Impella Medical Device Stuff

This is my first of many posts on the Impella system by Abiomed. It is going to be part of my "Cardiogenic Shock: Rise of the Machines" lecture for Portland in August 2020.

I am planning on covering LVADs, RVADs, ECMO, TandemHeart, etc. in the upcoming months but one does not need to work at an ECMO or transplant hospital to see an Impella. This post is targeted for the clinician or nurse who is caring for the patient and is curious as to what’s the next step. Not intended for repositioning the device or criteria for installing it. I’ll get there. Give me time. Besides, I took a break from the Ketamine for this today.

When managing a patient on the Impella, whichever of their devices, a question always comes up when the patient becomes hypotensive. Do they need vasopressors or ionotropes? This algorithm from the Detroit Cardiogenic Shock Initiative is a helpful guide, definitely not an end-all-be-all but it’s better than flying without any instruments. Every patient with an Impella NEEDS a swan. You need to be able to measure the right heart pressures appropriately. You also need to be able to have an idea of what your SVR is. Without these parameters handy, you’re in the blind and clueless. Honestly, you should consider transferring the patient out to another shop before they get too sick to salvage.

Calculating the CPO and PAPI is something that nurses do and let the physicians know when things are going south. My favorite is to get the call followed by a suggestion to start a new med. that shows they’re vested and I love that.

Even though I do not run ECMO or have an LVAD program at my shop, I’m fortunate that I have colleagues at nearby hospitals who respond to my texts promptly and are around to help. It’s a blessing. My fellowship training provided me with a great amount of experience to where I do what I know how to do and when I need to make that call, I make it. No shame. Patients come over ego.

-EJ

LINK TO PDF

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Be careful with Ketamine and Catecholamine-dependent Heart Failure

The Ketamine kick continues! I am not going to pretend I knew everything about everything as I've created this page over the last several months. People who walk around saying things like they were born with that knowledge sometimes need to be checked. We all had that one eye-opening day where it was like, "(explicative) I should have known that!"

I had some basic knowledge on ketamine but fortunately I have expanded that substantially over the course of working on my lectures. The whole "negative ionotrope" concept was something I was familiar with, but I never actually looked up in depth until colleagues such as the great Seiha Kim, David Convissar, and other great anesthesia colleagues who have more experience on the matter than I do. Not to mention that Seiha is both a pharmacist and an anesthesiologist.

A healthy heart should not have any issues with ketamine for sedation nor rapid sequence intubation, but, as mentioned in the Christ article linked, you can find a 21% decrease in cardiac index. This also brings me to the point where many clinicians focus on the blood pressure while ignoring the patients cardiac index/cardiac output. It makes us feel all warm and fuzzy inside to see the MAP > 65 as we keep on increasing our pressors but at the same time we have NO IDEA what this afterload increase is doing to the LV. We feel self-reassured but really our patients are going on a downward spiral. That's a discussion for another day. We really need more than a BP cuff or an a-line to get a true grasp of what's going on with our critically ill patient who is otherwise hemodynamically unstable.

-EJ

Link to Abstract

Christ G, Mundigler G, Merhaut C, Zehetgruber M, Kratochwill C, Heinz G, et al. Adverse cardiovascular effects of ketamine infusion in patients with catecholamine-dependent heart failure. Anaesth Intensive Care. 1997;25:255–259.

Link to Abstract

Bovill JG (2006). Intravenous anesthesia for the patient with left ventricular dysfunction. Semin Cardiothorac Vasc Anesth 10: 43–48.

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Ketamine + Morphine

Link to Abstract

Jennings PA, Cameron P, Bernard S, Walker T, Jolley D, Fitzgerald M, Masci K: Morphine and ketamine is superior to morphine alone for out-of-hospital trauma analgesia: a randomized controlled trial. Ann Emerg Med. 2012, 59: 497-503. 10.1016/j.annemergmed.2011.11.012.

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Ketamine: Mechanism of Action

Link to Abstract

Link to FULL FREE Article

K Hirota, D G Lambert, Ketamine: its mechanism(s) of action and unusual clinical uses., BJA: British Journal of Anaesthesia, Volume 77, Issue 4, Oct 1996, Pages 441–444.

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Pregabalin to Avoid Opioids

I’m hard at work on a protocol for my shop to decrease opioid usage as well as preparing my lectures on opioid sparing medications. Amongst those are the gabapentinoids. You’ve seen them often, I’m sure, mostly to treat neuropathic pain such as diabetic neuropathy as well as trigeminal neuralgia but what about for actual painful procedures? This family of medications reduce the abnormal hypersensitivity induced by inflammatory responses or nerve injury. What not just place it in the drinking water for our patients? That’s kind of where I’m going with this.

This study was published in 2011 and they gave patients Pregabalin, also known as Lyrica, to see how much opioids the pts would need. They got 150mg before the surgery and then 75mg twice a day until post-op day 5. The main drawback is how it delayed the time to extubation. I don’t know if I am interpreting the data correctly but patients on Pregabalin were on the vent for about 2 hours longer than those not on it. Perhaps the 150mg 1 hour before the surgery was too much. Either way, as noted on the abstract slide, it reduced the post-op consumption of opioids by 44-48%. That’s a big win.

Do you all routinely use Pregabalin or Gabapentin for pain management at your institutions? I’m going to go through more data on this topic in the upcoming week.

-EJ

Link to Abstract

Link to FULL FREE Article

Pesonen A, Suojaranta-Ylinen R, Hammaren E, Kontinen VK, Raivio P, Tarkkila P, Rosenberg PH. Pregabalin has an opioid sparing effect in elderly patients after cardiac surgery: a randomized placebo-controlled trial. Br J Anaesth 2011;106:873–81

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Magnesium for Sedation in Mechanically Ventilated Patients?

This is cool, really cool. We need more data, but this is a great start. I learned a lot of basic science from reading the introduction as well as discussion on this article and it all makes sense. I don't see myself using this anytime soon until there's a study where they add magnesium to a different agent that's not midazolam because I do not use benzodiazepines in my practice for sedation unless there are extreme cases.

I encourage you read this article yourself as it's interesting and I don't want to divulge too much out of respect for the authors.

-EJ



Link to Abstract

Link to FREE FULL PDF

Altun, Dilek. (2019). Can we use Magnesium for sedation in Intensive Care Unit for critically ill patients; Is it as effective as other sedatives?. Ağrı - The Journal of The Turkish Society of Algology. 31.

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Ketamine Continuous Infusions for Sedation in the ICU

One of the lectures I’m working on is regarding minimizing opioid utilization in the ICU on our critically ill patients on mechanical ventilation.

I honestly do not use ketamine as often as I’d like and I have been reviewing all the data behind continuous infusions over the last two days.

Unfortunately, the data isn’t incredibly robust (small sample sizes, mostly retrospective, heterogenous non-MICU patient populations) and there is a wide variation in the doses used in the different studies. This study published earlier this year used ketamine in conjunction with other agents, mostly propofol or fentanyl. The authors found that using ketamine decreases the doses the other agents with no changes in all the other outcomes. Most clinicians are looking for miracle drugs rather than incremental (albeit small) improvements here and there.

One of the problems I have with ketamine is, depending on how it’s mixed, is the sheer volume of the drip. I try to keep my patients potato chip dry and if the ketamine is basically a maintenance fluid, I’m not going to be as excited about it. 

Do you all use ketamine in your ICU for continuous sedation? Do you use it as monotherapy or with other infusions?



Link to Abstract

Garber, P. M., Droege, C. A., Carter, K. E., Harger, N. J. and Mueller, E. W. (2019), Continuous Infusion Ketamine for Adjunctive Analgosedation in Mechanically Ventilated, Critically Ill Patients. Pharmacotherapy, 39: 288-296.

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Analgesia and Sedation in the ICU

Link to Abstract

Sessler, C. N., Grap, M. J., & Brophy, G. M. (2001). Multidisciplinary Management of Sedation and Analgesia in Critical Care. Seminars in Respiratory and Critical Care Medicine, 22(02), 211–226.

Cardiogenic Shock: NICOM vs. Swan-Ganz Catheter

There are four types of shock: cardiogenic, distributive, obstructive, and hypovolemic.

I routinely make a big deal of volume resuscitation regarding septic shock which obviously falls under the distributive shock type. Part of the problem is that with all these well intentioned "Surviving Sepsis Campaigns", I feel that we are under-recognizing cardiogenic shock which can also present with hypotension and an elevated lactic acid. When you provide 30cc/kg of IVF arbitrarily because the "sepsis screen" pops up on your EMR forcing you to give the fluids, you end up causing harm to your patients.

This is where the history and physical plays a huge role. The physical should include a quick targeted POCUS/bedside echo to make sure you're not missing anything that's staring you in the face. If you see an RVOT on the parasternal long axis that's the size of a tennis ball, you're not dealing with sepsis. If you see an LV on the apical four chamber that is barely moving, you're likely not dealing with sepsis. Remember, if the patient is in septic shock, the systemic vascular resistance (SVR) hits the ground. There's no afterload for the LV to deal with. The LV will be clapping happily like a bodybuilder curling a 10lb weight. The "eyeball test" on POCUS is widely criticized but it has some uses.

But once you make the diagnosis of cardiogenic shock, how do you manage that patient? This is where I feel you may have some value in trending a CVP. I know Swan-Ganz catheters are out of favor, but I feel they're very useful if you know what to do with the numbers. Knowing how to apply the numbers clinically, though, takes some practice. Like everything else, you need to get your reps in. I'm fortunate that I trained at an institution where all the post-op hearts came out with a Swan. It was very helpful in my training and allowed me the opportunity to see the value in it rather than just being a nay-sayer. The Swan does have its limitations, though. It's not the easiest procedure to perform and it comes with some potential cardiac risks that I am not going to list here for the sake of my sanity. Is there something that we can use instead?

I will admit that I personally do not have any experience with the NICOM device. I look forward to playing with the technology one day. I like non-invasive things for my patients. I typically use another device which I will not name but I feel it is very helpful when used appropriately. No technology is perfect, not even the Swan. I was excited when I read this article because I was hoping for an out to not have to float Swans in this patient population. I also very much enjoyed how the authors conducted the study. Simultaneous measurements on the same patient was definitely the way to go and I applaud them on that.

Without boring you all with the details, the authors found that the NICOM correlates poorly with indirect Fick and therm-dilution measurements of cardiac output. The authors attribute it to the biorreactance technology being interfered with by pulmonary and interstitial edema. Makes sense to me. They also listed other factors as well which are on the full article. Nonetheless, what method do you use at your institution to manage cardiogenic shock?

-EJ



Link to Abstract

Rali, A. S., Buechler, T., Van Gotten, B., Waters, A., Shah, Z., Haglund, N., & Sauer, A. (2019). Non-Invasive Cardiac Output Monitoring in Cardiogenic Shock – The NICOMTM Study. Journal of Cardiac Failure.

Great article for indirect Fick
De Maria AN, Raisinghani A. Comparative overview of cardiac output measurement methods: Has impedance cardiography come of age? Congestive Heart Failure. 2000;6:60–73.

Indirect Fick Abstract

Indirect Fick PDF

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17 years from research evidence to clinical practice

Link to Abstract

Link to PDF

Morris ZS, Wooding S, Grant J. The answer is 17 years, what is the question: understanding time lags in translational research. J Roy Soc Med. 2011;104:510–20.

Although great care has been taken to ensure that the information in this post is accurate, eddyjoemd, LLC shall not be held responsible or in any way liable for the continued accuracy of the information, or for any errors, omissions or inaccuracies, or for any consequences arising therefrom.