Surgery- Intra & Postoperative

Question 1

Presentation of malignant hyperthermia

Answer 1

Sudden-onset muscle rigidity
Muscle hypermetabolism (fever, tachycardia)
Hypercarbia
Tachypnea
Difficulty Ventilating 
Rhabdomyolysis

Question 2

Management of malignant hyperthermia

Answer 2

Immediate cessation of anesthetic
Adm. of Dantrolene
Supportive care

Question 3

Mechanism of succinylcholine anesthesia

Answer 3

Depolarizing neuromuscular blocker.
Binding to postsynaptic acetylcholine receptors —> trigger influx of Na ions and efflux of k ions through ligand- gated ion channels.

Temporary paralysis (delayed depolarization of skeletal muscles)>

Question 4

Succinylcholine onset and offset

Answer 4

Rapid onset (45-60 seconds)
Rapid offset (6-10min)

Used in rapid sequence intubation

Question 5

ADR succinylcholine

Answer 5

Life threatening cardiac arrhythmia due to severe hyperkalemia

Question 6

Which patients are at increased risk of hyperkalemia arrhythmia with succinylcholine?

Answer 6

Pts with hyperkalemia and up regulation of acetylcholine receptors:

Extensive skeletal muscle injury
Burn injury
Disuse muscle atrophy
Degenerative muscle atrophy (stoke, GBS, polyneuropathy)

Question 7

What anesthesia should be used in patients with unregulated acetylcholine receptors?

Answer 7

Nondepolarizing neuromuscular blocking agents (e.g. vecuronium, rocuronium)

Question 8

Mechanism of arrhythmia risk with succinylcholine and extensive muscle injury

Answer 8

Extensive crush injury causes skeletal muscle lysis (rhabdomyolysis)—> release of K —> risk of hyperkalemia.

Muscle injury—> upregulation of postsynaptic acetylcholine receptors—> massive efflux of K with succinylcholine.

Question 9

ADR of propofol

Answer 9

Severe hypotension due to myocardial depression.

Contraindicated in patients with ventricular systolic dysfunction