Lipid Emulsion Infusion Rescues Dogs From BupivacaineInduced Cardiac Toxicity - PowerPoint PPT Presentation

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Lipid Emulsion Infusion Rescues Dogs From BupivacaineInduced Cardiac Toxicity

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Title: Lipid Emulsion Infusion Rescues Dogs From BupivacaineInduced Cardiac Toxicity


1
Lipid Emulsion Infusion Rescues Dogs From
Bupivacaine-Induced Cardiac Toxicity
  • Weinberg et. al.
  • Regional Anesthesia and Pain Medicine
  • Vol 28, No 3 (May-June), 2003 pp 198-202

2
Overview
  • Purpose
  • author previously demonstrated encouraging
    results in resuscitation of severe bupivacaine
    cardiac toxicity in rats treated w/ IV lipid
    emulsion infusion.
  • Authors wanted to test hypothesis that
    Bupivacaine-induced cardiac toxicity in dogs
    (larger non-rodent mammals) could also be treated
    w/ lipid emulsion infusion.

3
Overview
  • Methodology
  • Bupivacaine 10 mg/kg IV over 10 sec.
  • Resuscitation
  • internal cardiac massage x 10 min
  • Either saline or 20 lipid infusion _at_ 4 mL/kg
    bolus then 0.5 mL/kg/min x 10 min
  • EKG, MAP, pHm, pmO2 monitored

4
Overview
  • Significant findings
  • Survival after 10 min unsuccessful cardiac
    massage
  • 100 for lipid treated dogs
  • 0 for saline treated dogs
  • Hemodynamics (PmO2, pHm)
  • Improved during resuscitation w/ lipids vs.
    saline

5
Overview
  • Conclusion
  • Infusing lipid emulsions during resuscitation
    from bupivacaine-induced cardiac toxicity
    substantially improved
  • Hemodynamics, pmO2, and pHm
  • Substantially increased survival in dogs.

6
Authorship
  • Guy Weinberg et al
  • Department of Anesthesiology, University of
    Illinois at Chicago College of Medicine
  • Supported by Department of Anesthesiology at same
    school.

7
Audience
  • Anesthesiologists and all MDs

8
Impact
  • Increasing use of regional techniques
  • Bupivacaine-induced cardiac toxicity rare, but
    quite fatal
  • Could prove to be huge breakthrough

9
Introduction
  • Author clearly underlines significance of problem
    with opening statement
  • Bupivacaine overdose can lead to fatal cardiac
    toxicity in the form of severe arrhythmias and
    contractile dysfunction.
  • Situates his own research by discussing his
    previous research on rats.

10
Introduction
  • Hypothesis clearly stated
  • We hypothesized that lipid infusion following
    bupivacaine treatment would improve recovery of
    cardiac function, hemodynamics, and myocaridal
    metabolism compared with saline-treated controls.

11
Methodology
  • Approved by Institutional Animal Care Committee
  • 12 male non-purpose bread hounds (22-26 kg)
  • ? Randomly assigned to tmt vs. non-tmt arm
  • Non-blinded

12
Methodology
  • Instruments described
  • Very detailed description of tissue probe
  • Anesthetic technique
  • 5 mg/kg propofol
  • Intubated ventilated w/ 1.5 Isoflurane 30 O2
  • Details probe insertion, and surgical preparation
    of the animals etc.

13
Methodology
  • Details of bupivacaine overdose and subsequent
    resuscitation
  • 10 mg/kg bupivacaine over 10 sec
  • Time of circulatory arrest noted (HRlt10, MAPlt30)
  • d/c Isoflurane and started 100 O2
  • Internal cardiac massage initiated x 10min
  • 4 mL/kg bolus (over 2 min) either saline or lipid
    emulsion
  • followed by continuous infusion 0.5 mL/kg/min x
    10 min

14
Methodology
  • If NSR returned, internal cardiac massage
    continued until
  • MAPgt30mm Hg
  • 30 minute recovery measures recorded
  • All dogs sacrificed at the end.

15
Methodology
  • Statistics
  • Statistical analysis tools used by author clearly
    identified in statistics subsection of Methods
    section.

16
Results
  • Major findings presented clearly in results
    section
  • Tables and graphs included
  • Findings address research objectives stated

17
Discussion
  • Results validate authors hypothesis
  • Limitations discussed
  • Not blinded
  • But similar protocol before, during, after
  • No difference at baseline in hemodynamics,
    myocardial tissue measures
  • Difference not likely due to bias
  • Plus all dogs treated w/ lipid emulsion survived,
    and non treated w/ saline survived
  • When to start tmt
  • Dose of bupivacaine used

18
Discussion
  • Authors suggest further research in lipid based
    resuscitation for treatment of bupivacaine-induced
    cardiac toxicity
  • Optimum dose
  • Dosage regimen
  • Risks of rapid lipid emulsion infusions need
    study too

19
Discussion
  • Suggestion of possible benefit of Propofol
  • Known to suppress bupivacaine-induced seizures
  • Commonly formulated in a 10 lipid emulsion
    vehicle
  • Theoretically could be used before severe
    hypotention/cardiac depression
  • Standard dose 2 mg/kg Propofol only provides 3
    of dose of lipid in study

20
Editorial by Groban et al
  • Recommendations
  • Bupivacaine-induced toxicity
  • When CNS hyperactivity doesnt cease
  • Barbiturates, BZ or propofol
  • Standard ACLS 1st for cardiac arrest
  • Vassopressin over Epi (? Less drug induced VF,
    less acidosis)
  • Amiodarone over lido
  • Initiation of lipid infusion at earliest sign of
    severe LA cardiotoxicity (difficulty in tmt, good
    safety profile of lipids)

21
Editorial by Groban et al
  • Recommendations
  • Bupivacaine-induced toxicity
  • If no lipid infusion available, and standard ACLS
    NOT workingtry propofol
  • Animal experiments needed
  • Propofol as antidote
  • Tread w/ cautionnegative ionotrope
  • Propofol for sedation in surgery under regional
    anesthesia may reduced susceptibility to
    LA-induced toxicity
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