Fluid replacement helps treat hemorrhage and dehydration in pregnancy. Maternal hemorrhage is the largest single cause of global maternal mortality responsible for 125,000 deaths per year. When the body loses blood, blood pressure falls, the heart has a greater burden, and it is more difficult for the body to oxygenate its tissues. To compensate, the heart rate rises and breathing speeds up. In severe cases, the body will go into shock to divert blood to critical organs only.
Mechanism of Action
Fluid replacement treats dehydration and low blood pressure from bleeding by replacing the volume which was lost. The increased volume increases blood pressure and improves venous return to the heart. Plasma volume expanders can be crystalloid or colloid. Crystalloids like saline or Lactated Ringer’s are typically less expensive, but only about a quarter of the volume injected stays in the blood stream--the rest goes to the body's extracellular spaces. Colloid substances like Voluven or Hespan are suspensions of larger, insoluble molecules designed to stay in the vessels and keep the fluid there with osmotic pressure. Neither is considered superior in the treatment of obstetric hypovolemia. Volume expanders are typically indicated when blood loss exceeds 15% of total blood volume--typically about 5 liters. Fluid replacement is a first line treatment for the results of obstetric hemorrhage. More severe cases will require restoration of the blood's oxygen transporting capacity through blood transfution or blood substitutes.
Current use in High-Resource settings
For volume expansion, crystalloid and colloid solutions are readily available and frequently used with a large caliber intravenous access. These treatments are even available in ambulances or other unusual treatment locations. The use of colloids is sometimes avoided because of their expense, however they are sometimes preferred because of the low volumes required.
Application in Low-Resource settings
Crystalloid plasma volume expanders are readily available and used in tertiary care centers and some clinics as a staple product. There are both in country suppliers of saline solutions and some hospitals make their own.