Hypothermic Total Liquid Ventilation Is Highly Protective Through Cerebral Hemodynamic Preservation and Sepsis-Like Mitigation After Asphyxial Cardiac Arrest*
Total liquid ventilation provides ultrafast and potently neuro- and cardioprotective cooling after shockable cardiac arrest and myocardial infarction in animals. Our goal was to decipher the effect of hypothermic total liquid ventilation on the systemic and cerebral response to asphyxial cardiac arrest using an original pressure- and volume-controlled ventilation strategy in rabbits.Design:
Randomized animal study.Setting:
Academic research laboratory.Subjects:
New Zealand Rabbits.Interventions:
Thirty-six rabbits were submitted to 13 minutes of asphyxia, leading to cardiac arrest. After resumption of spontaneous circulation, they underwent either normothermic life support (control group, n = 12) or hypothermia induced by either 30 minutes of total liquid ventilation (total liquid ventilation group, n = 12) or IV cold saline (conventional cooling group, n = 12).Measurements and Main Results:
Ultrafast cooling with total liquid ventilation (32°C within 5 min in the esophagus) dramatically attenuated the post–cardiac arrest syndrome regarding survival, neurologic dysfunction, and histologic lesions (brain, heart, kidneys, liver, and lungs). Final survival rate achieved 58% versus 0% and 8% in total liquid ventilation, control, and conventional cooling groups (p < 0.05), respectively. This was accompanied by an early preservation of the blood-brain barrier integrity and cerebral hemodynamics as well as reduction in the immediate reactive oxygen species production in the brain, heart, and kidneys after cardiac arrest. Later on, total liquid ventilation also mitigated the systemic inflammatory response through alteration of monocyte chemoattractant protein-1, interleukin-1β, and interleukin-8 transcripts levels compared with control. In the conventional cooling group, cooling was achieved more slowly (32°C within 90–120 min in the esophagus), providing none of the above-mentioned systemic or organ protection.Conclusions:
Ultrafast cooling by total liquid ventilation limits the post–cardiac arrest syndrome after asphyxial cardiac arrest in rabbits. This protection involves an early limitation in reactive oxidative species production, blood-brain barrier disruption, and delayed preservation against the systemic inflammatory response.