A cardiac arrest is an abrupt disruption of the electrical signals causing irregular heartbeat. The result is that the heart stops pumping blood around the body, which can be fatal if it isn't treated immediately. Sometimes, a cardiac arrest may be triggered by exposure to extreme cold. This type of emergency is known as hypothermic cardiac arrest or simply hypothermic arrest. It's not as common as other types of cardiac arrest, but it can happen in adults and children if they remain in a cold environment for too long. This is when the body's core temperature falls below 35°C (95°F) due to exposure to freezing temperatures. Extreme cold can cause a sudden interruption in the flow of blood to the heart, which then suddenly stops beating.
Symptoms of hypothermic cardiac arrest
The International Commission for Mountain Emergency Medicine (ICAR MedCom) recognizes hypothermic cardiac arrest as the fourth stage of hypothermia. The first three stages are low, moderate, and high hypothermia. At stage 4, the patient is unconscious from AVPU (the Alert, Verbal, Painful or Unconscious), and there are no detectable vital signs.
An increased heart rate is one of the first signs that someone is experiencing a hypothermic cardiac arrest. This will be followed by a sudden drop in blood pressure and an irregular heartbeat that may become completely unresponsive. In many cases, the person will become unconscious, and their breathing will slow or stop completely. If the person's core temperature has fallen below 28°C, they could go into shock and lose consciousness completely. Suppose you notice any of these symptoms in a person standing or sitting outside in the cold. Don’t wait! Identify the problem and begin treating them immediately.
Why does a cold environment cause a heart attack?
A sudden drop in body temperature causes blood vessels to shrink and heart rate and blood pressure to increase. This natural reaction attempts to protect the body temperature from falling too low. However, if the temperature decreases, the blood vessels become so tight that blood can no longer flow through them. This interrupts the heart's ability to pump blood around the body, causing it to stop. When the heart stops pumping, a person's organs are deprived of oxygen and start to shut down. Without immediate treatment, death is almost certain.
How to recognize hypothermic cardiac arrest
Symptoms of hypothermic cardiac arrest are similar to those of other cardiac arrests, such as a heart attack.
However, they are often accompanied by an additional set of warning signs. These signs include:
- Intense shivering
- Paradoxical undressing
- Slurred speech
- Slow reaction time
- Memory loss
- Slow, shallow breathing (Cardiac arrhythmias)
- Weak pulse
Treatment for Hypothermic Cardiac Arrest
The most important thing to do when you recognize hypothermic cardiac arrest in a person is to check the pulse, monitor the breathing and start cardiopulmonary resuscitation and CPR.
If the person is unconscious or having difficulty in breathing, call for an ambulance.
While waiting for an ambulance, the next priority is to get the person out of the cold and warm them up as quickly as possible. Avoid any rough handling of the victim as this may cause deadly heart rhythms.
If the person is still conscious with little or no difficulty in breathing, bring the person indoors and have him remove any wet clothing. Wrap him in dry blankets or towels and apply warm water bottles or heating pads to the chest and abdomen. Counteract hypothermia by raising the person’s legs slightly and keeping them warm and still. Other home care remedies can be applied to reduce the cold, but a check by a healthcare provider is highly advisable.