Lessons

Total Intravenous Anesthesia (TIVA)

Total intravenous anesthesia (TIVA) traditionally refers to general anesthesia maintained by intravenous medications without using inhaled volatile (“gas”) anesthetics. To safely accomplish this, one must understand the pharmacokinetics involved with maintaining an appropriate plasma/brain concentration for a given medication (propofol, dexmedetomidine, opioids, ketamine, etc.) and the synergy/side effects of these agents.

Interestingly, there is mixed data suggesting TIVA may confer better analgesic effects compared to classical “balanced” anesthetics using inhaled agents. Additionally, TIVA tends to lead to smoother emergence from anesthesia, less nausea/vomiting post-operatively, and it avoids the risk of malignant hyperthermia.

So what are the drawbacks? One could argue that compared to measuring end-tidal concentrations of volatile agents to gauge anesthetic depth, there’s no good way to know how “deep” someone is under TIVA. The BIS monitor is often used to help with this endeavor, but it’s only an adjunct that should be interpreted in the entire clinical picture (ie, significant hemodynamic changes in response to surgical stimulus could suggest inadequate depth). Furthermore, TIVA is thought to be more expensive than volatile-based anesthetics, but it’s hard to really calculate the potential cost savings from such a technique (ie, fewer admissions for post-op nausea/vomiting?).

As a cardiothoracic anesthesiologist, I most commonly use TIVA in cases where intraoperative neuromonitoring is utilized (ie, thoracoabdominal aortic aneurysm repairs) since this technique interferes less with measuring evoked potentials. I go through plenty of propofol vials for these long cases!

Drop me a comment below with questions! 🙂

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2 Comments

  1. What’s your opinion on doing say, spinal surgery, utilizing around .5 MAC of gas plus a remifentanil infusion? I know the literature states that it’s possible to do this without interfering too much with the neuromonitoring. However, would you ever opt for this over straight TIVA alongside a remi infusion? In my experience I still feel that the use of .5 MAC volatile interferes with my neuromonitoring.

    1. Interesting question! When I was a resident, our intraoperative neuromonitorists were okay with a fixed MAC of volatile anesthetic (I typically did 0.5 MAC of sevoflurane) with, as you mentioned, IV anesthetics alongside it (I did some combination of propofol, sufentanil, remifentanil, ketamine, and dexmedetomidine depending on the situation). These cases were long but fairly homogeneous.

      Now as a cardiothoracic anesthesia fellow, we have to negotiate with our neuromonitorists to allow 0.2-0.3 MAC of isoflurane (which makes a HUGE difference) for cases like thoracoabdominal aortic aneurysm repairs which have significant variability. If we do a straight TIVA for these, we’d be using an inordinate amount of propofol. Additionally, the pharmacokinetics of these medications are altered when we’re on cardiopulmonary bypass. The bypass machine has the ability to bleed in volatile anesthetic which is what our perfusionists are comfortable doing. I’ll compromise with them and most often run 0.3 MAC of isoflurane with propofol and sufentanil drips.

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