Last Updated: 1/27/2010
This brochure is no longer available separately. It can only be purchased in our new "Guide to Malignant Hyperthermia In an Anesthesia Setting" brochure.
HOW IS THE ANESTHESIA MACHINE PREPARED FOR MHS PATIENTS?
Ensure that anesthetic vaporizers are disabled by removing, or taping in the "OFF" position.
Most vaporizers have a significant reservoir of anesthetic that cannot be drained, thus draining is not an acceptable choice. Some Hotline consultants recommend changing CO2 absorbent (soda lime or baralyme). Flow 10 L/min O2 through circuit via the ventilator for at least 20 minutes. If fresh gas hose is replaced, 10 minutes is adequate. During this time a disposable, unused breathing bag should be attached to the Y-piece of the circle system and the ventilator set to inflate the bag periodically. Use new or disposable breathing circuit. Use the expired gas analyzer to confirm absence of volatile gases, as some newer machines are not so easily cleaned of volatile agents. Newer anesthesia “work stations” may require up to 60 minutes for purging residual gases; consult manufacture information and information on the MHAUS website.
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HOW DOES THE ANTIDOTE DANTROLENE WORK?
Dantrolene is the only currently accepted specific treatment for MH. Dantrolene suppresses the exaggerated rise in muscle cell calcium that seems to trigger MH by binding to the calcium channel site in muscle that is responsible both for calcium release and, likely, calcium entry into the cell. Current evidence indicates that during the initiation of MH, intracellular calcium levels rise due both to abnormal release from the sarcoplasmic reticulum and calcium entry from the extracellular space; dantrolene restores the balance between calcium release, entry and uptake.
Dantrolene does not significantly potentiate the effects of non-depolarizing relaxants or interfere with reversal of muscle relaxants unless there is an associated neuromuscular disease. When dantrolene is used with non-depolarizing muscle relaxants, care should be taken to ensure muscle strength has returned prior to extubation
Dantrolene may cause significant muscle weakness in patients with pre-existing muscle disease and should be used with extreme caution in those patients. Sterile phlebitis may follow administration of dantrolene, and while not delaying administration; dantrolene should be infused through the largest possible vein. The sterile phiebitis can be later treated with warm soaks and elevation. When used with calcium channel blockers (verapamil or diltiazem), dantrolene may produce life-threatening hyperkalemia and myocardial depression. Otherwise there does not appear to be significant negative interaction with other drugs.
Once a patient has been successfully treated for 36 hours with intravenous dantrolene, he/she may be switched to oral dantrolene until the CK level is trending down and there is no further evidence of acidosis or hypermetabolism and temperature spikes.
WHO SHOULD STOCK DANTROLENE AND HOW MUCH?
All facilities, including ambulatory surgery centers and offices, where MH triggering anesthetics (isoflurane, desflurane, enflurane, sevoflurane, methoxyflurane, halothane and succinylcholine) are administered, should stock a minimum of 36 vials of dantrolene, along with the other drugs and devices necessary to treat an MH reaction. If none of these agents are ever in use in the facility, then dantrolene need not be kept at hand.
WHERE SHOULD DANTROLENE BE KEPT?
Dantrolene should be kept in or very close to the operating room, so that it is available immediately if MH occurs. Dantrolene may be stored at room temperature. A supply of sterile water for injection USP (without a bacteriostatic agent) should be kept nearby to mix with dantrolene before injection (60 ml/vial); the water for diluting dantrolene should not be stored in a refrigerator; it may be stored in a warming cabinet designed to maintain fluid temperatures between 35-40o° C. All anesthesia and surgical team members should be aware of this location.
ARE THERE ANY ADVANTAGES IN SHARING A SUPPLY OF DANTROLENE?
No. Minutes count in an MH emergency.
The Professional Advisory Council of MHAUS strongly recommends that an adequate supply of dantrolene be available wherever general anesthesia is administered. Responsibility for treatment rests with the facility where the surgery is performed. Sharing is not a good alternative.
CAN WARMING THE STERILE WATER FACILITATE MIXING?
MHAUS recommends using the manufacturer's instructions regarding the reconstitution of dantrolene. MHAUS acknowledges that warmed diluent (37-39°C) may expedite the reconstitution and delivery of dantrolene during an MH crisis, but we are unable to unequivocally recommend this practice as there is no evidence such practice would result in an improvement in clinical outcome. If used, warmed diluent (without bacteriostatic sterile water, only) should not exceed 39°C. Great care must be taken when using warmed fluids for intravenous administration, as various warming methods may produce wide variation in temperatures, and a potential for vascular burns exists if too hot a solution is used. While there is no published evidence, we do not believe that warmed solutions change the chemistry or structure of dantrolene.
WHAT IS THE COST OF DANTROLENE?
At this printing, the cost of maintaining 36 vials in stock is approximately $2,400* per year, a tiny fraction of most facility budgets and a very small price to pay for patient safety. The cardiac defibrillator, like other emergency drugs in an institution's "code carts" is a necessary emergency tool in all OR suites, is seldom used, and is paid for in time by each patient's charges. In fact, many hospitals have 30-50 such units deployed at all times. Dantrolene, an emergency drug that is kept in only one location within most institutions, is an appropriate parallel to that situation and, in this context, is relatively inexpensive when prorated.
Therapy should be aimed at prompt treatment of hyperkalemia, administration of dantrolene, hyper-ventilation, and cooling to target core temperature 38°C.
1. Dantrolene - 36 vials should be available in each institution where MH can occur, each to be diluted at the time of use with 60 ml sterile water for injection USP (without a bacteriostatic agent).
2. Sterile water for injection USP (without a bacteriostatic agent): Each vial of dantrolene should be reconstituted by adding 60 ml of sterile water for injection USP (without a bacteriostatic agent) and the vial shaken until the solution is clear. If the MH episode is proceeding rapidly, simply mix and inject. It is mandatory to get dantrolene to its effective site, the skeletal muscle. Daly during a fulminant episode may involve a failing circulation and lack of blood flow to muscle. This water should be at room temperature or may be pre-warmed to body temperature (38-39°C or 98-99° F). We advise that the sterile water be stored in 100 ml vials, not bags, to avoid accidental IV administration of this hypotonic solution.
3. Sodium bicarbonate (8.4%) - 50 ml x 5
4. Furosemide 40 mg/amp x 4 ampules
5. Dextrose 50% - 50 ml vials x 2
6. Calcium chloride (10%) 10 ml vial x 2
7. Regular insulin 100 units/ml x 1 (refrigerated)
8. Lidocaine* for injection, 100 mg/5 ml or 100 mg/10 ml in preloaded syringes (3). Amiodarone is also acceptable. ACLS protocols, as prescribed by the AHA, would be followed when treating all cardiac derangements caused by MH.
* Lidocaine or procainamide should not be given if a wide-QRS complex arrhythmia is likely due to hyperkalemia; this may result in asystole.
GENERAL EQUIPMENT
1. Syringes (60 ml x 5) to dilute dantrolene
2. Mini-spike® IV additive pins x 2 and Multi-Ad fluid transfer sets x 2 (to reconstitute dantrolene). Call MHAUS for ordering information.
3. Intravenous catheters 16G, 18G, 20G, 2-inch; 22G, 1-inch; 24G, 3/4-inch (4 each) (for IV access and arterial line)
4. NG tubes: (sizes appropriate for your patient population)
5. Toomy irrigation syringes (60 ml x 2) with adapter for NG irrigation
6. Micro drip IV set (x 1)
Monitoring Equipment
1. Esophageal or other core (e.g., nasopharyngeal, tympanic membrane, rectal, bladder, pulmonary artery catheter) temperature probes
2. CVP kits (sizes appropriate to your patient population)
3. Transducer kits for arterial and central venous cannulation
Nursing Supplies
1. A minimum of 3,000 ml of refrigerated cold saline solution for IV cooling
2. Large sterile Steri-Drape (for rapid drape of wound)
3. Urine meter x 1
4. Irrigation tray with piston (60cc irrigation) syringe
5. Large clear plastic bags for ice x 4
6. Small plastic bags for ice x 4
7. Bucket for ice
8. Test strips for urine analysis
Laboratory Testing Supplies
1. Syringes (3 ml) for blood gas analysis or ABG kits x6
2. Blood specimen tubes (each test should have 2 pediatric & 2 large tubes): (A) for CK, myoglobin, SMA 19 (LDH, electrolytes, thyroid studies); (B) for PT/PTT, fibrinogen, fibrin split products; and lactate; (C) CBC, platelets; (D) blood gas syringe (lactic acid level) If no immediate laboratory analysis is available, samples should be kept on ice for later analysis. This may well prove useful on retrospective review and diagnosis. Blood cultures are very useful and should be included to rule out bacteremia.
3. Urine collection container for myoglobin level. Pigrnenturia (e.g , brown or red urine and heme positive dipstick) indicates that renal protection is mandated, when the urine is centrifuged or allowed to settled, and the sample shows clear supernatant, i.e., the coloration is due to red cells in the sample.
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