OVERVIEW
- devices that warm blood during or prior to administration
USES
- Used with rapid transfusion rates (e.g. >50 mL/kg/hr), in already hypothermic patients or rare conditions where cold fluid delivery is problematic (e.g. cold agglutinins)
- massive transfusion (avoid hypothermia)
DESCRIPTION
Three main types/methods:
- Water-bath warmers
- Dry heat plate warmers
- Intravenous fluid tube warmers
Water-bath warmers
- warms IV fluid with prewarmed water; maximum temperature is 38°C and whilst cheap the system is inefficient at high infusion rates.
Dry heat plate warmers
- increases heat transfer capability of the material and enables an increase in temperature up to 41°C
- the IV fluid is warmed in a cassette between the heat plates.
Intravenous fluid tube warmers
- An outer layer allows warm water to circulate down one side and then up into a reservoir that surrounds this
- Tubing is heavy and long and only efficient at low flow rates (20–30 mL/min)
- Each requires a specially designed IV tube warmer coil
- fluid heating rate is a function of the power of the heating device
This means that although IV fluid warmers are the most efficient low flow rates, if higher flow rates are necessary a device using a dry heat plate is more effective at higher flow rates (because the metals used are more effective conductors than the fluids used in other systems)
METHOD OF USE
- routine warming of blood is not necessary
- If warming is clinically indicated a specifically designed commercial device should be used with both visible and audible alarms, to ensure that the blood is not heated above 41°C
- Blood warmers must be regularly serviced and maintained, as they can be very dangerous if they malfunction
- Blood should never be warmed by any other method
COMPLICATIONS
- Overheating of blood (risk of haemolysis)
- Air embolism
Chris Nickson
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of pi-web.eu, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
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