ECG

Chest X-ray

Echocardiography if indicated (see Tables 2.4, 2.5)

Arterial blood gases, pH and lactate; in refractory cases, central venous oxygen saturation and veno-arterial partial pressure of CO₂

Blood glucose

Plasma sodium, potassium, urea and creatinine

Full blood count

Group and screen (cross-match six units if acute haemorrhage suspected)

Coagulation screen if low platelet count, suspected coagulation disorder, jaundice or purpura

Blood culture

Urine stick test