investigations
Last reviewed 01/2018
- full blood count
- prothrombin time - may be increased
- urea and electrolytes - possible hypokalaemia
- blood glucose - possible hypoglycaemia
- blood gases - initially, respiratory alkalosis, followed by metabolic acidosis - except in children
- plasma salicylate level - take sample at 6 hours or earlier if indicated; repeat at 4 hourly intervals to ensure that level is not rising due to slow absorption. Interpretation: plasma level ( mg per litre)
- therapeutic range 150-250
- mild 250-500
- moderate 500-750
- severe poisoning > 750
- ranges for children approximately 0.6 of adult value
- chest X-ray - pulmonary oedema, ARDS
Notes:
- the presence of a metabolic acidosis is ominous even if the salicylate levels are not markedly elevated
- salicylate levels are less reliable if aspirin is being taken therapeutically