IV sedatives, anesthesia, airway management, and medical considerations

Question 1

5 IV sedatives we use

Answer 1

versed
propofol
fentanyl
ketamine
dexmedetomidine

Question 2

versed
main use?
onset? duration? dosage?
drug class? characteristics? half life?
reversal agent?

Answer 2

AKA Midazolam benzodiazepine, CNS depressant
short acting ;
half life is 1.5-2.5 hrs
onset : 2-5 mins
duration 30-60 mins
Dose usually given at 1-2 minutes at 0.02 - 0.03 mg /kg. - often .5 or 1 mg and titrated to effect
no single dose should exceed 2.5 mg
water soluble
reversal: flumazenil (0.2 mg q 1 min, max of 3 mg)

main use - before surgery

ACTS on GABA receptor - CHLORIDE complex in the CNS, this opens the chloride channels, allowing HYPERPOLARIZATION and increases the inhibitory effect of GABA in the CNS via INCREASE in channel frequency

Question 3

advantages of versed?
disadvantages?

Answer 3

advantages : used before surgery , decreases anxiety, causes drowsiness, and ANTEROGRADE amnesia (inhibiting formation of new memories)

disadvantage: can cause acute apnea with rapid IV administration.

Question 4

propofol
main use?
drug class? characteristics? half life?
initial dose?
maintenance dose?
reversal agent?

Answer 4

used for: sedation, induction, and GA
GABA - A receptor potentiation
rapid onset- high lipid solubility and rapid redistribution
clinical effect is approx 10 minues
it is biphasic - initial half life being relatively quick (40 mins) and its terinal half life being 4-7 hours

for r PSA in adults, propofol is given by slow injection in an initial loading dose of 0.5 to 1 mg/kg IV followed by doses of 0.25 to 0.5 mg/kg IV every one to three minutes as necessary until the appropriate level of sedation is achieved [23].

One reasonable approach to administration is to give 20 mg every 10 seconds (eg, a 50 mg dose would be given over 25 seconds), although there is no direct evidence demonstrating improved efficacy or safety using this regimen.
depresses cognition, decreases cerebral blood flow, intracranial pressure and cerebral oxygen consumption
*causes vasodilation (cardiac), and dose dependent respiratory depression

Question 5

advantages of propofol
disadvantages

Answer 5

A: reliable, antiemtetic (PONV), bronchodilation

D: can decrease BP, pain on injection, potential allergy w/ spy and egg, emulsion can support bacterial growth

Question 6

Fentanyl
main use?
drug class? characteristics? half life?
reversal agent?

Answer 6

Opiod
acts on u-opiod receptor
100x more potent than morphine and crosses blood brain barrier and placenta

half life is 3-7 hours- 75% in the urine, 9% in feces

reversal : naloxone (0.1 mg/kg IV) - short half life

Question 7

advantages and disadvantages for fentanyl use?

Answer 7

A: quick onset, short duration
D: causes resp. depression and rigid chest syndrome

Question 8

Ketamine
main use?
drug class? characteristics?

Answer 8

water soluble PCP derivative
causes dissociative anesthesia - temp. disconnection of cortex from thalamus, nystagmus can occur
causes bronchodilation, sedative, analgesic,

reduces CNS function by INHIBITING NMDA receptor activity

Question 9

advantages and disadvanages of ketamine

Answer 9

A: does NOT effect respiratory rate, causes bronchodilation, sedative, analgesic, CV stable (cardiovascular)
D: seizures, increased nausea, emergence delirium, hallucinations, increased secretions, increased ICP, HR, BP, and CO

Question 10

consider what with ketamine due to its disadvantages?

Answer 10

versed
gycopyrrolate or atropine
- GP can have negative cardiac effects esp considering ketamines increased effect on CO (cardiac output)
- GP is an anticholinergic and can reduce salivary gland and respiratory secretions

Question 11

dexmedetomidine
drug class / MOA
characteristics, half life

Answer 11

alpha 2 adrenergic receptor AGONIST- which INHIBITS the release of norepinephrine and thus the subsequent pain signals
biphasic blood pressure response
- short hypertensive phase and following subsequent hypotension

half life: 2-4 hours

Question 12

advantages and disadvantages of dexmedetoidine

Answer 12

A: does NOT surpress respiratory function
D: reduces cerebral blood flow

Question 13

GA vs sedation (general)

Answer 13

GA: loss of consciousness - eliminates all sensations
sedation: (minimal, moderate, deep)
- calming nerves with drugs without inducing a loss of consciousness

Question 14

NPO times
2 hrs? 4hrs? 6 hrs? 8 hrs?

Answer 14

2: clear liquids (including black coffee and pulp free clear juice_
4: breast milk
6: light meal (dry toast, break, crackers, cows milk)
8 hr: heavier meals, greasy / large meals

Question 15

characteristics that describe minimal sedation

Answer 15

ANXIOLYSIS : protective reflexes intact
responds normal to stimulation and verbal commands
respiration and cardiovascular function is unaffected

Question 16

characteristics of moderate sedation

Answer 16

AKA conscious sedation
- protective reflexes intact, responds purposfully to stimulation and verbal commands
spontaneous ventilation is adequate, cardiovascular function usually maintained.

Question 17

deep sedation characteristics

Answer 17

patient is NOT easily aroused, but will respond purposfully following painful stiimuli
- ventilators function may be impaired
- may need assistance to maintain airway
- cardiovascular function usually maintained

Question 18

characteristics of GA

Answer 18

not arousable, even with pain
ventilators function may be impaired
airway supported

Question 19

four stages of anesthesia with descriptions of each

Answer 19

1: analgesia, patient becomes sedated
2: excitation, increase in HR and BP, pt. can become combative - - dont want to wake pt. up in this state, if occurs it is more dangerous and consider sedating deeper prior
3: SURGICAL ANESTHESIA - HR and BP return to baseline, patient is deep enough for surgery to begin
4: coma - patient vitals collapse

Question 20

examples and brief description of anesthesia vapors

Answer 20

Isoflurane (ISO) - cardioprotective, but causes a slower wake up due to large solubility

Sevoflurane (SEVO) - good for mask induction and is the least pungent

Desflurane (DES) - good for obese patients, but irritating for smokers and asthmatics - tend to wake up faster since least soluble

Question 21

Mallampati Classification scale / Broadsky score

Answer 21

Class I: soft palate, fauces, uvula and tonsillar pillars visible
Class II: soft palate, fauces, uvula
Class III: soft palate, base of uvula
Class IV: only hard palate visible

Question 22

what classifies upper airway?
general

Answer 22

part ABOVE the cricoid cartilage
1. nose and paranasal sinuses
2. oral cavity
3. pharynx
4. larynx

Question 23

lower airway - general

Answer 23

1. trachea
2. L and R principal bronchi
3. secndary lobar bronchi
4. segmental tertiary bronchi
5. terminal bronchiole
6. respiratory bronchiole
7. alveolar duct and savs

Question 24

airway anatomy from nasopharynx –> trachea

Answer 24

Nasopharynx - from nose to soft palate
Oropharynx- soft palate to epiglottis
Hypopharynx- airway from epiglottis to esophagus
Larynx- inlet to the trachea and lungs
Trachea- extends from larynx to carina

Question 25

anesthesia grade view on cormack-lehane grading

Answer 25

classifies views based on views via a direct laryngoscopy
Grade I- Grade IV
grade I- full view of entre glottic aperture - including vocal cords
grade II- partial glottic view
IIA- partial view of the cords
IIB- only the arytenoids and epiglottis visible
grade III- view of epiglottis only
grade IV- no view of epiglottis or glottis

Question 26

3 main types of airway devices
describe each w/ pros/ cons.

success depends upon?

Answer 26

1. face mask - most basic, difficult to master but used most commonly for induction and extubation
2. LMA (laryngeal mask airway) - supraglottic device inserted into oropharynx above glottis - can be placed blindly. does NOT protect against laryngospasm or aspiration
3. Endotracheal Tube - inserted through mouth or nose, difficult to place, DOES protect against aspiration

success depends on patent airway, adequate seal and proper ventilation

Question 27

FiO2?

Answer 27

fraction of inspired oxygen - concentration of oxygen in the gas mixture

Question 28

percent of oxygen delivery in:
simple masks?
partial rebreathing?
non-breathing?
high flow / venturi masks?
nasal cannula?

Answer 28

simple masks - 35-60%
partial rebreathing - 50-60%
non-breathing - 95-100%
high flow / venturi masks - 25-60%
nasal cannula- 32 %

bag mask ventilation - used due to inadequate ventilation

Question 29

tx for bronchospams

Answer 29

epinephrine, ketamine, magnesium sulphate or aminophylline

head tilt, chin lift, jaw thrust

Question 30

main risk factors for laryngospasm?

Answer 30

light sedation, children > adults, instrumentation, vocal cord irritation, and OSA

Question 31

managing laryngospasms?
if have an IV placed?
if no IV placed?
if pt. becomes bradycardic?

Answer 31

continuous positive airway pressure
jaw thrust or presure on laryngospasm notch

if IV - give 0.5 mg/kg propofol to sedate deeper
if no IV- give 2 mg/ kg IV succinylcholine (depolarizing muscle relaxant- binds to motor end plate)
- intubating dose of 1-1.5 mg.kg IV (laryngospasm dose is 20% of intubating dose ~.25-.5 mg)
- can trigger MH - consider atropine if pt. becomes bradycardic

if no succinylcholine, consider rocuronium

Question 32

benzos changes to vital signs?

Answer 32

respiratory depression can occur (so reduction in resp. rate)

little reduction in BP and HR

Question 33

details about propofol.
effect of propofol on vital signs?
metabolized?
excreted?

Answer 33

highly lipid soluble
GABA receptor - increased chloride conductacne and causes hyperpolarization of neurons

DECREASES BP by 20-40% of baseline through both central and peripheral mechanisms
- BLOCKS sympothetic tone and allows parasympathetic vagal responses to predominate (blunting reflex tachycardia)
- hypotension could occur (particularly in elderly, med compromised or hypovolemic pts.)
- dose dependent resp. depression

BRONCHODILATORY properties
- NO histamine release

metabolized by:
- hepatic enzymes

• amnesia, loss of consciousness, anti-convulsant
  usually used with small increments of prop (10-30mg)

helps with DECREASE IN PONV, also assoc. with rapid awakening
can have SIGNIFICANT PAIN ON INJECTION

*if true soy allergy - cannot use

Question 34

details about ketamine?
effects on vital signs?

Answer 34

PCP derivative that produces a “dissociative anesthesia”
anterograde amnesia effect, intense analgesia

highly lipid soluble – rapid onset and relatively short duration

NO INTERACTION WITH GABA
NON SELECTIVE ANTAGONIST OF NMDA –> inhibiting an excitatory neuron –> analgesic effect in addition to likely interacting with opioid receptors and spinal cord

INDIRECT ACTIVATION OF SYMPATHETIC NS – increase in norepi by inhibiting reuptake of postganglionic sympathetic neurons
INCREASE IN HR AND BP (used in caution with cardiac pts)

no significant changes in respiratory rate
ASPIRATION STILL POSSIBLE
AIRWAY REFLEX usually in tact

BRONCHODILATOR
NO HISTAMINE RELEASE

INCREASES SALIVARY SECRETIONS AND PONV
- sometimes consider glycopylorate (anticholinergic to decrease secretions if necessary)

EMERGENCE DELERIUM – Pt. may experience visual and/or auditory hallucinations
- may be best attenuated with benzos - which should be routine when IV sedation techniques with ketamine are used

Question 35

versed details
effect on vital signs?

Answer 35

Midazolam –
sedation, anxiolysis, anterograde amnesia, muscle relaxing properties, and anti-convulsant activity
NO ANALGESIA
LITTLE / TO NO DIRECT effect on cardiovascular parameters
MINIMAL effects on resp rate – but can have a dose dependent reduction in resp.
large bolus doses will induce unconsciousness and apnea

METABOLIZED by hepatic enzymes – some can be clinically active and then EXCRETED by kidneys
dosing for conscious sedation, 0.05 to 0.15 mg/kg intravenously in divided doses is titrated to effect, typically given in 1- or 2-mg boluses every few minutes. Peak effect is seen in approximately 5 minutes. Dosage should be adjusted downward when given concurrently with other medications such as opioids or propofol.

Question 36

fentanyl details
opioid use in general in sedations
effects on vital signs?

Answer 36

Fentanyl details: high lipid solubility - high potency RAPID ONSET (1 MIN) and shorter duration of action (10-20 mins)
FENTANYL DOES NOT RELEASE HISTAMINE (like the other opioids can)
* at high dose bolus can be assoc with chest wall and glottic rigidity - making ventilation impossible)

used primarily for analgesia and to augment sedation / euphoria – drug alone DOES NOT produce amnesia or classic sedation or induce loss of consciousness - so used in combo with sedative hypnotics such as benzos and propofol to provide analgesia and augment desired level of sedation / GA

bind to opioid receptors located in pre-synaptic and post-synaptic neurons throughout CNS as well as PNS afferent nerves

RESPIRATORY DEPRESSION IS MOST COMMON AND PRONOUNCED SIDE EFFECT
- dose dependent drom decrease in resp response to arterial carbon dioxide levels in brainstem
- this can be more exacerbated with concurrent administration of other medications such as benzos, propofol and other opioids

BRADYCARDIA as a direct effect is more apparent with high doses of opioids and is due to centrally mediated vagal response (can be seen with fentanyl use)
MILD DROP IN HR

SUPRESS COUGH REFLEX
RELEASE HISTAMINE –> can see DECREASE IN BP SECONDARY to vasodilation, and pruritis, and erythema - esp at site of injection

NAUSEA / VOMITTING
CONSITPATION
URINARY RETENTION

Question 37

dexmedetomidine details - MOA?
effects on vital signs?

Answer 37

alpha 2 receptor AGONIST (8x more selective than clonodine -prototypical alpha 2 agonist)

have sedative, analgesic, and muscle relaxant properties in addition to their INHIBITION OF CNS SYMPATHETIC OUTFLOW and thus - ANTIHYPERTENSIVE effects

DECREASE ANESTHETIC REQUIREMENTS

can be used for procedural sedation in nonintubated pateints

Question 38

thyromental distance should be at least?
neck circumference that poses problem?

Answer 38

6 cm or approx 3 ordinary fingerbreadths

a short thyromental distance equates with an anterior larynx that is at a more acute angle and also results in less space for tongue to be compressed by laryngoscope blade

neck circumference greater than 17 m

Question 39

anesthesia preformed with an URI? (upper respiratory infection)

Answer 39

pathophysiologic changes occur in URI like increased nasal and lower airway secretions, increased airway edema and inflammation, and increased airway tachykinins –> all of these can result in laryngospasm, bronchospasm, severe coughing, airway hyperactivity, breath holding, diminished diffusion capacity, increased closing volumes, atelectasis, and postintubation croup

INCREASED RISK FOR HYPOXEMIS
- research shows patient with recent or active URI requires appox 30% less apneic time to desat. than does healthy patient.
- if pt. has SIGNIFICANT URI - elective surgery should be rescheduled

Question 40

coronary artery disease and myocardial infarction hx workup?
describe basic patho-phys

Answer 40

angina or shortness of reath with exercise may suggest ischemic heart disease,

**determining functional status using METs (Metabolic equivalents) helps assess disease severity, and the use of chronic and episodic vasodilator medications (including nitro) provides additional insight

Question 41

a-fib can predispose to?

Answer 41

a rapid ventricular rate that can lead to acute decompensation and heart failure.

Question 42

from respiratory perspective - obese, pediatric, and patients with comorbid med condistions have a reduced____ and may ___ more rapidly

Answer 42

reduced functional residual capacity and may desaturate relatively rapidly

Question 43

five key elements to enable appropriate risk stratification for office based anethesia?

Answer 43

1. ASA status
2. Functional status (METs)
3. Mallampati classification
4. BMI index
5. Airways access in event of airway compromise

Question 44

METs - general measurement of?
specific ratio of??

Answer 44

metabolic equivalents – sign. info from a cardio and pulmonary reserve can be obtained with this.
*reflects pt. exercise tolerance with one MET equivalent to 35 mL of oxyen per kilogram consumed per minute

• 3.5 mL O2 / kg/ min.

Question 45

METs scores and conversion of activity to number
what number should not be considered eligible to in office anesthesia?

Answer 45

functional status of less than 4 is poor
walking at 2mp
activities of daily living

moderte 4-7
cycling, climbing stairs, walking 4 mp

excellent above 7
squash, tennis, jogging, etc

Question 46

implications of increased BMI? how do you calculate BMI?
breakdown of BMi numbers and relatinoship to underweight, normal, overweight, obese, morbidily obese

Answer 46

Body mass index - take weight in kg and divide by meters 2 (height)

normal / overweight - not as worried about implications with this.

if above that - places pt. at more difficult airway to manage in addition to reduction in functional residual capacity - AVOID APNEA INDUCING DRUGS
underweight: <18.5
normal: 18.5 - 24.9
overweight: 25-29
obese: 30-40
morbidly obese: >40

Question 47

sternomental distance implication
include measurement above we worry

Answer 47

above 12.5cm – there is a positive predictive value of 82% for difficult intubation.

include length and diameter of neck

Question 48

general list of labs to review when considering anesthesia for patients related to
-cardiac
- BG
- INR
- SPo2

Answer 48

ECG for patients with cardiac disease (within 6-12 months)

Blood glucose levels nd hemoglobin A1c for diabetes (type I and II)

INR reports for patients taking warfarin (within 5 days

Question 49

contraindication to proceeding with surgery from cardiac persepective?

Answer 49

a hx of MI within last 6 weeks
after - prob okay but more time that passes less likely for adverse events

a lot of people have a PCA – percutaneous coronary angioplasty - which is very beneficial for patients - and a lot of the time these pts. are placed on DAPT (dual antiplatalet therapy) - involves the use of aspirin and either a glycoprotein IIB/IIIa inhibitor or an ADP antagonist (like clopidogrel) for at least 14 days, 30 days, and 3 months for procedures like balloon angioplasty, bare metal stents, and drug eluting stents, respectively.

even when treating this patients with LA only - may benefit from supplemental oxygen use

Question 50

a lot of patients with recent MI or CAD have had? are on?
drugs and implication in timing, etc?

Answer 50

a lot of people have a PCA – percutaneous coronary angioplasty - which is very beneficial for patients - and a lot of the time these pts. are placed on DAPT (dual antiplatalet therapy) - involves the use of aspirin and either a glycoprotein IIB/IIIa inhibitor or an ADP antagonist (like clopidogrel) for at least 14 days, 30 days, and 3 months for procedures like balloon angioplasty, bare metal stents, and drug eluting stents, respectively.

even when treating this patients with LA only - may benefit from supplemental oxygen use

Question 51

cardiac arrhythmias and drugs to avoid / implications

Answer 51

epinephrine containing drugs
ketamine- can cause increased chance for arhythmias

Question 52

a fib implication and what to know in regards to this

Answer 52

A-fib which should be able to be diagnosed
if pt. is on drugs like warfarin or other direct acting oral anticoagulants (DOACs) this can help determine if more potential for A-fib is likely

concerns with A-fib is the potential for aryhtmia to turn to RVR - rapid ventricular rate tht can leade to acute decompensatino and heart failure

anesthetic plan should limit the use of epinephrine and avoid excess fluid replaecements

Question 53

pts with chronic AF and rate greater than __? should…

Answer 53

rate greater than 90 BPM should be considered for cardiology referral to achieve optimal rate control

and those with implanted pacemakers and internal defibrillators (ICDs) warrant cardiac consultation and anesthesia should be reconsidered in an ambuatory surgical center or hospital OR.

Question 54

congestive heart failure details and basic definition and description
what is important to evaluate?

Answer 54

CHF is a progressive loss of the normal cardiac output -

symptoms of non compensated heart failure may include shortness of breath, peripheral edema, and or fatigue

the functional status( METs) provides valuable insight into disease severity

*many pts cannot tolerate acute changes in heart rate or blood pressure - and anesthetic plan should be to monitor on ECG

moderate - severe CHF are not candidates for office based.

Question 55

valvular heart disease and prosthetic valves implication

Answer 55

pts. may be referred for ultiple exts prior to placement - may or may not be suitable for in office procedure

consider scheduling multiple appts. to achieve necessary tx plan

once valve replacement has occured - patients are typically more stable

anticoagulation therapy will be continued after when the valve is alloplastic (ssynthetic)

xenografts (porcine) valves typically only require antivoagulants for 6 months

consult with cardiologist

Question 56

time to hemoglobin desaturation with initital FaO2 of 0.87

main factors that can cause desat and apnea more quickly?

graph showing
1. obese
2. normal child
3. moderately ill adult
4. normal adult

Answer 56

time from development of apnea until oxygen desat decline depends on several factors like

• pre-oxygenation level and functional residual capacity

*obese patients, pediatric patients and those with comorbid medical conditions have reduced FRC and will desat more rapidly

*this is the order
1. obese
2. normal child
3. moderately ill adult
4. normal adult

*this has all become better managed due to increased monitoring of ETCO2 – end tidal carbon dioxide

Question 57

what does monitoring the ETCO2 tell us

Answer 57

Monitoring end-tidal CO2 (ET-CO2) provides instantaneous information about. ventilation (how effectively CO2 gas is being exhaled/eliminated by the respiratory. system), perfusion (how effectively CO2 is being transported through the vascular.

** VENTILATION / PERFUSSION **

Question 58

hepatic disease details and implication to office based anesthesia

drugs that may be better to use / considered in anesthesia and why? - what property of the drug makes it a more reasonable choice for these patients?

Answer 58

various causes - including viral hepatitis, chronic alcoholism, and hepatotoxicity from drugs

many anesthetic drugs are bound to plasma proteins that are PRODUCED IN THE LIVER
- so could be producing less proteins and thus more free drug in the circulation

therefore, hepatic disease may result in an increased free drug within the circulation with the potential for ENHANCED AND PROLONGED DRUG ACTIVITY.

in addition – liver is responsible for some METABOLISM of drug – including opioids and benzos – hepatic disease can resul in an increased half life and prolonged anesthetic effect
↓ Blood flow to the liver
* ↓ Ability to metabolize drugs
* ↓ Albumin and protein binding

RAPIDLY REDISTRIBUTED DRUGS such as PROPOFOL - may be a better choice in these patients – consultation with PCP is encouraged.
**comprehensive metabolic panel!!!!

Question 59

renal disease details and implication to office based anesthesia

additionally the kidney is responsible for (other major things outside of what you’re thinking of immediately) and what this has implications in?

Answer 59

**URINARY excretion of drugs remains a major mechanism for drug elimination – drug elimination will be reduced with renal disease and thus a PROLONGED drug action, particularly when drug metabolites are active and also have a therapeutic effect

*kidney also responsible / involved in fluid balance and electrolytes homeostasis
- therefore with decreased kidney function – this can result in a decreased cardiovascular reserve as well as an increased predisposition to cardiac arrhythmias

↓ Glomerular Filtration Rate
* Fluid and electrolyte imbalance
* ↓ Capacity to excrete drugs and metabolites

consult with PCP and nephrologist is imp. in addition to comprehensive metabolic panel.

Question 60

drugs reasonable to avoid in the geriatric population?

Answer 60

benzo (delerium) and ketamine
ketamine (increase HR, BP) - in addition to delirium
It is prudent to avoid drugs that tend to result in postoperative delirium. Accordingly, it is reasonable to avoid benzodiazepines and ketamine where possible

Additionally, narcotics should be used judiciously following weight-based guidelines. The combined use of fentanyl and propofol works well with few side effects
and little likelihood of apnea or cardiovascular changes.