Anesthesia Emergency: Malignant Hyperthermia — Transcript

Full transcript

1. 0:00i'm max feinstein and i'm an anesthesia
2. 0:02resident at the mount sinai hospital in
3. 0:03new york city it's been said that
4. 0:05anesthesiology is characterized by hours
5. 0:08of boredom punctuated by moments of
6. 0:10terror and in this video i'm going to be
7. 0:13discussing something that can lead to
8. 0:14moments of terror a rare but potentially
9. 0:17life-threatening condition called
10. 0:19malignant hyperthermia if you find this
11. 0:21video interesting or helpful i'd really
12. 0:23appreciate it if you liked it and
13. 0:24subscribe to the channel let's dive in
14. 0:30malignant hyperthermia can be defined as
15. 0:33a life-threatening
16. 0:34hyper-metabolic state characterized by
17. 0:37dysregulated calcium which as you may
18. 0:40know plays a paramount role in muscle
19. 0:43contraction who does malignant
20. 0:44hyperthermia affect it affects people
21. 0:46who are both genetically susceptible and
22. 0:49have received exposure to a triggering
23. 0:52agent and those include a depolarizing
24. 0:54neuromuscular blocking drug called
25. 0:56succinylcholine as well as several
26. 0:59anesthetic gases including isofluorine
27. 1:02sibo fluorine and despalurin and also
28. 1:05halothane however halothane is not used
29. 1:08very commonly in the united states
30. 1:09although it is currently used in a
31. 1:11number of other places around the world
32. 1:13so depending on where you're practicing
33. 1:14this might be relevant how frequent is
34. 1:16it to be genetically susceptible to
35. 1:18malignant hyperthermia it's more
36. 1:20prevalent in kids with an estimated
37. 1:22prevalence of 1 in 15 000 pediatric
38. 1:26patients and less prevalent in adults
39. 1:28with an estimated prevalence of 1 in 40
40. 1:31000 patients it's really important to
41. 1:33keep in mind that even if someone is
42. 1:35genetically susceptible to malignant
43. 1:36hyperthermia that does not necessarily
44. 1:39mean that exposure to a triggering agent
45. 1:41is going to cause an episode of
46. 1:43malignant hyperthermia and that brings
47. 1:45me to my next point which is how often
48. 1:47an anesthesiologist might actually
49. 1:49expect to see malignant hyperthermia a
50. 1:51study that was published about 10 years
51. 1:53ago found that there were 84 identified
52. 1:56and reported events of malignant
53. 1:57hypothermia that occurred over a
54. 1:59five-year period and out of those 84
55. 2:02events eight of those patients died that
56. 2:04means that over the study period about
57. 2:061.6 people died in the united states
58. 2:10every year from an episode of malignant
59. 2:11hyperthermia by way of comparison every
60. 2:14year in the united states an average of
61. 2:1662 people are killed from a lightning
62. 2:19strike that means that on average in a
63. 2:22given year in the united states a person
64. 2:24is about 39 times more likely to die
65. 2:27from a lightning strike than they are
66. 2:29from an episode of malignant
67. 2:30hyperthermia and the really important
68. 2:32qualifier for that is that if an
69. 2:34anesthesiologist is prepared
70. 2:36then identifying and treating malignant
71. 2:38hyperthermia can be life-saving how do
72. 2:40you treat a patient who you think may
73. 2:42have malignant hyperthermia well first
74. 2:44it's important to understand what
75. 2:46exactly is going on when an episode of
76. 2:48malignant hyperthermia occurs if someone
77. 2:50who's genetically susceptible is exposed
78. 2:53to a triggering agent it may cause an
79. 2:56uncontrolled release of calcium in cells
80. 2:59basically throughout the body this
81. 3:01uncontrolled calcium release occurs in
82. 3:03muscles throughout the body causing them
83. 3:05to contract which is a process that uses
84. 3:08a lot of energy a lot of oxygen and
85. 3:11produces a lot of carbon dioxide or co2
86. 3:14there are a number of significant
87. 3:16complications that can arise from an
88. 3:17episode of malignant hyperthermia and
89. 3:20one that can manifest immediately and be
90. 3:22life-threatening is hyperkalemia which
91. 3:25is elevated potassium levels throughout
92. 3:27the body which can occur because
93. 3:29potassium regulation is also thrown off
94. 3:32during an episode of malignant
95. 3:33hyperthermia this in and of itself can
96. 3:35lead to a fatal cardiac arrest just as
97. 3:38an aside for anyone thinking about a
98. 3:40career in anesthesiology it's worth
99. 3:42pointing out that we are experts in
100. 3:44resuscitation including
101. 3:46advanced cardiac life support so if
102. 3:48there is a cardiac arrest or any other
103. 3:51type of life-threatening event that
104. 3:52occurs in or near an operating room then
105. 3:55we are very well equipped to handle that
106. 3:57other potential complications of
107. 3:58malignant hyperthermia include a
108. 4:00condition called disseminated
109. 4:01intravascular coagulation which in and
110. 4:04of itself can be fatal as well as organ
111. 4:06failure of basically any organ
112. 4:09especially including the brain as well
113. 4:11as the kidneys studies show that the
114. 4:13mortality rate associated with an
115. 4:15episode of malignant hyperthermia ranges
116. 4:17from 5
117. 4:18to 30 percent
118. 4:20where faster time to treatment is going
119. 4:22to lead to improved survival so how do
120. 4:25you take care of a patient who may have
121. 4:27malignant hyperthermia and be
122. 4:29susceptible to having an event during
123. 4:31your anesthetic the first consideration
124. 4:33is to make your patient the first
125. 4:36patient of the day reason being that
126. 4:38studies have demonstrated that overnight
127. 4:41the triggering agents that are present
128. 4:43inside of anesthesia machines actually
129. 4:45degrade when the machine is not in use
130. 4:48so you don't want to be using a
131. 4:50triggering agent like isofluorine or
132. 4:52sibo chlorine throughout the course of
133. 4:53the day and then take care of a patient
134. 4:56using that same machine which may have
135. 4:59some lingering molecules of a triggering
136. 5:01agent inside of it then as far as the
137. 5:03machine itself is concerned you actually
138. 5:05want to remove every replaceable part
139. 5:07that could potentially have come into
140. 5:09contact with the triggering agent that
141. 5:11includes the entire breathing circuit
142. 5:13the absorbent and if it's possible to
143. 5:16remove the vaporizers from the machine
144. 5:18then you should go ahead and take those
145. 5:20off if it's not possible to remove the
146. 5:22vaporizers then at the very least cover
147. 5:25them in red tape so it's abundantly
148. 5:27clear that they shouldn't be used
149. 5:29then if you have charcoal filters
150. 5:31available go ahead and place those on
151. 5:33your circuit and flush the circuit and
152. 5:36the anesthesia machine for a certain
153. 5:37period of time depending on whether you
154. 5:39have filters on and what type of
155. 5:41anesthesia machine you're using i should
156. 5:43point out that if you're not able to use
157. 5:45charcoal filters then it's really
158. 5:47important to keep your gas flows high
159. 5:50throughout the course of the anesthetic
160. 5:52because it's possible for triggering
161. 5:54agents to re-accumulate if the flows
162. 5:56aren't high enough a big challenge for
163. 5:59anesthesiologists is that an episode of
164. 6:01malignant hyperthermia isn't always very
165. 6:03easy to identify but if you think that
166. 6:06your patient may be having an episode
167. 6:07it's extraordinarily important to
168. 6:09initiate treatment as early as possible
169. 6:12due to the muscle contractions that
170. 6:13happen throughout the body during an
171. 6:15episode of malignant hyperthermia one of
172. 6:17the signs that may tip you off that your
173. 6:20patients having an episode is muscle
174. 6:22rigidity throughout the body and
175. 6:23especially in the masseter muscles of
176. 6:25the face keep in mind that muscle
177. 6:27rigidity doesn't always happen during
178. 6:29malignant hyperthermia and also keep in
179. 6:31mind that other conditions like
180. 6:32neuroleptic malignant syndrome can also
181. 6:34cause muscle rigidity so this in and of
182. 6:37itself isn't going to be the single
183. 6:38diagnostic indicator that a patient's
184. 6:41actually having an episode another
185. 6:42really important sign that your patient
186. 6:44may be having an episode of malignant
187. 6:46hyperthermia is hypercarbia which means
188. 6:49increased levels of co2 monitoring a
189. 6:51patient's exhaled co2 is one of the
190. 6:54american society of anesthesiologists
191. 6:56standards of care so we're always
192. 6:58watching a patient's end tidal co2 which
193. 7:00means what they're breathing off and so
194. 7:03if that in tidal co2 is rising and
195. 7:05especially if a patient is intubated and
196. 7:08we try to breathe off that co2 by either
197. 7:11increasing the respiratory rate and or
198. 7:13increasing the tidal volumes but the co2
199. 7:16is not going down then we have another
200. 7:18indicator that the patient may be having
201. 7:20an episode of malignant hyperthermia
202. 7:22other less specific signs of malignant
203. 7:24hyperthermia meaning ones that can be
204. 7:27present in a number of different
205. 7:28conditions include tachycardia or an
206. 7:31increased heart rate as well as an
207. 7:33increased temperature hence the name
208. 7:34malignant hyperthermia keep in mind that
209. 7:37monitoring temperature is part of the
210. 7:39american society for anesthesiologists
211. 7:41standards for basic anesthetic
212. 7:43monitoring overall making an
213. 7:45intraoperative diagnosis of malignant
214. 7:46hyperthermia can be pretty hard to do
215. 7:49but you have a higher likelihood of
216. 7:50making correct diagnosis that there are
217. 7:52at least two signs that are present as
218. 7:54far as timing goes the majority of
219. 7:56episodes of malignant hyperthermia occur
220. 7:59in the operating room during the
221. 8:00delivery of anesthesia and only a small
222. 8:03proportion of them occur after
223. 8:04anesthesia has finished in the
224. 8:06post-anesthesia care unit if you're
225. 8:08delivering anesthesia and you suspect
226. 8:11that a patient is undergoing an episode
227. 8:13of malignant hyperthermia then the very
228. 8:15first thing that you need to do is
229. 8:17discontinue whatever triggering agents
230. 8:19are currently being administered that
231. 8:21might include isofluorine or sibo
232. 8:23fluorine it's pretty unlikely that you
233. 8:25have a succimal choline infusion going
234. 8:27but if you do then you should stop that
235. 8:29if the surgery needs to continue but
236. 8:31you've just turned off an inhaled
237. 8:33anesthetic maintenance agent then you'll
238. 8:35need to switch over to a total iv
239. 8:37anesthesia or tiva for short this
240. 8:39commonly includes propofol which is not
241. 8:42a triggering agent for malignant
242. 8:43hyperthermia the next extremely time
243. 8:46sensitive intervention that needs to
244. 8:47occur is the administration of the
245. 8:50treatment which is dandruline dandruline
246. 8:52is a medication that blocks calcium
247. 8:55release from muscles and thereby
248. 8:57inhibits the pathophysiology of what's
249. 9:00going on during an episode of malignant
250. 9:01hyperthermia a patient's survival of an
251. 9:04episode of malignant hyperthermia is
252. 9:06directly related to the amount of time
253. 9:08that it takes for dandruline to be
254. 9:10administered for those who are
255. 9:11interested the dose of dandruline is 2.5
256. 9:14milligrams per kilogram administered
257. 9:17every 5 minutes and it's important to
258. 9:19monitor a patient's vital signs for
259. 9:21resolution of symptoms
260. 9:22and also keep in mind that treatment
261. 9:24with dandruline may need to continue
262. 9:26even after symptoms have resolved
263. 9:28because it's possible for them to
264. 9:29reoccur dandruline is an extremely
265. 9:32expensive medication and for that reason
266. 9:34it's not routinely kept in carts in
267. 9:37every single operating room but rather
268. 9:39in its own cart that's located centrally
269. 9:41to all of the operating rooms
270. 9:43i've covered medication cost in one of
271. 9:45my previous videos and i will say that
272. 9:48that became a very controversial subject
273. 9:50but i will just say that objectively
274. 9:52speaking the wholesale cost so what a
275. 9:55hospital pays in the united states on
276. 9:57average for a vial of dantrolene is 2581
277. 10:04for 250 milligrams that's the cost for a
278. 10:08formulation of dandruline that can be
279. 10:10reconstituted into five cc's of sterile
280. 10:13water and then injected that contrasts
281. 10:15with the other formulation of
282. 10:17intravenous dandruline which comes as 20
283. 10:20milligram files that cost 62 each but
284. 10:24each vial needs to be mixed with 60 ccs
285. 10:27of sterile water from a practical
286. 10:29standpoint this formulation of
287. 10:31dandruline is actually really tedious to
288. 10:33use because it takes a long time to draw
289. 10:37up enough dandruline to administer to a
290. 10:39patient who's having an episode of
291. 10:40malignant hyperthermia one also cannot
292. 10:43talk about dandruline without mentioning
293. 10:45that calcium channel blockers are
294. 10:47contraindicated because the use of
295. 10:49calcium channel blockers with dandruline
296. 10:51can precipitate a life-threatening
297. 10:53hyperkalemic arrest
298. 10:55also kept in the cart is refrigerated iv
299. 10:57fluid and in this case that's isolite
300. 11:00the administration of cold iv fluids is
301. 11:03one of the most effective ways to
302. 11:04rapidly cool a patient
303. 11:06another medication kept in the malignant
304. 11:08hyperthermia cart is a medication called
305. 11:10bicarbonate which can decrease the
306. 11:12acidity of urine thereby decreasing the
307. 11:16likelihood of kidney damage resulting
308. 11:18from myoglobin which came from ruptured
309. 11:21muscle cells to that end a diuretic
310. 11:24called furosemide is also recommended
311. 11:26for treatment during a malignant
312. 11:27hyperthermia episode because that can
313. 11:29increase urine output and theoretically
314. 11:31decrease the amount of renal damage the
315. 11:34malignant hyperthermia cart also
316. 11:35includes insulin which drives potassium
317. 11:38inside of cells decreasing the
318. 11:40likelihood of life-threatening
319. 11:42hyperkalemia and if you're going to be
320. 11:44administering insulin then in order to
321. 11:46keep the patient's blood sugar from
322. 11:48bottoming out you'll also probably need
323. 11:50to administer dextrose which is kept in
324. 11:52the cart as well the recommended
325. 11:53ventilator settings for treating a
326. 11:55patient with a suspected episode of
327. 11:57malignant hyperthermia is a hundred
328. 11:59percent fio2 at high flows and
329. 12:02hyperventilating the patient to try to
330. 12:04get the carbon dioxide off as much as
331. 12:06possible other important steps for
332. 12:08treating malignant hyperthermia include
333. 12:10making sure that a patient's urine is
334. 12:12being closely monitored so a foley
335. 12:14catheter will need to be inserted if
336. 12:16it's not already inserted and the
337. 12:18patient will need to be very closely
338. 12:19monitored in the icu after leaving the
339. 12:22operating room and if there's any
340. 12:24question about how to treat a patient
341. 12:26with a suspected episode of malignant
342. 12:27hyperthermia there's actually a hotline
343. 12:29that's staffed 24 7 by experts who can
344. 12:32guide you through any questions that you
345. 12:34may have
346. 12:35there are several ways that
347. 12:37susceptibility to malignant hyperthermia
348. 12:39can be diagnosed one is a fairly
349. 12:41invasive diagnostic test that is not
350. 12:44done in very many places in the united
351. 12:46states and also happens to be really
352. 12:48expensive and that's called a caffeine
353. 12:50halothane contracture test that
354. 12:52basically entails taking a fairly
355. 12:54sizable amount of a muscle sample and
356. 12:57then exposing it to both halothane which
357. 12:59is an anesthetic agent as well as
358. 13:01caffeine and seeing if the muscle
359. 13:03contracts because this test is so
360. 13:05invasive
361. 13:06and expensive and inconvenient it's not
362. 13:09routinely done except in people who have
363. 13:12a high suspicion of having had an
364. 13:13episode of malignant hyperthermia and
365. 13:16even in that case this test can't be
366. 13:18done within six months of a suspected
367. 13:20episode of millennium hypothermia
368. 13:22because it can throw off the test
369. 13:23results another way of identifying
370. 13:26people who are susceptible to malignant
371. 13:27hyperthermia is a blood test that can
372. 13:30identify certain genes that predispose
373. 13:32someone to it however these are not
374. 13:34particularly sensitive genetic tests
375. 13:36which means they don't always pick up
376. 13:38when somebody has susceptibility to
377. 13:40malignant hyperthermia that's because
378. 13:42there are a lot of different genetic
379. 13:43mutations that can lead to malignant
380. 13:45hyperthermia and we don't know what all
381. 13:47of those genetic markers are so we can't
382. 13:50test for all of them so if a patient's
383. 13:52had a negative blood test that's not
384. 13:54necessarily helpful but if a patient has
385. 13:56a positive blood test then that can be
386. 13:58something that can be helpful in
387. 14:00allowing other family members who are
388. 14:02genetically related to get identified as
389. 14:05carriers of a genetic mutation that can
390. 14:07lead to susceptibility for malignant
391. 14:09hyperthermia if you do have questions or
392. 14:12concerns about malignant hyperthermia
393. 14:13the person that you need to speak with
394. 14:15is your doctor because this is a youtube
395. 14:18video and this is not medical advice if
396. 14:20you found this video interesting you
397. 14:21might want to check out this video where
398. 14:23i go through a totally different type of
399. 14:25emergency that i actually did experience
400. 14:28in an operating room thanks very much
401. 14:30for watching i'll see you next time
402. 14:37[Music]