Brandon O – Page 8 – Critical Care Scenarios

TIRBO #47: Why do we prone?

A review of the physiological and practical reasons to position patients with ARDS in the prone position.

Lightning rounds #33: Transitioning to academics with Janelle Bludorn

We chat with Janelle Bludorn (@JanelleRBlu), former emergency medicine PA, Assistant Professor and Academic Coordinator at the Duke PA program, about transitioning from clinical work into teaching and academia.

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Resources

TIRBO #46: Being curious

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The value of being curious about practice differences, not judgmental.

Episode 66: Aortic dissection with Travis Hughes

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We explore aortic dissection with Travis Hughes, vascular surgery fellow from the University of Kentucky, including classification, medical management, and nuances of the surgical perspective.

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Takeaway lessons

Type B dissections do not involve the heart or coronaries, but Type A vs B nomenclature is falling out of favor versus more anatomically specific labeling; this system helps characterize the gray area between the innominate and the left subclavian.
The main sequelae of concern in type B dissection in end organ ischemia. This may be dynamic, due to movement of the flap to obstruct the feeding artery, or static, due to occlusion by thrombosis.
Hypotension is unusual in type B dissection and should be a red flag for another factor, such as involvement of the heart (coronary dissection, tamponade), or rupture.
Rupture is not a common event in dissection (as compared to aortic aneurysm), but can occur.
Medical management of type B dissection involves controlling the impulse against the dissection flap by reducing heart rate and blood pressure. SBP <120 and HR <80 are reasonable standard goals, but should be customized somewhat to the patient; allowing higher goals in a pain-free patient, particularly one who is experiencing sequelae of relative hypotension may be reasonable.
During initial presentation, impulse control may prevent dissection from extending over a period of hours. Later, once it has thrombosed and scarred, risk may be somewhat less.
Dissection involving the renal arteries can be explored using doppler ultrasound in skilled hands.
Focal neurologic deficit should prompt concern for both stroke, and (in the lower extremities) thrombosis.
First line is usually an IV beta blocker for heart rate and either IV beta or calcium channel blocker for BP. Esmolol is a classic beta blocker, although involves a large volume of infusate, and is not always very effective. Labetalol and nicardipine are nice choices. Nitroprusside is usually a rescue.
Favor the right radial artery for an arterial catheter, as the left arm will sometimes be needed for the repair.
Transition to oral agents as they stabilize. A repeat CTA 5-7 days from admission (often prior to discharge) is usually appropriate.
The most common indication for repair is aneurysmal degeneration at the dissection site. Extension of the dissection, in the setting of appropriate medical management, is less common although possible, and may also indicate the need for repair.
The primary goal of repair is to cover the entry to the dissection, and potentially stenting to expand the true lumen. When there is involvement of the iliac arteries, stenting is usually needed there. Malperfusion to visceral vessels is often corrected with these maneuvers, but they can be specifically stented or thrombectomy performed if needed.
Open repair of type B dissection has become vanishingly rare due to high morbidity and rare indication.
Stenting of the aorta creates risk for spinal cord ischemia, so keep BP higher. Extremity neuro changes should prompt driving the MAP >90, naloxone, and IV steroids.
Lumber drain placement probably reduces this risk, and can be placed either reactively or proactively. Neurosurgery and/or anesthesiology or interventional radiology may do this.
Shorter ischemic time to organs or extremities, and baseline vasculopathy (which gives time for the body to develop a tolerance to it), portend better recovery after revascularization. Prolonged ischemia to extremities may require amputation or at least fasciotomies to prevent compartment syndrome.
Aspirin and perhaps clopidogrel (with or without a load) will usually be needed post-operatively.
Infection of long-standing grafts are not common but can occur. Contrast imaging and perhaps tagged WBC scans (nuclear scintigraphy) can identify these. Surgical removal may or may not be possible and tends to be morbid.

TIRBO #45: SBT failure phenotypes

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What are the ways that patients fail breathing trials, and what can they tell us about how to optimize them for next time?

Lightning rounds #32: Creating a POCUS system with Leon Chen

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We chat with Leon Chen about his work setting up infrastructure for clinical POCUS at Memorial Sloan Kettering. Leon is an Adult/Gerontology Acute Care Nurse Practitioner in the ICU, Clinical Program Manager of Research and Simulated Learning, and an Associate Professor at Columbia University School of Nursing.

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References

Leon’s recent paper: Point-of-care Ultrasound (POCUS) Program for Critical Care Nurse Practitioners and Physician Assistants in an Oncological Intensive Care Unit and Rapid Response Team

TIRBO #44: The things I carry

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A brief discussion of the stuff in your pockets as you practice medicine.

Episode 65: Obstructive UTI with Ashley Winter

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We discuss the nuts and bolts of urinary infection with an obstructing stone with Ashley Winter (@AshleyGWinter), board certified urologist with a fellowship in male and female sexual medicine, and chief medical officer of Odela Health.

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Takeaway lessons

A patient with UTI (or even just undifferentiated sepsis) and a non-trivial ureteral stone generally needs decompression of the affected kidney, whether or not there is significant hydronephrosis on imaging. Hydro is sensitive to other factors, such as dehydration, but its absence does not rule out sepsis secondary to urinary obstruction. CT is more sensitive here than ultrasound, which is mostly useful for ruling in hydronephrosis. (Such patients will usually need a stent, not a nephrostomy, as the latter is difficult when there is little hydronephrosis.) From a urology perspective, the size and position of the stone is probably more important than the hydronephrosis.
That being said, be attuned to the possibility of a patient with another source of sepsis, and an incidental bacteriuria and kidney stone. Anesthesia and a urology procedure won’t help these people. A cleaner urinary sample (e.g. straight cath or Foley, if the initial sample was a “clean” catch) can sometimes help here.
Consider also that a completely obstructing stone may be hiding pyelonephritis because the bacteria and leukocytes cannot pass the stone. This is not a very common scenario, but can lead to a “clean” urinalysis, so consider it in a patient with an obstructing stone and septic picture.
Try to get a urine sample before giving antibiotics.
Intra-renal stones will usually not cause obstruction, but occasionally in the setting of abnormal anatomy they may, such as a stone in a caliceal diverticulum causing a local/segmental hydronephrosis.
Obstructing stone + UTI + unstable with sepsis = emergent decompression within hours. Overnight cases should generally be drained overnight. Stable patients can potentially wait longer.
Option #1 for decompression is a ureteral stent, which stretches from the intra-renal pelvis to the bladder, traversing the area of the stone, and is deployed via cystoscopy. Urine drains around the stent, not necessarily through it. Stents can usually only be left for a maximum of 3 months and should be removed when no longer needed (i.e. when serial imaging shows passage of the stone, or a procedure has been performed to remove the stone). Long-term stent requirements involve serial stent replacements. They are placed in the OR under some level of sedation. Very distorted anatomy, such as in oncology cases, may make it difficult to find the ureteral orifice or to traverse the ureter.
Option #2 is a percutaneous nephrostomy. These are placed by Interventional Radiology. The patient is proned (not possible in all patients), and imaging (usually ultrasound) is used to guide a needle to the renal pelvis, then a pigtail catheter using a Seldinger technique. This can often be done with local anesthesia only. Lack of significant pelvic dilation or large body habitus make these more difficult. The result is a nephrostomy tube and drainage bag, which can be aesthetically unappealing to many patients. Anticoagulation may be a contraindication since you’re puncturing the renal parenchyma. They are usually not intended to be permanent, but can be left long-term in some cases.
Stents tend to be more uncomfortable, sometimes creating flank pain or a sensation of the need to void even with an empty bladder. Urine can even reflux up the stent into the renal pelvis during voiding.
Urostomies can sometimes make the procedure to remove a massive intrarenal stone like a staghorn calculus, since percutaneous nephrolithotomy can use the pigtail for access. Smaller stones can be removed via ureteroscopy.
Some stones are impacted, which may be difficult to navigate across with a stent. Technical maneuvers can be attempted, but occasionally it can’t be done and nephrostomy needs to be done as a rescue.
Ultimately, stent vs nephrostomy often comes down to institutional and logistical considerations, such as availability of urology compared to IR. Many centers have policies on who to call first.
A common phenomenon is clinical deterioration after decompression. Some of this may be iatrogenic; both stenting and nephrostomy involve pressurizing the renal pelvis by injecting contrast, which can force out some bacteria into the circulation. Reducing the volume or rate of contrast injection may help with this.
Antibiotic coverage can be as routine for sepsis, but if there is complex urological history, remember to check prior cultures (including stone cultures, if available), which may reveal a history of resistant organisms.
Stented patients who fail to improve in the acute to subacute period may be experiencing stent migration. Check position with a plain x-ray (KUB); if the proximal portion is not curled, further imaging may be needed as it suggests it’s not in the kidney.
Stent removal can sometimes precipitate instability as well if there is some degree of infection present.