Although intravenous fluid bags all look similar, the fluids they contain can have markedly different effects on the human body. Intravenous fluids can be isotonic, meaning their electrolyte composition is similar to that of human blood; hypotonic, meaning that they contain a lesser concentration of electrolytes; or hypertonic, meaning that they have a higher concentrate of electrolytes than human blood. Although otherwise healthy people normally tolerate fluid overload without serious consequences, infusing too much IV fluid of any type can cause side effects. People with existing health issues can have serious complications.
Over-infusion of IV fluids may cause fluid retention. Swelling of the face, especially around the eyes, commonly occurs. Fluid may also accumulate in the legs, feet, ankles, hands and fingers. More serious effects include headache and cerebral edema, swelling of the brain, which can cause death, reports the 2008 "Medical Journal of Australia." Severe edema usually results from over infusion of hypotonic fluids, which leads to hyponatremia, or low sodium concentration.
Shortness of Breath
Fluid retention can lead to pulmonary edema, which causes shortness of breath, crackling sounds in the lungs, wheezing, difficulty breathing, chest pain and a change in breathing pattern. Congestive heart failure often precedes pulmonary edema, with excess fluid backing up into the lungs and accumulating in the extremities.
High Blood Pressure
Extra fluid circulating in the body can cause high blood pressure. Pulses may also feel stronger than usual, known as a bounding pulse and neck veins may become distended from the extra fluid volume. The heart may beat faster than usual and an extra heart sound, called a third heart sound, may be heard through a stethoscope, the Encyclopedia of Nursing and Allied Health reports.
Lethargy, anxiety, restlessness, decreased level of consciousness and eventually seizures can occur as a result of fluid volume overload from IV fluids. Permanent neurological problems can occur if sodium concentrations in the blood drop rapidly from fluid overload or if too rapid correction of sodium levels occurs. Hypernatremia, too much sodium in the blood, can occur in over infusion of hypernatremic fluids, leading to similar symptoms but including weakness and irritability. Death can occur from elevated sodium levels.
Urinary output may drop in people with fluid overload as fluid accumulates in tissues rather than being eliminated through the kidneys. Intake of fluid will exceed output, Nursing Care Plans explains. Urine concentration and specific gravity may change.