September FY20

[Kristen Horsman]

This month’s journal club is presented by Jen Pease. She chose an informative article that discusses the pharmacology, various uses, and benefits and limitations of using dexmedetomidine in practice. As many seasoned JHH providers have noticed, dexmedetomidine has become much more accessibly from pharmacy recently and this is a great review to incorporate this drug into practice.



This article is the Current review "Using Demedetomidine in Your Clinical Practice" Lesson 15 Volume 41 if you have a subscription. If not, the article can only be sent via an attachment. Please refer to the article attachment sent via email.



Questions to answer:


1. Describe the use of Dexmedetomidine as an anesthesia adjunct versus sole anesthetic in different surgeries and patient populations. How do you incorporate it into your practice?

2. Discuss the advantages, indications, limitations, and precautions of Dexmedetomidine.

[Jennifer Hannon]

1) I've used Precedex a lot in VA for the bariatric surgeries especially when the patients are morbidly obese and with CPAP in the PACU. It worked very well to run them at 0.03-0.06 to the PACU. It was combo'd with Desflurane mostly. As a sole anesthetic I've done DBS's where that's all they are on at 0.03. Sometimes a scalp block and sometimes a little low dose Remi, but mostly they are awake behind a clear drape for tremor exact positioning. It's great! We would preload in the preop area for the DBS's. I'm glad it's more readily available.

2) The biggest disadvantage I've encountered is hypotension, and usually about 30mins after the load. Like all medications, individualized care with regard to patient history would weigh the selection of precedex.

[Dahlia Rouchon, CRNA]

1. Dexmedetomidine as anesthesia adjunct is useful to decrease MAC, analgesia requirements, and assist in cases where neuro assessments are frequently done during or post procedure, i.e. (awake craniotomy for during), spinal fusions to support SSEP monitoring (as background IA can be used in lower doses), and to secure difficult airways among others to prevent respiratory depression and support cognitive interaction/cooperation during intubation. As a sole anesthetic, it may be useful for cases where patients request less opioid use and adjunct medications are employed, i.e. gabapentin, Tylenol, lidocaine infusions, etc. or cases in which regional anesthesia is utilized and sedation is supplemented with dexmedetomidine. I have incorporated it mostly to secure difficult airways where there is caution for sedation using versed or fentanyl, typically in morbidly obese patients for example. A slow loading dose over 10 minutes and monitoring for bradycardia is indicated for this is a common response.
2, Advantages noted are the sedative, analgesic and anxiolysis effects, and an ability to assess cognitive function. Indications as forementioned, with a low dose for craniotomies 0.2-0.7mcg/kg/hr. Precautions are for patients with cardiovascular disease as hypovolemia, severe bradycardia to even fatal sinus arrest have been reported so reconsider if past history of AV block. It's limitations include the main elimination by CYP450 therefore patients with pre-existing liver disease are not candidates for use. Precautions include the elderly and generally any case with sensitivity to GA as a whole.

[aileenm4]

we use Dex alot in pediatrics as a bolus for example in T&A cases, especially for severe OSA kids or infusions for longer cases like spine fusions. it also helps for emergence delirium prevention. I recently was in EP and the cardiologist said to not use Dex during ablation cases due to it slowing the HR and potentially disturbing the conduction pathway.

[Jocelyn Datud]

Dexmedetomidine has a good sedative, analgesic, and anxiolytic property. Also, it doesn't impact patient's respiratory status and can activate natural sleep pathways. Hemodinamically, the changes are modest and predictable. Most likely, bradycardia and hypotension can be seen depending on the dose. Due to these properties, it is a good adjunct for neurosurgery cases, vascular surgery, sedation, awake fiberoptic intubations and more. However, caution is needed in patients who are hypovolemic, +heart block, bradycardic, cardiogenic or septic shock, and for microvascular and flap surgery. Just like other medications, it should be adjusted with geriatric patients and patient's with hepatic disease. Personally, I usually use Dexmedetomidine as an adjunct during sedation cases. However, after reading this article, I am more inclined to incorporate it to other cases.

[Sarah Rollison]

1. Describe the use of Dexmedetomidine as an anesthesia adjunct versus sole anesthetic in different surgeries and patient populations. How do you incorporate it into your practice?

Dexmedetomidine is an excellent adjunct for anesthesia, and frankly I wished I used it more often. According to the article, Dex has the ability to decrease a patient's response to noxious stimuli and thus can decrease the overall MAC of inhaled agents, IV anesthetic agents, and opioid agents which may be beneficial for patients who may be prone to cardiovascular instability. Additionally, its sympatholytic activity can help to decrease the SNS response to surgical stimulation and intubation. Personally, my favorite use of Dex is for emergence. In my training, almost all of the locations I trained at had pre-drawn syringes of Dex in 4mcg/mL concentrations. This has saved me countless times during a rough emergence, especially for young healthy patients who may be more prone to a rough wake up. It provides a great amount of sedation without impacting the patient's respiratory status, which is so beneficial during wake up. I especially like to work it in in small increments during pediatric cases to avoid a lot of confusion/crying on wake up for the child. It isn't perfect, but it has saved me countless times.

2. Discuss the advantages, indications, limitations, and precautions of Dexmedetomidine.

Dex's indications include adjunct analgesic/sedative/anesthetic for a number of cases, including MAC/Sedation cases for cardiac/respiratory cripples, awake craniotomies, pediatric cases, emergence delirium, cardiovascular surgery, and many more. The advantages of dex include that it has analgesic and sedative properties while still maintaining respiratory and airway patency, and it helps to blunt the SNS response to stimulation such as laryngoscopy, intubation, incision, and overall surgical stimulation. A major limitation of Dex, especially for us, is its limited availability. It can be costly, and having a vial of dex in our pyxis may be a safety concern since vials of dex typically are supplied as 200mcg/mL, and we frequently only give 4mcg at a time. However, if we could have pre-drawn syringes of dex from pharmacy, this would be ideal. Of course it is wise to be aware of the precautions of dex, including that it may cause hypotension and bradycardia with increased doses.

[Jessica Hadley]

1. I have never used Dexmedetomidine as a sole anesthetic so I cant speak to it's use as a single agent. Honestly, I have only used it a handful of times since it's use has been so restricted until recently. The last time I used Dex it was for a patient who had a history of waking up violent from anesthesia. I ran Propofol with a small bolus of Dexmedetomidine and then an infusion for the case. It was an LMA case so I pulled it deep and let him emerge in PACU. He did beautifully. I would like to start using it more after reading this article especially in the obese with OSA population.

2. I think access is still a limitation, especially depending on the area you are in. If in JHOC or Wilmer you have to order the drip and then follow up with a phone call and then sometimes also have someone go pick it up. As Sarah mentioned, it would be much more convenient if we had it available in our pyxis. Others have also already touched on the possible cardiovascular side effects such as bradycardia/hypotension.

[jkim54]

1. Dexmedetomidine is more widely used in conjunction with other anesthetic agents, as it does a great job of synergistically working with other medications to achieve an effective level of anesthesia. Used together with other anesthetics, it decreases the requirements of these other agents while achieving effective sedation levels - without compromising the pt's respiratory status and sparing them from drastic hemodynamic changes. Due to the limited availability of Dexmedetomidine in our facility (except until recently) I am not as familiar with using it but am appreciative of this article to encourage more use of it in a variety of settings.

2. Dexmedetomidine is very effective as an sedative, anxiolytic, and analgesic agent without compromising respiratory status. It is a great drug for scenarios when the pt needs to be calm, cooperative and comfortable such as awake fiberoptics and awake craniotomies. Some of its limitations include hypotension and bradycardia thus should be avoided in pts with fragile hemodynamics. Caution and reduced dosages should also be considered for elderly pts and those with hepatic disease.

[Ben Waldbaum]

1. Personally, I am most comfortable using dexmedetomidine as an adjunct. I've used it many times for awake fibertoptic intubations and it has worked fantastically. Occasionally I'll use it as an adjunct with morbidly obese patients to decrease volatile anesthetic need.

2. The advantages are clear, sedation without respiratory depression, can be used in patient with renal failure, and quick emergence, and patients of all ages. It can cause bradycardia so with certain populations caution is advisable.

[Kels]

I have used dexmedetomidine a few times but never as my only anesthetic . Like many others on here I have used it as an adjunct and it seemed to work well . Times are changing for the better and it seems like this drug is easier to get a hold of in the main hospital compared to last year . Dexmedetomidine seems to be well liked by many practitioners due to advantages of the drug such as preventing anxiety , providing sedation and limited respiratory depression. After reading this article great caution should be taken with patients who are bradycardic , hypovolemic and have a history of heart block and poor liver function/ clearance

[Kelly Rechtin]

1) Agree that dexmedetomidine is best used as an adjunct. I have never used it as the sole anesthetic, nor have I heard of anybody using it in this manner. I currently do not incorporate it into my practice, due to the fact that it must be ordered from pharmacy. If it becomes more readily available in the pyxis, I would consider incorporating it into my practice.

2) Advantages are the superior sedative and analgesic effects without major compromise to respiratory status. Limitations would be that it has to be ordered from pharmacy in advance.

[Julienne Chandler]

1. Describe the use of Dexmedetomidine as an anesthesia adjunct versus sole anesthetic in different surgeries and patient populations. How do you incorporate it into your practice?


Where I trained, Dexmedetomidine was the sole anesthetic used for our TAVR cases. 0.3 mcg/kg bolus over 10 minutes and 0.3-0.7 mcg/kg/hr thereafter. After the valve was deployed and all was deemed well, we would shut if off. Patients drifted off to sleep comfortably and woke up nicely, some even able to transfer themselves from IR table back to stretcher. Rarely, fentanyl 12.5-25 mcg was given for someone really uncomfortable or having difficulty holding still. Patients maintained spontaneous ventilation and hemodynamic stability.

In pediatrics, dexmedetomidine was used as an emergence adjunct where I trained. I found it interesting that the article mentioned giving it with induction to decrease emergence delirium. Eitherway, I found it useful with school-aged up to young adults to decrease emergence delirium. 0.3-0.5 mcg/kg over 5 minutes. Kids and young adults woke up calmly, less crying, and less thrashing around. Emergence delirium can be quite violent and a safety issue for patients and staff. It can be difficult to maintain safety when arms and legs are swinging and prevent head injuries on the side rails.

Since coming to Hopkins, I have not used dexmedetomidine. I hope I will have some opportunities to incorporate it back into my practice.


2. Discuss the advantages, indications, limitations, and precautions of Dexmedetomidine.

Dexmedetomidine is helpful for attenuating sympathetic stimulation. The only noticeable side effect I have seen is bradycardia during TAVRs and some bradycardia in pediatrics. The reason I was taught to give dexmedetomidine at emergence as opposed to induction in children was to decrease the chance of bradycardia during induction, especially if succinylcholine is needed/given and since kids are parasympathetic driven.

I have noted that Dexmedetomidine is not easily available for use at Hopkins. I hope this changes and/or it is added to more of the existing protocols and clinical pathways.

[Wai-Ling Lo]

1. Describe the use of Dexmedetomidine as an anesthesia adjunct versus sole anesthetic in different surgeries and patient populations. How do you incorporate it into your practice?

Precedex is a highly sensitive α2-adrenoceptor agonist that possesses anxiolytic, sedative, and analgesic effects. I mainly use it as an adjunct to general anesthesia to reduce MAC and narcotics requirement or as preventive treatment for emergence agitation. I also used it in MAC sedation cases in obese pts with OSA.
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2. Discuss the advantages, indications, limitations, and precautions of Dexmedetomidine.

As mention in above, Dexmedetomidine possesses anxiolytic, sedative and analgesic effects without respiratory depression. It can be used as adjunct to GA to reduce MAC and narcotics requirement or for MAC sedation. However, the potential side effect of hypotension and bradycardia make it not suitable for patients with heart block or low EF. Moreover, hypotension and/or bradycardia may be expected to be more pronounced in patients with hypovolemia, diabetes mellitus, or chronic hypertension, and in older patients. Of note, bradycardia and sinus arrest have occurred in young healthy volunteers with high vagal tone. Dose reduction is required in elderly and patient with hepatic impairment.

[Anne McNulty CRNA]

I have used Dexmedetomidine during Bariatric surgeries. I never had any complications. I have used it for MAC cases as sole agent. It can leave you with a very sedated pt when you are learning how to titrate. It is so useful. It costs less than Remifentanil. I hope they will stock it in pyxis.

[LarSharVeA Bailey]

Dexmedetomidine as an adjunct decreases the MAC of other anesthetics; nothing esoteric there. As a sole anesthetic, I have used it for awake craniotomies. It is particularly useful in this case without another sedative because the probability of getting an assessment when it is required is far more predictable. I also like its use in chronic pain patients. It's similar to using clonidine as pre-emptive analgesia (one more receptor covered in the quest to decrease opioid use). Personally, I do not bolus, instead I typically connect the drip as soon as I arrive in the room starting at 1mcg/kg/hr and then connect monitors. As the case progresses, I wean (or not) as necessary. By the time surgery makes incision, plasma concentration is at a steady state.

This article is clearly in favor of the use of dexmedetomidine,and thus, disproportionately highlights the pros of the drug. I do agree that it is an amazing drug considering it's opioid sparring properties with alpha 2 receptor agonism, the lack of respiratory depression, and its null effect on SSEPs. The article neglects to mention, with adequate gravitas, the prolonged context sensitive half life, making a continuous dexmedetomidine drip inappropriate for use in prolonged cases. There have been cases here at Hopkins where BATS were called and patients were taken to stat CT scan to rule out brain injury. This misuse increased cost to the patient as there was no adverse outcome to detect, rather the cases required that the providers wait for the drug to be metabolized which would have resulted in awakening. In prolonged cases, perhaps a single pre-incision bolus would be more appropriate.