March Journal Club

[kristenhorsman]

I just recently had a patient whose mom had a history of MH and the daughter was having her first anesthetic. This article is a good review on Malignant Hyperthermia. I have attached the article to the monthly email for you to read and reference for the following two questions:

1. Have you ever personally had a patient who had Malignant Hyperthermia? Can you provide some details of your experience?
2. What are the precautions you take when a patient has a history or family history of MH? What are some of the telltale signs of MH?

[Jessica Hadley]

1. Yes I have taken care of a patient with a h/o MH. For preparation we removed the vaporizers, flushed the machine, changed the circuit, and added the special filters. We kept the MH kit just outside the room used TIVA for the case. Thankfully there were no issues.

2. For a patient with MH or family history of MH, I prep the machine as described above and avoid triggering agents (inhalational anesthetics and succinylcholine). Signs of MH include increased ETco2, tachycardia, tachypnea, elevated temp., skeletal muscle rigidity, hypotension, and dysrhythmias.

[kels]

1. Have you ever personally had a patient who had Malignant Hyperthermia? Can you provide some details of your experience?

I have not cared for a patient who had Malignant Hyperthermia or had a history of MH


2. What are the precautions you take when a patient has a history or family history of MH?

TIVA anesthetic
use the charcoal filter for the ventilator
remove succinylcholine from the anesthesia cart/ make sure access to this drug is limited/ removed
remove vaporizers from the ventilator / room


What are some of the telltale signs of MH?

elevated / increasing ETco2
increase in temperature
tachycardia
skeletal muscle rigidity

[Sarah Jazzar]

1) I had a patient who was anticipated to have MH but after he was discharged and had some genetic testing, we found out he did not have it. WHen preparing for his anesthesia, MH cart was located outside the OR door ready for use. Inhalation agents were removed. Filters were placed in the inspiratory and expiratory limb. Anesthesia machine was flushed. Succs was hidden and taped as a visual reminder.

2) In addition to what was mentioned previously, the procedure should be scheduled as a first case to allow adequate time for preparation of
the anesthesia workstation.
Telltale signs: increased ETCO2, HR, BP, RR, core temp (38.5C); generalized skeletal muscle rigidity, profuse sweating, mottled/cyanotic skin, ventricular dysrhythmias, mixed respiratory/metabolic acidosis.

[Jackie Howell]

1. Have you ever personally had a patient who had Malignant Hyperthermia? Can you provide some details of your experience?
I have not after 6 years of practice. I try to review the dantrolene dosing and treatment recommendations from time to time should that scenario arise in my career.

2. What are the precautions you take when a patient has a history or family history of MH? What are some of the telltale signs of MH?
As others have stated, removing the triggering agents (volatile anesthetic vaporizers & succinylcholine). Flush the machine based on the manufacturers recommendations, add a charcoal filter, change the soda lime, and be prepared with MH cart. Presenting signs: earliest sign is increased ETCO2, tachycardia, tachypnea, masseter spasm. Late signs are hyperthermia. Differential diagnosis to these symptoms could be light anesthesia, thyroid storm, pheocromocytoma, neuroleptic malignant syndrome, serotonin syndrome.

[kristenhorsman]

1. I have never experienced MH, I have only taken care of patients whom their family members have had MH.
2. As others have said, in those instances I have removed the vaporizers and done TIVA, taken sux out of my cart completely, added the charcoal filter and flushed the machine if necessary, changed the soda lime and we had the MH box in the room. The earlier signs of MH included increased end tidal, tachycardia, tachypnea, muscle rigidity and increased core temp.

[BelindaG]

1. No
2.The classic signs and symptoms of MH are due to a hypermetabolic response from the augmented release of calcium from the sarcoplasmic reticulum of the skeletal muscle: unexplained tachycardia, increasing EtCO2 and core temperature (1-2 deg/min!) following the administration of a volatile anesthetic and/or succinylcholine, mixed respiratory/metabolic acidosis/lactic acidosis, arterial hypoxemia, and hyperkalemia.
Optimally these cases should be the first cases of the day and should include new CO2 absorbent, O2 flush per manufacturers recommendation/ charcoal filters in line and vaporizers removed as well as PLAN for TIVA excluding trigger agents.

[Wai-Ling Lo]

1. Have you ever personally had a patient who had Malignant Hyperthermia? Can you provide some details of your experience?
Yes, I have taken care of a patient with a history of MH. We had a detailed preop assessment and reviewed old anesthesia record to see what were the anesthesia plan in the past. We removed all inhalation agent and succinylcholine, changed soda lime absorber and circuit, flushed the machine, placed charcoal filter on both inspiratory and expiratory limb of the circuit, had MH kit in room, and used TIVA for anesthesia. It was an uneventful case.

2. What are the precautions you take when a patient has a history or family history of MH? What are some of the telltale signs of MH?
The precautions were mentioned in the about. Early signs include: Increased end-tidal CO2, unexplained tachycardia, tachypnea (in the spontaneously breathing), generalized skeletal muscle rigidity, rapid increase in core temperature to 38.5ºC, profuse sweating, mottled/cyanotic skin, unstable systemic blood pressure, ventricular dysrhythmias, and mixed respiratory/ metabolic acidosis.

[Amy Swank]

1. Have not had a patient with MH. (thank goodness!)

2. Precautions taken with patient who has family history of MH or has personal history of MH: In addition to the precautions as stated above with regards to first case, flushing out machine (for a long time!) No sux, know where your Dantrolene and Dantrolene helpers are. I have also put the MHAUS phone number in my contacts on my cell phone- learned that little tip from a conference once. When you need it, you don't want to be scrambling to find that resource.
I learned in the article that the pre-administration of sedatives, barbiturates, propofol and early administration of a non-depolarizing muscle relaxant may delay or prevent the development of MH (although this should never be relied upon in the know susceptible individual- it is a helpful hint. In addition, conditions distinctly linked to MH include King-Denborough syndrome, central core disease, and Evans syndrome. Also, a rare subgroup of MH susceptible patients my develop MH to triggers such as environmental heat vigorous exercise and anxiety.

[Tracey Trainum]

1. Fortunately, I have never cared for a patient with MH or a patient with any risks/family history of MH
2. Precautions:
- First case of day - this allows for appropriate set up for the case as well as to provide an extra layer of safety precautions by ensuring the anesthesia machine is "clean" (not used on any other patients and is devoid of vaporizers, gases etc), also ensures the room is "clean' and devoid and of any anesthetic vapors or gas.
- Machine preparation: removal of all vaporizers, new CO2 absorber (prevent any possible rebreathing of any gases from exhausted system. Anesthesia machine should be flushed with high flow oxygen per manufacturer's guidelines which can take 10-100 minutes. New circuit placed with use of charcoal filters placed between inspiratory and expiratory limbs- this removes any residual volatile agent and ensuring agent concentration remains less than 5 ppm without any effect on nitrous oxide concentration.
- MH cart with two full rounds of Dantrolene on standby
- Avoid triggering agents for the case including inhalational agents and succinylcholine. Use regional when possible.
- "stress free" anesthetic to minimize tachycardia and stress response. There is a small subgroup of MH susceptible patients that may experience MH without a triggering agent. Administering an anxiolytic at start of case to help calm stress response can help avoid this.
- Close PACU monitoring for signs of hypermetabolism (unexplained tachycardia and fever). Urine can be tested for presence of myoglobin (signals presence of hypermetabolism)

Signs of MH:
Increased CO2
Unexplained tachycardia
Tachypnea
Muscle rigidity (masseter muscle rigidity on intubation can be a sign)
Rapid increase in core temp
Sweating
Dysrhythmias
Mixed respiratory/metabolic acidosis

Late signs:
Hyperkalemia
Elevated CK
Myoglobinuria
DIC
Cardiac arrest

[aileenm4]

I have never had a true MH event ( knock on wood), but have taken care of patients with family history
to prepare, hope its a first case start regardless, I have new soda lime, fresh circuit, , charcoal filters and flush machine as directions on filters stat after removing vaporizors off machine, haveMH box in room and do the case with non triggering meds TIVA
s/s tachycardia, rise in ETCO@ regardless of increase ventilation, ridginess, increase temp, increase K, arrythmias