The magic of furosemide

In acute pulmonary oedema, there is collection of fluid in alveoli.

The sequence of events is as follows.

👉Left ventricle is unable to pump adequate blood either due to systolic or diastolic failure.

👉Increased filling pressure in the left ventricle.

👉Transmission of increased filling pressure to left atrium, and then to pulmonary veins and then to pulmonary capillaries.

👉Increased pressure in the pulmonary capillaries causes oozing of fluid from pulmonary capillaries to alveolar lumen. This is pulmonary oedema.

Action of furosemide

👉Furosemide causes increase in systemic venous capacitance.

👉Fluid shifts from pulmonary circulation to systemic circulation.

👉Decrease in pulmonary hydrostatic pressure.

👉Back flow of fluid from alveoli to pulmonary capillaries.

👉Reversal of pulmonary edema.

👉The change in systemic hemodynamics occurs even before the diuretic action and therefore furosemide provides prompt relief in acute pulmonary oedema.