An observational study in Cardiac Arrest (CA), Resuscitated Sudden Cardiac Death and Post Cardiac Arrest Patient Who Was Treated by Hypothermia Protocol, sponsored by Assistance Publique - Hôpitaux de Paris. Recruiting at 2 sites in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-03-24.
Sponsored by Assistance Publique - Hôpitaux de Paris · Observational
Less than 10% of patients eliciting out-of-hospital cardiac arrest (OHCA) survive, although 30% can be resuscitated by Emergency services before admission in Intensive Care Units (ICU). The majority succumb to Post-Cardiac Arrest Syndrome (PCAS). PCAS is associated with high mortality (60-70%) and morbidity.
One proposed method of preventing the neurological and cardiac consequences of PCAS is to lower the body temperature to 33°C as quickly as possible. This approach is known as therapeutic hypothermia or Targeted Temperature Management (TTM). The Vent2Cool system, developed by Orixha, is a novel approach that enables the rapid induction of therapeutic hypothermia by using hypothermic Total Liquid Ventilation (TLV) to reach a protective temperature of 33°C within minutes.
The OverCool feasibility study, which started in April 2025, is designed to validate the clinical performance and safety of an ultra-rapid cooling approach combining ultra-rapid hypothermia induction using the Vent2Cool system, and maintenance and rewarming using the ArcticSun system.
The AfterCool study aims to evaluate long-term outcomes during a five-year follow-up of cardiac arrest survivors who were treated with ultrarapid cooling in the OverCool study.
Fewer than 10% of patients experiencing out-of-hospital cardiac arrest (OHCA) survive, although 30% can be resuscitated by emergency services before being admitted to intensive care units (ICUs). Many cardiac arrest patients who are initially resuscitated by first responders and/or EMS, however, are condemned to a 'second death' in the ICU due to severe neurological and multi-visceral sequelae from post-cardiac arrest syndrome (PCAS).
One proposed method of preventing the neurological and cardiac complications of PCAS is to lower the body temperature to 33°C as quickly as possible. This approach is known as therapeutic hypothermia or Targeted Temperature Management (TTM). However, the cooling power of available technologies is insufficient to induce therapeutic hypothermia, and they do not improve outcomes for most patients. Conversely, experimental reports clearly demonstrate that therapeutic hypothermia can dramatically improve clinical outcomes if applied within two to three hours of resuscitation.
The devices currently available for TTM are mostly external cooling devices, such as blankets, pads and suits. These devices have a cooling performance of less than 1°C per hour in the body's core and in vital organs with high blood flow. Orixha's Vent2Cool is a novel approach that enables the induction of ultra-rapid therapeutic hypothermia (URTH) by using hypothermic total liquid ventilation (TLV) to reach a protective temperature of 33°C within minutes.
The OverCool feasibility study, which has been approved by the French authorities and began enrolment in early 2025, is designed to test the feasibility of ultra-rapid cooling. It aims to validate the clinical performance and safety of an ultra-rapid cooling approach combining ultra-rapid hypothermia induction using the Vent2Cool system, and maintenance and rewarming using the ArcticSun system. OverCool will pave the way for other clinical investigations to demonstrate the superior clinical benefits of this new approach to hypothermic TTM compared to the standard of care.
The AfterCool study will follow cardiac arrest survivors who were treated with ultrarapid cooling in the Overcool study for five years. The AfterCool approach aligns with the need to evaluate long-term outcomes after cardiac arrest, as endorsed by the French AfterROSC network, which supports research into post-cardiac arrest patients.
Eligible subjects, after having received clear, impartial and complete information, and not having objected to participation in the study, will be included. At the inclusion visit, a detailed questionnaire regarding life status, quality of life, putative rehospitalization, cardiovascular, neurological and respiratory status will be administered.
At 6±1 months and 12±1 months after inclusion, and then yearly during a total period of 5 years, the patients or trusted persons or the close relatives or parents will be interviewed by phone, using the same questionnaire regarding life status, quality of life, putative rehospitalization, cardiovascular, neurological and respiratory status.
Cardiac arrest patient included in and alive at the end of the OverCool clinical investigation (28 days after the cardiac arrest)
Exclusion Criteria:
Patients who were resuscitated after cardiac arrest, treated with ultrarapid cooling as part of the OverCool clinical investigation and survived until the end of the investigation (28 days after cardiac arrest and subsequent Vent2Cool treatment).
Other: Short Form Health Survey (SF-36) · Other: Modified Rankin Score (mRS) · Other: Activity of Daily Living (ADL) questionnaire · Other: New York Heart Association (NYHA) Classification · Other: St George's Respiratory Questionnaire (SGRQ)
Heath-related quality-of-life is assessed using the SF-36 questionnaire, which is administered at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, in the form of a telephone interview.
The degree of disability/dependence is evaluated using the mRS scale at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, via telephone interview.
Level of independence is evaluated using the ADL questionnaire, which is administered at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, in the form of a telephone interview.
The extent of heart failure is assessed using the NYHA functional classification at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, via telephone interview.
Respiratory status is assessed using the SGRQ questionnaire at the inclusion visite, then at month 6, year 1, year 2, year 3, year 4 and year 5, via telephone interview.
Life status at 5 years
The primary endpoint is the life status at 5 years assessed by phone interview. Whenever possible, life status will be confirmed by reviewing the medical record.
Time frame: 5 years
Suspected cause of death
The suspected cause of death in the event of a death. Data are collected via interview. If the deceased is rehospitalised or receives additional care in a hospital that shares a medical database with centres participating in the Aftercool study, the information will be confirmed by reviewing the medical record.
Time frame: 5 years
Rehospitalization
Data are collected via interview. If a participant is rehospitalised or requires additional hospital care, and if that hospital shares a medical database with the centres of the Aftercool study, the information will be confirmed by reviewing the medical record.
Time frame: 5 years
Modified Rankin Scale (mRS) Score
The mRS scale is used to assess neurological status. mRS scale ranges from 0 (no residual symptoms) to 6 (dead). Higher scores indicate greater disability.
Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years
36-Item Short Form Health Survey (SF-36) score
The SF-36 questionnaire is a health-related quality of life scale, comprising eight scaled scores: vitality, physical functioning, bodily pain, general health perceptions, physical role functioning, emotional role functioning, social role functioning and mental health. Scores range from 0 - 100. Higher scores mean less disability.
Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years
Activity of Daily Living (ADL) score
Autonomy level is measured using a six-item ADL scale. Scores range from 0 (the patient is very dependent) to 6 (the patient is independent).
Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years
Cardiovascular adverse events
Cardiovascular adverse events that occurred between interviews: acute coronary syndromes, arrhythmias, stroke or other cerebrovascular events.
Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years
NewYork Health Association (NYHA) status
The extent of heart failure is assessed using The New York Heart Association (NYHA) Functional Classification. It enables patients to be classified into classes I to IV according to their symptoms, with class I corresponding to the best health.
Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years
Respiratory adverse events
Respiratory adverse events that occurred between interviews.
Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years
St-George's Respiratory Questionnaire (SGRQ) Score
The SGRQ questionnaire (PDF) has 50 items divided into three parts measuring symptoms, activity limitation and social and emotional impact of disease. Scores range from 0 to 100, with higher scores indicating more limitations
Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years
Home oxygen therapy
The need to resort to the use of home oxygen therapy between interviews.
Time frame: Baseline, 6 months, 1 year, 2 years, 3 years, 4 years and 5 years
Plan to share: No
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