Dental Hygiene Nitrous Oxide
What increments do you use to increase the nitrous oxide sedation level?
5%
What is the estimated tidal volume for adults and children?
5-7 L/min for adults, 3-4 L/min for children
The concentration of O2 should never fall below ----- %
50%
What could happen if the N2O tank is opened too quickly?
Opening the tank valves too quickly could cause rapid pressure increase, increasing the temperature, which can cause a chemical reaction resulting in fire or explosion.
Oxygen is stored as a -------- at ---------psi in what color cylinder?
Oxygen is stored as a GAS at 2000-2100 psi (full tank) in a GREEN steel cylinder. FYI-White is the international color.
CO2 and O2 are exchanged across capillary membranes in the alveoli by -----------.
Passive diffusion.
What does the scavenger system do?
Removes exhaled gas to keep nitrous oxide levels low in the ambient air of the treatment room (surrounding atmosphere). Connects to the office central evacuation system. Vents to the outside of the building and away from the windows and air intakes.
What percentage of nitrous oxide to begin at?
15%
20% N20 and 80% 02 has the same analgesic effect as ----- mg morphine
15mg
The atmospheric air volume of O2 is:
20.80%
The expired air volume of carbon dioxide is:
3.6%
To detect N2O in the air, the best instrument to use is: A. Infrared spectrophotometry B. Nitrous oxide dosimetry C. Balloon filled with water D. N2O spectrometer
A. Infrared spectrophotometry
All of the following are anatomically located in the lower airway except: A. Laryngopharynx B. Larynx C. Trachea D. Bronchi
A. Laryngopharynx
The primary muscle of respiration is: A. Lungs B. Diaphram C. External intercostals D. Abdominal rectus
A. Lungs
In cases of extreme overdose, which pharmaceutical agent would most likely be administered? A. Naloxone hydrochloride (Narcan) B. Enflurane (Ethrane) C. Isoflurane (Forane) D. Halothane (Fluothane)
A. Naloxone hydrochloride (Narcan)
When storing cylinders, it is important to: A. Have the cylinders vertical B. Have the cylinders attached to something C. Store away from heat
ALL ARE TRUE!!
The patient is given 5 minutes of O2 at the end of the appointment and has a headache. What should you do?
Administer more O2
What is nitrous oxide made from?
Ammonium nitrate
What are the 4 "a" properties nitrous oxide possesses?
Analgesic, Anxiolytic, (slight amnesia and weak anesthetic). An analgesic agent- reduces intensity of pain but does not eliminate it A weak anesthetic agent An anxiolytic agent- has sedative effects; reduces anxiety Has amnesia producing qualities- patient cannot recall severity of pain
Which areas will have the most nitrous absorption?
AreaS with the most blood flow.
At what level should you begin the administration of nitrous oxide? A. 5% B. 10% C. 15% D. 20% E. 25%
B. 10%
Who determines if a pregnant patient can have nitrous oxide? A. Dentist B. Physician C. Patient D. Hygienist
B. Physician
N20 may interfere with what vitamin?
B12
What should be taken before minimal sedation?
BP, Pulse, and Respiration (Detractor could be Weight)
T/F These are all relative precautions for the use of N2O: Patient taking bleomycin sulfate, Polycythemia vera, claustrophobia, cystic fibrosis, within 24 hours of scuba diving, increased intracranial pressure.
Bleomycin sulfate(used to tx. lymphomas and squamous cell carcinomas - may cause pulmonary problems), Claustrophobia, Cystic fibrosis, Within 24 hours of scuba diving, Increased intracranial pressure Not: Polycythemia vera(abnormal increase in RBC).
Most patients will achieve the desired clinical level of sedation at what percent of nitrous oxide? A. 10% - 20% B. 15% - 20% C. 25% - 45% D. 45% - 50% E. Usually over 50%
C. 25% - 45%
If you are delivering 4L of oxygen and 3L of nitrous oxide to your patient, what is the percent of nitrous oxide being delivered? A. 25% B. 33% C. 43% D. 50% E. 70%
C. 43% 4+3= 7 3/7= 42.8% nitrous
Increased tolerance to pain in the conscious patient is achieved by: A. General anesthesia B. Local anesthesia C. Analgesia D. None of the above
C. Analgesia
An acutely intoxicated patient comes to the office and wants nitrous. What is likely to occur? A. Increased chance of vomiting B. Increased sensitivity C. Decreased sensitivity D. No change
C. Decreased sensitivity
An anxious patient is in for SCRP of max right and presents with 4-8 mm pockets. What would be the proper pain management for this patient? A. Local anesthesia only B. Nitrous only C. Nitrous followed by local D. Lidocaine patch
C. Nitrous followed by local
Which is a contraindication to nitrous oxide sedation? A. Coronary graft or surgery B. Asthma C. Pulmonary blebs D. Heart problems
C. Pulmonary blebs Blebs: a term that refers to a smaller collection of air within the layer of the visceral pleura and can cause spontaneous pneumothorax events.
How are the patient's vital signs affected by administration of nitrous oxide at the appropriate levels of sedation? A. Pulse is accelerated; respiration and blood pressure remain unchanged B. Pulse, respiration, and blood pressure are all lowered significantly C. Pulse, respiration and blood pressure remain within normal range D. Pulse is reduced; blood pressure and respiration remain unchanged E. Blood pressure, respiration, and pulse are all accelerated
C. Pulse, respiration and blood pressure remain within normal range
What do you do when you are ready to take the patient off nitrous oxide sedation? A. Decrease nitrous slowly B. Squeeze reservoir bag, then administer O2 C. Take off nitrous and give 100% O2
C. Take off nitrous and give 100% O2
Why does nitrous oxide have a very rapid onset? A. It fills the lungs up to capacity very rapidly B. The bloodstream absorbs the nitrous oxide completely C. Very little of nitrous oxide is absorbed into the bloodstream D. It diffuses across the pulmonary tissues very slowly e. b and d
C. Very little of nitrous oxide is absorbed into the bloodstream
What are the effects of N2O on the cardiovascular system, central nervous system and the respiratory system?
Cardiovascular System: no negative effects, the extra 02 can be beneficial. Central Nervous System (CNS): depresses the CNS, but no significant negative effects. Respiratory System: may not be effective if the nasal passages are blocked; non-irritating to mucous membranes.
Breathing is also controlled voluntarily by the ------------.
Cerebral cortex.
Chronic nitrous abuse may have what effect?
Change in B12 metabolism
A bluish color of the skin is termed:
Cyanosis
What would the gauge read on a half full cylinder of oxygen? A. 325 psi B. 500 psi C. 750 psi D. 1000 psi E. 2000 psi
D. 1000 psi
A scavenging system should vacuum exhaled gases at how many liters per minute to be effective? A. 6-7 Lpm B. 12-15 Lpm C. 25 Lpm D. 45 Lpm E. 75 Lpm
D. 45 Lpm
What are the current recommendations by the National Institute for Occupational Safety and Health (NIOSH) for acceptable parts per million (ppm) of nitrous oxide in the dental office? A. 35 ppm B. 40 ppm C. 45 ppm D. 50 ppm E. A level has not been established by the NIOSH
D. 50 ppm
During respiration, the exchange between air and blood takes place in the: A. Bronchioli B. Alveolar ducts C. Alveolar sacs D. Alveoli
D. Alveoli
All of the following indicate too much tidal flow except________? A. Hissing from the nasal cannula B. Fluttering of eyelids C. Inflated bag D. Deflated bag
D. Deflated bag
The O2 fail-safe mechanism: A. Eliminates the chance of 70% Nitrous being delivered B. Allows nitrous to flow only when the nitrous flush button is activated C. Is found on all units manufactured after 1989 for use in the United States D. Ensures that nitrous will not be delivered if oxygen is not flowing
D. Ensures that nitrous will not be delivered if oxygen is not flowing
Which is true of nitrous in comparison to other gases? A. High solubility B. Greatest analgesic C. Has a slow rate of excretion D. Is the least toxic
D. Is the least toxic
Careful consideration should be taken regarding N2O/O2 sedation for patients with all of the following conditions except: A. Mental illness B. Alzheimer's disease C. Chemical dependency D. Seasonal allergies E. Middle ear disturbances
D. Seasonal allergies
-------- is nonspecific, unease, apprehension, or negative thoughts about what might happen during a dental appointment; source unknown.
Dental anxiety
------- is defined as an unpleasant mental, emotional, physiologic sensation derived from a specific dental-related stimulus; identifiable source.
Dental fear
Who is the most likely to abuse nitrous oxide sedation?
Dentists and hygienists
What are the muscles involved in breathing?
Diaphragm and intercostal muscles.
--------- is when headaches, lethargy, and nausea occur because of decreased O2 saturation levels in the blood, caused by the rapid exit of N20 on its termination. How can you prevent this from happening?
Diffusion Hypoxia. (When N20 exits the lungs faster than the N2 that replaces it which dilutes the supply of O2, and reduces the O2 blood saturation). Administer 100% O2 afterward for five minutes to prevent this from occurring.
Shortness of breathe is termed:
Dyspnea
The most commonly used gas cylinder in dentistry is:
E cylinder
If you were using a central supply nitrous oxide sedation system, which of the following components would you have that would not be used on a portable unit? A. Multiple flowmeter heads B. Large cylinders C. Copper pipes D. a and b E. All of the above
E. All of the above
Nitrous oxide is used in which areas of medicine? A. Dentistry B. Obstetrics C. Podiatry D. a and b E. All of the above
E. All of the above
Which of the following items may cause fire or explosion when working with nitrous oxide? A. Oil around the valves of the oxygen tank B. Grease around the nitrous oxide tank C. Lack of copper tubing used to distribute gases from the tanks D. b and c E. All of the above
E. All of the above
The optimum level of nitrous oxide is what percentage? A. 5% B. 10% C. 25% D. 50% E. Depends on the individual patients signs and symptoms
E. Depends on the individual patients signs and symptoms
T/F These are all relative precautions for the use of N2O: History of drug abuse or addiction, hemophilia, middle ear disturbances, multiple sclerosis, epilepsy, communication difficulties, leukemia, bowel obstruction,
FALSE Relative precautions: History of drug abuse or addiction, Middle ear disturbances and recent eye surgery(may prevent high doses from being administered due to increased pressure in the ear or eye), Multiple sclerosis, Epilepsy(can trigger a seizure), Communication difficulties, Bowel obstruction or sinus blockage(because of expansive nature of gas in a confined air space). Not: leukemia(cancer of the blood) or Hemophilia(Too long to clot).
----------- regulates the N2O industry.
FDA
T/F N2O should not be used in combination with local anesthetics.
False. N20/02 is used to enhance local anesthetic, but should NOT be used to substitute local anesthetic.
T/F In Michigan a dental hygienist can administer N20/02 sedation without DDS supervision.
False; DHY's can administer N20/02 sedation ONLY under direct DDS supervision.
T/F At the end of the titrate down the N20 by increments of 5% until at 100% oxygen and administer the oxygen for 5 minutes.
False; Discontinue the nitrous flow completely (no need to titrate down) and give 100% O2 for at least five minutes (or 5 minutes for every 15 minutes of nitrous exposure).
T/F N20 provides direct skeletal muscle relaxation and is okay to use for people with multiple sclerosis, muscular dystrophy, cerebral palsy and myasthenia gravis.
False; N20 does NOT provide direct skeletal muscle relaxation, but it does so indirectly. So OK to use with multiple sclerosis, muscular dystrophy, cerebral palsy and myasthenia gravis.
T/F N20 is okay to use for peopke with ulcers, GERD (Gastroesophageal reflux disorder), and bowel obstructions.
False; Not OK FOR BOWEL OBSTRUCTION.
T/F N20 affects the liver in the presence of liver impairment.
False;N20 is not metabolized by the liver, nor does it effect the liver in the presence of liver impairment.Ok to use with Hepatitis, Jaundice and Cirrhosis.
Is nitrous a solid, liquid or gas at room temperature?
Gas
Under no circumstances should ---------------------- come in contact with the gas or gas delivery system; potential explosion!
Grease, oil, or other lubricating substances.
Who first used nitrous oxide for medical purposes?
Horace Wells
Who was the first to chronically inhale pure N2O and describe the analgesic properties?
Humphrey David
Inadequate oxygenation ventilation is termed:
Hypoxia
Should you avoid nitrous if the patient is on barbiturates?
If on barbiturates avoid nitrous. They are already sedative agents. Same holds true of drugs used for sleeping.
----------- is based on the fact that no two individuals react the same way in response to a drug or treatment modality. What works for one may not work for another.
Individual biovariability
N20 has a rapid onset of action (< 5 minutes) and quick recovery because ----------
It has low solubility.
What is nitrous oxides weight in comparison to air?
It is heavier than air.
Nitrous has a rapid rate of absorption because:
It is not metabolized in the blood
The lower respiratory system consists of what 4 things?
Larynx, Trachea, Bronchi and Bronchioles. Larynx: contains vocal cords, cough reflex; N20 sedation SHOULD allow cough reflex to remain intact Trachea: muscular tube bifurcates into R and L bronchi, contains carina (back up cough mechanism) Bronchi: R shorter than L, more foreign objects aspirated into R lung Bronchioles: continuous division of the bronchi but w/o cartilage
The amount of gas brought into the lungs each minute is referred to as.
MINUTE VENTILATION.
List some indications for the use of N2O:
Mild anxiety/apprehension, Hypersensitive gag reflex, Cardiovascular disease (O2 enrichment coupled with stress reduction), Hypertension, Asthma (stress induced for example), Cerebral palsy, Mental retardation, Allergy to local anesthesia, Intolerance for long appointments and Labor and delivery.
All units manufactured in US are designed to deliver a minimum of ----% O2 at all times and NO MORE than -----% N20 at any time.
Minimum of 30% O2 at all times and NO MORE than 70% N20 at any time.
The flow meter restricts the oxygen flow to a minimum of ------- liters per minute.
Minimum oxygen flow 3 L/ min 30%.
Nitrous oxide molecule displaces --------- in the lungs.
Nitrogen
N2O is stored as a ------------ at -------- psi in what color cylinder?
Nitrous oxide is stored as a GAS + LIQUID at 750 psi (full tank) in a BLUE steel cylinder.
Can you detect N20 in the blood or urine?
No
The upper respiratory system consists of what 4 things?
Nose, Nasopharynx, Oropharynx, and Laryngopharynx. Nasopharynx: tonsils, adenoids, eustachian tubes Oropharynx: entrance into larynx and esophagus Laryngopharynx: starts at the epiglottis, which directs material into esophagus to avoid trachea; contains the larynx; made of cartilage to protect larynx.
T/F These are all relative precautions for the use of N2O: Pregnancy, respiratory obstruction, anemia, COPD, psychological impairment, methoglobinemia, emphysema, chronic bronchitis,
Pregnancy Consult with physician prior to any nitrous use during pregnancy (high rate of spontaneous miscarriage, especially during first trimester). Respiratory obstruction such as a stuffy nose prevents patient from inhaling the anesthetic. COPD/Emphysema/Chronic bronchitis** - compromises the patient's ventilation and increases carbon dioxide partial pressure. Psychological impairment - these patients may experience euphoria or altered state (evaluate prior to nitrous use if patient is on phenothiazines, TCAs, lithium). Not: anemia or methoglobinemia (abnormal breakdown of RBC).
What is the one absolute contraindication for the administration of nitrous oxide?
Recent eye surgery using ocular gas bubble.
---------- converts high pressure of gas in the cylinders to a usable, lower level.
Regulator valve
Who discovered N2O?
Sir Joseph Priestly
The amount of air that enters or leaves the lungs during ONE respiratory cycle is -----------. What is the average amount in milliliters for an adult?
TIDAL VOLUME, (avg. adult is 500 ml).
T/F N20 alters mood and increases pain-reaction threshold but does not totally block pain sensations.Peripheral vasodilatation is produced by N2O administration - patient may appear flushed. Little or no effect on respiratory or other body systems and there are no significant drug interactions.
TRUE
The -------- and --------- control breathing automatically.
The Pons and medulla oblongata
Dead space is:
The distance from the gas source to patient's lungs.
The ebb-and-flow movement of air during respiration is called:
Tidal flow
What should you instruct the patient about eating prior to the procedure?
To avoid fasting and heaving meals prior to procedure (eat light).
T/F Chronic abuse of N2O may lead to neuropathy, kidney, liver problems, vitamin B12 deficiency, peripheral neuropathy, accidents (frostbite, lung damage from pressure), asphyxia (lack of 02 to brain) and suffocation.
True
T/F Chronic exposure of N2O affects vitamin B12 metabolism, possibly resulting in bone marrow depression and anemia; megaloblastic hematopoiesis and leukopenia can result. An increase in miscarriage and birth defects can occur in female dental personnel without a proper scavenging system.
True
T/F N20 should not be used with bowel obstructions but is okay with ulcers.
True
T/F N2O has no negative effects on the endocrine system. It is okay to use with diabetics, people with thyroid gland dysfunctions and adrenal dysfunctions.
True
T/F Nitrous oxide does not negatively affect the cardiovascular system to produce any physiologic changes. Nitrous oxide has a minimal effect on heart rate. As with blood pressure, it may decrease as anxiety is lowered.
True
T/F There are no reported allergies to nitrous oxide.
True
-------- regulates the packaging and transportation of N20.
US Department of Transportation (DOT)
How should vital signs be post appointment?
Unchanged
When is a pulse oximeter mandated?
Use of pulse oximeter is not mandated for minimal sedation, but is mandated for moderate sedation according to the ASA.
What position should the tanks be stored in?
Vertical position.
------- is the amount of air a person can expel from the lungs after a maximum inspiration.
Vital capacity
Who inhaled ether believing that a more potent anesthetic gas was necessary for pain relief?
William Morton
Are there any concerns of using N2O for people with: cancer, middle ear disturbances, mind altering conditions, nutritional or eating disorders or people taking sedative hypnotic medications for sleep induction?
YES: Middle ear disturbances, mind altering conditions, people taking sedative hypnotic medications. Pressure can affect middle ear and eyes; MD consult if infection, surgical procedures have been done, etc. Cancer: no negative effects, can provide additional comfort in final stages. Mind altering conditions: must be used with caution or contraindicated-mental illness, mental retardation, autism, Alzheimer's, drug and alcohol abusers (individual determination- see future slide on indications).Nutritional/eating disorders: no effects. Can intensify sedative-hypnotic drugs. Can enhance the effects of drugs to induce sleep or when drowsiness is a side effect (anti-histamines, codeine, etc.).
Should you have the patient remove their contacts prior to the procedure?
Yes
Are there any contraindications for a pregnant women with N20? Does N20 cross the placenta barrier?
You must obtain consent from their MD (not the dentist!) if N2O must be used. N2O does cross the placental barrier.