Allergic
allergic reactions with LA mostly associated with which kind of LA
esters (PABA) metabolite
causes of LAST
excess plasma concentration of drug
entrance into the systemic circulation from inactive tissue redistribution and clearance metabolism
*accidental direct IV injection
what precedes seizures with systemic toxicity
drowsiness and facial twitch
lidocaine at 5 mcg/mL has
circumoral numbness but no CV effects
Goal of treatment for systemic toxicity
prompt airway managemnt
circulatory support
removal of LA from receptor sites
what is methyparaben
preservative to both esters and amides
*similar structure to PABA
*use preservative free*
other factors that can LAST
patient comorbidities, medication, location and technique od block, LA used and dose
treatment for CNS systemic toxicity
100% O2 to inhibti hypoxemia and metabolic acidosis
hyperventilation
barbituates/benzodiazepines/ propofol
epi as an additive
high plasma concentrations of lidocaine
block cardiac Na+ channels
slowing conduction of cardiac impulses prolonging PR intervals, and QRS widening
standard of care for intralipid - lipid emulsion
creates lipid compartment; provides fat for myocardial metabolism
Bolus: 1.5 mL/kg of 20% lipid emulsion
Infusion: 0.25 mL/kg/min for at least 10 min
1st 30 min: 3.8 mL/kg (1.2-6 mL/kg)
is there a cross sensitivity between esters and amides
no
magnitude of LAST depends on
dose
vascularity of site
epi use
physiochemical properties
seizure treatment for LAST
supplemental O2
benzo (versed/diazepam)
propofol, if hemodynamically stable
muscle relaxant (SCh or NDNMBD)
intralipid: lipid emulsion
accidental IV bupivicaine causes
cardiopulmonary bypass
sign of IgE mediated anaphlyaxis
rash, urticaria, laryngeal edema with our without hypotension and bronchospasm
when should plasma levels of lidocaine be monitored
epidural > 900 mg
what is transient neurologic symptoms (TNS); causes and treatment
Moderate to severe pain (lower back, buttocks, and posterior thighs) within 6 to 36 hours after an uneventful single-shot SAB
unknown cause, Lidocaine > other LAs
treatment: trigger point injections and NSAIDs (recovery in 1 to 7 days)
predisposing factors for CV system effects with LAST
pregnancy - low plasma cholinesterase/plasma protein
arterial hypoxemia, acidosis, or hypercarbia
beta-blockers, dig, ca++ channel blockers
epi and phenylephrine
supportive epi dose during LAST
10-100 mcg
majority of adverse responses that are often attributed to an allergic reaction are instead manifestations of
excess plasma concentrations of LA
what electrolyte imbalance promotes seizures with LA
what is cauda equina syndrome (CES), and what is associated with it?
diffuse injury at the lumbosacral plexus, having a varying degree of sensory anesthesia, bowel and bladder sphincter dysfunction, and paraplegia
associated with lumbar disc herniation, prolapse, or sequestration with urinary retention
which LAs are most likely to cause CV effects with LAST
bupivicaine > ropivicaine > lidocaine
TXWES reference guide
bolus 1.5 mL/kg over 1 min
gtt 0.25 mL/kg/min
Repeat bolus Q3-5 min up to 3 mL/kg total
Increase gtt to 0.5 mL/kg/min
continue gtt until hemodynamically stable
max total dose 8 mL/kg