A multicenter, single-arm, prospective, interventional trial to evaluate therapeutic hypothermia with intravascular temperature management (IVTM) in post-cardiogenic cardiac arrest, post-return of spontaneous circulation (ROSC) patients in Japan.

The objective of this study is to verify that therapeutic hypothermia performed by intravascular cooling using the investigational device (IVTM) can control body temperature appropriately in post-cardiogenic cardiac arrest, post-ROSC patients.

Inclusion Criteria:

1. Non-traumatic in-hospital or out-of-hospital cardiac arrest
2. Unwitnessed cardiac arrest (Ventricular fibrillation), or witnessed cardiac arrest (ventricular fibrillation, pulseless electrical activity, asystole within 15 minutes following onset)
3. Patient is at least 20 years of age and less than 80 years of age with consent is given
4. In the judgement of an investigator or sub-investigator, the patient is unable to follow verbal instructions
5. Therapeutic hypothermia using the investigational device can be initiated within six hours of Return of Spontaneous Circulation (ROSC)
6. Written consent can be obtained from a legally acceptable representative

Exclusion Criteria:

1. Traumatic cardiac arrest (blunt trauma, penetrating trauma, burns, exsanguination, suffocation, smoke inhalation, near drowning, etc)
2. Accidental hypothermia with core body temperature less than 35.0°C
3. Pregnant or of child bearing potential
4. Patient has given or indicated a Do Not Resuscitate (DNR) order
5. Femoral venous access is contraindicated by previous surgey, medical history, anatomy or the like
6. An inferior vena cava filter is in place
7. Patient has severe bleeding (Pulmonary hemorrhage, gastrointestinal hemorrhage, etc.)
8. Intracranial hemorrhage as confirmed by CT scanning
9. Hemodynamic instability despite use of vasopressor agents and cardiac stimulants
10. Heparin hypersensitivity
11. Serious systemic infectious diseases (sepsis, etc.)
12. Platelet count less than 30,000/mm3
13. Serious hepatic dysfunction
14. Serious renal impairment
15. Using percutaneous cardiopulmonary support (PCPS)
16. Using continuous hemodiafiltration (CHDF)
17. Therapeutic hypothermia has been otherwise implemented between ROSC and the start of the study (excluding the rapid infusion of non-glucose-containing cold electrolyte fluid, or non-glucose-containing cold plasma volume expander)
18. The patient's core body temperature cannot be monitored
19. Currently participating in another clinical trial or has participated in another clinical trial within the past six months
20. in the judgement of an investigator or sub-investigator, participation in this clinical trial is inappropriate for the patient