<prompt> A 60-year-old patient, known case of Hypertension for the past 25-year underwent renal artery Doppler which showed narrowing and turbulence in right renal artery. If the diameter of lumen is reduced by 50, how much blood flow will be reduced?14 th18 th116 th132 nd  <response>: Ans. c 116thRef: Ganong, 25th edp.573Poiseuille-Hagen formula is:FPA -PB pr48eLSo, according to the above formula, blood flow is directly proportional to the fourth power of radiusSo, if the radius is halved, then blood flow decreases by 2 to the power 4 times which is 16 times 