Nitrous Oxide

Question 1

Nitrous Oxide MOA

Answer 1

-Release of endogenous opioids in CNS + GABA receptors (similar to benzodiazepines)
-Can depress CNS (avoid use with other CNS depressants
-Rapidly absorbed + secreted via lungs

Question 2

Recovery from Nitrous

Answer 2

-Movement of NOS from circulation back into lungs may dilute O2 in lungs > diffusion hypoxia
-Give 100% O2 at end of procedure for at least 5 mins to clear NOS from lungs

Question 3

Contraindications NOS

Answer 3

-1st trimester pregnancy (folate depletion)
-Trying to conceive (decrease fertility)
-Pneumothorax
-Impaired LOC
-Head/maxofacial injuries
-Obstructive airway disease
-Airway obstruction/burns
-Aged less than 12 months
-Undiagnosed abdominal pain - bowel obstruction/ileus

Question 4

NOS Adverse Reactions

Answer 4

-Over Sedation (sedation score >2) - reverse by mixing to 100% O2
-If pt stops breathing they must be ventilated with bag-valve-mask (ambu bag) to clear NOS
-N & V (associated w/ prolonged use >15 mins)
-NOS= cerebral vasodilator -> increases cerebral blood flow and intracranial pressure