Target Controlled Infusion (TCI): Understanding its Benefits and Limitations

Target-controlled infusion, or TCI, is a method of drug administration rapidly gaining popularity in the medical field. TCI involves using computerized systems to calculate and control the infusion rate of a drug to achieve a specific target concentration in the patient's bloodstream.

The history and mechanics of TCI

Enhancements in understanding the pharmacodynamics of opioids and anaesthetic drugs led to the development of TCI—a method of IV drug administration in the 1980s. Initially developed by Schüttler and Schwilden, TCI leverages sophisticated computer programs to predict the plasma concentration level at a given site and helps regulate the level of anaesthetic input into the bloodstream through syringe pumps. Today, TCI-enabled syringe pumps from manufacturers such as Clarity Medical are the mainstay of anaesthesia teams worldwide.

How does TCI work?

The TCI system uses a mathematical model that considers the patient's weight, age, sex, and other factors to determine the optimal dose of the drug. An anaesthesiologist sets the target drug concentration based on the patient's needs and the type of procedure.

Once the target drug concentration is set, the TCI system uses sensor feedback that monitors the patient's vital signs to adjust the infusion rate and maintain the desired drug concentration. The pump is programmed to deliver the drug continuously, with minor adjustments made automatically to keep the concentration within a set range.

What is a typical use case for TCI?

Anaesthesia administration during surgical procedures is a typical use case scenario for target-controlled infusion (TCI). Here is an example:

• > Hospital staff prep the patient for surgery and insert an IV line.
• > The anaesthesiologist inputs the patient's weight, age, and other relevant information into the TCI system.
• > The anaesthesiologist then chooses the required drug and sets the target concentration based on the patient's needs and the type of procedure.
• > The TCI system then starts infusing the drug at a calculated rate based on the patient's vitals and the target concentration.
• > The system monitors the patient's vital signs, such as heart rate, blood pressure, and oxygen saturation, and adjusts the required infusion rate to maintain the desired drug concentration.
• > Based on the patient's vitals, the anaesthesiologist can adjust the target concentration or the infusion rate as needed during the procedure.
• > Once the procedure or surgery is complete, the infusion is gradually reduced or stopped, and the patient can recover.

Using TCI in this scenario allows for precise control over the amount of anaesthesia administered to the patient, improving safety and comfort during the procedure. It also allows for more efficient administration, reducing the need for manual calculations and adjustments by medical staff.

What are the benefits of TCI?

One of the main benefits of TCI is precise drug dosage control. TCI systems use sophisticated algorithms to calculate the right amount of drug needed to achieve the desired therapeutic effect based on patient-specific factors such as age, weight, and medical history. This ensures that the patient receives optimal drug dosage, reducing the risk of adverse effects.

• > Rapid dosage adjustment: With TCI, doctors can rapidly adjust drug dosages as needed. Traditional drug administration methods involve bolus injections or continuous infusions, which can be challenging to adjust according to changes in the patient's condition. TCI systems, on the other hand, can quickly and accurately adjust drug dosages in response to changes in the patient's vital signs or other clinical indicators.
• > Precise dosing: TCI provides precise control over the dosing of intravenous drugs, allowing for more accurate titration of medication to meet the patient's needs. This can help reduce the risk of under or over-dosing, preventing incidents of adverse effects or inadequate anaesthesia.
• > Consistency: TCI maintains a consistent drug concentration in the patient's bloodstream, which helps avoid fluctuations in drug levels caused by manual administration.
• > Safety: TCI can help minimize the risk of adverse drug reactions by ensuring the concentration remains within a therapeutic range. Additionally, the computerized system can alert the medical team if the drug concentration deviates from the intended target, allowing for rapid intervention.
• > Efficiency: TCI can streamline the administration of intravenous drugs, reducing the need for manual calculations and adjustments. This can help save time for medical staff and may reduce the overall cost of care.
• > Patient comfort: TCI can provide a more comfortable experience for patients, as doctors can tailor drug dosage for patients. This can help reduce side effects and ensure the patient receives adequate anaesthesia or pain management during medical procedures.

Are there limitations to the usage of TCI?

Despite its apparent benefits, TCI has some limitations that hospitals must consider before implementation. Some limitations of TCI include:

• > Variability in drug pharmacokinetics: The accuracy of TCI depends on the accuracy of the mathematical model used to calculate the infusion rate. However, individual patient variability in drug pharmacokinetics can make it difficult to predict drug concentrations in the bloodstream accurately.
• > Need for patient monitoring: TCI requires continuous monitoring of the patient's vital signs, such as heart rate, blood pressure, and oxygen saturation, to ensure that the drug concentration remains within a safe and effective range.
• > Operator error: TCI requires careful programming and monitoring by medical staff to ensure accurate dosing and safe administration. Human error, including incorrect programming or failure to respond to alerts can quickly lead to adverse events.
• > Limitations of TCI for some drugs: TCI may not be suitable for all drugs, particularly those with complex pharmacokinetics or medications with narrow therapeutic ranges.

While TCI can be a valuable tool in specific medical applications, you must consider its limitations before deciding on its implementation. Healthcare providers should carefully weigh the benefits and risks of TCI and ensure that appropriate patient monitoring and staff training are in place to ensure safe and effective administration.

Clarity Medical's TCI-enabled syringe pumps

Clarity Medical offers world-class TCI-enabled syringe pumps for the precise and safe administration of intravenous drugs in anaesthesia and pain management. Implemented successfully at premier research hospitals in India and abroad, Clarity Medical's syringe pumps incorporate advanced software algorithms to calculate and control drug infusion delivery rates as low as 0.1ml/hr and offer up to four bolus modes for total control.

Conclusion

TCI is a promising method of drug administration that offers several benefits, including precise dosing control, rapid adjustment of dosages, and efficient use of drugs. Using TCI syringe pumps can help your hospital transform its standards of care for the better.