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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?
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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 |
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what is the consent document you use?
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"nitrous oxide sedation to help your childs dental visit"
|
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If the gauges read full, are the tanks open?
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No not necessarily
|
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what is your starting flow rate for oxygen?
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6L/min
|
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how will you titrate in the nitrous?
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start by increasing nitrous to 10%
wait 1 minute and titrate by additional 10% wait 1 minute and titrate by 5% increments |
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what do you do all the time?
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continuously observe for patient responsiveness, color, respiratory rate
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why do you ensure patient remains on 100% oxygen when discontinuing nitrous?
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to prevent room contamination
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what should a chart entry look like for nitrous?
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-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 |
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At Douglas, how do you respond to an emergency while giving nitrous?
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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 |
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what is the most important safety feature of nitrous?
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"titration"
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what is the average amount of nitrous a patient needs ?
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30-40%
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"anoxic anaesthesia"
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100 % nitrous
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"relative anaesthesia"
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nitrous with oxygen
|
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what is another safety feature of modern nitrous units?
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cannot administer less than 20% oxygen
|
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what are some benefits of digital systems?
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-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 |
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what are some concerns raised about nitrous?
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-sexual awareness
-potential biohazards to exposure -abuse |
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what can be permanent but is generally reversible after chronic abuse of nitrous?
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neuropathy
|
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Cases of record with respect to sexual awareness and impropriety while under nitrous have 3 elements that place the practitioner at risk
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-without assistant
-high concentrations -failure to titrate |
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what enzyme does nitrous effect?
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methionine synthetase
|
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what is this enzyme responsible for?
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vitamin B12 metabolism
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The two most common causes for nitrous contamination in the office are?
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-patients talking
-patients mouth breathing |
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what is the most effective way to monitor tract nitrous oxide?
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infrared nitrous oxide analyzer
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what was the most used oral sedative for pediatrics?
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chloral hydrate
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what was the prototype sleeping aid but subject to overdose in the mid 19th century?
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barbituates
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what are the main anxiety relievers in dentistry?
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benzodiazepines
|
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this drug has active metabolites Trichloroethanol and trichloroacetic acid. What is this drug and what is the therapeutic index, and onset?
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Chloryl hydrate
-fast onset of action (30 mins) -narrow therapeutic index *you are getting kids drunk essentially. (4-6 hours) |
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what is the maximum of chloryl hydrate?
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1g. MUST BE GIVEN IN OFFICE
|
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what drug:
-alcohol-death -addictive -GABA receptor complex -narrow therapuetic index |
Barbituate
|
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what drug has a wide margin of safety and what does this mean?
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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 |
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what benzo was created 1963?
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Valium (1/2 life is age. So 30 years old =30 hours half life)
|
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nitrazepam
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1965
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Temazepam
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1969
|
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what patients need 1/2 dose of benzos?
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obstructive sleep apnea patients
"relative contraindication" |
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5 things to remember about benzos
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-increase affinity GABA receptor
-anticonvulsant -decreased muscle tone (OSA px) -sedative/anxiolytic -anterograde amnesia |
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benzo contraindication?
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acute narrow angle glycoma
|
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what type of properties do bezos have?
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anticholinergic
|
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so what are some adverse effects of benzos?
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-respiration depression (not obstruction)
-cardio depression -disinhibition (px becomes hysterical) -dependence/addiction |
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when is benzo sensitivity increased?
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-elderly
-liver disease -other CNS depressants |
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when is it decreased?
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-smoking (bc it induces liver enzymes)
-recent use of benzos , ethanol or other depressants |
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does it depend on the size of the patient as to your dosing?
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NO its HOW ANXIOUS the patient is
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what will fix obstruction 99% of the time in minimal/mod sedation?
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oral airway!
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What is the last resort?
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flumazenil
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how is it delivered?
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IM
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is it substitute for proper management?
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NO
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what is the problem with it?
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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!
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Benzodiazepines -pregnancy. How do u handle this?
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-not recommended "pump and dump, 24 hours before store the milk and up to 24 hours after dump"
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Chlordiazepoxide
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intermediate onset
long half life daytime drowsiness |
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do you promise anterograde amnesia?
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no you cannot guarantee it!
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Diazempam
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fast onset
long half life daytime drowsiness |
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what is the dose for diazepam?
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5-20 mg
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what drug has an intermediate half life with no active metabolites and is more rapid when delivered sublingually?
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Lorazepam (Ativan)
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what is the dose for Ativan?
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.5 -4 mg
|
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which benzo has antidepressant effects and intermediate half life with active metabolites?
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Alprazolam
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what is the dose for Alprazolam
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.25-1mg
|
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what are the 2 short acting benzos?
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Triazolam and Midazolam
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what is the difference in the two drugs?
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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!
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what is the pediatric dose for Midazolam?
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.5mg/kg up to a MAX of 20 mg
|
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what is the triazolam dose?
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.125-.5 mg (that is 2 pills!)
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This drug is a non benzo sedative which is not used in dentistry alot and is reversed by flumazenil
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Zopiclone.
-Gaba receptor and fast onset -some anterograde amnesia -active metabolite |
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DO non benzos have anxiolytic properties?
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no
|
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anti nauseant properties
sedation as a side effect sedative efficacy-less |
Antihistamines (H1 receptor blocker)
|
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anticholinergic side effects
short to intermediate half life fast onset. (24-50mg) dose |
Diphenhydramine (Benadryl!)
|
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what are the pharmacodynamic drug interactions you must worry about?
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-ehtanol
-other CNS depressants |
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what are the pharmacokinetic interactions?
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-Hepatic CYP450 3A4
-midazolam, triazolam, diazepam (these raise the seizure threshold and you will only see cardio collapse so lower your LA ! ) |
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Is redistribution related to the metabolic half life?
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no. redistribution away from site/receptor due to blood rich-->vessel poor area
|
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what are some CYP P450 inducers?
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antiepileptics
corticosteroids antibiotics |
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what are some CYP 450 inhibitors?
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HIV-protease inhibitors
Nelfinavir Ritinovir |
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what are the minimal sedation drugs of choice for a short appointment?
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midazolam
triazolam |
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what about long appointments?
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lorazepam
diazepam |
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if you give someone palatal anaesthesia, and this does not provoke movement what kind of sedation is this considered?
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GA!!
|
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what decreases in geriatric patients?
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physiology
-cardio -cerebral blood flow renal and hepatic blood flow pulmonary function |
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what does this mean?
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the pharmacodynamic changes have a greater effect so use lower doses and shorter acting agents
|
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what do you avoid in renal disease?
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chloral hydrate
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do you adjust the dose?
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no
a single dose acceptable |
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When would you consider lowering the dose?
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hepatic disease
|
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when would u consider the antihistamines for oral sedation?
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respiratory disease.
usual doses are acceptable stress can trigger asthmatic attacks |
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use what for epilepsy?
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benzodiazepines
|
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what are some great things to keep in mind for diabetes patients
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-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 |
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what leads to right heart failure in obstructive sleep apnea patients?
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air way obstruction
C02 increase leading to pulmonary vasculature resistance Right ventricular hypertrophy cor pulmonale right heart failure |
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this anatomy serves to filter airborne particles humidify and warm inspired gases
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upper airway
|
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are alveoli part of the upper airway?
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yes
|
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what are the main structural components of the larynx?
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thyroid and cricoid cartilages
arytenoid cartilages epiglottis |
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What is the dual lung supply?
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1. pulmonary circulation (gas exchange)
2.bronchial circulation (lung parenchyma) |
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where does the bronchial circulation drain to?
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left side of heart via pulmonary veins
|
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where is the physiologic dead space?
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anatomic dead space and the alveolar dead space
|
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in dead space what is lower V or Q?
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Q!
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in a shunt , what is lower, V or Q?
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V!
there is decreased ventilation for the perfusion |
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2 examples of shunts?
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atelectasis (collapsed alveoli)
pneumonia |
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Alveolar ventilation
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the amount of air breathed in per minute that reached the alveoli and participates in gas exchange
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dead space ventilation
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the part of minute ventilation that does not take part in gas exchange
|
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alveolar ventilation + dead space ventilation
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minute ventilation
|
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what are the muscles of active expiration?
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internal intercostals
abdominal muscles |
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what are the major muscles of inspiration?
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diaphragm and external intercostals
|
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where are the chemoreceptors that control breathing?
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centrally (brain stem) and peripherally (carotid bodies)
|
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what does the central control respond to?
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CSF hydrogen ion concentration in turn determined by C02 which diffuses freely across barrier
|
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what do the peripheral chemoreceptors respond to?
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fall in 02
-profound hypoxia required for significant activation |
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Haldane effect
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when the body is hypoxic (low02) , hemoglobin can carry more C02 to liberate it from the body bc it is not occupied by 02
|
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what % of oxygen in the blood is carried in the RBCs?
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97%
|
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70% of C02 in the blood is present as?
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HCO3 bicarbonate ions
|
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obstructive lung disease
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difficult to get air out of lungs
low FEV1/FEVC |
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restictive lung disease
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difficult to get air into lungs
high FEV1/FVC |
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chronic bronchitis "blue bloaters"
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an obstructive lung disease in the large airways that results in increased cardiac output and decreased ventilation
|
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What does this VQ mismatch lead to in chronic bronchtiis?
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hypoxemia and polycythemia
hypercapnea and resp acidosis -right ventricle enlargement and failure bc hypertention of pulmonary vessels |
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Emphysema "pink puffers"
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an obstructive lung disease in the alveoli which leads to decreased ability to oxygenate blood and the body lowers cardiac output and increases ventilation
|
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what does this VQ mismatch result in?
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limited blood flow through fairly oxygenated lung . the low cardiac output leads to tissue hypoxia and muscle wasting and weight loss
|
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restrictive lung disease
|
intrinsic lung disease of the parenchyma
extrinsic lung diseases loss of lung compliance |
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On a PFT , if the FVC and the FEV1 are bpth >85% predicted values (normal) what do you do?
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look no further! it is within normal limits
|
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what if either of them are low?
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risk of disease
|
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if the % predicted for FEV1/FVC is 88%-90% then the patient has what?
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restrictive !
|
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if FEV1/FVC is low (69% or lower) then the patient has what?
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obstructive!
|
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what is bad?
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spark+gauze+oxygen
|
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oxygen supports
|
combustion
|
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room air
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21%oxygen
|
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what can oxygen toxicity lead to?
|
restrictive lung disease (pulmonary fibrosis)
|
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a pleasant room temperature gas that is non flammable
|
nitrous
ammonium nitrate-->nitrous + water vapor |
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nitrous is ____and ____
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anti nociceptive
anxiolytic |
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flumazenil
|
reverses benzo
|
|
naloxane
|
reverses opioid
|
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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 |
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nitrous has biochemical disturbances like B21 inactivity via methionine synthase, so what patients do u avoid?
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-cancer px and pernicious anemia
|
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what is a reasonable exposure level to nitrous?
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400 ppm
|
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is there evidence that a direct causal relationship exists between repro health and scavenged nitrous?
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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?
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>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
|
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which is most soluble. Ether,sevoflurane or nitrous?
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ether has the highest solubility and nitrous has the lowest
|
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what does this mean??
|
ether takes FOREVER to induce, where as nitrous is very rapid induction (on/off)
|
|
most nitrous
|
gets exhaled out
|
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a higher concentration and a greater duration of use of nitrous increases?
|
nausea and vomiting
|
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what relieves this?
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slow induction
|
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what is the "thorp tube" on a nitrous unit?
|
N20 flowmeter tube
|
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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
|
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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 |
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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 |
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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
|
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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 |
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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
|