Malignant hyperthermia — susceptible patient

Top concerns

1. 1.Triggers are exactly two classes: volatile anesthetics and succinylcholine — everything else is fair game
2. 2.Machine preparation: remove/disable vaporizers, flush per manufacturer guidance or use activated-charcoal filters, fresh circuit and absorbent
3. 3.Dantrolene immediately available (full supply, commonly stocked as 36 vials of the 20 mg formulation; initial dose 2.5 mg/kg IV)
4. 4.Earliest signs: unexplained rising EtCO₂ + tachycardia; rigidity and temperature are later
5. 5.Masseter muscle rigidity after succinylcholine historically flagged susceptibility — treat as a warning event
6. 6.Family history counts: RYR1 inheritance is autosomal dominant — a first-degree relative's event changes today's plan

Drug do's and don'ts

• AVOIDAll volatile agents— Triggers. TIVA (propofol + opioid ± ketamine/dexmedetomidine) instead.
• AVOIDSuccinylcholine— Trigger. Rocuronium covers RSI needs (sugammadex for reversal).
• PREFERNitrous oxide, local anesthetics, nondepolarizing NMBDs— All non-triggering — regional/neuraxial fully acceptable.

Airway & positioning

• No airway implications from susceptibility itself — plan per patient as usual

Pearls

• MHAUS hotline: 1-800-644-9737 — put it on the board before a susceptible case.
• Rising EtCO₂ that outruns your minute-ventilation math is the alarm — don't wait for temperature.

Suggested reading

• MHAUS professional guidelines (mhaus.org)
• Miller's Anesthesia, 9e

Educational quick-reference only — defer to clinical judgment, institutional protocols, and the primary texts above.