Nitrous Flashcards
what is a normal reading for a patients pulse oximetry?
94-99%, under 90 is considered low
what is the average flow that will be used for nitrous?
5-6 liters per minute
what % nitrous do most pts begin to feel symptoms?
at 30% nitrous, 80% of pts begin feeling symptoms,
10% of pts are 30%
after the procedure, do what?
100% O2 for 3-5 minutes
then 5 minutes of room air (help prevent diffusion hypoxia)
-record vital signs
-modified romberg test
what is the romberg test?
- stand with feet together
- eyes closed
- nose-finger contact
what is recorded in the N2O note?
- N2O/O2 titrated to max of ___% for ___ min
- how it was tolerated
- 100% O3 for ___ minutes at the end
- patient remained awake and cooperative
- pt fully alert and oriented at discharge
stage 1 of Anesthesia
plane 1-no analgesia
plane 2- partial analgesia
plane 3- partial amnesia, analgesia
what are the signs of nitrous overdose?
- restless, combative, incoherent
- pt feels uncomfortable, disoriented
- uncooperative, fails to respond to commands
- cries, laughs
- hard angry stare
- profuse sweating
- patient can go into stage 2 of anesthesia (excitement)
- nausea
what should you do for a patient with nitrous overdose?
- 100% oxygen
- push O2 flush
- lift mask from nose and squeeze reservoir bag
- flush again and replace mask
eye signs
- Analgesia: normal pupil size and response to light
- Excitement: pupils dilated, lateral (and superior) eye movement
chronic exposure of nitrous in dental workers has been associated with:
- spontaneous abortion
- reduced fertility
- birth defects
- liver, kidney, and general neurological disease
what defines chronic exposure?
an exposure that exceeds 50 ppm of Nitrous oxide as an 8 hour time weighted average
what should the ppm of nitrous be at (ideally) in the ambient air?
25 ppm
what are the absolute contraindications for the use of nitrous?
-Acute URI (upper resp infect) or nasal obstruction
-active infectious bronchitis
-first trimester of pregnanc
(those are the 3 he wants us to know, but for boards also know.. sever neuromuscular disease, or a pneumothorax, bowel obstruction, inner ear infection)
what are the relative contraindications for nitrous?
- pregnancy after the first trimester
- psychiatric instability
- acute asthma (?)
- Severe COPD ?
- Recent eye surgery (can react with agents used and increase intraocular pressure)
primary site of action for nitrous
-cerebral cortex
onset of N2O
within 2 minutes of conc change
-rapid recovery
what is the second gas effect?
when a less potent gas (nitrous) is added in high concentration to a more potent gas (like sevoflurane), the potent gas will have a more rapid uptake
diffusion hypoxia
- at the completion of the procedure, N2O diffuses rapidly out of the blood and into alveoli
- O2 content in alveoli is diluted, with possible headache and nausea
- prevent with 100% O2 for 3-5 min after procedure
definition of analgesia
-the diminution or partial elimination of pain in the conscious patient
definition of general anesthesia
a drug-induced loss of consciousness during whcih patients are not arousable, even by painful stimulation
what are the colors of the different tanks?
- green is good (oxygen)
- blue and turn you blue (nitrous)
what is the approx concentration of O2 in the air?
21%
what is “DISS?”
- diameter index safety system
- basically the ends of the hoses are different diameters so things are put in the right place
PISS
- pin index safety system
- This feature assures that the oxygen gas cylinder is not inadvertently hooked into the nitrous oxide line and vice-versa
- the oxygen tanks have pins that are PARALLEL and the nitrous pins are off-set
how is the volume of gas assessed for the O2 and nitrous?
- oxygen is measured by pressure (need at least 500 lbs pressure O2)
- nitrous by weight
which way do you turn the valve to open the tanks
to the left
what is the first thing you do when you are setting up nitrous?
set the flow/concentration of oxygen
