UMEM Educational Pearls - By Cody Couperus-Mashewske

The Venous Excess Ultrasound (VExUS) exam integrates IVC, portal, hepatic, and renal vein findings to assess venous congestion and guide management, such as diuresis, in critically ill patients.

Technique:

1. IVC: Measure the IVC diameter. If <2 cm, significant congestion is unlikely, and further assessment is not well validated.
2. Hepatic & Portal Veins: Use a curvilinear probe with color Doppler in the RUQ. The hepatic vein flows away from the probe (blue), and the portal vein, with thicker walls, flows toward the probe (red).
3. Hepatic Vein Doppler: Apply pulse wave Doppler to the hepatic vein or a tributary. If the waveform is not clear, try a different vein.
4. Portal Vein Doppler: After evaluating the hepatic vein, place PW Doppler on the portal vein.

Tips:

• Start from the right upper quadrant, Doppler signals are often easier to obtain and interpret here.
• Delay learning renal vein assessment until comfortable with the other views.
• If the IVC is hard to see subcostally, try a transhepatic view and adjust probe orientation (rotation and fanning).

Interpretation:

• Hepatic Vein: A normal hepatic vein waveform reflects atrial contraction (a wave), atrial filling during ventricular systole (S wave), and atrial filling during early diastole (D wave). As congestion worsens, the proportion of atrial filling during ventricular systole (S wave) decreases and eventually reverses.
• Portal Vein: Normally shows continuous flow. With congestion, it becomes more pulsatile.

Sometimes when other clinical information is contradictory, having the extra data point of the VExUS exam can be extremely useful to determine the best plan for a patient. Practice looking for the portal/hepatic veins and getting the waveforms on patients with a CLEAR clinical picture of venous congestion, then practice on more difficult cases.

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Getting reliable venous and arterial access is crucial when resuscitating critically ill patients. These lines can be difficult due to patient and situation specific variables. 

Micropuncture kits contain a 21-gauge echogenic needle, a stainless-steel hard shaft/soft-tip wire, and a 4 Fr or 5 Fr sheath and introducer. The micropuncture kit offers several advantages that can help overcome difficult situations:

• Small, Sharp Needle: Easier puncture of compressible vessels.
• Echogenic Design: Improved visibility under ultrasound.
• Smooth Tissue Penetration: Moves through tissue more easily than a typical 18-gauge needle.
• Flexible Wire Tip: The 0.018-inch wire is soft, lacks a J-loop, and navigates tight corners and calcifications better than a standard J-tip wire. This is especially useful when entering at a steep angle or accessing small vessels.

To use a micropuncture kit, gain vessel access with the needle and wire, railroad the sheath and introducer into the vessel, remove the wire, then remove the introducer. Now you have a 4 Fr or 5 Fr sheath in the vessel. This is typically used to introduce a normal central line wire. 

For arterial lines, you can place them directly over the wire without dilation. Keep in mind that the 4 Fr sheath (1.3 mm OD) and 5 Fr sheath (1.7 mm OD) are larger than a typical arterial line catheter (18g = 1.27 mm OD). If you dilate then you will cause hematoma.

Find out where your department stores micropuncture kits and get familiar with their components. While it adds an extra step to the procedure, it could make the difference between securing the line or not.

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Euglycemic DKA (eDKA) is a medical emergency requiring prompt attention. It is caused by an imbalance of insulin and glucagon leading to ketone accumulation (1-3). In addition to typical risk factors for DKA, those for eDKA include SGLT-2 inhibitor use and pregnancy, with 30% of DKA cases in pregnancy presenting euglycemic (4, 5).

eDKA presents with an anion gap metabolic acidosis, ketosis/ketonuria, & blood glucose less than 250 mg/dL.

Diagnosis requires ruling out other causes of anion gap metabolic acidosis, including toxic ingestions.

The cornerstone of eDKA management is ensuring enough dextrose to allow needed insulin administration to reverse ketone accumulation.

Pitfalls

• Not giving enough insulin to reverse ketosis due to concern about low blood sugars
• Not giving enough dextrose to support sufficient insulin dosing
• Not uptitrating insulin for refractory acidosis caused by eDKA

Pearls

• Start insulin with at least 0.05 units/kg/hour along with IV dextrose (3,5,7,9)
• Start IV dextrose at 5-10 g/hr (9). This will be 100-200 mL/hr of a 5% dextrose solution (dextrose should be added to either normal or ½ normal saline to avoid causing hyponatremia!)
  • Dextrose concentrations: D5 = 50 g/L || D10 = 100 g/L || D20 = 200 g/L
• Euglycemic DKA may present WITHOUT ketonuria if the patient is on an SGLT-2 inhibitor (7,8) – send a beta hydroxybutyrate!
• eDKA is most common in the first two months of SGLT-2 inhibitor use, but can happen at any time (6)

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