Carotid compression
Carotid compression involves reducing arterial blood flow to the brain by external compression of one or both of the common carotid arteries to induce sensations of lightheadedness or cause loss of consciousness.[1] This can be performed using several specific techniques such as the sleeper hold. Many of the considerations of carotid compression overlap with breath control, although carotid compression typically does not include restriction of airflow and has several additional unique risks.
| Other names | Sleeper hold |
|---|---|
| Health risk | High |
| Legal risk | High |
Background
The common carotid arteries are large arteries which provide most of the blood flow to the brain. When blood flow to the brain is restricted:
- Consciousness is lost within seconds
- Permanent brain damage occurs within minutes
- Death is all but certain after 10 minutes
When carotid compression is applied, the subject will typically experience presyncopal symptoms for a few seconds prior to losing consciousness.[1] Presyncopal symptoms include:
- Lightheadedness
- Feelings of warmth
- Vision changes (loss of color vision, vision going dark or closing in)
When syncope occurs (i.e. consciousness is lost), the subject will have no ability to control their body and may exhibit specific involuntary signs, such as:
- Eyes rolling back into the head
- Loss of muscle tone
- Abnormal posturing
- Abnormal or obstructed breathing
When consciousness returns, subjects can exhibit brief seizure-like activity prior to regaining control of their body and awareness of their surroundings. Initially, subjects are often quite disoriented, feeling as if they woke up from a dream with no memory of the events immediately preceding loss of consciousness. Full memory typically recovers several seconds later.
Appeal
Methods
- The "sleeper hold", which uses the arm or leg to in a triangular hold which occludes both carotid arteries from lateral compression. When properly executed, this hold does not apply pressure to the trachea (windpipe) and airflow is not restricted.
- Direct compression using the fingers or hands
Risks
The major risks of carotid compression include:
- Stroke
- Injury to airway or vascular structures
- Bodily injury from falling when consciousness is lost
- Airway obstruction or aspiration
- Cardiac arrest (from the carotid sinus reflex)
Risk mitigation
Even with advanced knowledge and training in specific techniques, carotid compression cannot be made completely safe. In general, techniques for carotid compression aim to apply the minimum pressure required to achieve the desired effect without compressing or stretching nearby airway or other vascular structures.
It is critically important to recognize when unconsciousness occurs and immediately restore normal blood flow to the brain, as when restriction of flow is prolonged after consciousness is lost, the unconscious person will not have any further added experience, while the risk of permanent injury greatly increases. Recognition of the loss of consciousness from carotid compression is non-trivial. Often subjects will exhibit involuntary reflexes such as abnormal posturing and may keep their eyes open which may be misinterpreted as them not "being out" yet leading to prolonged compression.
Loss of consciousness can occur very rapidly with limited warning. When this occurs, subjects will completely lose control of their bodies and must be prevented from falling. Furthermore, it is important that to carefully position the subject into an appropriate recovery position which does not obstruct the airway and facilitates restoration of blood flow to the brain. The individual should be laid down with their head on the ground. If consciousness does not immediately return, the legs should be elevated to promote additional blood flow to the brain. If the subject remains unconscious, the presence of pulses should be assessed and CPR may be required.
When consciousness is regained, subjects may have seizure-like involuntary movements and be extremely disoriented and should be prevented from accidentally injuring themselves or others until they have fully recovered.
Carotid compression should never be practiced when carotid plaques could be present due to the high risk of plaque dislodgement and embolic stroke. More than 50% of older adults (>60 years old) have some degree of carotid plaque formation. Middle-aged adults (40-60 years old) can develop carotid plaques, with higher prevalence among those with risk factors (hypertension, high cholesterol, smoking, diabetes, cardiovascular disease).