Does lowering the body temperature of donors following brain death improve the quality of transplanted organs?

Key messages

• Lowering the body temperature of donors in the intensive care unit before retrieving organs may not improve how soon the organ starts to work in the recipient.

• Lowering the body temperature of donors may not reduce the number of organs that could be used for transplant or cause any safety problems (such as heart issues).

• One-year survival of the transplanted organ was only reported by three of the four studies. Quality of life and heart disease for the recipients at 12 months were not reported in any of the studies. Key organ-related measures at 12 months (e.g. heart: heart function; pancreas: the need for insulin) were not reported.

What is solid organ transplantation?

Solid organ transplantation is a surgical procedure where a solid organ (kidney, heart, liver, lung or pancreas) is transferred from one person - the donor - to another person - the recipient. It is the optimal treatment for people living with end-stage organ failure. However, there remains a shortage of optimal organs for donation. Many organs come from people who are brain dead (where a person has permanent and irreversible loss of brain function) in an intensive care unit. The process of brain death is known to cause significant injury to organs. Therefore, efforts to optimise the care of these donors should be maximised to achieve the best outcomes and graft function in the transplant recipients.

Why lower the body temperature of donors, and how is it done?

Lowering the body temperature of donors to below normal core temperature (< 35.5°C) may slow the body's processes, helping to keep the organs healthier until they are retrieved and transplanted. This can take place in the intensive care unit between brain death and organ donation. Lowering the body temperature may be achieved by allowing donors to spontaneously cool to the target temperature, using fans, ice packs, or specific external cooling systems to promote the lowering of the body temperature of the donor, or bladder irrigation, invasive cooling lines or temperature-controlled humidified gases used during ventilation to achieve the desired core temperature. The degree of therapeutic hypothermia can also be classified as mild (34.0°C to 35.5°C), moderate (32.0°C to 33.9°C), moderately deep (30.0°C to 31.9°C) and deep (< 30°C).

What did we want to find out?

We wanted to see whether lowering the body temperature of donors makes organs healthier and improves outcomes for recipients after an organ transplant. We were interested in:

• how soon donated organs started working;

• whether the transplant was successful;

• whether the recipient survived (and for how long).

What did we do?

We searched for studies that assessed whether lowering the body temperature of donors was effective and if it caused unwanted effects. Donors in the studies had to have irreversible loss of all functions of the entire brain or irreversible loss of the capacity for consciousness and an irreversible loss of the ability to breathe. Recipients had to be receiving solid organs such as kidney, heart, liver, lung or pancreas. Studies could be set anywhere in the world.

What did we find?

We found four studies with 2096 donors that looked at the effect of lowering the body temperature of donors prior to transplantation. Two studies looked at kidney transplantation, and two studies looked at multiple solid organs (kidney, liver, lung, heart, pancreas). Studies were undertaken in the USA and France.

Kidney transplantation

Lowering the body temperature of donors compared to keeping them at normal body temperature:

• may not reduce the time it takes for transplanted kidneys to start working (4 studies, 3015 recipients);

• may make no difference to survival of the transplanted kidney one year after transplant (3 studies, 2075 recipients);

• may make no difference to how many kidney recipients survived for a year after transplant (1 study, 526 recipients).

Other organs

Lowering the body temperature of donors compared to keeping them at normal body temperature:

• may not reduce the time for transplanted lungs to start to work (1 study, 99 recipients);

• may not reduce the time for transplanted livers to start to work (1 study, 262 recipients);

• is unlikely to reduce the number of organs available for transplant (4 studies, 4265 recipients).

Lowering the body temperature of donors compared with keeping them at normal body temperature may not cause any problems with the donors (such as heart issues) (3 studies, 2015 donors).

What are the limitations of the evidence?

The small number of studies investigated, and the donor organs transplanted were the major limitations of this review. One-year survival of the transplanted organ was only reported by three studies. Quality of life and heart disease for the recipients at 12 months were not reported in any of the studies. Key organ-related measures at 12 months (e.g. heart: heart function; pancreas: the need for insulin) were not reported. Most studies focused on kidney donors and recipients, with very little information for other solid organs.

How up to date is this evidence?

The review is current to September 2025.