Chronic salicylism and intubation risk

The older patient. In a series of severe salicylate poisoning, the patients who died were significantly older than the survivors, with mortality as high as 33 per cent in patients over 70, and delayed presentation, coma, hyperpyrexia, pulmonary oedema and acidaemia were more common in the fatal cases; the plasma concentration alone could not determine prognosis.^[5]

Thresholds with impaired kidney function. EXTRIP recommends extracorporeal treatment above 6.5 mmol/L (90 mg/dL) and suggests it above 5.8 mmol/L (80 mg/dL) when kidney function is impaired, and recommends it for altered mental status or acute respiratory distress syndrome requiring oxygen regardless of the concentration.^[2] With non-cardiogenic pulmonary oedema a patient may not tolerate the fluids needed for alkalinisation, which can make haemodialysis necessary.^[4]

Alkalinisation pitfalls. Hypokalaemia is the most common complication of urine alkalinisation, and alkalinisation cannot be achieved while hypokalaemia persists.^[3][4]

Why intubation is dangerous. When salicylate-poisoned patients are ventilated at conventional settings the respiratory alkalosis is abolished and more salicylate enters the central nervous system; in a case series all seven patients with post-ventilation gases were acidaemic and two died within hours.^[6]