INTRAVENOUS INFUSION OF FLUIDS

 

INTRODUCTION: When fluid output exceeds fluid intake, volume deficits may result. Shock, dehydration, or electrolyte loss may occur; large deficits are fatal, unless treated. The following are some common reasons for fluid depletion: 

1) Loss of gastrointestinal (GI) fluids due to vomiting, diarrhea, chronic laxative use, or GI suctioning. 

2) Excessive sweating during hot weather, athletic activity, or prolonged fever. 

3) Severe burns. 

4) Hemorrhage. 

5) Excessive diuresis due to diuretic therapy or uncontrolled diabetic ketoacidosis.

PURPOSE OF ADMINISTERING IV FLUIDS: The immediate goal in treating a volume deficit disorder is to replace the depleted fluid. In non-acute circumstances, this may be achieved by drinking more liquids or by administering fluids via a feeding tube. In acute situations, IV fluid therapy is indicated. Regardless of the route, careful attention must be paid to restoring normal levels of blood elements and electrolytes as well as fluid volume. IV replacement fluids are of two basic types namely; crystalloids and colloids.

CRYSTALLOIDS: Crystalloids are IV solutions that contain electrolytes and other substances that closely mimic the body’s ECF. They are used to replace depleted fluids and to promote urine output. Crystalloid solutions are capable of quickly diffusing across membranes, leaving the plasma and entering the interstitial fluid and ICF. It is estimated that two thirds of infused crystalloids will distribute in the interstitial space.

COMPONENTS OF IV FLUIDS: Isotonic, hypotonic, and hypertonic solutions are available for that purpose. Sodium is the most common crystalloid added to solutions. Some crystalloids contain dextrose, a form of glucose, commonly in concentrations of 2.5%, 5%, or 10%. Dextrose is added to provide nutritional value: 1 L of 5% dextrose supplies 170 calories. In addition, water is formed during the metabolism of dextrose, enhancing the rehydration of the patient. When dextrose is infused, it is metabolized, and the solution becomes hypotonic.

EFFECTS OF IV FLUIDS: Infusion of crystalloids will increase total fluid volume in the body, but the compartment that is most expanded depends on the solute in this case, sodium, concentration of the fluid administered. Isotonic crystalloids can expand the circulating intravascular (plasma) fluid volume without causing major fluid shifts between compartments. Isotonic crystalloids such as normal saline are often used to treat fluid loss due to vomiting, diarrhea, or surgical procedures, especially when the blood pressure is low.

Because isotonic crystalloids can rapidly expand circulating blood volume, care must be taken not to cause fluid overload in the patient. Infusion of hypertonic crystalloids expands plasma volume by drawing water away from the cells and tissues.

RELATED;

1.  PLASMA VOLUME EXPANDERS

2.  BODY FLUIDS

3.  ANATOMY AND PHYSIOLOGY

REFERENCES