Indocyaninegreen for Injection Introduction
1. General Information
Indocyaninegreen for Injection is a diagnostic agent primarily used in various medical imaging and functional assessment procedures. The active ingredient, indocyaninegreen (ICG), is a tricarbocyanine dye. It is formulated as a powder for injection that needs to be reconstituted with sterile water before use. Once reconstituted, it forms a green - colored solution. ICG is highly protein - bound in the bloodstream and is rapidly cleared by the liver without undergoing significant metabolism, making it a valuable tool for evaluating liver function and blood flow in different tissues.
2. Mechanism of Action
When administered intravenously, indocyaninegreen binds strongly to plasma proteins, mainly albumin. It circulates in the bloodstream and is selectively taken up by the hepatocytes (liver cells) without being excreted into the bile canaliculi via the enterohepatic circulation. Instead, it is directly secreted into the bile. By measuring the rate of disappearance of ICG from the bloodstream over time, healthcare providers can assess the liver's functional capacity, including its blood - flow rate, hepatocyte uptake ability, and excretory function. In addition, due to its unique optical properties, ICG can be used in fluorescence imaging techniques. When exposed to specific wavelengths of light, ICG emits fluorescence, which enables real - time visualization of blood perfusion and tissue viability in surgical and interventional procedures.
3. Indications
3.1 Liver Function Assessment
ICG is widely used to evaluate liver function in patients with various liver diseases, such as hepatitis, cirrhosis, and liver tumors. By calculating parameters like the ICG plasma disappearance rate (ICG - PDR) and the retention rate of ICG at a specific time point (e.g., 15 minutes after injection, ICG - R15), clinicians can obtain quantitative information about the liver's synthetic, uptake, and excretory functions. This helps in the diagnosis, prognosis assessment, and treatment planning for liver - related disorders.
3.2 Surgical and Interventional Guidance
In surgical procedures, especially those involving the liver, biliary tract, or blood vessels, Indocyaninegreen for Injection is used for fluorescence - guided imaging. It allows surgeons to visualize the boundaries of liver tumors, identify the blood supply and drainage patterns of the liver segments, and ensure complete resection while minimizing damage to healthy tissues. In minimally invasive procedures like laparoscopic or robotic surgeries, ICG - based fluorescence imaging provides enhanced visualization, improving surgical precision and safety. Additionally, it can be used to assess the patency of blood vessels and the viability of tissues during vascular surgeries and organ transplants.
3.3 Ophthalmic Applications
In ophthalmology, ICG angiography is used to evaluate the blood vessels in the choroid layer of the eye. By injecting ICG intravenously and capturing images of the fluorescent signal emitted by the dye as it circulates through the choroidal blood vessels, doctors can detect various ocular disorders, such as age - related macular degeneration, choroidal neovascularization, and certain types of retinal diseases. This helps in early diagnosis and appropriate treatment of these conditions.
4. Dosage and Administration
4.1 Dosage for Liver Function Assessment
The typical dosage for assessing liver function is 0.5 - 5 mg/kg of body weight, administered as a rapid intravenous injection. The exact dosage may vary depending on the patient's age, overall health status, and the specific purpose of the assessment. After injection, blood samples are collected at regular intervals (usually at 0, 5, 10, 15, and 30 minutes) to measure the concentration of ICG in the plasma, which is then used to calculate the relevant liver function parameters.
4.2 Dosage for Surgical and Imaging Guidance
For surgical and interventional procedures, the dosage is usually 0.25 - 2 mg/kg. The injection can be given as a single bolus or as multiple small doses depending on the surgical requirements. In fluorescence - guided surgeries, the imaging system is adjusted to detect the ICG - induced fluorescence, providing real - time visual feedback to the surgical team.
4.3 Dosage for Ophthalmic Applications
In ophthalmic ICG angiography, the typical dosage is 25 mg (usually reconstituted from a 25 - mg vial) administered intravenously. The imaging process starts shortly after the injection to capture the dynamic flow of the dye through the choroidal blood vessels.
5. Precautions and Contraindications
5.1 Contraindications
Indocyaninegreen for Injection is contraindicated in patients with a known hypersensitivity to indocyaninegreen or any of the components used in the formulation. It should also not be used in patients with severe allergic reactions to other diagnostic dyes. Additionally, in patients with significant cardiac or pulmonary insufficiency, careful consideration is required, as the injection may cause transient hemodynamic changes.
5.2 Precautions
Before administration, it is essential to inquire about the patient's medical history, especially regarding allergies, liver and kidney function, and other underlying health conditions. Since ICG is excreted by the liver, patients with severely impaired liver function may experience prolonged retention of the dye, which may affect the accuracy of the test results and increase the risk of adverse reactions. In such cases, dosage adjustment or alternative diagnostic methods may be necessary. The reconstituted ICG solution should be used immediately after preparation, as it is unstable and may degrade over time, affecting its diagnostic efficacy.
5.3 Special Populations
In elderly patients, the dosage may need to be adjusted based on their individual physiological status, especially considering potential age - related changes in liver and kidney function. Pregnant and breastfeeding women should use ICG with caution, as the safety of the dye during these periods has not been fully established. Adequate evaluation of the benefits and risks to both the mother and the fetus/infant is required before administration.
6. Adverse Reactions
The most common adverse reactions associated with Indocyaninegreen for Injection are mild and transient, including nausea, vomiting, and a feeling of warmth or flushing at the injection site. These symptoms usually resolve on their own within a short period. Less common but more serious adverse reactions may include allergic reactions, ranging from mild skin rashes to severe anaphylaxis. In rare cases, transient changes in blood pressure and heart rate may occur, especially in patients with pre - existing cardiovascular conditions. If any severe or persistent adverse reactions occur, immediate medical attention should be sought, and appropriate treatment measures should be taken.
In conclusion, Indocyaninegreen for Injection is a versatile diagnostic agent with important applications in liver function assessment, surgical guidance, and ophthalmology. When used properly, with careful consideration of dosage, precautions, and potential adverse reactions, it can provide valuable information for clinical diagnosis, treatment planning, and surgical procedures, contributing significantly to patient care.
