nitrous

Question 1

level of nitrous not to exceed

Answer 1

dont ever exceed 50% oxygen and 50% nitrous

• never deliver less than 21% oxygen
• as this is what is found in room air

Question 2

tell patients they might feel what with nitrous

Answer 2

tingly around the lips
sense of euphoria

anyxiolysis should occur and the pt. should feel more relaxed

Question 3

typical level of nitrous that is sufficient

Answer 3

30-50% nitrous

Question 4

does flow rate change?

Answer 4

no - but the distribution between the two gases adjusts

Question 5

dial for oxygen?
dial for nitrous?
explain the flow rate

Answer 5

bigger black one = oxygen

narrow dial above black dial = nitrous - done as a %

as you titrate to effect -
from 0 to 50% to nitrous
the flow rate of oxygen will stay at 6 when its 100% - as 50% of gas converts to nitrous
it will result from 3 L from oxygen and 3L from nitrous
* which maintains the flow of 6L

Question 6

nitrous oxide contraindications

Answer 6

COPD (blebs) 
Pneumothorax 
Bowel obstruction
Retinal surgery, middle ear surgery 
- because nitrous readily diffuses into "dead space" and will expand that space-- which in a bleb or pneumothorax will collapse the lung 
- in eye it increases pressure 

2. respiratory infection
3. pregnancy - in first trimester it can impact B12 and folate metabolism - which is needed for fetal development and if deficient can cause neural tube defects
   .4 psych pts.
4. marijuana use
   6.chronic nitrous
5. pulmonary hypertension

Question 7

diffusion hypoxia/ fink effect

Answer 7

[Paraphrased] he described that when water-soluble gas (ie nitrous oxide) is inhaled in large quantities/high concentration, the nitrous oxide dissolves rapidly into the blood stream following the gradient more readily than oxygen or CO2 can diffuse
(Essentially, nitrous diffuses more efficiently/rapidly down it’s concentration gradient)
When a patient is recovering from N2O (ie when you shut off the Nitrous Oxide), the gradient shifts
Due to the gradient shift, the nitrous diffuses out of the blood (high concentration) and into the alveolus (low concentration) more readily than any oxygen
If the quantity of nitrous crossing OUT is large, then the partial pressure and concentration of oxygen (and CO2) in the alveolus is REDUCED resulting in hypoxia due to the abundance of nitrous occupying the alveolus transiently as it diffuses out
This can be avoided by increasing the concentration of Oxygen when recovering from N2O anesthesia to 100% (nitrous concentration to Zero)for 5 minutes.

Question 8

some common side effects of nitrous use

Answer 8

even with proper titration these can occur

Common side effects are:
Difficulty Breathing
Chest Pain
Dizziness
Headache
Xerostomia
Hallucination
Paranoia
Transient Dysphoria (an unpleasant feeling of unease)

If patients express dissatisfaction with the experience, discontinue immediately and flush with 100% O2 for 5 minutes