Skip to main content

"Lipid sink effect"..Does it really exist?

There´s evidence of intravenous lipid emulsions being effective antidotes in systemic local anesthetic toxicity.

The most popular theory on the mechanism of action being the so called ‘lipid sink effect’.

The idea is that lipid globules sequester lipophilic substances, thereby reducing plasma concentrations of the toxin.

It is a popular theory, but so far the – mostly animal – studies are conflicting regarding the real mechanism of action.

 In fact, we don’t even know if it’s an effective therapy.

 A study in Anestesia Analgesia in 2011 tries to shed some light.

The studyPigs were injected with toxic systemic doses, of either Bupivacaine or Mepivacaine.
They were then randomized into treatment with either Ringer’s Acetate or lipid emulsion. Plasma concentrations and hemodynamic effects (the treatment parameters) were recorded while the pigs were being treated.

ResultsThere were no overall significant differences in Bupivacaine or Mepivacaine plasma concentrations between the ringer and emulsion groups. So, no evidence of a lipid sink effect there. Furthermore, comparison of heart rate and MAP at all time-points, failed to demonstrate any effect of lipid infusion over Ringer’s Lactate.

Clinical implications:

In this very small study, there was neither any demonstrable ‘lipid sink effect’ nor evidence of efficacy of treating local anaesthetic systemic toxicity with lipid emulsion.
So then, how does this fit in with the many promising case reports? The authors suggest there could be another unknown mechanism, other than sequestration.

However the lipid sink effect does exist. Local anaesthetics probably aren’t lipophilic enough. Other, more lipophilic drugs, like Amiodarone, are effectively sequestered.

Litonius ES, Niiya T, Neuvonen PJ, Rosenberg PH. Intravenous Lipid Emulsion Only Minimally Influences Bupivacaine and Mepivacaine Distribution in Plasma and Does Not Enhance Recovery from Intoxication in Kids.
Anesth Analg. 2011 Oct 24.
Labels:

Comments

Post a Comment

Popular posts from this blog

power injectable peripherally inserted central catheters

Clinical experience with power injectable peripherally inserted central catheters in intensive care patients     Introduction In intensive care units (ICU), peripherally inserted central catheters (PICC) may be an alternative option to standard central venous catheters, particularly in patients with coagulation disorders or at high risk for infection. Some limits of PICCs (such as low flow rates) may be overcome by the use of power-injectable catheters . Method We have retrospectively reviewed all the power injectable PICCs inserted in adult and pediatric patients in the ICU during a 12-month period, focusing on the rate of complications at insertion and during maintenance. Results We have collected 89 power injectable PICCs (in adults and in children), both multiple and single lumen. All insertions were successful. There were no major complications at insertion and no episodes of catheter-related blood stream infection. Non-infective complications ...
1 comment
Read more

Falling from Height...The Prognostic factors

Falls from Height is Knwon to cause major morbidities and mortalities.  There are several prognostic factors for survival that have been identified: Height Age Type of surface Body part that touches the ground first Two other factors are important, but do not have a significant effect on mortality: Circumstances of the fall (suicide, accident, escape) Initial impact with an object before impacting the ground Height . Overall, about half of victims die at the scene, and a total of 70% die before they reach the hospital . The median height leading to death is about 49 feet, or about 4 to 5 storeys. 100% of victims die after falling 85 feet, or about 8 storeys. Age . Mortality increases with age due to pre-existing medical conditions and decreased physiologic reserve. Type of surface . The type of surface struck (i.e. grass, water, construction debris) can also have an effect on secondary injuries and survival. Mortality after striking a hard surface is nearly doubl...
Post a Comment
Read more

The 12 decision making steps for post dural puncture headache treatment

Treatment decision-making algorithm for postdural puncture headache. 1. When diagnosis is made, all patients should receive supportive measures (reassurance, bed rest, analgesics, hydration, quiet environment). 2. Severity of symptoms should be classified using VAS scale (mild 1–3, moderate 4–6, severe 7–10). 3. Virtually all patients will improve in time even without additional therapy. (dashed lines) 4. Symptoms worsen or fail to resolve within 5 days. 5. Patient preference dictates the choice between pharmacologic (less effective) and epidural blood patch (EBP). 6. In patients with severe symptoms, EBP is strongly suggested. 7. The most common pharmacologic measure is  caffeine  prescription. 8. The failure, worsening, or recurrence of symptoms after pharmacologic measures favors the use of EBP. 9. In addition to EBP, other epidural treatment options can be considered in select patients (eg,  dextran , saline). 10. A period of 24 h should lapse before repeating EBP. 11...
1 comment
Read more