Temperature control can generally be achieved by setting the ECMO heater temperature to the desired temperature but may need to be adjusted slightly (by 0.5 -1°C below or beyond target) according to the patient’s own balance of heat production and loss. Commonly in scenarios of volume resuscitation in an exposed patient, the temperature may drop below desired and the heater can be used to avoid hypothermia.
Rarely the internal heat production causes the body temperature to be in the febrile range. A fever despite ECMO and no active warming should be taken very seriously and the patient be worked up for the differential diagnosis of fever, in particular sepsis.
Note: if the heater temperature is set more than 1°C below the temperature of the returning blood the heater eventually alarms (see picture below). If an even lower body temperature is desired the heater alternatively can be turned off to avoid the alarm whilst carefully monitoring the body core temperature.
In this patient, the returning blood has a temperature of 37°C, whereas the set temperature is 35.3°C – more than 1°C below triggering the alarm.
Awake patients
In awake patients who experience discomfort due to feeling hot or cold establishing a correct core temperature reading would be the first step. Further, the heater temperature can be adjusted for individual patient preference. The acceptable range of body temperature is at the discretion of the treating intensivist.
Target temperature management post cardiac arrest
36°C as per standard, adjust heater temperature accordingly to achieve the aim. This is very achievable and should be followed.
Approach to the patient below 36°C post ECPR
In the absence of contraindication in particular haemorrhage, the patient should be rewarmed stepwise by setting the heater temperature and monitoring patient temperature carefully by 0.5°C per hour to 36°C. In case of massive haemorrhage the heater can be used to keep the body temperature above 35°C however it is prudent to not overshoot once transfusion stop to avoid temperatures above 36.5°C.
More about the heater can be found here