Malignant Hyperthermia - 8
The Caffeine-Halothane Contracture Test (CHCT)
The muscle biopsy and the CHCT should be performed at centers with appropriate familiarity and expertise.
- the current "gold standard" test for MH.
- recently standardized in North America
- the usual biopsy site is the quadriceps muscle (vastus lateralis or medialis)
- Because of the size of the biopsy (2 Grams), it is recommended that patients weigh at least 20 kg. Most centers will not biopsy patients < 5 yrs old.
- 2 to 3 months should have elapsed since the most recent (presumed) MH episode
- anesthesia for biopsy
- use nontriggering agents
- regional anesthesia often used (nerve blocks or neuraxial block)
- avoid direct infiltration of muscle with local anesthetic
- dantrolene should be avoided
- the muscle tissue should be handled as little as possible and not stretched
- the test should be performed within 5 hours after the biopsy
- costs approximately $6,000 - $10,000 (covered by most US health insurance companies)