Harmful effects of nitrous oxide (laughing gas).

The Institute of Mental Health, Bach Mai Hospital, has submitted a report assessing the impact of N2O gas on human health to the Department of Science and Training, Ministry of Health .

Nitrooxide, also known as "laughing gas," a term coined by Humphry Davy due to its euphoric effects when inhaled, a characteristic that led to its use as a recreational substance, is on the World Health Organization's list of essential medicines.

Illustrative image.

Nitrogen oxide , with the chemical formula N2O, is a chemical widely used in many fields such as industry, medicine, and the food industry.

However, in recent years, the use of nitrous oxide for recreational purposes worldwide has been increasing rapidly, especially in bars, nightclubs, and festivals.

According to a 2016 report in the UK, nitrous oxide is the most popular recreational drug. In Vietnam, there have been numerous cases of poisoning due to the use of this product at medical facilities recently.

Furthermore, a report from the Institute of Mental Health indicates that the use of nitrous oxide can have serious health consequences. The abuse of nitrous oxide, especially among teenagers, requires special attention.

N2O acts very quickly and produces physiological effects (such as pain relief, euphoria, and hallucinations) within seconds of inhalation. Peak concentrations are reached after about 1 minute and disappear within a few minutes without a hangover, and users can return to normal activities shortly after inhalation.

Therefore, nitrous oxide is used as a recreational drug because of its ability to produce a short-term "high." Most recreational users are unaware of its toxicity to the brain and its potential to cause acute and chronic damage.

Nitrogen oxides are one of the greenhouse gases contributing to global warming. According to statistics, nitrogen oxides account for 6% of total greenhouse gas emissions in the United States, originating from human activities such as agriculture, fuel burning, wastewater management, and industrial processes.

In the fuel industry, nitrogen oxides are used as oxidizers in rocket propellant fuels and in racing to increase engine power output.

In the food industry, N2O is used as a leavening and foaming agent (R942) in the production of whipped cream. Nitrogen oxides are also present in the atmosphere as part of the nitrogen cycle. These molecules remain in the atmosphere for an average of 121 years before being removed by bacteria in the soil, ultraviolet rays in solar radiation, or destroyed through chemical reactions. 5

For recreational use, nitrous oxide is often sold in pre-filled balloons or small pressurized metal containers designed for the food industry.

Industrial production of nitrous oxide involves heating ammonium nitrate to 250°C and then removing impurities such as NH3, N2, NO2, and HNO3 using specialized equipment. Poisoning can occur if nitrous oxide containing these impurity gases is inhaled.

Nitrogen oxide is typically stored in cylinders below its critical temperature, so it exists as a vapor within a volume of liquid nitrogen oxide. These cylinders are filled to accommodate the pressure increase as the vapor phase expands. Filling cylinders and storing them above the critical temperature poses a risk of explosion.

Nitrous oxide has been used in dentistry and surgery, as an anesthetic and analgesic, since 1844. (Sneader, Drug Discovery). In the early days, the gas was delivered through simple inhalers consisting of a breathing bag made of rubber cloth.

Today, nitric oxide is used in hospitals via relatively automated analgesics, anesthesia machines, and medical ventilators, providing a precisely metered stream of nitric oxide mixed with oxygen at a 2:1 ratio.

Nitric oxide is a weak general anesthetic and is therefore not typically used alone in general anesthesia but rather as a carrier gas (mixed with oxygen) for stronger general anesthetics such as sevoflurane or desflurane. The use of nitric oxide in anesthesia may increase the risk of postoperative nausea and vomiting.

Dentists use a simple machine to store and dispense the mixture for patients to inhale while awake; the machine has a flow meter to ensure the analgesic gas mixture maintains a consistent ratio of oxygen at all times, with a minimum of 30% oxygen and a maximum upper limit of 70% nitric oxide.

Inhaled nitric oxide is frequently used to relieve pain during childbirth, trauma, oral surgery, and acute coronary syndrome. Its use during labor has been shown to be a safe and effective supportive measure for women during childbirth.

In the UK and Canada, Entonox and Nitronox are commonly used by ambulance crews (including unregistered practitioners) as a fast-acting and highly effective analgesic gas.

50% nitric oxide may be considered for use by non-professional first responders trained in pre-hospital settings, as its use as an analgesic is relatively easy and safe.

N2O inactivates cobalamine (also known as vitamin B12) through the oxidation of Cob(I) alanine to cobalamin(III), resulting in functional vitamin B12 deficiency, particularly in individuals with low blood B12 reserves.

According to Gilman's research, N2O has analgesic effects through its action on the opioid system. N2O activates opioid neurons in the brain, releasing endogenous opioids in the brainstem, inhibiting neurons from releasing gamma-aminobutyric acid (GABA), thereby activating noradrenergic pathways and ultimately alleviating pain sensation.

The effects of N2O are also mediated through α1-adrenergic and α2-adrenergic receptors in the spinal cord. In addition, N2O blocks NMDA receptors, increasing inhibition of dopamine neurons by GABAergic neurons, particularly in the ventral roof and nucleus accumbens, leading to a dopamine surge.

Regarding the consequences, studies on the region-dependent effects of N2O on dopamine, noradrenaline, and NMDA receptors have explained the euphoric manifestations, psychotic symptoms (delusions, hallucinations), and impulsive and aggressive behavioral disorders seen clinically.

According to Oussalah et al. (2019), exposure to N2O can lead to serious consequences. A 2016 global psychoactive substance use survey of over 100,000 respondents from more than 50 countries showed that 4% of infrequent N2O users experienced symptoms of neurological damage, with approximately 3% reporting paresthesia.

The most common acute clinical symptoms include paresthesia (80%), unsteady gait (58%), and limb weakness (43%). Less common acute clinical symptoms include hemiplegia, numbness of the limbs, and vestibular disorders.

In a global survey of psychoactive substance users, alongside neurological symptoms, psychotic symptoms can also appear acutely, such as paranoia, hallucinations, and cognitive impairment.

Prolonged, continuous use of N2O is associated with serious chronic consequences, such as peripheral neuropathy, myelopathy, and demyelinating diseases, collectively known as demyelinating polyneuropathy (GDP). These conditions clinically manifest as muscle weakness, vestibular dysfunction, and numbness, which can eventually lead to limb paralysis.

Recent studies based on spinal cord magnetic resonance imaging (MRI) have shown progressive spinal cord degeneration, specifically in the posterior and lateral columns of the spinal cord, in N2O users.

A positive correlation was found between N2O use levels and myelopathy and GDP levels, and most long-term N2O users (average: 300 nitrous oxide balloons/day for 6 months) showed signs of cobalamin deficiency neuropathy.

Cobalamin (vitamin B12) supplementation causes significant neurological improvement or even recovery in most patients; however, some patients will only recover partially, with persistent neurological symptoms such as paresthesia, limb weakness, and/or paralysis.

Furthermore, prolonged use of N2O can also lead to the appearance of psychiatric symptoms (anxiety, depression, mania, psychosis, cognitive impairment, and delirium).

Psychiatric symptoms may occur concurrently with neurological disorders (paresthesia, numbness, gait disturbances, weakness, limb paralysis) or may appear independently without accompanying neurological disorders.

Common psychiatric manifestations include: depression, hypomania, anxiety, psychotic disorders such as paranoia, hallucinations (auditory hallucinations, visual hallucinations), behavioral disorders (impulse behavior, aggression, violent behavior), or personality changes.

People who abuse N2O may also exhibit cognitive disorders such as memory impairment, speech disorders, perceptual disturbances, and delirium.

In conclusion, the report from the Institute of Mental Health states that N2O has been discovered, produced, and widely applied in industry and medicine. However, recently, the abuse of N2O as a recreational substance has been increasing rapidly and is difficult to control.

The consequences of improper use of N2O, beyond the recommended guidelines, are very serious, affecting many organs and systems in the body.

Common neurological injuries include spinal cord injuries and polyneuritis caused by demyelination, resulting in symptoms such as paresthesia, unsteady gait, and weakness in the limbs.

Psychiatric disorders such as paranoia, hallucinations, behavioral disorders, mania, depression, anxiety, and cognitive impairments. These are accompanied by risks of abuse, dependence, and concomitant use of other psychoactive substances (addictions).

Several case studies have also indicated the risk of death from N2O, with findings of respiratory and cardiovascular damage.

Source: https://baodautu.vn/tac-hai-cua-khi-cuoi-nitro-oxide---n2o-voi-suc-khoe-con-nguoi-d226276.html