Anesthetic Agents, Adjuncts, and Techniques
Agents, adjuncts and techniques
The Anesthetic Agents, Adjuncts, and Techniques domain tests IV and inhalational agents, opioids, neuromuscular blockers, reversal, local anesthetics and monitored anesthesia care. Expect dose calculations and contraindications.
- Induction: propofol 1.5–2.5 mg/kg (hypotension, pain on injection); ketamine 1–2 mg/kg (bronchodilation, emergence); etomidate 0.2–0.3 mg/kg (hemodynamic stability, adrenal suppression); midazolam as adjunct.
- Neuromuscular blockade: succinylcholine 1–1.5 mg/kg (depolarizing; contraindicated in hyperkalemia, burns beyond 24–48 h, denervation, malignant hyperthermia susceptibility); rocuronium 0.6–1.2 mg/kg. Sugammadex 2–4 mg/kg for routine reversal, 16 mg/kg for immediate reversal of 1.2 mg/kg rocuronium.
- Neostigmine 0.03–0.07 mg/kg with glycopyrrolate or atropine; confirm train-of-four.
- Local anesthetics: lidocaine maximum 4.5 mg/kg plain, 7 mg/kg with epinephrine; bupivacaine 2–3 mg/kg; 1% = 10 mg/mL, so calculate volume carefully.
- MAC and context-sensitive half-time explain inhalational potency and prolonged infusions.
Worked example
A 70 kg patient needs 2% lidocaine without epinephrine. Maximum dose = 4.5 mg/kg × 70 = 315 mg. Concentration 2% = 20 mg/mL. Maximum volume = 315/20 = 15.75 mL. With epinephrine, maximum = 7 × 70 = 490 mg, or 24.5 mL. The reasoning hinges on converting percent concentration to mg/mL before dividing.
Traps that cost marks
Do not give succinylcholine in a patient with a recent spinal cord injury or major burns without considering hyperkalemia. Do not confuse mg with mL. Do not assume sugammadex reverses succinylcholine; it does not.