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
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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
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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.
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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
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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
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Overview
- Conclusion
- Infusing lipid emulsions during resuscitation
from bupivacaine-induced cardiac toxicity
substantially improved - Hemodynamics, pmO2, and pHm
- Substantially increased survival in dogs.
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Authorship
- Guy Weinberg et al
- Department of Anesthesiology, University of
Illinois at Chicago College of Medicine - Supported by Department of Anesthesiology at same
school.
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Audience
- Anesthesiologists and all MDs
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Impact
- Increasing use of regional techniques
- Bupivacaine-induced cardiac toxicity rare, but
quite fatal - Could prove to be huge breakthrough
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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.
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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.
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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
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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.
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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
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Methodology
- If NSR returned, internal cardiac massage
continued until - MAPgt30mm Hg
- 30 minute recovery measures recorded
- All dogs sacrificed at the end.
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Methodology
- Statistics
- Statistical analysis tools used by author clearly
identified in statistics subsection of Methods
section.
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Results
- Major findings presented clearly in results
section - Tables and graphs included
- Findings address research objectives stated
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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
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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
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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
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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)
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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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