Tox: Salicylates

Salicylates
-Pepto, oil of wintergreen, liniments in vaporizers
-delayed or erratic absorption; toxic levels usu in 6 hrs; peak 10-60 h with syst release preps
-gelatinous gastric mass and delays gastric emptying
-ASA > hyrolyzed to salicylate > pH 7.40 all ionized; acidemia inc passage through BBbarrier
-1) stim medulla > inc in resp rate -> resp alk
2) inc cat, inc CO2, inc glycolysis, production of organic acids incl lactate, pyruvate, ketoacids > met acidosis w/inc gap
3) vomiting > vol contraction alkalosis
-salicylate's struct is similar to vit K, lg chronic doses my cause low PT by inhibition of vit K

si/sx
-acute < 150 mg/kg mild tox with n/v/gi irritation
-acute 150-300 mg/kg mod tox w/v/hypervent, sweating, tinnitus; asa level 30 mg/dl
-if coingest resp suppressive drugs > resp acidosis
-acute >300mg/kg severe tox w/fever, ams, renal fail, pulm edema, ards, rhabdo, gi perf, gi hem
-kids - present w/in few hours; <4>4 have mixed acid-base disturb as in adults
-chronic - usu elderly, hypervent, tremor, pailledema, agitation, paranoia, bizarre behav, mem loss, confusion, stupor; consider in unexp nonfocal neuro and behav abnl, w/acid-base disturb, tachypnea, noncard pulm edema
-kids - hypervent, vol depletion, acidosis, marked hypokalemia, cns disturbance, fever (often mistaken for infxn), renal failure

Rx:
-monitor
-IV
-FSBS
-labs: lytes, glc, bun, cr, cbc, pt, salicylate level, tylenol level, abg
-act charcoal 1g/kg, multiple doses not helpful
-whole bowel irrigation if sustained release or enteric coated
-Fluids (NS) for vol dep, all subs fluids in D5
-second IV line for
-bolus 1-2 meq sodium bicarb, then 100-150meq (2-3 amp) sod bicarb to 1 L D5W infused at 1.5 to 2.0 x pt's maintenance rate; adjust to maintain urine pH > 7.5
-potassium 40 meq when uop is established
-monitor lytes - alkalinization decreases K level, keep at least 4.0
-HD for clinical deterioration despite rx, renal insuff or failure, severe acid-base disturb, ams, ARDS
-FFP and vit K for hemorrhage due to elevated PT
-salycilate levels q 2 hrs until peak, then q 4-6 hrs unti nontoxic
-except w/ ecasa or sr formulations, can d/c from ed if improvement occurs, not sig acid-base abnlty, and declining serial salicylate levels
-psych referral if intentional