resuscitation, which could increase kidney availability for organ donation.