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212 Cards in this Set

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when at douglas college and treating with nitrous, what must the treating student do if they must leave the op?
discontinue nitrous and oxygen and provide 100% oxygen for 5 mins prior to leaving the patient

-the assisting dental student must stay with the patient
what is the consent document you use?
"nitrous oxide sedation to help your childs dental visit"
If the gauges read full, are the tanks open?
No not necessarily
what is your starting flow rate for oxygen?
6L/min
how will you titrate in the nitrous?
start by increasing nitrous to 10%
wait 1 minute and titrate by additional 10%
wait 1 minute and titrate by 5% increments
what do you do all the time?
continuously observe for patient responsiveness, color, respiratory rate
why do you ensure patient remains on 100% oxygen when discontinuing nitrous?
to prevent room contamination
what should a chart entry look like for nitrous?
-time of day nitrous begun and ended
-"titrated to effect" and final concentration
-details if it was ineffective
-response and demeanor prior to discharge
-indication that 100% oxygen was administered prior to discharge and for how long
At Douglas, how do you respond to an emergency while giving nitrous?
alert the clinical instructor of potential problem
turn off nitrous and administer 100% O2
check airway
check breathing
check circulation
call 2400 to summon First Aid to the Clinic
what is the most important safety feature of nitrous?
"titration"
what is the average amount of nitrous a patient needs ?
30-40%
"anoxic anaesthesia"
100 % nitrous
"relative anaesthesia"
nitrous with oxygen
what is another safety feature of modern nitrous units?
cannot administer less than 20% oxygen
what are some benefits of digital systems?
-total flow and percent of O2 displayed digitally
-infection protocol
-built in alarms for gas depletion
-internal self monitoring
-automatically delivers oxygen at the end, no flush button
-can display flow rate of either gases
what are some concerns raised about nitrous?
-sexual awareness
-potential biohazards to exposure
-abuse
what can be permanent but is generally reversible after chronic abuse of nitrous?
neuropathy
Cases of record with respect to sexual awareness and impropriety while under nitrous have 3 elements that place the practitioner at risk
-without assistant
-high concentrations
-failure to titrate
what enzyme does nitrous effect?
methionine synthetase
what is this enzyme responsible for?
vitamin B12 metabolism
The two most common causes for nitrous contamination in the office are?
-patients talking
-patients mouth breathing
what is the most effective way to monitor tract nitrous oxide?
infrared nitrous oxide analyzer
what was the most used oral sedative for pediatrics?
chloral hydrate
what was the prototype sleeping aid but subject to overdose in the mid 19th century?
barbituates
what are the main anxiety relievers in dentistry?
benzodiazepines
this drug has active metabolites Trichloroethanol and trichloroacetic acid. What is this drug and what is the therapeutic index, and onset?
Chloryl hydrate
-fast onset of action (30 mins)
-narrow therapeutic index

*you are getting kids drunk essentially. (4-6 hours)
what is the maximum of chloryl hydrate?
1g. MUST BE GIVEN IN OFFICE
what drug:
-alcohol-death
-addictive
-GABA receptor complex
-narrow therapuetic index
Barbituate
what drug has a wide margin of safety and what does this mean?
Benzos have a wide margin of safety unlike chloryl hydrate and barbituates.

This means if you give a little more benzo, you arent going to kill someone
what benzo was created 1963?
Valium (1/2 life is age. So 30 years old =30 hours half life)
nitrazepam
1965
Temazepam
1969
what patients need 1/2 dose of benzos?
obstructive sleep apnea patients
"relative contraindication"
5 things to remember about benzos
-increase affinity GABA receptor
-anticonvulsant
-decreased muscle tone (OSA px)
-sedative/anxiolytic
-anterograde amnesia
benzo contraindication?
acute narrow angle glycoma
what type of properties do bezos have?
anticholinergic
so what are some adverse effects of benzos?
-respiration depression (not obstruction)
-cardio depression
-disinhibition (px becomes hysterical)
-dependence/addiction
when is benzo sensitivity increased?
-elderly
-liver disease
-other CNS depressants
when is it decreased?
-smoking (bc it induces liver enzymes)
-recent use of benzos , ethanol or other depressants
does it depend on the size of the patient as to your dosing?
NO its HOW ANXIOUS the patient is
what will fix obstruction 99% of the time in minimal/mod sedation?
oral airway!
What is the last resort?
flumazenil
how is it delivered?
IM
is it substitute for proper management?
NO
what is the problem with it?
it takes 20 seconds for the px to go from sedated to awake. But it will wear off! and u dont know when and the sedative will still be in the px system!
Benzodiazepines -pregnancy. How do u handle this?
-not recommended "pump and dump, 24 hours before store the milk and up to 24 hours after dump"
Chlordiazepoxide
intermediate onset
long half life
daytime drowsiness
do you promise anterograde amnesia?
no you cannot guarantee it!
Diazempam
fast onset
long half life
daytime drowsiness
what is the dose for diazepam?
5-20 mg
what drug has an intermediate half life with no active metabolites and is more rapid when delivered sublingually?
Lorazepam (Ativan)
what is the dose for Ativan?
.5 -4 mg
which benzo has antidepressant effects and intermediate half life with active metabolites?
Alprazolam
what is the dose for Alprazolam
.25-1mg
what are the 2 short acting benzos?
Triazolam and Midazolam
what is the difference in the two drugs?
Well, Triazolam doesnt have any active metabolites, whereas Midazolam does. Also, oral Midazolam is more a pediatric drug of choice, but it has a horrible taste so mix it with something else. Unfortunately only IV in Canada which is mainly for adults!
what is the pediatric dose for Midazolam?
.5mg/kg up to a MAX of 20 mg
what is the triazolam dose?
.125-.5 mg (that is 2 pills!)
This drug is a non benzo sedative which is not used in dentistry alot and is reversed by flumazenil
Zopiclone.
-Gaba receptor and fast onset
-some anterograde amnesia
-active metabolite
DO non benzos have anxiolytic properties?
no
anti nauseant properties
sedation as a side effect
sedative efficacy-less
Antihistamines (H1 receptor blocker)
anticholinergic side effects
short to intermediate half life
fast onset.

(24-50mg) dose
Diphenhydramine (Benadryl!)
what are the pharmacodynamic drug interactions you must worry about?
-ehtanol
-other CNS depressants
what are the pharmacokinetic interactions?
-Hepatic CYP450 3A4
-midazolam, triazolam, diazepam (these raise the seizure threshold and you will only see cardio collapse so lower your LA ! )
Is redistribution related to the metabolic half life?
no. redistribution away from site/receptor due to blood rich-->vessel poor area
what are some CYP P450 inducers?
antiepileptics
corticosteroids
antibiotics
what are some CYP 450 inhibitors?
HIV-protease inhibitors
Nelfinavir
Ritinovir
what are the minimal sedation drugs of choice for a short appointment?
midazolam
triazolam
what about long appointments?
lorazepam
diazepam
if you give someone palatal anaesthesia, and this does not provoke movement what kind of sedation is this considered?
GA!!
what decreases in geriatric patients?
physiology
-cardio
-cerebral blood flow
renal and hepatic blood flow
pulmonary function
what does this mean?
the pharmacodynamic changes have a greater effect so use lower doses and shorter acting agents
what do you avoid in renal disease?
chloral hydrate
do you adjust the dose?
no
a single dose acceptable
When would you consider lowering the dose?
hepatic disease
when would u consider the antihistamines for oral sedation?
respiratory disease.
usual doses are acceptable
stress can trigger asthmatic attacks
use what for epilepsy?
benzodiazepines
what are some great things to keep in mind for diabetes patients
-maintain calorie intake pre and post op
-morning appointment <2-3 hours
-clear liquids and apple juice up to 2 hours before appointment
-Food <6 hrs
what leads to right heart failure in obstructive sleep apnea patients?
air way obstruction
C02 increase leading to pulmonary vasculature resistance
Right ventricular hypertrophy
cor pulmonale
right heart failure
this anatomy serves to filter airborne particles humidify and warm inspired gases
upper airway
are alveoli part of the upper airway?
yes
what are the main structural components of the larynx?
thyroid and cricoid cartilages
arytenoid cartilages
epiglottis
What is the dual lung supply?
1. pulmonary circulation (gas exchange)
2.bronchial circulation (lung parenchyma)
where does the bronchial circulation drain to?
left side of heart via pulmonary veins
where is the physiologic dead space?
anatomic dead space and the alveolar dead space
in dead space what is lower V or Q?
Q!
in a shunt , what is lower, V or Q?
V!
there is decreased ventilation for the perfusion
2 examples of shunts?
atelectasis (collapsed alveoli)
pneumonia
Alveolar ventilation
the amount of air breathed in per minute that reached the alveoli and participates in gas exchange
dead space ventilation
the part of minute ventilation that does not take part in gas exchange
alveolar ventilation + dead space ventilation
minute ventilation
what are the muscles of active expiration?
internal intercostals
abdominal muscles
what are the major muscles of inspiration?
diaphragm and external intercostals
where are the chemoreceptors that control breathing?
centrally (brain stem) and peripherally (carotid bodies)
what does the central control respond to?
CSF hydrogen ion concentration in turn determined by C02 which diffuses freely across barrier
what do the peripheral chemoreceptors respond to?
fall in 02
-profound hypoxia required for significant activation
Haldane effect
when the body is hypoxic (low02) , hemoglobin can carry more C02 to liberate it from the body bc it is not occupied by 02
what % of oxygen in the blood is carried in the RBCs?
97%
70% of C02 in the blood is present as?
HCO3 bicarbonate ions
obstructive lung disease
difficult to get air out of lungs
low FEV1/FEVC
restictive lung disease
difficult to get air into lungs
high FEV1/FVC
chronic bronchitis "blue bloaters"
an obstructive lung disease in the large airways that results in increased cardiac output and decreased ventilation
What does this VQ mismatch lead to in chronic bronchtiis?
hypoxemia and polycythemia
hypercapnea and resp acidosis
-right ventricle enlargement and failure bc hypertention of pulmonary vessels
Emphysema "pink puffers"
an obstructive lung disease in the alveoli which leads to decreased ability to oxygenate blood and the body lowers cardiac output and increases ventilation
what does this VQ mismatch result in?
limited blood flow through fairly oxygenated lung . the low cardiac output leads to tissue hypoxia and muscle wasting and weight loss
restrictive lung disease
intrinsic lung disease of the parenchyma
extrinsic lung diseases
loss of lung compliance
On a PFT , if the FVC and the FEV1 are bpth >85% predicted values (normal) what do you do?
look no further! it is within normal limits
what if either of them are low?
risk of disease
if the % predicted for FEV1/FVC is 88%-90% then the patient has what?
restrictive !
if FEV1/FVC is low (69% or lower) then the patient has what?
obstructive!
what is bad?
spark+gauze+oxygen
oxygen supports
combustion
room air
21%oxygen
what can oxygen toxicity lead to?
restrictive lung disease (pulmonary fibrosis)
a pleasant room temperature gas that is non flammable
nitrous

ammonium nitrate-->nitrous + water vapor
nitrous is ____and ____
anti nociceptive
anxiolytic
flumazenil
reverses benzo
naloxane
reverses opioid
those tolerant to benzos can be cross tolerant to?
anxiolytic effects of nitrous
nitrous is thought to block the binding of?
NMDA
-inhibition of excitatory neurotransmission
nitrous has biochemical disturbances like B21 inactivity via methionine synthase, so what patients do u avoid?
-cancer px and pernicious anemia
what is a reasonable exposure level to nitrous?
400 ppm
is there evidence that a direct causal relationship exists between repro health and scavenged nitrous?
no
scavenging can reduce Nitrous to under 50ppm
a non selective depressant of the CNS
the "wimp" of general aneasthetic agents
nitrous
MAC
minimum alveolar concentration
the amount of drug necessary to inhibit movement in 50% of patients when a painful stimulus is applied
MAC for nitrous?
>104%
blood-gas partition coefficient
this refers to the solubility in the blood. The more solubility in the blood means that it will stay in the blood. There fore a low solubility means RAPID induction
which is most soluble. Ether,sevoflurane or nitrous?
ether has the highest solubility and nitrous has the lowest
what does this mean??
ether takes FOREVER to induce, where as nitrous is very rapid induction (on/off)
most nitrous
gets exhaled out
a higher concentration and a greater duration of use of nitrous increases?
nausea and vomiting
what relieves this?
slow induction
what is the "thorp tube" on a nitrous unit?
N20 flowmeter tube
what does the reservoir bag do?
help dilute room air minimally into what patient breathes incase patient takes deep breath. We dont want the breath to dilute the N20
what is the color coding?
nitrous is blue
oxygen is white
what are some safety features?
air inlet valve and color coding
dimension and weight of cylinder E
4.5 x 29.5
21 lbs
cylinder H
9 x 55
130 lbs
compressed oxygen cylinders. What is the Full psi and the capacity of cylinder E?
2000

660 liters
cylinder H?
2200

6909 liters
How long would a tank last at 3l/min and 1000 psi?
its 1/2 full (1000 psi) so capacity/2 = 660/2=330 L

330L/3L/min = 110 min
what about the nitrous cylinder?
the full psi is 750-800, which is the same for half full. The capacity is 1590 .

we dont know , bc when the meter starts to drop we have around 250 L of gas left and no liquid left , its all gas
regulators
the reducing valves
lower gas pressure to 50psi
yoke
hold the cylinders to unit. Minimum of 2x02 cylinders
continuous flow unit : low pressure system
reducing valve
flowmeters
reservoir bag
nasal hood
permit delivery of precise volumes of gases
L/min
3 types
flowmeter!

-rotameter
-ball
-rod
Flowmeter, what is always on the right?
oxygen (white/green)
allows air to enter if units is not operating and closed when gas flows
emergency air intake valve
what compromise the "rubber" goods
reservoir bag
conducting tubes
breathing apparatus
full face mask
nasal cannula
nasal hood
how big is the adult reservoir bag
5 L
primary and secondary function of reservoir bag
primary-provide extra gas for deep ventilation
secondary-monitor respiration
what are the safety features of our nitrous units?
-pin index safety system
-Diameter index safety system
-minimum oxygen flow
-minimum oxygen percentage
-oxygen fail safe
-emergency air inlet
-oxygen flush button
-reservoir bag
-color coding
what are some signs of early to ideal N20 sedation
light headedness
tingling of hands and feet
wave of warmth
vibrations throughout body
numbness e
euphoria
signs of deeper sedation to mild over sedation
Hearing more acute
visual images confused
sleepiness
sweating
dreaming
laughing
nausia
increased movement
lacrimation
what are the signs and symptoms of over sedation?
persistent closing of mouth
spontaneous mouth breathing
patient fails to respond rationally
patient states he is falling asleep
what do u do when oversedation occurs>
decrease N20 by .5 to 1.0 lpm
increase 02 flow by same 1pm
theoretical diffusion hypoxia
when N20 is stopped, the concentration in the blood is higher than the alveoli, so N20 fills the alveoli and displaces oxygen so breathing room air at this time after nitrous can cause alveolar hypoxia
so...
put on 100% oxygen for 3-5 mins
where can there be sources of N20 from a high pressure system?
worn wall connectors
loose/cracks high pressure hose connections
what about a low pressure system?
loose , defective or missing gaskets and seals
worn defective bags and breathing tubes
loosely assembled slip joints
3 reasons for inhalation sedation failures?
biological variability
nasal obstruction
extreme anxiety
Describe the constant liter flow technique
once you have established a 5-6 lpm 02 flow, you titrate nitrous by moving the oxygen down and the nitrous up so that the total flow rate will always add up to 6.

-the % of N20 will be : N20/02 +N20
-so if your 02 lpm is 4.5 and your nitrous is 1.5, then the % nitrous will be 1.5/6= 25
wat do u need to get prior to oral sedation appointment?
consent!
when is your sweet spot with Triazolam?
1hr and 15 mins so time injection for this point
what is your pre sedation checklist?
ROADS
-Reversal agent
-oxygen tank
-Ambubag
-Drugs (emergency)
-Suction
can u ask the dental assistant to give px the drug?
no, u must
studies show faster onset and higher plasma levels with sublingual administration of what drug?
Triazolam
if the patient is able to respond to verbal commands, then you have...
NOT passes your intended level of sedation, well done
when will you expect the triazolam to start wearing off?
2.5- 3hrs after administration
what do u do when u see the effects of the triazolam starting to wear off near the end of an appointment and your patient is still anxious about the treatment that follows
-supplement near the end of the appointment with carefully titrated nitrous. The patient should be awake and be able to have a convo with you
what needs to happen post op?
escort
call a day later to see if px was happy with the level of sedation acheieved
what if the .25 triazolam had no effect on paul?
bump it to .375 mg next appointment
expect success rates of _______ in those with a moderate level of anxiety
70-85%
how should the appointment length be determined?
drug of choice based on the patients medical history
long appointments
ativan (4-6 hours)
Benadryl (Diphenhydramine)
25-50 mg

Anticholinergic side effects
triazolam
.125-.5 mg

good for short appointments (2-4 hrs)
Lorazepam
.25-4 mg

good for longer appointments >3hrs
diazepam
2-10 mg

best administered the evening before sedation appointment given long half life
eszopiclone
(Lunesta)
1-3 mg
CYP450 metabolism
Zolpidem (Ambien)
5-10mg
not contraindicated in pregnancy
Zaleplon (sonata)
5-20 mg
good for short appointments (1-2hrs)
chloryl hydrate
general CNS depressent that acts rapidly and if given alone can induce sleep in approx 30 mins
barbituates-not recommended
support addiction
unpleasant side effects
greatly increased effect with other CNS depressents-cause death with alcohol
narrow margin of safety
Benzodiazepines
efficacy equivalent or greater than any other classes of sedatives
enviable safety profile
MOA of benzos
promote binding an influence major inhibitory neurotransmitter GABA
This causes Cl- influx and negative membrane potential therefore less responsive to stimuli
do benzos open the Cl- channel?
no. (safety profile !!)
they bind to specific BZ receptor on the GABA receptor complex.
there is no effect if GABA is not present!
Diazepam
"grandfather benzo" and very influenced by aging, interactions and hepatic dysfunction
Lorazepam
less affected by variables
intermediate acting benzo
lower lipid solubility than diazepam (longer sedative effect)
inactive metabolites
.5-4mg
triazolam
rapid onset and short duration
no metabolites
beter sublingual
.125-.5 mg
influenced by aging, hepatic dysfunction and interactions like diazepam
Midazolam
medication of choice for peds
no advantage over triazolam in adults unless they cannot swallow the tablets
non benzo GABA agonists
zolpidem
zopiclone
eszopiclone
zaleplon
zolpidem 10mg
rapid onset
no metabolites
not contraindicated in pregnancy or narrow angle glaucoma -ADVANTAGE OVER BENZO
antagonist for zolp?
flumazenil
zopiclone 7.5-15mg
similar to zolp
Zaleplon 5-20 mg
faster onset than zop/zolp
increased in asians so be conservative
What is Ramelteon?
melatonin receptor agonist
no anterograde amnesia found in benzos
reversed by flumazenil?
nope
Black box warning for <2 yrs of age due to fatal respiratory depression
Promethazine
patients may feel anticholinergic side effect and patients with angle closure glaucoma should be avoided, so prob not the best for geriatrics
anithistamines
Diphenhydramine
hydroxyzine
renal and hepatic patients
use benzos
avoid chloral hydrate bc its renally cleared
resp disease
antihistamines
benzos
epilepsy
benzo bc of anticonvulsant activity
some antiepileptic drugs are hepatic enzyme inducers that may increase clearance of sedative drugs and shortening their duration
how many canadians have some fear towards the dentist ?
1/3
of those who have cancelled an appointment, how many are in the high fear category?
49.2%
who is 2.5 x more likely to have dental anxiety?
women
do age and education have an impact?
no
who discovered N02 and 02
Joseph Priestly
in 1795 who used nitrous on himself to relieve a tooth ache
Humphry Davy
1846
William morton used ether to successfully extract a tooth
1847
Nathan Keep gave first obstetric anesthetic
1949
leonard Monheim founded the department of anesthesiology in pittsberg dental school