Lung-cOnservative Liquid VEntilation for the Induction of Ultra-Rapid COOLing After Cardiac Arrest

Overview

Out-of-hospital cardiac arrest (OHCA) affects over 356,000 individuals annually in the United States, with fewer than 10% surviving to hospital discharge, mirroring statistics from Europe. Post-cardiac arrest syndrome (PCAS), a condition causing multi-organ dysfunction, is a leading cause of mortality despite successful resuscitation efforts. Targeted temperature management (TTM) is recommended for comatose patients post-resuscitation to mitigate PCAS, but optimal temperature targets and cooling methods remain unclear. Experimental studies suggest that therapeutic hypothermia (32-34°C), induced rapidly after resuscitation, may provide significant clinical benefits. Total liquid ventilation (TLV) with breathable liquids has been proposed to achieve ultra-rapid therapeutic hypothermia (URTH). This approach uses the lungs as a heat exchanger to achieve ultra-rapid cooling while maintaining normal gas exchange. It enables a reduction in core body temperature to the hypothermic range (33.0 ± 0.5°C) within 45 minutes in relevant experimental models. The OverCool study is an open-label, single-arm, multi-centric pilot trial designed to evaluate the performance and safety of Vent2Cool, a medical device intended to induce ultra-rapid therapeutic hypothermia by TLV in resuscitated cardiac arrest patients. The primary objective is to demonstrate Vent2Cool's ability to achieve a target core temperature of 33.0 ± 0.5°C within 60 minutes from start of procedure in resuscitated patients admitted to the Intensive Care Unit following intra- or extra-hospital cardiac arrest. Secondary objectives include assessing procedural safety, cooling performance, feasibility in emergency settings, clinical outcomes, and the impact on biological markers.

The "American Heart Association's 2022 Update" estimates that over 356,000 out-of-hospital cardiac arrests (OHCA) occur annually in the United States. These figures are consistant with data from European countries, where fewer than 10% of OHCA patients survive, despite 30% being successfully resuscitated before admission to intensive care units (ICU). The majority of these patients succumb to post-cardiac arrest syndrome (PCAS), a condition characterized by multi-organ failure. To mitigate the severity of PCAS, current guidelines recommend continuous core temperature monitoring and active fever prevention through targeted temperature management (TTM) in patients who remain comatose following resuscitation from cardiac arrest. While TTM with a target temperature range of 32-36°C has been previously evaluated and applied in specific subpopulations, there is insufficient evidence to universally recommend one target temperature over another within this range. Conversely, experimental studies have demonstrated that the protective effects of therapeutic hypothermia (32-34°C) are strongly influenced by the rate of cooling initiated after resuscitation. These findings suggest that very early application of hypothermia may provide greater benefits compared to simply avoiding fever, emphasizing the importance of timely intervention. In this context, Total Liquid Ventilation (TLV) with breathable liquids has been investigated in animal studies as a method to achieve ultra-rapid therapeutic hypothermia (URTH) following cardiac arrest. This innovative approach uses the lungs as a potent heat exchanger to achieve ultra-rapid cooling while preserving normal gas exchanges. TLV has demonstrated the capability to lower body core temperature from normothermia to the hypothermic range within 45 minutes, irrespective of body weight, in relevant experimental models. Furthermore, unlike earlier techniques of partial liquid ventilation, this method employs a lung-conservative liquid ventilation approach, which has been shown to be safe. The objective of the present OverCool study is to evaluate the performance and safety of the Vent2Cool device, designed to induce URTH by TLV safely following cardiac arrest. Accordingly, OverCool is an open-label, single arm, non-comparative, multi-centric pilot study. The study primary objective is to demonstrate the ability of Vent2Cool to achieve a core body temperature of 33.0±0.5°C in less than 60 min after the start of the procedure in resuscitated patients admitted in the ICU after an intra- or extra-hospital cardiac arrest. The main secondary objectives are to demonstrate the safety of the procedure, the cooling performance, the ability to implement the procedure in the emergency setting of post-cardiac arrest management, the clinical outcomes and impact on biological markers.