From the Guidelines
Yes, ECMO can cause cooling of body temperature, as evidenced by the ability to deliberately set the heat exchanger to cool the blood below normal body temperature, effectively lowering the patient's core temperature 1.
Introduction to ECMO Temperature Management
ECMO involves circulating blood outside the body through an external circuit, where the blood passes through a heat exchanger component. This heat exchanger can be used for targeted temperature management, particularly in cases of cardiac arrest, severe neurological injury, or when neuroprotection is desired.
Cooling Mechanism
The cooling effect occurs because the ECMO circuit exposes blood to room temperature or to deliberately cooled components, allowing heat to dissipate from the blood. Additionally, unintentional cooling can occur during ECMO if the heat exchanger is not properly managed to maintain normothermia.
Clinical Guidelines
According to recent guidelines, continuous monitoring of core temperature and active prevention of fever (> 37.7 °C) are recommended 1. Mild-moderate hypothermia (33–36 °C) for 24–48 h in VA ECMO, especially ECPR, is considered reasonable and may be considered 1. However, hypothermia in VV ECMO is not recommended 1.
Temperature Management
The medical team closely monitors the patient's temperature during ECMO and can adjust the heat exchanger settings to either maintain normal body temperature or achieve controlled hypothermia as clinically indicated. Targeted temperature management is crucial, and recent studies suggest maintaining hypothermia (33-36°C) for the first 24 hours, then gradual rewarming to normothermia at 37°C 1.
Key Considerations
- Avoiding arterial hypoxemia (PaO2 < 70 mmHg) and severe arterial hyperoxia (PaO2 > 300 mmHg) is recommended 1.
- Maintaining mean arterial pressure > 70 mmHg and individualizing blood pressure goals based on comorbidities and cerebral autoregulation are essential 1.
- Rewarming should be achieved slowly, with a consensus rate of about 0.25–0.5 °C of rewarming per hour, to avoid rebound hyperthermia 1.
From the Research
ECMO and Temperature Regulation
- ECMO (Extracorporeal Membrane Oxygenation) is a life-support therapy that can be used to regulate body temperature in patients with severe hypothermia 2, 3.
- The therapy involves pumping blood outside the body to a membrane oxygenator, where it is warmed or cooled before being returned to the body.
- Studies have shown that ECMO can be effective in rewarming patients with severe hypothermia, with some studies reporting faster rewarming rates compared to conventional rewarming methods 3.
Cooling Effects of ECMO
- While ECMO is often used for rewarming, it can also be used to cool the body temperature in certain situations.
- However, there is limited evidence to suggest that ECMO can cause cooling of temperatures as a primary effect.
- The primary function of ECMO is to provide respiratory and cardiac support, and temperature regulation is a secondary benefit 4, 5.
Clinical Applications of ECMO
- ECMO is commonly used in critically ill patients with respiratory or cardiac failure, and its use has increased significantly in recent years 5, 6.
- The therapy can be used in a variety of clinical settings, including emergency departments, intensive care units, and operating rooms.
- While ECMO can be an effective treatment for severe hypothermia, its use should be carefully considered and individualized to each patient's specific needs and circumstances 2, 3.