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Questions and Answers
What is the primary reason for using iodinated contrast media?
What is the primary reason for using iodinated contrast media?
Which of the following is NOT a characteristic used to classify iodinated contrast media?
Which of the following is NOT a characteristic used to classify iodinated contrast media?
What is a key difference between high-osmolality and low-osmolality iodinated contrast media (ICM)?
What is a key difference between high-osmolality and low-osmolality iodinated contrast media (ICM)?
What is a potential adverse effect of iodinated contrast media related to its osmotic properties?
What is a potential adverse effect of iodinated contrast media related to its osmotic properties?
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Which of the following is a characteristic of an idiosyncratic reaction to iodinated contrast media?
Which of the following is a characteristic of an idiosyncratic reaction to iodinated contrast media?
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Which of the following is NOT a common symptom of an idiosyncratic reaction to iodinated contrast media?
Which of the following is NOT a common symptom of an idiosyncratic reaction to iodinated contrast media?
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What is the mechanism of action of theophylline in the management of contrast-induced nephropathy (CIN)?
What is the mechanism of action of theophylline in the management of contrast-induced nephropathy (CIN)?
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What is a possible strategy for preventing contrast-induced nephropathy, based on current evidence?
What is a possible strategy for preventing contrast-induced nephropathy, based on current evidence?
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Which type of tissue damage can occur due to extravasation of iodinated contrast media?
Which type of tissue damage can occur due to extravasation of iodinated contrast media?
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What is a characteristic of indocyanine green (ICG) that makes it useful in fluorescence-guided surgery?
What is a characteristic of indocyanine green (ICG) that makes it useful in fluorescence-guided surgery?
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Which of the following is NOT a potential application of fluorescence-guided surgery?
Which of the following is NOT a potential application of fluorescence-guided surgery?
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What is a significant adverse reaction potentially associated with Indocyanine Green (ICG) use?
What is a significant adverse reaction potentially associated with Indocyanine Green (ICG) use?
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How is indocyanine green (ICG) typically administered for fluorescence-guided surgery?
How is indocyanine green (ICG) typically administered for fluorescence-guided surgery?
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What is the half-life of Indocyanine green (ICG) in the body?
What is the half-life of Indocyanine green (ICG) in the body?
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What is the recommended storage solution for Indocyanine green (ICG) after reconstitution?
What is the recommended storage solution for Indocyanine green (ICG) after reconstitution?
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What is a potential adverse effect of methylene blue in patients taking antidepressants?
What is a potential adverse effect of methylene blue in patients taking antidepressants?
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Which of the following are potential adverse effects of methylene blue?
Which of the following are potential adverse effects of methylene blue?
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How does methylene blue affect pulse oximetry readings?
How does methylene blue affect pulse oximetry readings?
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What does oxyhemoglobin primarily absorb?
What does oxyhemoglobin primarily absorb?
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What effect do IV dyes have on oximetry technology?
What effect do IV dyes have on oximetry technology?
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In addition to serotonin toxicity, which of the following is a risk associated with methylene blue?
In addition to serotonin toxicity, which of the following is a risk associated with methylene blue?
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Which element is common in the monitoring of oxygen saturation?
Which element is common in the monitoring of oxygen saturation?
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What can be misleading about bispectral index readings when methylene blue is administered?
What can be misleading about bispectral index readings when methylene blue is administered?
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What is the maximum dosage of Methylene Blue that can be administered per kilogram of body weight?
What is the maximum dosage of Methylene Blue that can be administered per kilogram of body weight?
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What is the peak absorption and excitation wavelength for Indigo Carmine?
What is the peak absorption and excitation wavelength for Indigo Carmine?
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Which of the following is a contraindication for Methylene Blue administration?
Which of the following is a contraindication for Methylene Blue administration?
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What is the half-life of Indigo Carmine?
What is the half-life of Indigo Carmine?
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What is a potential effect of Methylene Blue related to blood pressure?
What is a potential effect of Methylene Blue related to blood pressure?
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How is Methylene Blue commonly administered?
How is Methylene Blue commonly administered?
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For what reason might Methylene Blue be administered during liver transplantation?
For what reason might Methylene Blue be administered during liver transplantation?
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What is the typical dosage range for Methylene Blue when administered intravenously?
What is the typical dosage range for Methylene Blue when administered intravenously?
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Which of the following conditions may lead to an increased risk when using Methylene Blue?
Which of the following conditions may lead to an increased risk when using Methylene Blue?
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What safety information is lacking regarding Indigo Carmine?
What safety information is lacking regarding Indigo Carmine?
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Study Notes
Intravenous Contrast Media (ICM)
- Introduced in the 1950s, ICMs are commonly prescribed drugs.
- They enhance radiologic imaging.
- ICMs generally have a good safety record, with adverse effects often mild and self-limiting, but severe, life-threatening reactions are possible.
- ICMs are classified based on modifications of a 2,4,6-tri-iodinated benzene ring.
Osmolality
- Osmolality is related to chemical structure.
- High-osmolar ICMs (Renografin, Hypaque, Conray) have a higher risk of adverse effects.
- Low-osmolar ICMs (Omnipaque, Isovue, Optiray, Ultravist) are preferred due to fewer adverse events and less chemotoxicity. They are more costly but less damaging to tissue if extravasated.
Osmotic Effects
- ICMs can transiently decrease renal blood flow and glomerular filtration rate (GFR).
- ICMs can have a dehydrating effect.
ICM Reactions
- ICM reactions can stem from direct cellular toxicity, enzyme induction, or activation of complement, fibrinolytic, kinin, or other systems.
- Reactions are classified as idiosyncratic or nonidiosyncratic.
- Contrast-induced nephropathy (CIN) is a possible complication.
Idiosyncratic Reactions
- These reactions happen within 20 minutes of injection, independent of the dose.
- They aren't true hypersensitivity reactions (no IgE antibodies involved).
- They're common in patients with prior ICM reactions, asthma, or allergies.
- Recurrence isn't guaranteed.
Symptoms of Idiosyncratic Reactions
- Skin reactions (hives, pruritus).
- Gastrointestinal issues (nausea, vomiting).
- Sweating (diaphoresis).
- Cardiovascular problems (high or low blood pressure, tachycardia or bradycardia, arrhythmias, syncope, seizures).
- Severe cases can lead to death.
- Respiratory distress (bronchospasm, pulmonary edema).
Nonidiosyncratic Reactions
- These reactions can be delayed (30 minutes to 7 days after injection).
- They may resemble flu-like symptoms.
- They are of concern in pregnancy as the ICM can cross the placenta.
- ICMs may be mutagenic, and nonionic agents are favored for administration.
Nonidiosyncratic Cardiovascular Reactions
- ICMs can affect the myocardium directly.
- Vasovagal reactions are possible, often leading to angina or syncope.
- There is a heightened risk of peripheral vasodilation, hypotension, ventricular arrhythmias and cardiac arrest.
- High-osmolar fluids with ICM can also lead to hypertension and pulmonary edema.
Other Nonidiosyncratic Reactions
- Possible reactions include neuropathy, polyarthropathy, site reactions from extravasation, tissue damage, compartment syndrome.
- Other reactions include metallic taste, nausea, vomiting, constipation, pruritus, syncope and depression.
- ICMs can exacerbate existing cardiac conditions, arrhythmias, pheochromocytoma, sickle cell anemia, hyperthyroidism, and myasthenia gravis.
Contrast-Induced Nephropathy (CIN)
- CIN involves a significant elevation in creatinine (>50% baseline) and up to 25% of patients experience sustained renal insufficiency / oliguria.
- Pre-existing renal insufficiency significantly increases CIN risk.
- Other factors increasing risk include CHF, aging, the use of NSAIDs or aminoglycosides, repeated injections and large doses of ICM.
- Contributing factors include high ICM viscosity, high osmolarity, dehydration, and underlying tubular damage.
Management Considerations
- Pre-operative assessments are crucial, and equipment and drugs for managing emergencies should be readily available.
- For non-idiosyncratic reactions, treatment is focused on symptoms.
- For moderate or severe reactions including anaphylaxis or severe cardiovascular compromise/failure, airway, breathing and circulation must be managed promptly. Antihistamines (H1 and H2 blockers), epinephrine, corticosteroids and IV fluids to correct hypotension are crucial.
Management Considerations for CIN
- Adequate hydration, supportive treatment and measures directed at restoring volume and electrolyte balance are imperative.
- The use of specific therapies like antioxidants and the adjustment of factors that increase CIN risk, are necessary.
Management Considerations: Prevention
- Prevention strategies include considering corticosteroids, especially after a patient has suffered a prior severe reaction.
- Other prevention measures, such as lower-level support, for prevention include the administration of antihistamines before and after the procedure.
Contrast Media in Specific Procedures
- Fluorescence-guided surgery uses fluorescent contrast agents to enhance visibility in minimally invasive procedures like sentinel lymph node mapping, tumor detection, visualization of vital structures and tissue perfusion.
Indocyanine Green (ICG)
- ICG is a nonspecific contrast agent used in the near-infrared region.
- It has an absorption/emission at 800-850 nm.
- A 25 mg vial of sterile green powder is reconstituted, and used within 6 hours.
- Hypersensitivity reactions such as hives are possible, and antihistamines, corticosteroids, and epinephrine might be required.
- Anaphylaxis is also a possible severe adverse reaction.
Indigo Carmine
- Indigo Carmine is a nonspecific contrast agent in the near infrared region.
- It has uses like cystoscopy for ureteral injury and flow assessments, and in obstetrics for amniotic fluid leak assessment.
- It is administered intravenously or intramuscularly.
- Half-life is 4-5 minutes, and dose is 5 mL.
- Pregnancy safety is not fully established.
Methylene Blue (MB)
- MB is another nonspecific contrast agent, used in near-infrared region with absorption/emission around 700 nm, with less tissue penetration than ICG.
- Common formulations include ampules and prefilled syringes.
- It is incompatible with normal saline and must be diluted in 50mL of D5W before administration.
- Important to avoid in patients with G6PD deficiency, severe hepatic or renal impairment.
- Black box warning for fetal harm exists.
Methylene Blue Adverse Reactions
- A potent adverse effect of MB is fatal serotonin toxicity in patients taking antidepressants.
- Hemolysis, hypersensitivity reactions, hypertension, angina, and reduced perfusion are also possible.
Oximetry Interference
- IV dyes interfere with oximetry readings.
- Pulse and cerebral oximetry are affected by dyes that impact red and infrared wavelength absorption ratios, leading to falsely low oxygenation readings.
- This is particularly concerning with the use of methylene blue.
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Description
This quiz covers the fundamentals of Intravenous Contrast Media (ICM), including their classification, safety, and effects on osmolality and renal function. Learn about the differences between high-osmolar and low-osmolar ICMs, as well as the potential reactions and adverse effects associated with their use in radiologic imaging.
