In short: the decision is no longer about how cold a system can make a patient. Since TTM2, post-arrest care has moved from mandatory hypothermia at 33 °C towards actively controlled temperature with fever avoidance for at least 72 hours. What separates one system from another is how precisely it holds a target over three days, how it handles the transitions between cooling, rewarming and normothermia, and what it costs to run at your real case volume.
This guide sets out the questions an intensive care unit should answer before writing a tender for a therapeutic hypothermia or targeted temperature management system.
What the system has to do today
The TTM2 trial compared hypothermia at 33 °C with normothermia and found no significant difference in six-month mortality (Dankiewicz et al., 2021). The comparator arm was not left without temperature control: it was actively managed, with early treatment of fever. The ERC–ESICM guidelines that followed recommend continuous core temperature monitoring and active prevention of fever above 37.7 °C for at least 72 hours in patients who remain comatose after cardiac arrest (Sandroni et al., 2022).
For equipment, this has two consequences. The system has to hold a narrow upper limit, not only reach a low target, and it has to do so for longer than a classic hypothermia protocol ever required. A unit that bought equipment for 24 hours of maintenance per patient now needs it for three days, and the full arc – induction, maintenance, controlled rewarming and continued fever prevention – has to run on one device without being rebuilt at every handover. The individual phases are described in our step-by-step guide to the TTM protocol.
The indications go beyond cardiac arrest. Controlled temperature management is also used after ischaemic stroke, in newborns with hypoxic-ischaemic encephalopathy, in febrile patients, during endovascular procedures and in trauma. A unit that expects to treat more than one of these groups should say so in the specification.
Surface or intravascular
This is usually the first question, and the evidence has narrowed it considerably. A systematic review and network meta-analysis by Ramadanov and colleagues found no significant difference in neurological outcome or survival between intravascular cooling and surface cooling with temperature feedback; surface cooling without feedback performed worse (Ramadanov et al., 2022). A post hoc analysis of the TTM2 trial compared the two approaches again in out-of-hospital cardiac arrest patients (Awad et al., 2025).
The meaningful line is therefore not between surface and intravascular, but between systems with closed-loop feedback and systems without it. Within the feedback-controlled group, the choice between surface and intravascular comes down to the unit’s own circumstances:
- Intravascular systems need central venous access and the skills to place a catheter, and carry the risks that come with it: infection, bleeding, vascular injury and thrombosis.
- Surface systems need no vascular access and can be started by the nursing and medical staff already on the unit.
The questions that decide it
| Question | What it determines |
|---|---|
| Does the system regulate from the patient’s core temperature continuously? | Whether it is a closed-loop system. Without feedback, surface cooling performs worse – this is the one requirement not to compromise on. |
| Can one device run the whole therapy: cooling, maintenance, controlled rewarming and fever prevention? | Whether protocols have to be rebuilt or the patient moved to different equipment between phases. |
| Can complete protocols be stored on the unit? | Whether settings survive shift changes without being re-entered by hand. |
| Can it warm as well as cool? | Whether the same device covers rewarming, normothermia and active warming, or a second system is needed. |
| How many temperature measurement sites can it monitor? | Whether a second site can cross-check the core probe if it is displaced over a 72-hour run. |
| Are the covers disposable, reusable, or both? | The running cost. Over five years this is usually the largest single difference between systems. |
| Which body regions do the covers treat? | Access to wounds, drains, surgical fields and lines during therapy, and whether non-standard patients can be treated. |
| Does it record and export the temperature curve? | Whether protocol compliance can be documented for clinical review and audit. |
| How many patients will be on therapy at the same time, for three days each? | How many devices the unit needs. |
| Who installs, trains and services it in your country? | How quickly a fault is fixed and staff are trained when the team changes. |
Precision over three days, not cooling speed
With fever avoidance recommended for at least 72 hours, much of the clinical task is maintenance: holding the patient within a narrow band, without overshoot, through sedation changes, shivering and repositioning, for days rather than hours.
That task depends on the control algorithm. A system that reads core temperature continuously and adjusts output in both directions, taking account of how the patient’s temperature responds, will hold a target that a system working from a fixed water temperature will chase. It is worth asking manufacturers how their automatic programmes respond to a patient’s thermal inertia, how rewarming rate is set and limited, and how the device behaves if the core probe signal is lost.
Count the devices for 72 hours
The change in guidance has an operational side that is easy to miss. A protocol that holds normothermia and prevents fever for 72 hours after return of spontaneous circulation occupies a device roughly three times longer than one built around 24 hours of maintenance. Units that read TTM2 as “we cool less now” and reduced their equipment are the ones most likely to run short. We cover this in more detail in our article on fever prevention after cardiac arrest.
When sizing the fleet, start from the number of post-arrest, stroke and other admissions that will need temperature control, multiply by the realistic duration of therapy, and allow for the cases that overlap.
Consumables decide the cost
The price of the control unit is the most visible number in a tender and rarely the most important one. Covers, pads or catheters are used for every patient, and over the life of the system their cost usually outweighs the purchase price. Systems differ here more than anywhere else, so it is worth checking whether covers are single-use only or also available in reusable versions.
It is worth modelling five years at the unit’s real case volume rather than comparing the price of one patient set. A system with both disposable and reusable covers lets the hospital decide its own consumable model, and change it later, rather than inheriting one from the manufacturer.
Where TrueCool fits
EM-MED’s TrueCool is a non-invasive, feedback-controlled surface system for therapeutic hypothermia and targeted temperature management. It regulates continuously from the patient’s core temperature, works as a hypo/hyperthermia unit that cools and warms with the same covers, runs the full therapy from cooling to controlled rewarming with complete protocols stored on the unit, and offers covers in both disposable and reusable versions. It is indicated for post-arrest care, including hypothermia after cardiac arrest, ischaemic stroke, neonatal hypoxic-ischaemic encephalopathy and the other groups listed above.
EM-MED is a family-owned manufacturer from Kraków with more than 30 years on the medical market, exporting to over 40 countries through national distributors. Approximately 2,500 EM-MED devices are in use worldwide.
Frequently Asked Questions
Is surface cooling as effective as intravascular cooling?
When the surface system uses temperature feedback, published evidence found no significant difference in neurological outcome or survival between the two. Surface cooling without feedback performed worse (Ramadanov et al., 2022).
What is the most important specification for an ICU cooling system?
Closed-loop control from the patient’s core temperature.
Do we still need a cooling system if we now target normothermia?
Yes. Guidelines recommend active prevention of fever above 37.7 °C for at least 72 hours in comatose post-arrest patients. Holding that limit reliably is a closed-loop task, and it occupies a device for longer than a classic hypothermia protocol did, so most units need more device time, not less.
Why does the consumable model matter so much?
Because covers or catheters are used for every patient. Over five years their cost usually exceeds the price of the control unit, and it is the number that differs most between systems.
Can one system be used for neonates?
Neonatal hypoxic-ischaemic encephalopathy is a recognised indication for therapeutic hypothermia, and the American Academy of Pediatrics has published guidance on cooling in this group (Zanelli et al., 2026). Ask the manufacturer specifically which covers and settings are available for newborns.
How many devices does a unit need?
Count the expected admissions needing temperature control, multiply by about three days per patient, and allow for overlap.
Sources
Dankiewicz J, Cronberg T, Lilja G, et al. Hypothermia versus Normothermia after Out-of-Hospital Cardiac Arrest. New England Journal of Medicine. 2021;384(24):2283–2294. doi:10.1056/NEJMoa2100591
Sandroni C, Nolan JP, Andersen LW, et al. ERC-ESICM guidelines on temperature control after cardiac arrest in adults. Intensive Care Medicine. 2022;48(3):261–269. doi:10.1007/s00134-022-06620-5
Ramadanov N, Arrich J, Klein R, Herkner H, Behringer W. Intravascular Versus Surface Cooling in Patients Resuscitated From Cardiac Arrest: A Systematic Review and Network Meta-Analysis With Focus on Temperature Feedback. Critical Care Medicine. 2022;50(6):999–1009. doi:10.1097/CCM.0000000000005463
Awad A, Jonsson M, Holgersson J, et al. Intravascular vs. surface cooling in out-of-hospital cardiac arrest patients receiving hypothermia after hospital arrival: a post hoc analysis of the TTM2 trial. Intensive Care Medicine. 2025;51(4):721–730. doi:10.1007/s00134-025-07883-4
Zanelli SA, Wusthoff CJ, Lucke AM, Kaufman DA. Therapeutic Hypothermia for Neonatal Hypoxic-Ischemic Encephalopathy: Clinical Report. Pediatrics. 2026;157(2):e2025073627. doi:10.1542/peds.2025-073627