All Narked Up!!!

Kaitlin Johnson

1 Martini, 2 Martini, 3 Martini, FLOOR! As college students we are all well aware of the effects of intoxication, but what some people may not know is that you can achieve these same feelings of euphoria as a result of scuba diving to depths greater than 33 meters! It is sometimes called the martini effect (due to the fact that scuba instructors often compare its effects to that of chugging 1 martini on an empty stomach, for every 10 meters you descend after an initial 33 meters) but it is more commonly known as, NITROGEN NARCOSIS. And it is a condition that is caused by excess nitrogen accumulating in your body’s blood and tissues. 

If we break it down from a scientific point of view it can be described as follows. . . 

As a diver descends they go from breathing enriched air nitrox gas (21% oxygen, 79% Nitrogen) at atmospheric pressure at the surface, to breathing more pressurized air at greater depths. This pressurized air enters the lungs of the diver in a more concentrated state. This is in large part due to Henry’s Law, "the amount of a gas that dissolves into a liquid at a given temperature is directly proportional to the partial pressure of that gas." At greater depths the partial pressures of both nitrogen and oxygen are higher and they diffuse into the body more readily. Through breathing, these concentrated gasses travel into a diver’s body through the alveoli (tiny air sacks in your lungs that increase the surface area for oxygen exchange), and disperse into the blood stream. From the blood stream the gases then diffuse into tissues, as they go from an area of high concentration to an area of low concentration. The longer you stay at these extreme depths the more nitrogen diffuses into your tissues until your tissues become saturated. This accumulation of nitrogen can then result in a narcotic effect (aka a feeling of intoxication). This is due to the ability of the nitrogen to block or delay transmission of signals within the nervous system. Over accumulation of oxygen is not a problem because the body uses up the excess oxygen in normal body functions, such as metabolism, and it never has time to accumulate. 

The precise mechanisms for how nitrogen narcosis effects the nervous system is still highly debated. However, through extensive research a couple of plausible mechanisms for this response have been suggested. One theory is that these narcotic effects are caused by a ligand that blocks the NMDA receptor, an important receptor in the proper functioning of nerve synapses. Blocking this receptor can lead to possible enhanced effects of GABA_A receptors (ligand gated ion channel that have the ability to inhibit action potentials from successfully occurring) and therefore inhibit neurotransmission in the central nervous system. Furthermore, an extended suppression of proper neurotransmission has been shown to induce general anesthesia, which is considered to be a form of narcosis. Still, other theories have suggested that the increased levels of dissolved nitrogen in a nerve cell’s phospholipid bi-layer may alter its ion permeability and ultimately cause mechanical interference with nerve transmission.

Okay hopefully your still with me, the bulk of the straight science is mostly over with :-) . . .

Regardless of the mechanism, the symptoms experienced are generally the same and can include any or all of the following: a false sense of security, sleepiness, delayed muscle response, impaired judgement, slowed response times, decreased coordination, tunnel vision, hallucinations, and in some individuals they have reported a feeling of euphoria. (See below video of an artistic interpretation of the euphoria potentially experienced whilst deep diving.)

As a scuba instructor, I myself, have witnessed “Narked” divers (exhibiting signs of nitrogen narcosis) and occasionally it can be rather entertaining. After all, who wouldn’t enjoy seeing there dive buddy attempting to break dance 40 meters underwater! However, to the avid scuba diver it should also ring bells of alarm. It is vital that all scuba divers be in a clear state of mind while diving so that they can properly work their dive gear and safely descend and re-ascend from their dives. It is when divers become overconfident or careless that accidents occur. And unfortunately for some they end up paying the ultimate price. (See scuba diving accident caught on tape below.) 

So while being in a state of intoxication at 33 meters underwater may have sounded entertaining to some, the link above shows just how dangerous it can be, and I can not stress enough the importance of understanding these dangers. Lipski’s accident was a worst case scenario, and fortunately most nitrogen narcosis incidents do not end this badly. In most cases nitrogen narcosis is extremely easy to treat. The most important factor being, you and your dive buddy’s ability to identify the signs and symptoms and treat them quickly. If you suspect your dive buddy or yourself of being “narked” then you should signal to your buddy, and slowly rise up a few feet and wait for some of the nitrogen to diffuse back out of your body. If you are still feeling the effects of narcosis then try rising up a few feet further and the symptoms should dissipate. If the symptoms do persist then you should end the dive and begin your proper ascent, being sure to observe all safety stops. Nitrogen narcosis generally has no long term effects, only in a few extreme cases have individuals reported memory loss. In most cases once back on the surface, the excess nitrogen has been vented from your tissues and your conscious thinking has returned. 

In conclusion, if you want to get narked up, do it at the bar. Embarrass yourself on the dance floor so that you don't end up on the ocean floor! 

References:

1. Carl, E., B. Thomas, B. McKenzie, and J. Pennefather. 2012. Diving medicine for scuba divers. Carl Edmunds. North Styne Manly, Australia. 

2. Rostain, J.C., and N. Balon. 2006. Recent neurochemical basis of inert gas narcosis and pressure effects. Undersea and Hyperbaric Medicine 33: 197-204.

3. William, P. 1975. Diver narcosis, from man to cell membrane. Journal of the south pacific underwater medicine society 5: 20-22.

2010. Divemaster manual. Padi. Rancho Santa Margarita, CA. 

Images:

1. Julie Gran. Scuba man martini morph. Retrieved from http://juliegran.com/pages/image2.html