I just noticed this while I was watching videos on the recent Detroit EMS snafu and it dawned on me that I had seen this before.
Several weeks ago while I was detailed to another station we made a call next door to a high school for an unconscious person. A passerby told us they saw a kid go down in the parking lot and that we needed to check out, so we self dispatch over to the parking lot.
We find a 16 y/o M, now a little bit more conscious and screaming in pain. His only outward injury was a lac to the back of his head where he hit the ground. He had no past medical history, vitals were normal except for an elevated heart rate around 120 BPM, RR was about 22 and unlabored, as he was screaming and maintaining his own airway. Clear and equal breath sounds, moves all his extremities well. He is uncooperative with our attempts to assess his head and back pain, so he gets a collar and a board for transport.
Once we immobilize him and get him in the back of the ambulance, he decides to finally cooperate and tell us that his only his head hurt from where he hit his head. He doesn’t give us exact details as to why he passed out or how, but his mother (that the school ran to call as opposed to calling the fire dept) tells us he has none. The kids around him said he was holding his breath like part of a game, which I didn’t understand at first. I attributed it to our patient just being immature about and argument with a girl or someone, but it makes more sense now.
Turns out this is quite common, it even has it’s own page over at Wikipedia. It has not even been studied, but anecdotally some reasons for playing this “game” include:
- Getting out of class
- Peer pressure
- To get a high or increase the effect of an existing high
How It’s Done
Those attempting to “play” will use several methods that both result in cerebral hypoxia. Strangulation and self-induced hypocapnia are two different methods, both common, and are both confused with each other.
Strangulation involves using a ligature to compress the internal carotid artery, reducing or cutting off blood flow to the brain, inducing the hypoxia. This results in two other significant responses. Baroreceptors in the neck that are compressed will increase vasodilation in the brain resulting in a drop in blood pressure that helps maintain consciousness. Also, the brain will send a signal along the vagus nerve to the heart, resulting in a dramatic reduction in heart rate and stroke volume. This will eventually result in asystole which is difficult to reverse without extremely fast treatment.
Self-induced hypocapnia results from hyperventilation, and the high level of CO2 caused numbness and tingling as well as light-headedness. This is then followed by a “hard breath hold.” This causes stimulation of the vagus nerve through a Valsalva maneuver, resulting in syncope. Alkalosis produces the sense of euphoria sought through the increase of the blood pH.
Another side effect of the alkalosis in the brain is vasoconstriction, and the Valsalva maneuver produces a sudden increase in blood pressure and rapid onset of hypoxia induced unconsciousness. The sequence of events looks something like this:
- Decrease in partial pressure of alveolar CO2.
- Decrease in partial pressure of arterial CO2.
- Increase in blood pH, (respiratory alkalosis).
- Vasoconstriction of blood vessels supplying brain.
- Pooling of the blood present in the brain at the time.
- Brain rapidly uses up oxygen (O2) available in the pooled blood.
- O2 concentration in the brain drops.
- Unconsciousness from hypoxia of cerebral tissue.
Under normal circumstances, the brain will divert blood away from other body organs in order to perfuse itself and maintain a normal oxygen level, but since the vessels are constricted blood is not able to be brought in. The brain was a very low tolerance for oxygen deprivation because it has no reserves, so this results in consciousness.
Both mechanisms are reverasable within a few seconds as the concentration of CO2 rises and respirations resume. Short term memory loss and muscle spasms are common, rarely will there be any permanent damage or death but the risk increases with the use of a ligature or when it is being played alone.
Long Term Damage
The hypoxia could result in long term brain cell death, however studies about how a person would need to be hypoxic in order for this to occur are controversial. The CDC found that the rates of death and disability are higher among juvenile males, and the rates of death caused by the game are underreported due to false attributions to suicide. The CDC also found that 82 deaths have occurred since 1995 resulting from this game directly. Indirect injuries may occur from use of ligatures or secondary trauma.
Assessment and Treatment
EMS providers should examine all juveniles that have had syncopal episodes for signs of strangulation or bloodshot eyes. Scene observations for objects that could be used for ligatures should be noted in PCR’s and reported to the hospital at transfer of care. ECG monitoring and 12 lead ECG’s are always recommended, and hypocapnia can be detected using waveform capnography.
Hypocapnia can be reversed using forced positive pressure ventilation and in conjunction with capnography the amount and volume of ventilations can be titrated in order to bring numbers closer to normal range (35-45 mmHg) and ventilations used to maintain that as needed. The patient should regain consciousness with the maintainence of CO2 around normal levels and if they do not regain a respiratory drive sufficient for oxygenation, intubation may became necessary. Progressive airway management will be required on any unconscious patient where it is suspected they have been playing this game.
Be aware and be ready, we may see more of these.