Anesthesia & Pharmacology

Question 1

Cormack-Lehane Classification

Answer 1

• Grade 1: Full view of glottis
  
  • Grade 2a: Partial view of glottis
  • Grade 2b: Only posterior extremity of glottis seen or only arytenoid cartilages
  • Grade 3: Only epiglottis seen, none of glottis seen
  • Grade 4: Neither glottis nor epiglottis seen

Question 2

Difficult intubation

Answer 2

= LEMON = Look externally / Evaluate 3-3-2 rule / Mallampati score / Obstruction / Neck Mobility

Question 3

Difficult BVM

Answer 3

= BONES = Beard / Obese / No teeth / Elderly / Sleep Apnea / Snoring

Question 4

Difficult surgical airway

Answer 4

= SHORT = Surgery / Hematoma / Obesity / Radiation distortion or deformity / Tumor

Question 5

• Propofol - Receptors and Dose

Answer 5

GABA + NMDA + Mu + Histamine + Serotonin

dose: 2-4mg/kg induction then 50 mcg/kg/min

Question 6

ketamine dosage

Answer 6

• dose: 1-2mg/kg induction (dose comes in 50mg vial) 0.1-5 mcg/kg/min maintenance

Question 7

Fentanyl dosage

Answer 7

• dose: 1 to 2 mcg/kg (25 to 100 mcg)

Question 8

Morphine Dose

Answer 8

• Dose: 2-5mcg/kg induction & 50-100mcg/hr maintenance

Question 9

Midaz Dose

Answer 9

• Dose: 0.2mg/kg induction loading; 0.01 to 0.05 mg/kg Δ(0.5 to 4 mg) / infusion 0.02 to 0.1 mg/kg/hour infusion (2 to 8 mg/hour)

Question 10

succ contraindications

Answer 10

• Malignant hyperthermia history (personal or family)
  
  • myopathic metabolic disorder = sympathetic hyperactivity, muscular rigidity, acidosis, & hyperthermia
• Neuromuscular disease involving denervation (note SCh is safe in myasthenia gravis)
• Muscular dystrophy
• Stroke over 72 hours old
• Rhabdomyolysis
• Burn over 72 hours old
• Significant hyperkalemia

Question 11

roc dose + mechanism

Answer 11

• 0.8-1.2 mg/kg onset <1 min - dur 45min

ACh antagonists - competitive blocker - non-depolarizing

Question 12

succ dose

Answer 12

ACh agonists - depolarizing

• 1.5mg/kg duration 8 min

Question 13

Vasopressors and Doses

Answer 13

• Phenylephrine 20-200mcg/min 50-100mcg push
• Norepinephrine 0-20mcg/min
• Vasopressin 0.01-0.04 units/min

Question 14

Inotropes and Doses

Answer 14

• Epinephrine 0-20mcg/min
• Milrinone 0.125-1.0mcg/kg/min
• Dopamine 0-10mcg/kg/min
• Dobutamine 0-20mcg/min

Question 15

MOI of

• Dopamine
• Vasopressin
• Milrinone

Answer 15

Dopamine = ↑norepinephrine release = ↑cAMP = vasoconstrictor

• Vasopressin = V1 receptor on smooth muscles = vasoconstrictor
• Milrinone = inhibits PDE3 = ↑cAMP = ↑ Ca2+ = ↑cardiac muscle contractility + ↑smooth muscles relaxation in vasculature = ↓SVR
  • cAMP = ↑ Ca2+
  • PDE breaks down cAMP into AMP

Question 16

Midaz advantages and disadvantages

Answer 16

• Advantage: A potent amnestic and anxiolytic agent with an immediate onset of action and a short duration of effect when administered short­term (<48 hours)
• Disadvantages: Hepatically metabolized by CYP3A4 to active metabolites that may accumulate and cause prolonged sedation if delivered long­term. Half­life may be prolonged in critically ill patients with hepatic or renal impairment. Risk of delirium. Also, it interacts with drugs used in the ICU (eg, some antiretrovirals, azole antifungals) that alter CYP metabolism such that excess sedation can occur with concomitant use of midazolam and drugs metabolized by CYP3A4.

Question 17

Midaz MOI

Answer 17

• GABA - inhibitory terminals produce GABA (G-aminobutyric acid) - ↓ Ca influx during AP invasion of presynaptic axon = blocks transmitter release from terminal = presynaptic inhibition (inhibitory neurotrasmitters cause HYPERpolarization via transient ↑ permeability to Cl (moves in) or K (moves out) = moves away from threshold
  
  • Cortex & RAS
  • Anterograde NOT retrograde amnesia
  • PARADOXICAL responce - they are disinhibited = can be restless and more agitated
  • benzo’s can worsen long term cognitive function in elderly - i.e. dumbdumbs for the next 6 months

Question 18

Ketamine Advantages and Disadvantages

Answer 18

• Advantages: A potent dissociative sedative­anesthetic with marked analgesia that maintains cardiac output and mean arterial pressure without inhibition of respiratory drive. Doesnot inhibit protective reflexes.
• Disadvantages: Sympathetic stimulation (ie, increased heart rate and myocardial oxygen demand, elevated intracranial pressure and systemic blood pressure), hallucinations, delirium upon withdrawal, tonic­clonic movements, dissociative experiences, unpleasant recall, hypersalivation, nausea, and vomiting.

Question 19

Ketamine MOI

Answer 19

• “short-acting non-barbiturate anaesthetic” = NMDA Uncompetitive Antagonist
• NMDA (N-methyl-D-asparate) receptor ANTAGONISM + CNS sympathetic outflow stimulation
  
  • NMDA = cerebrum/cortex/thalami/brainstem = excitatory receptor = must remain open to transmit signals from spinal column into brain (usually open w Glutamate) = closed to pain sensation in dorsal horn neurons

Question 20

Propofol Advantages and Disadvantages

Answer 20

• advantages: potent sedative­hypnotic associated with an immediate onset and rapid awakening upon discontinuation when administered for short­term use. Metabolism is reportedly unaltered in hepatic or renal impairment and subject to few significant drug interactions. Infusion is readily titratable to desired depth of sedation, minimizing risk of oversedation. Propofol effectively decreases intracranial pressure, lowers cerebral metabolism, controls intractable seizures
• disadvantages: hypotension, bradycardia, respiratory depression, decreased myocardial contractility, elevated triglycerides, and rarely propofol infusion syndrome, potential allergens (egg, soy, peanut). No analgesic effects.