Nitrous Oxide Flashcards
What are the long term side effects of Nitrous Oxide?
- Inhibition of Methionine Synthetase
2. Spontaneous Abortion
Nitrous Oxide in the first 3-5 minutes?
Dissolves in Serum
Transported in blood as FREE GAS
It does NOT combine with hemoglobin
it does NOT undergo biotransformation
Rapid uptake, absorbed quickly from alveoli held in simple solution in serum
What decreases the minimum alveolar concentration of nitrous oxide?
Narcotics
(Minimum alveolar concentration or MAC is the concentration of a vapor in the alveoli of the lungs that is needed to prevent movement (motor response) in 50% of subjects in response to surgical (pain) stimulus. MAC is used to compare the strengths, or potency, of anaesthetic vapor)
What drug is most like Nitrous Oxide?
Hydroxyzine
Antihistamine
It can treat anxiety, nausea, vomiting, allergies, skin rash, hives, and itching. It can also be used with anesthesia before medical procedures.
Analgesic
Anxiolytic (used to reduce anxiety.)
What is the threshold of N2O in ppm?
The NIOSH recommended exposure limit (REL) for N2O is 25 ppm as a time-weighted average (TWA) during the period of anesthetic administration.
This REL is intended to prevent decreases in mental performance, audiovisual ability, and manual dexterity during exposures to N2O.
The American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV ) for N2O is 50 ppm as an 8-hour TWA
N20 solubility in blood?
Very limited solubility
Blood/Gas partition coefficient of .47
The coefficient is defined as the ratio of the concentration IN blood to the concentration in gas that is in contact WITH that blood, when the partial pressure in both compartments is equal.
The more soluble the inhaled anesthetic is in blood compared to in air, the more it binds to plasma proteins in the blood and the higher the blood–gas partition coefficient.
A patient is experiencing acute otitis media, is Nitrous a Oxide ok to administer?
No.
Nitrous oxide is known to increase pressure in the air spaces of the body.
Anyone that has ear concerns or the inability of the ear to release pressure on its own (due to ear infections, ear surgeries, eustachian tube dysfunction) can suffer from serious side effects such as hearing changes or even rupture of the ear drum in extreme cases.
What condition would be N20 be contraindicated?
Phenylketonuria
Also called PKU, is a rare inherited disorder that causes an amino acid called phenylalanine to build up in the body. PKU is caused by a defect in the gene that helps create the enzyme needed to break down phenylalanine.
Individuals who have low or marginal of vitamin B12 levels are therefore at risk from nitrous oxide anaesthesia. This is clearly a risk factor in some patients with PKU
What is the mechanism of N20?
It is thought to have an effect on the Gamma Aminobutyric Acid (GABA) cells increasing inhibition of nerve cells causing drowsiness and sleep.
Nitrous oxide produces a mild analgesic effect at subanesthetic concentrations. The mechanism for this effect most likely involves an interaction with the endogenous opioid system because it is abolished by administration of the opioid antagonist, naloxone.
What IS N20?
NITROUS OXIDE is a DISSOCIATIVE inhalant that can cause ANALGESIA, depersonalisation, derealisation, dizziness, euphoria, and some sound distortion (flanging). In some cases, it may cause slight hallucinations and have a mild aphrodisiac effect. Research has also found that it increases suggestibility and imagination.
The minimum threshold above which N2O is most likely to cause moderate sedation is?
40%
Should never go above 50% concentration
