Aspirin Toxicity 

 

 

Background

 

  • Aspirin is converted to its active metabolite salicylic acid, salicylates at toxic levels are metabolic poisons that: 

    • Uncouple oxidative phosphorylation 

    • Interfere with the Krebs cycle

    • Lead to accumulation of lactic acid & ketoacids

 

 

Considerations

 

  • Emergency/full stomach

  • Consider other toxins 

  • Potentially life threatening emergency requiring monitoring: 

    • Arterial line for frequent blood work

    • Consult toxicology/ICU/nephrology 

  • Severe acidosis:

    • Severe AGMA (keto-lactic) with compensatory respiratory alkalosis 

    •  ↓ pH favours tissue (e.g. brain) passage → toxic effects

  • Respiratory:

    • Respiratory alkalosis is compensatory mechanism as alkalinization assists renal elimination 

    • Cautious intubation: will not tolerate apnea & ICU ventilator required 

    • Non-cardiogenic pulmonary edema can occur

  • Central nervous system:

    • Uncooperative & co-intoxications

    • Profound ↓ LOC

    • Cerebral edema

    • Neuroglycopenia

  • Assess severity & timing:

    • Activated charcoal if  < 1hour

    • Serums ASA levels (note that peak levels can be delayed by 6 hours)

 

 

Treatment

 

  • Rapid assessment & stabilization of ABCs

  • GI decontamination with activated charcoal:  

    • 1st dose: 1g/kg up to 50 grams PO, followed by 25 g PO q2h x 3 

  • Volume resuscitation unless cerebral or pulmonary edema is present

  • Empirical glucose if altered LOC even if normal serum glucose

  • Urine alkalinization with NaHCO3:

    • Bolus: 1 meq/kg IV bolus

    • Maintenance: 150 meq NaHCO3 in 1 L of D5W, 

      • Start 2x maintenance 

      • Titrate to urine pH > 7.5.  

      • Continue until serum salicylate < 30 mg/dL

    • Monitor & avoid

      • Volume overload

      • Hypokalemia

  • Avoid intubation if possible but it may be necessary for:

    • Airway protection

      • Lavage/charcoal 

      • GCS < 8

      • Too agitated & delirious for medical procedures such as CVC placement & hemodialysis

    • Severe hypoxemia from ASA-induced pulmonary edema

    • Maintenance of hyperventilation if respiratory failure occuring (compensation for AGMA)

  • Hyperventilate:

    • An abrupt ↓ in salicylate-induced hyperventilation may lead to life-threatening acidosis

    • ICU ventilator available

  • Hemodialysis indications:

    • Coma or cerebral edema

    • Pulmonary edema or fluid overload (limits NaHCO3 administration)

    • Renal failure that interferes with salicylate excretion

    • Lethal salicylate concentration > 100 mg/dL (7.2 mmol/L)

    • Refractory AGMA despite aggressive management

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