Guidelines for Contrast Administration

Guidelines for Contrast Administration - Pre-Scan Prep & Shield Up!

• Patient Assessment:
  • History: Allergies (prior reaction), asthma, renal (eGFR), diabetes (metformin), myeloma, pheo, thyroid.
  • Renal Function: Check eGFR.

    ⭐ High risk for PC-AKI if eGFR < 30 $mL/min/1.73m^2$ with iodinated contrast.

• Informed Consent: Discuss & document risks, benefits, alternatives.
• Hydration: Crucial for at-risk patients (oral/IV). Ensure adequacy.
• Premedication (Prior Mild/Moderate Reaction):
  • Corticosteroids: Prednisolone 30-40mg (12 & 2h pre-scan).
  • Antihistamine: Diphenhydramine 25-50mg (1h pre-scan).
• Metformin Management: Hold if eGFR < 30 $mL/min/1.73m^2$ or AKI. Resume 48h post, if renal stable.
• Fasting: Usually 4-6h for elective procedures (minimizes aspiration risk).

Guidelines for Contrast Administration - Agent Choice & Smart Dose!

• Agent Choice
  • Prefer Non-ionic agents: LOCM (Low Osmolar Contrast Media) or IOCM (Iso-Osmolar Contrast Media).
  • IOCM (e.g., Iodixanol) best for high-risk patients (e.g., eGFR < 45 mL/min/1.73m², diabetes, myeloma).
• Smart Dose (ALARA Principle)
  • Minimum effective volume/concentration. Typical Iodinated dose: 1-1.5 mL/kg.
  • Monitor cumulative dose, especially in repeat studies.
• Iodinated Contrast & Renal Function (eGFR in mL/min/1.73m²)
  • eGFR > 45: Standard protocol.
  • eGFR 30-45: Caution. Pre-hydration. Use LOCM (IOCM preferred).
  • eGFR < 30: High CIN (Contrast-Induced Nephropathy) risk. Avoid if possible. If essential: IOCM + aggressive max hydration.

    ⭐ For patients with eGFR < 30 mL/min/1.73m², if iodinated contrast is vital, IOCM is the agent of choice, preferred with robust periprocedural hydration to mitigate CIN risk.

• Gadolinium-Based Contrast Agents (GBCAs) & Renal Function
  • eGFR < 30 mL/min/1.73m²: Avoid Group I GBCAs (highest NSF risk). Prefer Group II GBCAs if essential.

![Image placeholder: Visual guide to contrast choice based on eGFR and risk factors]

Guidelines for Contrast Administration - Safe Injection, Smooth Flow!

• IV Access:
  • Secure peripheral IV, preferably 18-20G (antecubital fossa ideal).
  • Confirm patency with saline flush; check for free flow.
• Pre-Procedure Checklist:
  • Verify patient ID, informed consent, and allergy history.
  • Double-check contrast agent, concentration, dose, and expiry date.
  • Consider warming contrast media to body temperature to ↓ viscosity & ↑ patient comfort.
• Injection Technique:
  • Monitor injection site continuously (visual/palpation) for signs of extravasation (pain, swelling).
  • Follow contrast with a saline flush (e.g., 20-30 mL) to ensure complete delivery and clear tubing.
• Documentation: Record agent, volume, injection rate, site, and any immediate adverse events.

⭐ Always ensure the IV line is patent and running well before connecting a power injector. Test injection with saline is crucial to prevent extravasation, especially with high flow rates used in CT angiography (CTA).

Guidelines for Contrast Administration - Reaction Rescue, Code Ready!

• Reaction Triage & Action:
  • Mild (urticaria, nausea): Antihistamines (Diphenhydramine 25-50 mg IV/IM).
  • Moderate (bronchospasm, angioedema): Epinephrine (0.1-0.3 mg IM/SC), O2, IV fluids.
  • Severe (anaphylaxis, shock): Epinephrine (0.3-0.5 mg IM or 0.1 mg IV slow), CPR, ACLS. ⚠️ Call Code Blue!
• Preparedness:
  • Accessible crash cart: Stocked & checked daily.
  • Trained team & established protocols.
• Vulnerable Groups - Dose/CM Adjustments:
  • Renal Impairment (eGFR <30 mL/min/1.73m²): Pre-hydration, use iso-osmolar or low-osmolar CM, avoid NSAIDs.
  • Pregnancy: Crucial indications only; non-iodinated CM if possible.
  • Pediatrics: Weight-based dosing (e.g., Iohexol 1-2 mL/kg); ensure hydration.

⭐ Pre-treatment (e.g., corticosteroids, antihistamines) is strongly recommended for patients with a prior moderate-severe allergic-like reaction to the same class of contrast media or multiple severe allergies.

High‑Yield Points - ⚡ Biggest Takeaways

• eGFR <30 mL/min/1.73m² is critical for iodinated contrast; assess risk, consider alternatives.
• Prior moderate/severe allergic reaction requires premedication (steroids, antihistamines).
• Ensure adequate hydration pre/post-procedure, especially for high-risk patients.
• Metformin: Hold 48h post-contrast if eGFR <60 or AKI.
• Breastfeeding: Generally safe; minimal contrast excretion into milk.
• Extravasation: Elevate limb, apply appropriate cold/warm compresses.
• Promptly manage acute adverse reactions (anaphylactoid vs. chemotoxic).