Single-syringe total intravenous anesthesia (TIVA) represents an evolution of conventional TIVA techniques. It combines propofol and remifentanil in a single syringe to provide simultaneous hypnosis and analgesia. Traditional TIVA typically uses separate target-controlled infusion (TCI) pumps or manual infusions for hypnotic and opioid agents. The single-syringe approach aims to simplify equipment requirements, reduce infusion pump utilization, and streamline workflow while maintaining predictable pharmacodynamic effects. Recent prospective and laboratory investigations have renewed interest in this method, particularly in ambulatory and resource-limited settings (1).
The pharmacologic rationale for single-syringe TIVA lies in the complementary profiles of propofol and remifentanil. Propofol provides rapid-onset hypnosis with favorable recovery characteristics, and remifentanil, an ultra-short-acting μ-opioid receptor agonist metabolized by nonspecific esterases, provides readily titratable analgesia. When combined in a fixed ratio, both agents can be delivered proportionally, potentially maintaining a stable balance between hypnosis and analgesia throughout the procedure. Bennion et al. recently reported on a prospective cohort study that evaluated the feasibility of single-syringe propofol-remifentanil TIVA and demonstrated its ability to provide acceptable hemodynamic stability in clinical practice (1). Their findings suggest that with proper patient selection and vigilant monitoring, this simplified method can achieve anesthetic conditions similar to those of more complex infusion strategies.
A key consideration in single-syringe TIVA is the stability of remifentanil when mixed with propofol’s lipid emulsion. Since propofol is an oil-in-water emulsion, concerns have been raised about the potential impact of combining the two drugs on remifentanil’s concentration, distribution, and overall reliability within the syringe. Any inconsistency in the mixture could alter dosing accuracy and reduce the predictability of anesthetic depth.
However, Westley et al. demonstrated in laboratory studies that remifentanil concentrations remained consistent in propofol–remifentanil admixtures over clinically relevant time periods (2). These findings support the practical compatibility of the combined preparation when prepared correctly. In clinical use, maintaining consistency requires careful aseptic technique, standardized drug ratios, and adherence to recommended time limits for syringe use. When these precautions are followed, the mixture provides stable and dependable drug delivery.
From a systems perspective, single-syringe TIVA may also improve efficiency. Analyses of propofol administration techniques demonstrate that induction method and pump usage influence drug utilization and waste. Windler et al. demonstrated that infusion practices can significantly impact the volume of propofol discarded after anesthesia induction (3). Single-syringe approaches consolidate agents into one syringe and reduce the number of pumps required.
Professional recommendations emphasize that safe TIVA practice, whether single- or dual-syringe, requires comprehensive monitoring, including continuous electrocardiography, noninvasive blood pressure monitoring, pulse oximetry, capnography, and, when appropriate, processed electroencephalographic monitoring (4). Guidelines also stress the importance of understanding pharmacokinetic interactions, preparing drug mixtures under aseptic conditions, and being prepared to manage hypotension, bradycardia, or respiratory depression (5). Because single-syringe TIVA fixes the propofol–remifentanil ratio, clinicians must recognize that rapid adjustments in analgesic depth independent of hypnotic depth are limited compared with dual-infusion techniques. Consequently, careful patient selection and anticipation of surgical stimulation intensity are essential.
References
1. Bennion N, Brower TS, Ballard CR, et al. Single-Syringe Total Intravenous Anesthesia With Propofol and Remifentanil: A Prospective Cohort Study. Anesth Analg. Published online May 30, 2025. doi:10.1213/ANE.0000000000007581
2. Wylie N, Beale L, Westley I. Consistency of remifentanil concentrations in propofol-Remifentanil infusions. A laboratory-based study. Paediatr Anaesth. 2022;32(6):727-731. doi:10.1111/pan.14427
3. Windler F, Coburn M, Bette B, Fingerhut D, Jacobi A, Kruse P. Effects of manual and syringe pump induction of total intravenous anaesthesia on propofol waste: a single-centre retrospective analysis. Br J Anaesth. 2024;133(6):1459-1464. doi:10.1016/j.bja.2024.10.002
4. Obara S, Kamata K, Nakao M, Yamaguchi S, Kiyama S. Recommendation for the practice of total intravenous anesthesia. J Anesth. 2024;38(6):738-746. doi:10.1007/s00540-024-03398-2