Design of the OverCool study: Lung-conservative liquid ventilation for the induction of Ultra-Rapid Cooling after Cardiac Arrest (OverCool)

Abstract

Background

The therapeutic window within which induced hypothermia might be effective after cardiac arrest is still unknown. In animal cardiac arrest models, early induction and faster cooling are independently associated favorable outcome. However, induction of Ultra-Rapid Therapeutic Hypothermia (achieving core body temperature of 33.0 ± 0.5 °C within 60 min after the start of the procedure) still need to be evaluated in the human setting. Total liquid ventilation with temperature-controlled breathable liquids provided such rapid cooling (i.e. >15 °C/h cooling rate) in both small and large animals. This method was shown to improve neurological outcome in animals. A new medical device system, Vent2Cool, was developed for clinical use in the Intensive Care Unit to achieve ultra-rapid therapeutic hypothermia by total liquid ventilation to patients.

Materials and methods

The non-blinded and single-arm OverCool pilot trial will evaluate the feasibility, cooling performance and safety of ultra-rapid therapeutic hypothermia by total liquid ventilation in 24 patients resuscitated after in- or out-of-hospital cardiac arrest. Inclusion criteria will include presumption to start ultra-rapid cooling procedure in the Intensive Care Unit within less than 120 min after resuscitation. The primary outcome will be the achievement of a core temperature of 33.0 ± 0.5 °C, as well as successful return to conventional gas ventilation within <60 min after procedure initiation. Secondary outcomes will include time to reach target temperature, vital status, systemic and pulmonary parameters and modified-Rankin Score at 28 days post- cardiac arrest.

Conclusion

The OverCool study is a pilot study to validate performance and safety of ultra-rapid therapeutic hypothermia using total liquid ventilation for resuscitated cardiac arrest patients.

Registration and authorization

NCT06798818. Authorized by the French “Agence nationale de sécurité du médicament et des produits de santé” and “Comité de Protection des Personnes” (Ethics Committee).