Patient Evaluation and Care

• Hernia


  Occurs when an organ or fatty tissue squeezes through a weak spot in the fascia, a thin casing of connective tissue that surrounds and holds an organ, blood vessel, or muscle in place
• Thrombus


  A blood clot that is stationary and does not move, but if dislodged by an instrument used in IR it can travel to and obstruct smaller vessels
• Informed consent


  State-dependent and should include access complications, catheter/guidewire manipulation, contrast agent reactions, sedatives/analgesics, and other required medications
• Preprocedure testing

  Routine (screening) or selective (directed), focusing on renal function and coagulation status
• Contrast-induced nephropathy


  Marked by a rise in serum creatinine 1-3 days after the study, resolving at 7-10 days
• Measures to prevent contrast-induced renal dysfunction

  1. Use low osmolar contrast materials

  2. Limit total contrast volume

  3. Consider carbon dioxide, gadolinium, or MRA as alternatives

  4. Use pharmacologic regimens to reduce likelihood
• Coagulation and hematologic parameters

  Routine assessment is unnecessary for most diagnostic and therapeutic vascular procedures, but testing is done for procedures with higher bleeding risk

  
• Selective coagulation testing

  • Bleeding time
  • Fibrinogen
  • Hemoglobin and hematocrit

  
• INR


  Standardizes variability in thromboplastin assays to warfarin anticoagulation, with a target therapeutic range of 2.0 to 3.0

  
• Diet and hydration

  Patients are limited to clear liquids within 8 hours and made NPO within 2 hours to avoid nausea and vomiting
• Medications

  Insulin-dependent diabetics reduce morning dose, metformin is withheld, antihypertensives are taken, anticoagulants are managed, and preprocedure sedation may be given
• Contrast reaction pretreatment


  Standard regimen includes steroids (mandatory) and histamine receptor blockers (optional)
• acetylcysteine (Mucomyst)


  An antioxidant that acts as a scavenger of oxygen free radicals and inhibitor of certain proteins implicated in kidney damage from contrast media
• Sodium bicarbonate infusion


  More effective than saline hydration in prevention of contrast nephropathy in patients with renal dysfunction
• Theophylline


  An antagonist of adenosine, which has been implicated in contrast-related nephropathy by a vasoconstrictor effect leading to reduced glomerular filtration
• 1. acetylcysteine (Mucomyst)


  An antioxidant that acts as a scavenger of oxygen free radicals and inhibitor of certain proteins implicated in kidney damage from iodine-based contrast media
• Sodium Bicarbonate Infusion


  1. 154 mEq/L as 3 mL/kg/hr bolus for 1 hour before contrast administration, followed by 1 mL/kg/hr for 6 hours afterward

  2. Found to be more effective than saline hydration in prevention of contrast nephropathy in patients with some degree of renal dysfunction undergoing cardiac catheterization
• Procedures where antibiotics are generally used

  • All biliary procedures
  • Genitourinary procedures (with noted exceptions)
  • Drainage of suspected abscess collections
  • Therapeutic vascular procedures leading to tissue ablation (e.g., chemoembolization)
  • Transjugular intrahepatic portosystemic shunt (TIPS) procedure
  • Endograft placement
• Procedures where prophylactic antibiotics are generally not indicated

  • Routine angiographic procedures
  • Urinary tract tube changes and checks in patients with intact immune systems
  • Clear fluid aspirations (e.g., renal cyst)
• Procedures where use of prophylactic antibiotics is controversial

  • Placement of implanted vascular access devices
  • Hemodialysis access treatment
  • Intravascular stent placement
  • Thrombolysis procedures
  • Non-neoplastic embolization procedures
  • Gastrostomy
• Radiation Safety


  • The radiation dose to the patient can be minimized by: limiting fluoroscopy time, careful beam collimation, use of lead shields
  • Transient skin damage may occur after a dose of 2 Gy
  • Permanent damage usually requires doses above 5 Gy
  • Procedures with greatest risk include TIPS, embolization, intravascular stent placement, and uterine artery embolization
  • Operators should protect themselves by use of protective clothing, such as body aprons, thyroid shields, and leaded glasses, and by other methods, such as beam collimation, use of last image hold, and use of moveable leaded barriers during fluoroscopy and manual acquisition of digital images
• Infectious Disease Precautions


  • The risk of transmission of blood-borne pathogens from physician to patient during vascular and interventional procedures is vanishingly small, but the risk of transmission from patient to operator is very real
  • Universal precautions should be followed, including use of surgical gowns, masks, protective eyewear, and two pairs of gloves
• Patient Monitoring


  • The interventionalist should note the baseline vital signs before the procedure begins
  • Patients undergo continuous cardiac monitoring, continuous pulse oximetry, and cuff blood pressure measurement every 5 to 10 minutes, depending on the patient's condition

  
• Sedation and Analgesia


  • Patients undergoing vascular and interventional radiologic procedures always experience some anxiety and pain, but the degree of discomfort may not reflect the invasiveness of the procedure
  • Reassurance is an important method to reduce anxiety and pain
  • The goals of sedation during interventional procedures are: relief of pain, anxiolysis, partial amnesia, and control of patient behavior
• Conscious Sedation


  In most cases, the goals of sedation can be met with moderate (conscious) sedation, in which the patient is calm, drowsy, and may even close his eyes but is responsive to verbal commands and able to protect his reflexes and airway
• Standard Analgesic and Sedative Agents Employed During Vascular and Interventional Procedures

  • Narcotics
  • Benzodiazepines
  • Neuroleptic Tranquilizers
• Midazolam (Versed)


  • A short-acting benzodiazepine that acts on GABA receptors to cause central newous system depression (including anxiolysis and antegrade amnesia)
  • Its onset of action is 2 to 4 minutes, and the duration of action is about 45 to 60 minutes
• Fentanyl (Sublimaze)


  • A short-acting narcotic opioid analgesic that also is metabolized by the liver
  • Its onset of action is 2 to 4 minutes, and the duration of action is about 30 to 60 minutes
  • Additional doses are generally required every 3 to 10 minutes to maintain a continuous level of comfort
• Overmedication


  The primary signs are a drop in oxygen saturation and respiratory depression
• Treatment of Adverse Events and Reactions

  • Successful management depends on recognizing problems quickly, acting promptly, and employing basic resuscitative efforts: continuous patient monitoring, protecting the patient's airway, securing the intravenous line and administering fluid replacement as needed, giving supplemental oxygen, calling for assistance early
• Hypoxia


  Low oxygen levels, the patient becomes cyanotic (especially extremities such as the tip of the fingers) because of the lack of oxygen
• Flumazenil (Romazicon)


  A benzodiazepine antagonist, the initial dose of 0.2 mg given by IV push may be repeated up to a total dose of 3 mg

  
• Atropine


  • A muscarinic, cholinergic blocking agent that affects the heart, bronchial and intestinal smooth muscle, central nervous system, secretory glands, and iris
  • The initial dose is 0.5 to 1.0 mg IV, which may be repeated every 3 to 5 minutes up to a total dose of 2.5 mg

  
• Sublingual Nifedipine vs Labetalol


  Sublingual nifedipine (10 mg) was once considered the first-line agent due to its rapid onset of action (5 to 10 minutes), but many practitioners have turned to the nonselective beta-blocker labetalol due to reports of life-threatening hypotension with nifedipine
• Other agents to consider in patients with refractory hypertension are metoprolol, esmolol, and nitroglycerin paste
• Mild Contrast Media Agent Reaction

  • Patient reassurance should be the first step, and mild reactions produce urticaria or nausea and vomiting
  • Persistent nausea and vomiting may be treated with an intravenous antiemetic, such as prochlorperazine 2.5 to 10 mg or droperidol 0.625 to 1.25 mg
• Mild Contrast Media Agent Reaction


  Produces urticaria or nausea and vomiting
• Nausea and vomiting usually occur with the first dose of contrast material and are self-limited
• Hives


  Self-limiting, resolves on its own
• Moderate Contrast Agent Reaction

  • Manifested by mild bronchospasm or wheezing, mild facial or laryngeal edema, or isolated hypotension with tachycardia