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Pharmacology and Equipment in Interventional Radiology

Pharmacology and Equipment in Interventional Radiology

RAT TEST - EQUIPMENT

  • RAT Test Overview

    • Individual RATs with each question worth 4 marks.

    • Uncertainty allows for multiple answers. Marks assigned for correct answers.

  • tRAT

    • Completed in groups with a common set of questions.

    • Marks are assigned based on ticks for correct answers (1 to 4 ticks correspond to 4, 3, 1, or 0 marks).

Learning Outcomes

  • Comprehend the basic principles of pharmacology.

  • Identify common drugs used in interventional radiology (IR) procedures.

  • Highlight the radiographer's role in drug administration, monitoring, and patient care during IR.

  • Discuss safety, legal, and ethical considerations in pharmacological practices.

  • Link to module learning outcome: Demonstrate imaging techniques, patient radiation protection, and drug/contrast agent preparation.

Importance of Pharmacology

  • Enhances procedural outcomes.

  • Ensures patient comfort and safety.

  • Supports minimally invasive techniques.

Role of Radiographers in Drug Administration

  • Administer drugs under supervision.

  • Monitor and identify adverse reactions.

  • Ensure drug safety and maintenance of proper documentation.

Administration of Drugs

  • Definition: Application of a drug to the body.

  • Routes of Administration: Methods through which drugs are introduced into the body.

  • Selection Considerations:

    • Physical characteristics of the drug.

    • Required speed of absorption.

    • Necessary concentration at specific body areas.

    • Patient condition and related factors.

Pharmacokinetics

  • Involves the movement of drugs through absorption, distribution, metabolism, and elimination.

Absorption

  • More common routes in IR are intravenous (IV) or intra-arterial (IA) for rapid action.

  • Factors affecting absorption:

    • Blood flow at administration site.

    • Drug formulation.

Distribution

  • Transports drugs from the bloodstream to tissues/organs. Influenced by:

    • Perfusion to target organs.

    • Plasma binding proteins.

    • Blood-brain barrier.

Metabolism

  • Chemical modification of drugs for elimination, primarily via the liver.

  • Enzyme activity and first pass effect are critical components.

Elimination

  • The body removes drugs through:

    • Renal excretion.

    • Hepatic (liver) excretion.

    • Other pathways including sweat, lungs, saliva.

Pharmacodynamics

  • Examines the biological effects of drugs, including mechanisms of action and dose-response relationships.

Mechanisms of Action

  • Agonists: Activate receptors to produce a effect.

  • Antagonists: Block the action of agonists.

  • Enzyme Inhibitors: Interfere with enzyme action.

Dose-Response Relationships

  • Therapeutic Effect: Desired outcome.

  • Toxic Effect: Undesired harmful effects.

  • Dose-Response Curve: Graphical representation of drug response over varying doses.

Factors Influencing Drug Efficacy

  • Age, comorbidities, and drug interactions significantly impact outcomes.

Common Drug Categories in IR

  • Contrast Agents:

    • Enhance imaging by highlighting blood vessels and structure functionality.

    • Types include iodinated contrast media, gadolinium-based agents, and barium sulfate.

    • Considerations: adverse reactions, warming of agents, and injection pressures.

  • Anticoagulants and Antiplatelets:

    • Used to manage clotting, examples include heparin, warfarin, clopidogrel, and aspirin.

  • Sedation:

    • Involves relaxation without pain relief, often paired with analgesics.

    • Drugs like midazolam are utilized for sedation in prolonged procedures.

  • Analgesics:

    • Minimize pain during procedures often through intravenous administration.

    • Examples include lidocaine (local anesthetic) and fentanyl or morphine (analgesics).

Embolization

  • Involves blocking abnormal blood vessels using materials like coils or glue.

  • Clinical indications:

    • Control or prevent bleeding, manage uterine fibroids, occlude tumors, and treat AVMs.

    • Thrombolytics

  • Thrombolytics: Dissolve abnormal clots (e.g., alteplase, Urokinase).

    • Essential for maintaining blood circulation and preventing tissue damage.

Vasodilators and Vasoconstrictors

  • Control vascular tone for optimal imaging and treatment.

  • Examples include nitroglycerin (vasodilator) and epinephrine (vasoconstrictor).

Antibiotics

  • Prevent infections during high-risk IR procedures (e.g., cefazolin, vancomycin).

Safety, Legal, and Ethical Considerations

  • Patient Monitoring: Focus on vital signs, including blood pressure, heart rate, and oxygen saturation.

  • Adverse Reactions: Recognizing and managing mild to severe reactions associated with drug administration.

Legal Responsibilities of Radiographers

  • Responsible for ensuring drugs are properly prescribed/administered under supervision, following protocols for drug storage and handling.

Ethical Considerations

  • Need for informed consent regarding off-label drug use and clear communication about potential side effects to patients.

Management of Complications

  • Bleeding: Monitor vital signs and assist in treatment.

  • Allergic Reactions: Prompt recognition and management critical, including administration of epinephrine.

  • Contrast Induced Nephropathy: Awareness of risk factors and preventative actions such as hydration and monitoring renal function.

Discussion Points

  • Address challenges faced by radiographers in IR concerning pharmacology.

Case Study Example

  • Discussion of a scenario involving angioplasty procedures and monitoring responses to sedation.

Conclusion

  • Encouragement for questions and clarifications.