Total Intravenous Anaesthesia

Definition

Total intravenous anaesthesia (TIVA) is a technique of providing general anaesthesia entirely with intravenous drugs — with no inhalational agent. Typically a continuous propofol infusion provides hypnosis and a short-acting opioid (e.g. Remifentanil) provides analgesia, with a muscle relaxant if needed. Infusions are often controlled by a target-controlled infusion (TCI) pump.

Target-controlled Infusion (tci)

A TCI pump uses pharmacokinetic models to calculate and continuously adjust the infusion rate needed to achieve and maintain a chosen target blood (or effect-site) concentration of the drug, which the anaesthetist titrates to clinical effect. This makes running an intravenous anaesthetic as controllable as adjusting a vaporiser.

Advantages & Indications

TIVA offers a smooth, clear recovery with less postoperative nausea and vomiting (propofol is anti-emetic), avoids the environmental pollution and the triggers of malignant hyperthermia associated with volatile agents, and gives a stable anaesthetic where inhalational agents are unsuitable. Specific indications: patients susceptible to malignant hyperthermia, those with severe PONV, neuroanaesthesia, procedures needing a shared airway (rigid bronchoscopy) or tubeless field, and transfers.

Context-sensitive Half-time

The suitability of a drug for infusion depends on its context-sensitive half-time — the time for its concentration to halve after stopping an infusion, which lengthens the longer the infusion has run. Propofol and remifentanil have short, relatively context-insensitive half-times, giving predictable rapid recovery even after long cases — which is why they are the mainstays of TIVA.

Depth Monitoring & Safe Conduct

Because the classic sign of light anaesthesia — movement — is abolished when a muscle relaxant is used, and because a failed intravenous line delivers no anaesthetic at all, the safe conduct of total intravenous anaesthesia depends on meticulous attention to the delivery system and to depth monitoring. The cannula and the whole length of the infusion line are kept visible and are checked for disconnection, leakage or tissuing; a dedicated cannula or an anti-reflux and anti-siphon valve arrangement is used; and processed-EEG depth-of-anaesthesia monitoring is often employed, particularly when relaxants are given, to reduce the risk of accidental awareness that is the technique’s most feared complication.

Advantages, Disadvantages & Indications Summary

Weighing up the technique, the advantages of total intravenous anaesthesia are a smooth and clear recovery with a low incidence of nausea and vomiting, the avoidance of the environmental pollution and the malignant-hyperthermia trigger associated with volatile agents, and haemodynamic and airway conditions that suit specific procedures; the disadvantages are the need for reliable, secure intravenous access, the greater dependence on equipment (infusion pumps and their programming), the cost, and the risk of awareness if delivery fails. These trade-offs explain its clear indications — the malignant-hyperthermia-susceptible patient, the patient with severe postoperative nausea, neuroanaesthesia, and operations on a shared or unprotected airway such as rigid bronchoscopy — where its benefits outweigh its demands.

Preferred where malignant hyperthermia risk or PONV is a concern.

• TIVA = general anaesthesia with IV drugs only (no volatile) — usually propofol + short-acting opioid.
• TCI pumps target a chosen blood/effect-site concentration using pharmacokinetic models.
• Advantages: clear anti-emetic recovery, no MH trigger, no pollution; good for MH-risk, PONV, neuro, shared airway.
• Key risk: awareness if the IV fails (relaxant masks signs) — keep line visible; use depth monitoring.
• Suitable drugs have a short context-sensitive half-time (propofol, remifentanil).