For each clinical disturbance A–E, select the best option for its possible cause from the follow-ing list

A. Option 4 Peripheral circulatory failure. In circulatory failure such as may occur in severe shock or haemorrhage, the fall in venous return to the heart lowers central venous pressure.

B. Option 2 Respiratory failure. The retention of CO2 in respiratory failure leads to an acidosis that is compensated for by generation of bicarbonate by the kidney.

C. Option 1 Renal failure. In renal failure, failure to excrete acid residues of metabolism causes acidosis. Anaemia is often seen since erythropoietin is normally manufactured by the kidneys.

D. Option 3 Heart failure. In heart failure where the heart cannot pump forward all the blood being delivered to it, there is a rise in central venous pressure that increases the diastolic filling of the heart.

E. Option 5 Liver failure. The liver is responsible for the deamination of amino acids and the conversion of the NH4 residues into urea