From the Guidelines
A suitable mixture for Total Intravenous Anesthesia (TIVA) using a single syringe administration typically consists of 50 mcg/ml of alfentanil and 10 mg/ml of propofol. This combination is based on the pharmacological characteristics of both drugs, as outlined in the Difficult Airway Society guidelines for awake tracheal intubation in adults 1. The onset of action for alfentanil is 2-3 minutes, with a duration of action of 15 minutes, while propofol has an onset of action of 30 seconds, with a duration of action of 5-10 minutes.
To prepare the mixture, combine 40 mg of alfentanil (400 mcg/ml) and 200 mg of propofol (10 mg/ml) in a 20 ml syringe, creating a solution where each ml contains 20 mcg of alfentanil and 10 mg of propofol. For induction, 0.5-1 ml per 10 kg of body weight is recommended, followed by maintenance infusion of 0.5-1 ml/kg/hour, titrated to clinical effect. This combination works synergistically, with propofol providing hypnosis and amnesia, while alfentanil delivers analgesia.
Key considerations when using this mixture include:
- Monitoring the patient for respiratory depression, hypotension, and bradycardia
- Having resuscitation equipment readily available
- Administering the mixture within 6 hours due to propofol's lipid emulsion supporting bacterial growth
- Using aseptic technique when preparing the mixture
- Titration of the maintenance infusion to clinical effect, as the combination can cause hemodynamic instability. The vasodilatory effects of propofol can be partially offset by the use of alfentanil, as outlined in the characteristics of drugs used commonly during awake tracheal intubation 1.
This combination is particularly useful for short procedures requiring rapid recovery, and its use should be guided by the principles of target-controlled infusion (TCI) and the pharmacological characteristics of the individual drugs, as described in the guidelines 1.
From the Research
Suitable Mixtures for 1 Syringe TIVA
To determine a suitable mixture of alfentanyl and propofol for 1 syringe Total Intravenous Anesthesia (TIVA), we can look at the evidence provided by various studies.
- A study from 2000 2 used a mixture of 45 ml of propofol 1% and 2,500 micrograms of alfentanil in a 50-ml syringe for TIVA in patients undergoing orthopedic surgery. This mixture was found to be effective, with comparable intubation conditions and hemodynamic responses to intubation as an inhalational anesthetic technique.
- Another study from 1998 3 investigated the use of propofol and alfentanil for TIVA in major thoracic surgery. The study found that continuous infusions of propofol and alfentanil provided safe and reliable TIVA, with no significant differences in heart rate or blood pressure between groups.
- However, it's worth noting that the optimal mixture of alfentanyl and propofol may vary depending on the specific patient population and surgical procedure. For example, a study from 2014 4 compared the use of sufentanil and alfentanil in combination with propofol for TIVA in breast surgery, and found that patients in the sufentanil group had less postoperative pain and required less opioid medication.
Key Findings
- A mixture of 45 ml of propofol 1% and 2,500 micrograms of alfentanil in a 50-ml syringe was found to be effective for TIVA in orthopedic surgery 2.
- Continuous infusions of propofol and alfentanil provided safe and reliable TIVA for major thoracic surgery 3.
- The optimal mixture of alfentanyl and propofol may vary depending on the specific patient population and surgical procedure 4.
Considerations for 1 Syringe TIVA
- The use of a single syringe for TIVA may be convenient, but it's essential to ensure that the mixture is stable and effective for the specific patient population and surgical procedure.
- The studies provided do not directly address the stability of alfentanyl and propofol mixtures in a single syringe, so further investigation may be necessary to determine the optimal mixture and storage conditions.