Intravenous Contrast Media M3 PP

Contrast agents are used in procedures like CT scans. They're not frequently used by anesthesiologists, but they might be given for surgeries or in offsite settings.

A contrast agent's chemical structure determines its physical and chemical properties. It's an essential factor in its safety and effectiveness.

Osmolality refers to the concentration of dissolved particles in a solution. It's important in contrast media because it impacts the risk of adverse effects.

High osmolality contrast agents, like Renografin and Hypaque, have a higher risk of side effects. They are less commonly used than low osmolality agents.

Low osmolality contrast agents are non-ionic monomers, such as Omnipaque and Isovue. They are preferred due to their safer profile.

Low osmolality contrast agents have fewer adverse events, lower chemotoxicity (less harmful to cells), and less tissue damage in case of extravasation. However, they tend to be more expensive.

Contrast agents can potentially impact the kidneys, so they are part of the renal pharmacology module.

Contrast media generally have a good safety record. However, severe and life-threatening reactions can still occur. These reactions are often mild and self-limited.

A rapid decrease in renal blood flow and glomerular filtration rate caused by a large dose of contrast media, often followed by diuresis. This occurs due to the osmotic effect of contrast media on the kidneys, drawing water from the blood into the urine.

Directly damaging or killing cells, increasing the activity of certain enzymes, activating the complement and fibrinolytic systems, and triggering inflammatory processes.

Reactions to contrast media that occur within 20 minutes of injection and resemble anaphylaxis but are not caused by IgE antibodies. Often triggered by the release of histamine and other inflammatory mediators.

The risk of idiosyncratic reactions to contrast media is higher in patients with asthma, history of allergic reactions, and extensive food and environmental allergies.

A serious condition that can develop after contrast media injection, occurring 30 minutes to a week later. It presents with flu-like symptoms, headache, nausea, and may not be readily linked to the contrast media.

Contraindications to contrast media during pregnancy because it can cross the placenta, potentially cause DNA mutations, and even fetal hypothyroidism.

A negative effect of contrast media on the heart, causing a decrease in myocardial contractility and potential for arrhythmias.

A reflex reaction to contrast media causing a sudden drop in heart rate (bradycardia) and blood pressure (hypotension), potentially leading to syncope.

A potential complication of contrast media administration due to rapid fluid overload. This can lead to increased blood pressure and pulmonary edema.

Tissue damage caused by contrast media leaking outside the blood vessel, leading to swelling, bruising, and potential for compartment syndrome.

A condition caused by pressure build-up in a muscle compartment, often due to extravasation. It can lead to severe pain, swelling, and potentially tissue damage.

A metallic taste, nausea, vomiting, constipation, itching, syncope, and seizures. These can occur as reactions to contrast media.

The use of isotonic intravenous fluids (IV fluids) during anesthesia to help maintain fluid balance and reduce the risk of complications when using contrast media.

Patients who have previously experienced a reaction to contrast media should be closely monitored for potential adverse events. This is due to the risk of re-exposure.

A risk factor for contrast media reactions in which a patient's respiratory system is particularly sensitive to stimuli, increasing the likelihood of allergic-like responses.

A condition that can worsen after receiving contrast dyes. It involves the adrenal glands releasing catecholamines.

A type of anemia where red blood cells are abnormally shaped, which can be aggravated by contrast dyes.

Kidney dysfunction occurring 1-3 days after contrast dye administration, characterized by elevated creatinine and potential renal insufficiency.

A potent vasoconstrictor that increases during CIN, reducing blood flow to the kidneys.

A potent vasodilator that decreases in CIN, promoting vasoconstriction.

The narrowing of blood vessels, which occurs in CIN, reducing blood flow to the kidneys.

A process involving oxidative stress, cellular lesions, and potential renal failure, occurring in CIN.

The process of administering medications that block the effects of histamine and may be used to treat contrast-induced allergic reactions.

The process of administering medications that block the effects of histamine, often used to treat contrast-induced allergic reactions.

Drugs like Diphenhydramine (Benadryl) and Famotidine (Pepcid) that are used to treat allergic reactions or reduce stomach acid.

The process of administering fluids intravenously to support circulation, particularly in cases of low blood pressure.

Fluids with a similar osmotic pressure as blood, preventing cell damage.

A condition causing fluid loss and dehydration, often associated with severe diarrhea or vomiting.

The process of carefully assessing a patient's medical history and physical condition before any procedure.

The process of monitoring a patient's vital signs, such as heart rate, blood pressure, and breathing, during a procedure.

A drug that helps to restore blood flow to the kidneys, preventing a condition called contrast-induced nephropathy.

The drug acts as an antioxidant, protecting tissues from damage caused by free radicals, and promotes blood vessel dilation.

It might be used in some cases to help open up constricted airways.

It helps to neutralize excess acid in the blood, which can sometimes occur after a contrast dye reaction.

They help to remove excess fluid from the body, which can be beneficial in some cases.

It's not typically recommended to stop routine diuretic medications. If a patient is already taking diuretics or ACE inhibitors, it is usually ok to continue those medications.

They can help treat severe bronchospasm, which can occur as a complication of a contrast dye reaction.

It can help to widen the airways and improve breathing.

They help to block the release of histamine, which is a chemical that can trigger allergic reactions

A standard of care for preventing severe reactions to contrast dye.

They help to prevent the blood vessels from becoming too narrow, which can cause problems like low blood pressure.

It's a type of near-infrared light spectrum, fluorescent agent that is injected into a patient's body.

They are used to improve visualization during surgery, helping surgeons to identify specific tissues and structures.

It's the most common fluorophore used in surgery.

The ICG is injected into the blood and travels to the liver. Then the green dye will be taken up by tumor cells.

Indocyanine green (ICG) is a dye used in surgery to enhance visualization of blood flow, specifically in certain surgical procedures. It is especially useful for detecting leaks in blood vessels and identifying healthy tissues during surgery.

ICG is typically mixed in a small amount of sterile water, usually 5 milliliters, to create a concentrated solution for surgical administration.

The dosage of ICG for adults is usually 5 milligrams, while children typically receive half of that amount. The maximum safe dose is 2 milligrams per kilogram of body weight.

ICG is primarily excreted by the liver and bile, with a rapid elimination half-life of a few minutes.

Hepatic and biliary uptake and clearance are the primary mechanisms for ICG elimination from the body, resulting in a rapid elimination half-life of a few minutes.

ICG can cause allergic reactions, including hives and hypersensitivity. In rare cases, severe anaphylaxis with potential fatality can occur.

Indigo carmine, another contrast agent similar to ICG, is less frequently used in modern practice.

Indigo carmine is often used in cystoscopy procedures. It can also be used in obstetrics to assess amniotic fluid leaks.

Indigo carmine can stimulate alpha adrenergic receptors, leading to vasoconstriction. This may result in an increase in Systemic Vascular Resistance (SVR) and Pulmonary Vascular Resistance.

Methylene blue is another contrast agent similar to ICG but has a lower capacity to penetrate tissues compared to ICG. It is often used in the ICU setting.

Methylene blue is incompatible with normal saline solution and should be diluted in D5W (5% dextrose in water) if necessary.

Methylene blue is contraindicated in pregnant patients due to its potential for fetal harm. It is categorized as a pregnancy category X.

Methylene blue is also contraindicated in patients with G6PD deficiency. This is because it can lead to hemolytic anemia in individuals with this genetic condition.

Methylene blue can be used to treat methemoglobinemia by reducing the ferric iron (Fe3+) in methemoglobin back to its ferrous state (Fe2+).

Methylene blue is contraindicated in patients with hepatic or renal impairment and those taking certain antidepressant medications like SSRIs, MAOIs, and tricyclic antidepressants.

The use of these contrast agents must be carefully considered and coordinated between the anesthesia provider, the surgeon, and the pre-operative team to ensure appropriate timing and administration.

Methylene blue's chemical structure can be altered in the body, shifting between a reduced form (leucomethylene blue) and an oxidized form (ferric iron state).

Methylene blue's mechanism of action involves reducing ferric iron (Fe3+) to ferrous iron (Fe2+) in methemoglobin, restoring its oxygen-carrying capacity.

Methylene blue's vasoconstrictive effects result from its ability to inhibit nitric oxide synthase, the enzyme that produces nitric oxide, a vasodilator.

Methylene blue can also inhibit guanylate cyclase, the enzyme that produces cyclic GMP, a smooth muscle relaxant, contributing to vasoconstriction.

Methylene blue's vasopressor actions make it useful in situations like Vasophlegia syndrome, septic shock, refractory hypotension, anaphylaxis, and even liver transplants.

Methylene blue can interfere with oximeter readings by absorbing and emitting light in a way that's different from hemoglobin, potentially leading to falsely lower oxygen saturation readings.

Methylene blue can potentially interfere with bispectral index (BIS) readings, which assess brain activity, but the exact mechanism is not fully understood - potential vasoconstriction might play a role.

Methylene blue is a potent monoamine oxidase inhibitor (MAOI), mimicking the mechanism of action of MAOI antidepressants and potentially contributing to serotonin toxicity.

High doses of methylene blue, especially with antidepressants, can lead to serotonin syndrome, a potentially fatal condition characterized by excessive serotonin levels in the central nervous system.

Methylene blue's administration route can vary depending on the indication: IV infusion for vasopressor effects, IV push for methemoglobinemia, but it should always be given slowly.

Methylene blue can cause adverse effects like hemolysis (red blood cell destruction), hypersensitivity, hypertension, angina, and reduced perfusion in tissues like the mesentery and skin.

Methylene blue is highly bound to albumin, a protein in the blood, affecting its distribution and duration of action.

Methylene blue's average dose is 1 mg/kg, but the specific dose depends on the indication and patient factors.

Methylene blue is particularly useful in cardiac surgery after bypass to treat Vasophlegia syndrome, a condition of low blood pressure and reduced blood flow to the extremities.

Methylene blue can be helpful in managing septic shock, a potentially life-threatening condition characterized by widespread inflammation and low blood pressure.

Methylene blue is sometimes used in refractory hypotension (unresponsive low blood pressure), anaphylaxis (severe allergic reaction), and even liver transplants, though research is still ongoing in these areas.