Entonox/ Nitrous oxide (ANALGESIC DRUG) Flashcards
What are the pharmacokinetics of nitrous oxide?
Absorbed: inhaled
Distributed: through plasma proteins
Metabolised: lung cells
Excreted: exhalation
What are the indications for nitrous oxide?
Moderate to severe pain
Labour pain
How is nitrous oxide presented on the road?
In a metal cylinder that is blue and white
A combination of 50% nitrous oxide and 50% oxygen
What are the contra-indications for nitrous oxide?
Can cause harm to individuals with closed body cavities (air trapped within the body where expansion could be dangerous). Nitrous oxide will diffuse in this space meaning an increase in pressure.
Examples include:
. chest injury with suspected pneumothorax
. Severe head injury with impaired consciousness (due to possible intracranial pressure)
. Decompression sickness (injury caused by a rapid decrease in pressure like individuals who have dived in <24 hours). Nitrous oxide can cause nitrogen bubbles within the bloodstream to expand making the issue worse.
. Violently disturbed psychiatric patients
. Individuals who have had intraocular injection of gas <8 weeks (injection within the eye).
. Abdominal pain with suspected intestinal obstruction (ask if bowels have been normal for them)
What are the pharmacodynamics for nitrous oxide?
JRCALC: Inhaled as an analgesic agent (pain relief)
Nitrous oxide causes opioid peptide release in the brain stem leading to reduced responses to an individual’s brain and body.
Takes 3-5 mins to become effective however for maximum effect may take 5-10 mins.
What are the adverse effects for nitrous oxide?
dizziness
nausea/ vomiting
JRACLC
minimal side effects
What is the dosage/administration for nitrous oxide?
Self-administered via facemask or mouthpiece
JRCALC: Children can take nitrous oxide as long as they can follow instructions to self-administer themselves.
what are the cautions for nitrous oxide?
pt at risk of pneumothorax (collapsed lung),
pneumomediastinum, (air in the mediastinum- space in the chest between the lungs)
pneumoperitoneum (air in the peritoneal cavity- located in the abdomen)
What type of drug is nitrous oxide
An analgesic (pain relief)
An anxiolytic (reduces anxiety)
