Anesthesia Considerations 

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