Author: Bryan Boling

I'm a critical care nurse practitioner and co-director of the Critical Care APP Fellowship Program at the University of Kentucky. I split my clinical time between the Neurocritical Care Service, the Surgical Critical Care Service, and the ECMO Service. I'm also an Adjunct Faculty Member in the Acute Care Nurse Practitioner Program at Georgetown University. I have a passion for education and #FOAM.

Frank Starling’s Curve

OK, it’s not actually Frank Starling’s curve, it’s the Frank-Starling curve, named for Otto Frank and Ernst Starling. But for some reason, a lot of people refer to it as if it is named for some guy named Frank Starling. It’s a pedantic pet peeve of mine. But, I digress…

The Frank-Starling Curve, often referred to just as the Starling Curve is a super-duper important (of you’ll forgive the technical jargon) concept in cardiac physiology. Understanding it is key to resuscitation of critically ill patients. Fortunately, Rishi Kumar does a great job of explaining it.

Airway Notes: Bag Mask Ventilation

So, I’m starting a new mini-series called “Airway Notes” over on my Instagram. Each Friday (sorry it’s a day late for the first one!), I’ll be covering a little bit of airway management. This week, we’re going to discuss the most important airway management skill, bag mask ventilation. So, head on over to Instagram and check it out. If you’re not already following me on Instagram, this is a great reason to start! Check back every Friday for more. My plan is to eventually move on to other topics and make Friday the day when these original posts show up.

Vasopressor Receptors

Different vasopressors have different functions and these functions dictate why we choose certain pressors at certain times. We’re all familiar (hopefully) with the fact that epinephrine is a positive inotrope as well as a vasopressor while phenylephrine is pure vasoconstrictor. This is why we choose epi over phenylephrine when we need inotropy and why phenylephrine will actually make hypotension secondary to cardiogenic shock worse.

These differences in function are dictated by the different receptors on which the pressor drugs act. In addition to different functions, some vasopressors with the same general effect (vasoconstriction) act on different targets (catecholamine vs non-catecholamine) and so can have a synergistic effect. Adding vasopressin to norepinephrine for a patient in septic shock, for example, can help even beyond the fact that norepi is at its limit. This is why adding vasopressin before maxing out norepi is often beneficial. Additionally, vasopressin is less affected by blood pH, so it will work in patients with extreme acidosis where norepi will not.

Eddy Joe Gutierrez has a great Instagram post on this with a nice slide showing how the different pressors work.

Hepatorenal Syndrome

Have you heard of hepatorenal syndrome (HRS) but don’t really understand it? At it’s core, HRS is renal dysfunction as a result of liver disease. It’s common in patients with end-stage liver disease (ESLD) and among patients undergoing liver transplant. The good news for the kidney is, its not really a kidney problem. It’s a liver problem. So, fixing the liver is the fix for the kidneys. DocSchmidt has a really good Instragram post covering the pathophysiology, diagnosis, and treatment of HRS. All in < 2 mins!

Harlequin Syndrome in ECMO

One of the big complications of VA ECMO is something called Harlequin Syndrome, also known as North-South Syndrome. It happens when the oxygenated blood being returned from the ECMO circuit mixes with the deoxygenated blood being ejected from the heart (there was a big reason the patient was put on ECMO, remember?). This is actually sometimes a good sign, because it means the heart is able to pump (you were on VA because of heart problems). But, the lungs haven’t really recovered yet, hence the deoxygenated blood being ejected. And so, despite the good news of better heart function, the patient still may end up in life-threatening hypoxia from this mixing.

As usual, countbackwardsfrom10 is our go-to for all things cardiac surgery, and he has a nice Instagram post explaining this phenomenon and what to do about it.

Brain Bleeds on CT

Head CTs are often mysterious to people who don’t practice neurocritical care (or related specialty). But there are some things that are not so subtle and a large hemorrhage is among them. But, there are a few different types that you should be able to differentiate between. It’s critical to be able to differentiate between a subdural hematoma and an epidural hematoma, as one is almost always a medical emergency. Through in subarachnoid hemorrhage and you’ve got three types of hemorrhage to sort out.

Medical Guidelines has a nice Instagram post to help you out.

Calcium in MTP

Transfusing a lot of blood presents a lot of problems (not the least of which being that the patient needs a lot of blood to begin with!). Chief among those is likely the coagulopathy that results from a depletion of coagulation factors due to losing whole blood (PRBCs, plasma, and platelets) but only getting PRBCs back. Massive transfusion protocols (MTP) helps to address this by transfusing additional products in some sort of “proper” ratio (what that ratio IS is up for debate), but even if you transfuse PRBCs, FFP, and platelets in proper balance, you can still run into another life threatening complication. And I’m not talking about TACO (although that certainly is a problem). It’s one that may not be as readily recognized or remembered, but one that can wreak havoc with your resuscitation. Hypocalcemia.

Banked blood contains citrate as a preservative for storage. Citrate binds calcium and renders it inactive. Giving lots of banked blood can result in hypocalcemia. Hypocalcemia can cause all sorts of problems including hypotension (probably ALREADY a problem in someone requiring MTP) and seizures.

Pharmbythegram has a really nice post summarizing the role of calcium administration during MTP. Hopefully, you’ll now always remember to give calcium along with PRBCs, FFP, and platelets.

How Was Your Summer?

Well, I know that the official end of summer (Labor Day) is still a little ways off, but my kids are back in school as of this week and things are settling back into the Fall routine. And so, I’m back to (hopefully) regular posts on the blog! Starting this week, you’ll begin to see posts again (although I have been sharing intermittently on Twitter and Instagram over the summer). It’s been a nice break, but I’m glad to be back.

Did you do anything really cool over the summer? I enjoyed some time away with family, but one really cool thing I did that was critical care related, was to attend the Resuscitative TEE Workshop in New York. I HIGHLY recommend it if you’re interested in critical care echocardiography. Click here for more info.

That’s all for now, but the best of #FOAMed is coming soon!

Summer Vacation, Teaching, and More…

The past month or so has been extremely busy. I’ve been traveling and teaching a lot, some in person, some remote. In the past 2 months, I’ve spoken at the Association of Post-Graduate APRN Programs meeting in Florida, the Townsend Cardiovascular Nursing Symposium in Wichita (remotely), the Memorial Sloan-Kettering Cancer Center Critical Care Symposium in NYC (again, remotely), the American Association of Critical Care Nurses National Teaching Institute in Houston, Georgetown’s extra long on campus intensive in Baltimore (twice as long as usual because we had to make up for the January one being cancelled due to COVID), and the Society of Point of Care Ultrasound’s iScan event in Indianapolis. I also did a guest lecture for the ACNP program at University of Central Florida (remotely) and my usual Georgetown teaching and clinical duties.

All of them were a bunch of fun and I’m so grateful to get to do what I love, but it was pretty consuming and I haven’t been able to do much on this blog. I had the best of intentions on picking things back up as soon as I was home, but…summer. One of the worst parts of being a grown up is the lack of a summer break. Even teaching at Georgetown, we don’t get a break because our program runs year-round.

But my wife (who is a teacher/stay at home mom) and my kids are on summer break. And so, I’ve decided that I need to join in. And that means that something has to slow down. I still plan of sharing anything cool that I come across on Twitter and IG and will still post some short stuff on the blog. But I do plan on returning to a regular schedule later in the summer or fall, including more original content.