Oral Boards Prep 1

MOA

100

Propofol, discuss MOA

Propofol primarily act on the GABA-A receptors, by prolong the opening duration of Chloride channel and resulting in hyperpolarization of the cell
there is new knowledge that propofol also work by antagonism of the NMDA receptors

200

Which induction medication produces adrenal suppression (extra points if you can discuss MOA)

Extra point if you can also name most prominent side effect of this medication

Etomidate produces transient adrenal suppression by inhibiting 11 β-hydroxylase. which causes accumulation of 11-deoxycorticosterone

myoclonus

300

Compare and contrast MOA of non-depolarizer vs depolarizer

Presynaptically, NDMRs decrease Ach release.

• thru blockade of pre-synaptic Ach auto-receptors (inhibition of positive feedback)
• Clinically this is seen as “fade” with repeated nerve stimulation.
• Fade represents the decrease in Ach release

Postsynaptically

• NDMRs act through competitive antagonism at postsynaptic muscle membrane.
• Only one α subunit on the nAchR needs to be blocked to prevent action potential propagation

Sux’s action in muscle relaxation occurs because it mimics the action of Ach

• Structurally it is 2 molecules of Ach linked together
• Neuromuscular blockade (NMB) develops because at least one sux molecule attaches to the α subunit of the nAchR (the other α subunit can be occupied by Ach or Sux molecule) the depolarized membrane cannot respond to subsequent releases of Ach (Phase I blockade), it maintains a hyperpolarized state

400

Compare and contrast MOA of Anticholinesterase drugs and Sugammadex

extra points if you can differentiate between at least 2 anticholinesterase drugs

Sugammadex: 

-encapsulating, binding and inactivating Roc or Vec (not approved for Pan - off label use, do not use)

-Through inactivation, a concentration gradient occurs shifting the NMB away from the NMJ, reversing paralysis

-Stops only once cleared by the kidneys

Neostigmine and Edophonium 

-The primary mechanism of anticholinesterases in reversing NMB is through inhibition of AchE in the NMJ

-Through inhibition of AchE, more Ach is available in the synaptic cleft

-More Ach creates a concentration gradient that prefers the NDMR to displace from the nAchR

500

Compare and contrast the MOA of non-particulate antacid, H2 blocker, PPI

extra points if you can name 1 med from each category, dose, and when to give them

Bicitra -> neutralizes gastric content and increases pH, 30ml, 15-30 min prior

H2 -> competitively blocks H2 to decrease acid secretion (no chaneg in pH, LES, or mobility), C-300 F-20 R-50 over 30 min, 60-90 min prior

PPI -> binds to proton pump (aka hydrogen, K , ATPase) to inhibit secretion of H ions -> decreasing gastric acid production. px - 40mg, lansoprazole 30mg, IV 1 hr prior, PO 3 hrs prior

Complications, Considerations and Therapies

100

Pneumothorax, discuss diagnosis and treatment

Diagnosis

• Decreased SpO2
• Decreased EtCO2
• Decreased Vt
• No breath sounds or decreased sounds on affected side
• Wheezing
• Increased peak pressures
• Hypertension (if severe)
• If untreated, severe, and pt is desaturating and acidotic -> hypotension - late sign

Txt

• Exsufflate 
• 100% O2
• Turn off anesthesia
• Chest tube placement -> definitive txt
• Supportive -> fluids and pressors PRN

200

CO2 gas embolus, discuss diagnosis and treatment

Diagnosis

• Decreased O2 saturation
• Decreased or loss of EtCO2
• Hypotension or loss of BP
• Mill-Wheel murmur <- specific to CO2 gas embolus
• Detected at the 2nd ICS at the right sternal border

Txt

• Exsufflate 
• 100% O2
• Turn off anesthesia
• Administer fluid/pressors
• Turn pt on Left lateral decubitus position
• Placement of CVC and aspirate
• If airlock is large -> will aspirate air and restore blood flow
• If continuing => ACLS algorithm

300

Contraindications for Laparoscopic Surgery – General

• Coagulopathy
• Comorbidities
• Pulmonary HTN
• Poor EF bc and increase in afterload can cause an CHF
• Severe COPD

400

Postdural puncture HA 

-Discuss etiology

-Clinical presentation

-high risk groups

-txt

• etiology: loss of CSF though the meninges, decrease CSF pressure —> decrease brain buoyancy —> traction intercranial nerves —> headache
• Clinical presenat
  • ion: frontal occipital headache, radiating to neck, shoulder, postural in nature = sitting up or stand makes it worse
  • photophobia, tinnitis,
  • 6hrs —> 2 days post op
• high risk groups:
  • young females (progesterone/estrogen changes affect cranial cavity)
  • large cutting needles
• palliative tx:
  • fluids 3-5L per day
  • bed rest
  • IV caffeine —> stimulates CSF production
  • tylenol
• curative tx: 2person job
  • epidural blood patch: blood clot over the meningeal hole —> decrease CSF leakage
  • 1 try 90% effecting, 2nd time 99% effective
• 
  
  1. place epidural needle one interspace below the interspace where the puncture occurred and leave the needle in place
  2. draw 10-20ml of pts blood from arm and inject the entire volume into the epidural space and withdraw the needle
  3. pt choose any position that is comfortable and remain there for 30-60 mins before ambulating

500

The anesthetic considerations of injecting dye during an intraoperative cholangiogram are:

Bradycardia

Sphincter of Oddi spasm (prevent to allow catheter to pass)

Allergic reaction

Name that landmark (and anatomy)

100

Name the spinal levels that

keeps the diaphragm alive

cardioaccelerator fibers- bradycardia

vasodilation from blocked SNS

C3-C5 (keeps the diaphragm alive)

T1-T4 (cardioaccelerator fibers- bradycardia)

T5-L1 (vasodilation from blocked SNS)

200

For the below surgeries what level block would you consider

perianal/rectal 

lower extremities 

hernia/pelvic/appy

upper abd/CS

perianal/rectal (L1-2)

LE (T10)

hernia/pelvic/appy (T6-8)

upper abd/CS (T4-6)

300

Discuss Celiac reflex (location, stimulus, response, pathway)

• Location: abdomen

• Stimulus: streching of abdominal cavity, traction of the organ, stretch the peritoneum

• Response: PNS pre-dominance

• Neural pathway:

  afferent

  celiac plexus to vagus nerve the brain

  efferent

  brain to vagus to the heart

400

Discuss baroreceptor and chemoreceptor 

Baroreceptor

• location: carotid sinus and aortic sinus (aortic arch)

• Afferent Response ->pressure receptors ->Stretch of Baroreceptors in Carotid Sinus and Aortic Arch (aortic sinus)
• Efferent Response

  Parasympathetic predominance -> decrease heart rate,  decrease contractility= decrease cardiac output

  Sympathetic inhibition

  Heart (¯heart rate, ¯ contractility=¯cardiac output)

  blood vessels (Vasodilation) 

  decrease in Arterial Blood Pressure

Chemoreceptor

• Location: Peripheral and Central

  Peripheral: carotid body and aortic body

  stimulation ( in order): decrease O2 concentration, increase CO2, increase H ion

  • Response: increase sympathetic nervous system stimulation

                     decrease parasympathetic nervous system

• response: excitation of cardiac and resp center in the brain (increase RR and TV)

  Neural pathway: same as baroreceptors

  Anesthetic consideration: hypoxia- most serious issue

  cause extreme SNS dominance to compensate for oxygen delivery for a prolonged period, but eventually cardioacceletory center in the center become so hypoxic, they wil become brady and very soon asystole

  Also inhibited by anesthetics - so waking someone up after general

  1. turn off gas
  2. let the CO2 increase a bit so pt can respond

500

Define and give an example of the different types of dead space: anatomic, alveolar, physiologic

extra points if you know how to calculate Vd (whats the name of the eqn)

anatomic -> air w/in conducting airways (nose and mouth to terminal bronchioles)

alveolar -> alveoli that are ventilated, but not perfused (decreased pulmonary blood flow)

physiologic -> anatomic + alveolar 

Bohrs -> Vd/Vt = ((PaCO2 - PeCO2)/PaCO2)

Overachiever

100

The cricothyroid muscle is innervated by which nerve

superior laryngeal nerve

200

Name the muscles that the recurrent laryngeal nerve innervates

extra points if you can name the muscle action

Posterior cricoarytenoid -> abducts TVC

Lateral cricoaryetenoid -> adducts TVC

thyroarytenoid -> adducts TVC

transverse arytenoid -> adducts FVC

oblique arytenoid -> adducts FVC

thyroepiglottic -> closes laryngeal aditus

aryepiglottic -> closes laryngeal aditus

300

Whats is another name for droperidol 

Discuss the side effects and contraindications

anti-psychotic-butyrophenone

Side effects: 

- decreased BP

-increased HR and dysrhythmias

-CNS -> restlessness, drowsiness

-Extrapyramidial effects: dystonias and akathisia 

Contraindications

- Parkinsons

-SBO

-Seizure d/o

-pre-existing extrapyramidal s/s

-taking phenothiazine and butyrophenone drugs

400

What is the Bezold-Jarisch response?

a triad of severe vasodilation, bradycardia, and hypotension

500

Define Ficks law of diffusion

give the formula

extra points if you can give a clinical application/example

• The rate of diffusion (effusion) of a substance (gas) across a membrane is:

  1. Directly proportional to the:

     (1) surface area of the membrane

     (2) solubility of the gas through the membrane

     (3) the partial pressure gradient of the gas across the membrane

  2. Inversely proportional to the:

     (1) temperature of the gas,

     (2) molecular weight of the gas

     3. the thickness of the membrane

• Diffusion = (Surface Area x Solubility x Partial Pressure Gradient) / (Temperature x Molecular Weight x Distance)

Ex: 

• Surface area

  1. Greater surface area, greater diffusion

  2. Clinical Application: A decreased surface area causes a decrease diffusion of oxygen into the body and decrease diffusion of carbon dioxide out of the body causing hypoxemia and hypercarbia.

  3. Clinical Examples:

     Pulmonary disease (e.g. chronic obstructive pulmonary disease or emphysema), alveolar collapse (e.g. post-operative atelectasis, hypoventilation, pneumothorax), or pulmonary resection (e.g. segmentectomy, lobectomy, pneumonectomy)

Things to know

100

Discuss LEMON and RODS and MOANS (MOONASS)

• LEMON - identify risk for difficult intubation

  L look externally-short neck and chin

  E evaluate thyromental distance, joint extension, TMJ mobility

  M mallampati

  O obstruction - airway obstruction, stridor, neck hematoma, tumor

  N Neck mobility

• RODS predicts ease of supraglottic device placement and ventilation

  
  

  Restricted mouth opening

  Obstruction

  Distorted airway

  Stiff lungs

• The accronym MOOANSS assesses the ability to bag mask ventilate

  
  

  Mask seal (beards, anatomy, NGT)

  Obstruction of airway

  Obesity

  Age > 55

  No teeth

  Stiff lungs

  Sleep apnea/snoring

200

Post MH emergency concerns include

1. Complications with dantrolene (muscle weakness & liver failure)
2. Reoccurence of MH
3. CV status
4. Neurological status
5. Acid/base status
6. DIC
7. renal failure from myoglobinuria

300

Follow the pathway for difficult airway algorithm (bare bones). Start from intubation attempts after induction of GA

1. Initial unsuccessful -> call for help, returning to sponanteous ventilation, awakening the pt

2. Face mask, consider LMA

3. Cric

400

Compare and contrast gas laws (boyles, charles, gay-lussacs)

Boyles P1V1 = P2V2

• At a constant temperature, the pressure of a gas will

  vary inversely with the volume

• At a constant temperature, as volume decreases, pressure

  increases

• At a constant temperature, as volume increases, pressure

Charles V1 / T1 = V2 / T2

1. At a constant pressure, a volume of gas is directly proportional to the temperature
2. At a constant pressure, as temperature increases, volume increases
3. At a constant pressure, as temperature decreases, volume decreases

Gay-Lussacs P1 / T1 = P2 / T2

• At a constant volume, the pressure of a gas is directly proportional to the temperature
• At a constant volume, as temperature increases, pressure increases
• At a constant volume, as temperature decreases, pressure decreases

500

Max allowable blood loss -> Whats the formula?

extra points what are the estimated blood volume for an adult and infant?

MABL = EBV x ((starting hgb - target hgb)/starting hgb))

70ml/kg and 80ml/kg