In short: a hospital warming cabinet is not only for infusion fluids. Contrast agents, irrigation solutions, peritoneal dialysis fluids, blankets, gowns and neonatal items all pass through the same kind of cabinet, and each of them has a different reason for being warmed. The useful question is not whether a cabinet can hold them, but which of them your departments actually need warm, at what point of care, and whether they can share one setting.
The case for warming intravenous fluids is well established and does not need repeating at length. Inadvertent perioperative hypothermia increases the risk of surgical wound infection and lengthens hospital stay (Kurz et al., 1996), and warming intravenous and irrigation fluids is one of the measures used to prevent it (Campbell et al., Cochrane, 2015). This article is about everything else that goes into the cabinet.
What a warming cabinet is designed to hold
EM-MED’s EmTherm cabinets are specified for six categories of load: infusion fluids, irrigation fluids, contrast agents, peritoneal dialysis fluids, textiles and medical accessories. In daily use the list is longer. Hospitals also warm mannitol solutions, syringes and instruments, and on neonatal units the cabinet is commonly used for baby clothes, blankets and bottles of infant formula.
These loads do not share a single clinical rationale. Some are warmed to protect the patient’s core temperature, one is warmed because of how it behaves during injection, and some are warmed so that the first thing touching a patient’s skin is not cold. That difference is what decides how a cabinet is set up and where it stands.
| Load | Why it is warmed | Where it is typically used |
|---|---|---|
| Irrigation fluids | Used in direct contact with tissue in open body cavities; NICE names a thermostatically controlled cabinet for them | Operating theatre |
| Contrast agents | Warming the more viscous agents is associated with fewer extravasations | Radiology, CT, cath lab |
| Peritoneal dialysis fluids | Fluid introduced directly into the peritoneal cavity | Nephrology |
| Blankets, gowns, textiles | Reduce heat loss from the skin before, during and after procedures | Theatre, recovery, emergency department, wards |
| Neonatal items | Newborns lose heat quickly and have limited capacity to regulate it | Neonatology, neonatal ICU |
| Syringes, instruments, accessories | Held ready at the set temperature | Theatre, procedure rooms |
Contrast media: the one load warmed for a different reason
Contrast agents are warmed for a different reason from most of the cabinet’s load. The evidence concerns what happens during injection, and it depends on how viscous the agent is.
The clinical evidence is specific, and it is worth reading precisely. In a study of more than 24,000 CT injections, Davenport and colleagues compared a period in which iopamidol was warmed to 37 °C before administration with a period after warming was stopped. For the more concentrated and more viscous iopamidol 370, stopping warming was associated with a significant increase in extravasations and overall adverse events. For the less viscous iopamidol 300, warming made no measurable difference. (Davenport et al., Radiology, 2012.)
In that study the benefit concerned the more viscous agent. For departments that use such agents, the practical point is that contrast kept in medical warming cabinets is already at temperature when it is needed.
Irrigation fluids: the largest volume, and the one the guideline names
During surgery, irrigation fluid – mostly saline – is used to rinse the operative field and remove blood, in direct contact with tissue in an open body cavity. The NICE guideline on perioperative hypothermia recommends that all irrigation fluids used intraoperatively be warmed in a thermostatically controlled cabinet to 38–40 °C (NICE CG65, recommendation 1.3.9). For this load the guideline does not leave the method open; it names a cabinet.
That makes theatre the setting where capacity matters most. The cabinet has to hold enough warmed stock for the busiest session, not for an average day. The practical side of sizing is covered in our guide to choosing an IV fluid warming cabinet.
Peritoneal dialysis fluids and mannitol
Peritoneal dialysis fluid is introduced directly into the peritoneal cavity, so its temperature on entry is the temperature the patient receives. Peritoneal dialysis fluids are one of the loads a warming cabinet is designed for, so the bags can be held at temperature until they are used.
Mannitol, often given on intensive care to reduce oedema and pressure, is another solution that is warmed before use. On units where it is given regularly, keeping it in a warming cabinet means it is ready when needed rather than prepared under time pressure.
Hospital textiles: more than comfort
Warm blankets are the most visible use of a warming cabinet, and the easiest to underestimate. Heat is lost through the skin, and a warmed blanket placed over a patient before, during or after a procedure reduces that loss. It is a simple measure that supports normothermia alongside warmed fluids, rather than replacing them. Our earlier article on warming medical textiles looks at the clinical side in more detail.
Two practical considerations apply here. First, where fluids and textiles are both needed in volume, or need different settings at the same time, they are often kept in separate cabinets. Second, infection control. Where infection control requirements extend to the warmed items themselves, UV-C disinfection of the load surface is the feature that addresses it. EmTherm cabinets use UV-C lamps that disinfect pathogens – fungi, bacteria and viruses, including coronaviruses – on the surface of the load being warmed.
Neonatal units: a different kind of load
Newborns, and preterm infants in particular, lose heat quickly and have limited capacity to regulate their own temperature. On neonatal units the warming cabinet is therefore used less for large fluid volumes and more for the items that come into contact with the baby: blankets, clothes and bottles of infant formula. It is one of the uses most popular with neonatal nurses.
Why the heating method matters with mixed loads
A cabinet that holds bags, bottles, syringes and folded blankets at the same time has to warm them evenly, regardless of shape or position. EmTherm cabinets use convective heating through forced air circulation: the heating element sits outside the load space, and a fan distributes warmed air through the chamber. The temperature is the same throughout the cabinet, and fluids never come into direct contact with the heating element. For mixed loads, that uniformity is what makes it possible to put different items in one cabinet and trust the setting.
Convection also has a practical consequence for speed. When the warming medium is air at a given temperature, the rate at which a bottle warms depends on that temperature, not on the brand of cabinet. The way to warm faster is to raise the temperature temporarily, which is what a boost function does. In practice, cabinets are run continuously and restocked as warmed items are used, so that the load in the cabinet is always ready.
Setting it up: one cabinet or several
Where several departments warm different loads, it usually makes sense to place cabinets by use rather than by item. A short checklist helps:
- List every load each department actually warms, not only IV fluids.
- Group loads that can share one temperature setting, and separate those that cannot.
- Place the cabinet where the load is used: beside the scanner for contrast, in or next to theatre for irrigation fluids, on the unit for neonatal items.
- Size each cabinet to the busiest session it serves.
- Decide at purchase whether you need UV-C disinfection of the load and temperature data recording, because both are harder to add later.
EM-MED supplies fluid warmer cabinet units in several loading capacities, from benchtop units for a treatment room to large mobile cabinets for theatres and central sterilisation.
Frequently Asked Questions
Can contrast media be warmed in the same cabinet as IV fluids?
Yes, a warming cabinet is designed for contrast agents as well as infusion fluids.
Does warming contrast make a clinical difference?
For the more viscous agents, yes. Davenport and colleagues found that stopping warming of iopamidol 370 to 37 °C was associated with more extravasations and adverse events, while for the less viscous iopamidol 300 warming made no measurable difference.
Should blankets and fluids be warmed together?
They can be, but where both are used in volume and need different settings at the same time, separate cabinets work better.
What does the guideline say about irrigation fluids?
NICE CG65 recommends that all irrigation fluids used intraoperatively be warmed in a thermostatically controlled cabinet to 38–40 °C.
Is a warming cabinet useful on a neonatal unit?
Yes. Newborns lose heat quickly, and neonatal nurses use cabinets to keep blankets, clothes and bottles of infant formula warm and ready.
What does UV-C add?
It disinfects pathogens on the surface of the warmed load, not only the cabinet interior. It is relevant where infection control requirements extend to the warmed items themselves.
How quickly does a cabinet warm its load?
It depends on the room, the container and the starting temperature, so there is no single figure. Cabinets are designed to run continuously with stock replenished as it is used, and a boost function raises the temperature temporarily when faster warming is needed.
Sources
Davenport MS, Wang CL, Bashir MR, Neville AM, Paulson EK. Rate of contrast material extravasations and allergic-like reactions: effect of extrinsic warming of low-osmolality iodinated CT contrast material to 37 °C. Radiology. 2012;262(2):475–484. doi:10.1148/radiol.11111282
National Institute for Health and Care Excellence. Hypothermia: prevention and management in adults having surgery. NICE guideline CG65, recommendation 1.3.9.
Kurz A, Sessler DI, Lenhardt R. Perioperative normothermia to reduce the incidence of surgical-wound infection and shorten hospitalization. New England Journal of Medicine. 1996;334:1209–1215. doi:10.1056/NEJM199605093341901
Campbell G, Alderson P, Smith AF, Warttig S. Warming of intravenous and irrigation fluids for preventing inadvertent perioperative hypothermia. Cochrane Database of Systematic Reviews. 2015;(4):CD009891. doi:10.1002/14651858.CD009891.pub2