Patients having acute cardiac failure do not show pedal oedema, because :
A. The plasma oncotic pressure is high
B. There is renal compensation
C. There is an increase in cardiac output
D. There is a fall in the systemic capillary hydrostatic pressure
Correct answer : D. There is a fall in the systemic capllary hydrostatic pressure
Edema is due to increase in capillary hydrostatic pressure or decrease in plasma oncotic pressure. Acute cardiac failure is usually due to decrease in cardiac output and hypotension. Capillary hydrostatic pressure falls and hence edema is not seen.