Do We Make Trauma Patients Worse............

[Bernhard]

actual studies for post-CPR hypothermia state, that an ice cold (+4°C) infusion decreases body core temperature ("only") by 1,5°C per hour, when given 30ml/kg body eight. Double dose will give almost double temperature decrement. So, there may be a significant hypothermic effect considering higher infusion volume per time on trauma patients, but then those infusions usually are not ice cold. On the other hand, the rather thin infusion line hanging between bottle and needle should be considered as additional cooling factor, especially in chilly circumstances.

Still have to do some calculations for typical infusion volumes and probable fluid temperatures - or find an existing study/calculation covering this.

Sorry for constantly answering on my own posts, but finally I found something I want to share. Following calculation seems somewhat reasonable, at least from a mathematical viewpoint (source: an educational script about accidental hypothermia in EMS by a physician, german language):

Fluid volume per body weight reducing the core temperature by 1°C:

• initial infusion temperature 20°C: 52 ml/kg
  
• initial infusion temperature 22°C: 61 ml/kg
  
• initial infusion temperature 28°C: 108 ml/kg
  
• initial infusion temperature 33°C: 307 ml/kg
  

Do the math..according to this, with a 70kg patient you need ~3600ml (more than 7 bags of 500ml!) of a 20°C (room temperature) infusion to reduce body temperature by 1°C.

So maybe the infusion isn't the real problem.

[chbare]

The problem with a trauma patient is they are often already hypothermic, have an underlying acidosis and may already be developing a coagulopathy. These three issues are sometimes collectively referred to as the trauma triad of death (acidosis, hypothermia, coagulopathy). Even modest changes in temp may lead to significant problems. We already have ischaemic tissue and acidosis with a possible pre-existing hypothermia. Unfortunately, we already like have conformational changes (proteins) occurring.

[krumel]

I worked for a service that did routinly check the patient body temp. in an trauma...And can just support chbare's post...quite a lot of patients we saw were (mild) hypothermic.

Coming back to the "microwave" myth: Interestingly we heard this myth in Europe, too.

A mail to one of the "big brands" revealed the following:

According to them there is a certain (small) hazard as household-microwaves warming fluids tend to have a very "dissimilar" heat intake. Own experiments of the company did show that some ares might get "hotspots" where the temperature does exceed the limitations the plastic bag can stand. This may cause a "washing off" of certain flexibilizers.