Prolong exposure Bone marrow depression, Neurological deficiencies peripheral neuropathies and pernicious anemia

N2 (nitrogen), NO (nitric oxide), NO2 (Nitrogen dioxide), NH 4 ammonia water vapor and CO (carbon monoxide)

The higher the concentration of the gas inhaled, the more rapidly arterial tension of the gas increases Fresh gas will be pushed into the lungs from the anesthesia machine= increase arterial N 2 O arterial tension So its important to start the Nitrous slowly and not blast it high in the beginning

Occurs when a second inhalation anesthetic is administered along with N 2O-O 2 Extreme uptake of N 2O will form a vacuum at alveoli that forces other air ( in this case, other inhalational agent) into the lungs

As the N2O is rushed out of the body, it will take other airs out including CO2 Lowering CO 2 tension in blood will cause respiratory depression S/s: Headache, Nausea, Lethargy  hangover effect

N20 sedation Flashcards by Caleb Houghton

Nitrous Oxide N2 O
* happy/sad?
* emotions/inhibitions of pt?

Nitrous Oxide a.k.a. laughing gas
Nitrous oxide does NOT make a person happy or sad
Decreases the inhibitions of the patient
Increases the intensity of emotions

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Physical properties n2o

Only inorganic anesthetic gas in clinical use
Colorless and odorless
Capable of oxygen supporting combustion

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n2o effects on pulmonary, cardio, and renal systems

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Toxicity of n2o

Prolong exposure Bone marrow depression, Neurological deficiencies peripheral
neuropathies and pernicious anemia

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n2o production

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Impurities of n20

N2 (nitrogen), NO (nitric oxide), NO2 (Nitrogen dioxide), NH 4 ammonia
water vapor and CO (carbon monoxide)

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most dangerous impurity of n2o

NO is most dangerous impurity
* Combine with Hg and prevent O 2 absorption and may also react with water vapor
to form acid = damage pulmonary epithelium = pulmonary edema
* NO is form when N2 O is heated above 450 0 C

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n2o hydrous state

N20 is anhydrous

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n2o Properties
* iritation, smell, color?
* CNS?
* Specific gravity?
* Wall of the cylinder maybe cold due to?

Properties
* Nonirritating, sweet-smelling, colorless gas
* ONLY nonorganic compound other than CO2 that has CNS depressant
properties
* Specific gravity if 1.53 vs air (1)
* Wall of the cylinder maybe cold due to heat needed for vaporization into
gaseous state

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Solubility n2o

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is n2o oxygen usable

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n2o flammable/explosive

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Potency of n2o
* compared to other anesthetic gases
* solubility compared to n2/o2

Potency
* Least potent of the anesthetic gases
* N2O is
* 35X more soluble in plasma than N2
* 100X more soluble in plasma than O2

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cns depression with n2o+o2

N2O + O 2 = CNS depression
* Some patient may get delirium
* Very few people will get Stage III anesthesia ( surgical anesthesia)

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Optimum concentration of N 2O for production of
analgesia while maintaining patient cooperation is?

Optimum concentration of N 2O for production of
analgesia while maintaining patient cooperation is
35%

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n2o mixture similar to morphine?

20%:80% mixture N2O-O 2 = 10-15mg of morphine

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special properties of n2o

concentration effect and second gas effect

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Concentration Effect

The higher the concentration of the gas inhaled, the more rapidly arterial tension of the gas increases
Fresh gas will be pushed into the lungs from the anesthesia machine= increase arterial N 2 O arterial tension
So its important to start the Nitrous slowly and not blast it high in the beginning

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2nd Gas Effect

Occurs when a second inhalation anesthetic is administered along with N 2O-O 2
Extreme uptake of N 2O will form a vacuum at alveoli that forces other air ( in this case, other inhalational agent) into the lungs

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how does n2o inhalation work

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mechanism of n2o

analgesic and anxiolytic

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What happen when the N 2O session is over

N2O diffused out of the blood and into the alveoli as rapidly as it diffused into the blood during the induction
If patient simply breath room air and not O2  Patient may get diffusion hypoxia
Prevention: administer 100% O2 for 3-5 mins at the termination of the procedure

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Diffusion Hypoxia

As the N2O is rushed out of the body, it will take other airs out including CO2
Lowering CO 2 tension in blood will cause respiratory depression
S/s: Headache, Nausea, Lethargy  hangover effect

N2O at CNS

Actual mechanism of action is unknown
Almost all form of sensation are depressed.
Mild Depression on CNS at Cerebral cortex
Area postrema (vomiting center) of Medulla is not affected unless hypoxia or anoxia is present

n2o at CV system

* No clinically significant effect * Slight depression of myocardial contraction * Slight increase in vascular smooth muscle to norepinephrine

n2oirritation at pulmonary system

* Not irritating to pulmonary epithelium * Ok for Asthma

n2o at GI

no effect

n2o at renal

no efffect

n2o and hematopoesis

* Inhibits methionine synthetase> impair B12 metabolism > decreased Bone Marrow function = Pernicious anemia (Vitamin B12 anemia) * Long term exposure ( > 24 hr exposure) = transient bone marrow depression

n2o and skeletal mm

Does not produce relaxation of skeletal muscle

o2 properties

* Clear colorless, odorless * Specific gravity of 1.105

o2/n2o cylinders | colors/psi

Advantages of Inhalational Sedation: * Onset? * recovery? * N2O metab? * Able to? * No? * side effects? * ADRs? * Nitrous Does have?

* Onset of action is similar to IV sedation * Fast recovery (3-5 mins) * N2O is not metabolized by body * Able to Titrate ( administer small incremental dose until the desired clinical action is obtained) * No injection * Few side effect * No adverse reaction to body organ/ system * Nitrous Does have analgesic properties (20% n2o=10-15mg morphine)

Disadvantages of n20 inhalation

Contraindications to inhalation sedation

* No absolute contraindication * Claustrophobic patients * Compulsive personality ( take charge) * Children with severe behavior problems * Upper respiratory tract infection * COPD ( chronic bronchitis, Emphysema) * Pregnancy

Indications of inhalation sedation

Armamentarium for inhalation sedation

Compressed-gas cylinders safety and psi

* Cylinder are designed to handle 1.66 times the usual pressure * Example: Usual 2000 psi O 2 cylinder is designed to hold up to 3400 psi

Handling of cylinders * Never use? * Storage position? * drop? * temps to avoid? * valves? * "cracking"

* Never use grease, oil or lubricant * Store in vertical position * Don’t drop them * Avoid heat and fluctuating temperature * Close all valves tightly even when its “empty” * “Cracked” cylinder before use= Let some gas out before connecting to the system

Cylinder sizes

* From a small A size to large HH size * Portable Nitrous oxide unit uses “E cylinder for both Oxygen and N2O

O2 cylinder

* Full E Cylinder is about 1900 psi in gaseous state only * Psi will decrease as O2 is being used

N2O cylinder

* Full E cylinder has gaseous 750 psi and liquid states * 750 psi will stay there until the moment of empty tank

# o2 cylinders per n2o cylinders

2.5

Regulator ( Reducing valves)

* Reduce incoming cylinder pressure to ~50psi

Reservoir bag

* 3 liter reservoir bag is commonly used in Dentistry * Provide additional gas on demand if patient exceed the gas flow being delivered * Monitoring respiration

Scavenging nasal hood

* Eliminate exhaled N2O from the ambient air

Preoperative instructions for inhalation * food? * flow rates? (adult vs kid) * COPD and CHF with partial obstruction? * Reservoir Bag?

* No heavy meal 4 hours prior to N2O-O2 sedation * Determine proper flow rate for the patient * 6L/min flow of 100% O2 for adult * 3-5L/min for smaller pediatric patient * COPD and CHF with partial obstruction may require larger volume * Reservoir Bag

Minimum O 2 delivering to Nitrous Oxide sedation patient is ?

Minimum O 2 delivering to Nitrous Oxide sedation patient is 30%

Inhalational sedation technique, begin with? titration?

General Algorithm to a sedation appt

How do you determine the “right” flow volume

* Reservoir bag * Reservoir bag remains partially inflated and deflates and inflates partially with each breath usually indicates that the minute volume is adequate

Totally Deflated reservoir bag causes?

* Minute volume of gas is inadequate * Large leak at the nasal hood * Vacuum on the scavenging system is too high

Overly Inflated reservoir causes?

* Minute volume of gas is too great * Hose obstruction

progression of n2o effects on pt

How do you know if you are “in the zone”? | proper level n2o?

* Relaxation of hands * Slower verbal responses * Difficulty in phrasing replies * Slower physical responses

discharging the pt | primary determinant and vital signs

Complications of n2o