Medical Imaging Contrast Agents and Venipuncture Procedures

Guidelines for Administering Contrast Agents in Medical Imaging

• Patient history should be reviewed before administering contrast agents to avoid risk, especially in patients with sickle cell anemia, severe asthma, drug allergy, adverse reaction to contrast media, or impaired kidney function.
• Patient education is necessary before contrast administration, and technologists should provide information to patients and caregivers to improve treatment outcomes.
• Patient preparation may include a restricted diet and bowel preparation before administering oral contrast agents.
• Proper preparation of contrast media includes using the correct dose based on patient weight and age, checking for expiration dates, and using aseptic technique.
• Contrast administration by hand requires careful attention to the puncture site, aspiration of a small amount of blood, and monitoring for extravasation.
• Contrast administration by power/pressure injector requires checking the integrity of venous access, matching the gauge of the angiocatheter with the rate of contrast media flow, flushing the catheter and tubing with sterile saline solution, and avoiding alternative access sites.
• Adverse reactions to contrast media may be local or systemic, and require immediate action including stopping contrast administration, cold compress, medication, and follow-up care.
• Contrast reactions can range from mild to severe, and severe reactions can be life-threatening, requiring emergency care.
• Emergency procedures for anaphylactic shock include seeking immediate help, injecting epinephrine into the outer muscle of the thigh, administering oxygen and IV antihistamines and cortisone, and performing CPR if necessary.
• NSF (Nephrogenic Systemic Fibrosis) is a rare but serious condition associated with the use of gadolinium-based contrast agents in patients with renal disease, hypertension, or diabetes.
• ACR Guidelines on renal function and dialysis provide detailed information on the risk factors for NSF.
• The FDA requires a black box warning on the labeling of prescription drugs or drug products associated with serious hazards, including contrast agents.

Guidelines for Administering Contrast Agents in Medical Imaging

• Patient history should be reviewed before administering contrast agents to avoid risk, especially in patients with sickle cell anemia, severe asthma, drug allergy, adverse reaction to contrast media, or impaired kidney function.
• Patient education is necessary before contrast administration, and technologists should provide information to patients and caregivers to improve treatment outcomes.
• Patient preparation may include a restricted diet and bowel preparation before administering oral contrast agents.
• Proper preparation of contrast media includes using the correct dose based on patient weight and age, checking for expiration dates, and using aseptic technique.
• Contrast administration by hand requires careful attention to the puncture site, aspiration of a small amount of blood, and monitoring for extravasation.
• Contrast administration by power/pressure injector requires checking the integrity of venous access, matching the gauge of the angiocatheter with the rate of contrast media flow, flushing the catheter and tubing with sterile saline solution, and avoiding alternative access sites.
• Adverse reactions to contrast media may be local or systemic, and require immediate action including stopping contrast administration, cold compress, medication, and follow-up care.
• Contrast reactions can range from mild to severe, and severe reactions can be life-threatening, requiring emergency care.
• Emergency procedures for anaphylactic shock include seeking immediate help, injecting epinephrine into the outer muscle of the thigh, administering oxygen and IV antihistamines and cortisone, and performing CPR if necessary.
• NSF (Nephrogenic Systemic Fibrosis) is a rare but serious condition associated with the use of gadolinium-based contrast agents in patients with renal disease, hypertension, or diabetes.
• ACR Guidelines on renal function and dialysis provide detailed information on the risk factors for NSF.
• The FDA requires a black box warning on the labeling of prescription drugs or drug products associated with serious hazards, including contrast agents.

Venipuncture: Types of Blood Vessels, Choosing a Suitable Vein, and Procedure

• There are three types of blood vessels: veins, arteries, and capillaries.
• Venipuncture is performed only on veins.
• Veins have valves that open and close with muscle contraction to help blood flow.
• The most suitable vein for venipuncture should be evaluated through palpation and visual inspection.
• Veins near sites of infection, bruising, phlebitis, edematous tissue, and previous venipuncture should be avoided.
• Age, weight, medications, temperature, and patient anxiety are factors that influence vein selection for venipuncture.
• Techniques to improve venous access include applying a tourniquet, opening and closing the fist, lowering the arm below heart level, and light tapping of the vein.
• Students in California are not allowed to perform venipuncture on patients, but they can observe and learn during clinical externship.
• Venipuncture to inject contrast material is permitted for certified radiologic technologists who have completed an approved training course.
• The larger and fuller median cubital and cephalic veins of the arm are used most frequently, but the basilic vein on the dorsum of the arm or dorsal hand veins are also acceptable for venipuncture.
• Areas to be avoided when choosing a site include extensive scars, hematoma, edematous extremities, and sites where venipuncture has been recently performed.
• The procedure for venipuncture includes identifying the patient correctly, verifying their condition, applying a tourniquet, selecting the venipuncture site, preparing the patient's arm, inserting the needle, removing the tourniquet, checking for infiltration/extravasation, removing the needle, and pressing down on the gauze.