Malignant Hyperthermia Flashcards
What is Malignant Hyperthermia?
A potentially fatal inherited disorder that is associated with the use of anesthetic gases and the depolarizing muscle relaxant Succinylcholine.
What do the anesthetic gases do to cause MH in a patient?
They cause a series of chain reactions that increase the intracellular calcium ion concentration. This causes a severe hypermetabolic state where the skeletal muscles become rigid, the HR increases, the body metabolism increases, and the body temp increases, causing a life threatening situation
What is the mortality rate for patients experiencing MH, if there is early recognition and prompt treatment?
Less than 5 %
When can MH develop?
At any point within 1 hour of anesthesia up to 72 hours post exposure.
What are often the first signs of an impending MH crisis?
- Unexplained tachycardia
- Premature ventricular contractions
- Muscle rigidity, or continuous overall rigidity
- Increased ETCO2
What are late s/sx of MH?
- Increased core body temperature (as much as 1.8-3.6 degrees F every 5 minutes)
- Myoglobinuria
- Renal function alterations
- Rhabdomyolysis.
What should be done if there is a severe or sudden onset of MH under Anesthesia?
- Call for assistance and halt procedure unless emergent
- Use non-triggering anesthesia agents
- Have anesthesiologist discontinue all MH triggering agents and succinylcholine
- Hyperventilate the pt with 100% oxygen at 10 LPM
- Bring in MH cart and obtain vials of IV dantrolene sodium from cart
- Reconstitute IV Dantrolene Sodium by mixing powder with recommended amount of sterile water, and shake vigorously.
- Administer at 2.5mg/kg-10mg/kg until the patient decreases symptoms
- Replenish supply in case needed again in next 72 hours
- Obtain blood gases, electrolytes and BG
- Treat metabolic acidosis, hyperkalemia, arrhythmias.
- Monitor pt core temperature and begin cooling measures until pt reaches 100.4
- Assist if arterial or central line is needed.
- Transfer to PACU or CCU for at least 24 hours until pt is stable.
Can MH events relapse?
Yes 25% of patients with MH relapse, and the relapses can be fatal.
Should patients with a history of MH wear a medical bracelet?
yes
How should Hyperkalemia be treated during MH?
- Calcium Chloride 10mg/kg, up to max of 2000mg
OR
Calcium Gluconate 30mg/kg, upt o 3000mg - Give Sodium Bicarbonate
- Administer 10 units of regular insulin in 50ml of 50% dextrose
(Insulin shifts potassium back into the cells; calcium treats cardiac toxicity; sodium bicarbonate treats acidosis.)
How should life-threatening arrhythmias be treated during MH?
IV lidocaine hydrochloride 2%
OR
Procainamide
(DO NOT give CCB because they may increase current hyperkalemia or cause cardiac arrest in the presence of dantrolene.)
How should renal function be monitored during MH?
- Insert a urinary catheter with a temperature sensor to monitor UO of at least 2ml/kg/hr
- Administer mannitol and furosemide, up to four doses each.
DO NOT ADMIN LR, it may contribute to the patient’s acidosis.
Calculate the mannitol dose based on the mannitol contained in the dantrolene sodium solution.
