People who lose a lot of blood as the result of an emergency could be saved by cooling their face with ice water.
This was the conclusion that researchers at the University at Buffalo, NY, came to after conducting preliminary tests with healthy volunteers who underwent a simulation of moderate blood loss.
The findings featured at the recent Experimental Biology 2017 meeting in Chicago, IL, and they are also reported in an abstract published in a supplement to the FASEB Journal.
The researchers explain that blood loss causes central hypovolemia - a condition in which there is a drop in blood volume in the heart and in the blood vessels of the lungs.
In severe instances, blood loss can also decrease blood pressure and result in cardiovascular decompensation - a condition that is caused by a sudden and steep drop in blood pressure and results in insufficient oxygen supply to the brain, heart, and other vital organs.
Even when the bleeding has stopped, there may still be a significant risk of cardiovascular decompensation.
Estimates for the United States suggest that after a traumatic injury, the number of deaths due to hemorrhage, or blood loss, is second only to that caused by central nervous system injury. Over 35 percent of pre-hospital deaths are due to blood loss, as are over 40 percent of deaths that occur in the first 24 hours of the injury.
Simulation mimics blood loss
For the new study - which the researchers urge should be regarded as a preliminary investigation of how effective the method might be - 10 healthy volunteers aged 22 years on average underwent a simulation of blood loss.
Such an experimental setup mimics what happens in a person's circulation when they lose around 1.5 liters of blood and then the application of a tourniquet stops them losing any more blood.
The volunteers (7 men and 3 women) were randomly assigned to be treated either with a bag of ice water or a bag of body temperature water (the control treatment) applied to the forehead for 15 minutes following the simulated blood loss.
The team measured a number of cardiovascular indicators during the treatment time. These included blood pressure and peripheral resistance, which is the ability of arteries to resist blood flow. Peripheral resistance increases when arteries constrict.
May raise blood pressure by raising peripheral resistance
The results showed that there was a marked increase in blood pressure during treatment with ice water but there was no change during the control treatment.
There was also a sustained increase in peripheral resistance during the ice water treatment, while there was no change in this measure in the control treatment.
The researchers conclude that: "Face cooling during simulated moderate blood loss increases blood pressure through an increase in total peripheral resistance."
However, they are keen to point out that the technique should not be used until after active bleeding has stopped - such as after a tourniquet is applied. Blood loss will worsen, not reduce, if blood pressure increases during active bleeding.
They suggest that further studies should now be done to find out the types of emergency cases and situations in which face cooling is likely to be effective. They also wish to carry out a clinical trial.
"We believe that cooling the face could potentially be used as a quick and temporary method to prevent cardiovascular decompensation after blood loss once active bleeding has stopped. We think that this technique could be used by first responders or combat medics on the battlefield to give additional time for transportation or evacuation."
Prof. Blair Johnson, first author