Carolinas Case Conference - Dr. S. Pecevich

Bleeding AV Fistulas

• AV Fistula vs. AV Graft
  • Fistula
    • Surgically connect artery to vein
    • Goal is to increase flow and pressure into the vein for access
    • About 2-3 months to mature for use
  • Graft
    • Foreign body
    • Tubing connects artery to vein
    • Only 2-3 weeks before able to access
    • Higher complication rate: thrombosis, infection
• Pink or white skin exposed in a Graft patient? Skin breakdown is a huge concern. Requires urgent evaluation.
• Uncontrolled bleeding? Hold pressure but with intention! Plug the source of bleeding directly. Wrapping with miles of Coban just diffuses the pressure elsewhere.
  • If you place a tourniquet, there may still be bleeding--likely venous ooze
  • Be wary of sutures--the dilated AV fistula gradually starts to fuse with skin. When you throw a suture, you may actually be insulting the VEIN itself
• Pseudoaneurysm vs. Aneurysm
  • Pseudoaneurysm: fibrous collection of blood that does not include all 3 vessel layers. Seen more commonly with grafts, likely from repeated cannulation
    • Can be diagnosed with ultrasound, also usually seen on physical exam
  • Aneurysm: Includes all 3 vessel layers. Unclear etiology. Likely from pressure.
• Hemorrhagic shock? Put the triple lumen down. Fluids are more quickly administered using LARGE diameter SHORT catheters. Peripheral IVs are just as fast, if not faster, than a large Cordis when administered with high pressure. (Poiseuille's law)

 
Agitated Delirium

• IM Ketamine works for agitated delirium and there is now evidence to suggest this. This can be administered IV and IM. IV dosing is 1-2mg/kg and IM dosing 4-6 mg/kg. Remember, you can’t “over-dissociate” someone, be confident in dosing.
• Concerns for respiratory depression with over sedation? Watch your end tidal CO2 and don’t hesitate to use nasopharyngeal airway.
• Do not talk yourself out of a lumbar puncture. If this is unattainable, at least give the patient the antibiotics necessary to cover for meningitis / encephalitis.
• Agitated patient? Unlikely to be traumatic brain or central nervous process (outside of infection). You will need the head CT but understand that these pathologies more likely to cause somnolence and depressed mental status.
• Watch out for your staff. Demanding IV access in the restrained patients with 5 security guards in the room is a safety risk. Use your IM medications instead and then place IV later.

 
Drugs and Considerations

• Lorazepam -- GABA agonist, slow onset, longer peak action, poor onset IM. Be wary of stacking Lorazepam doses because the peak action of about 20 minutes can seem like an eternity.
• Midazolam -- GABA agonist, fast onset, short peak of action, works well IM. You can generally bag a patient through midazolam over sedation with the anticipation it will wear off quickly. Be wary of synergism in EtOH intoxicated patient.
• Haloperidol/Ziprasidone -- dopamine receptor antagonist, rarely an immediate effect. QT prolongation, NMS and dystonic reactions to be considered. Hot patient with clonus or dystonia?--probably want to avoid.
• Dexmedetomidine -- alpha2 agonist, respiratory depression is rare, great for alcohol withdrawal. Be wary of hypotension/bradycardia--this is essentially IV clonidine

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