Focusing on the dangers of D5W

Nursing, Oct 1997 by Metheny, Norma

Overuse of this seemingly harmless I.V. fluid could injure or even kill your patient

Find out whyand how to prevent harm.

AFTER AN UNCOMPLICATED CHOLECYStechomy, 25-year-old Abigail Glover semed to be recovering well. But during the night, she became nauseated; she also failed to void, although she'd received nearly 1 liter of lactated Ringer's solution and 1 liter of D^sub 5^W.

The next day, she complained of a headache. That night, she was found unresponsive and went into respiratory arrest. In the tragic end to this true story, Ms. Glover died several days later, after her family decided to remove life support.

The cause of death? Hyponatremic encephalopathy, or brain swelling caused by hyponatremia, the result of an excessive infusion of DSW. You may think that this intravenous (I.V.) fluid can do little harm, even when too much is given or when it's given too fast. But inappropriate use of DSW has caused the deaths of numerous young women following simple surgical procedures.

In this article, I'll describe why D^sub 5^W can cause problems for any postoperative patient, why postoperative hyponatremia can be life-threatening to women of childbearing age, and the steps you can take to prevent serious problems. First, let's take a closer look at the fluid itself.

What's in the bag

An electrolyte-free fluid, D^sub 5^Wcontains 50 grams of glucose and provides about 170 calories per liter. But more important than what's in this fluid is what's missing from it-sodium. As D5W is administered I.V., it dilutes the patient's serum and decreases the concentration of sodium in serum. The normal range is 136 to 146 mEq/liter; levels below 136 mEq/liter indicate hyponatremia.

The problem can be complicated by the body's normal physiologic response to the stress of surgery. As you recall, in the first 2 to 4 postoperative days, patients have higher-than-normal levels of antidiuretic hormone (ADH)-as much as 5 to 50 times their preoperative values. Pain, nausea, and vomiting can also increase ADH secretion.

A patient who receives a large volume of water (as is possible with D5W) when her ADH level is high retains too much water, although this overload usually won't create visible edema. Most of the water from the diluted plasma moves into the cells. The resulting cellular edema is most dangerous in the brain, where tissue expansion is limited by the cranial vault.

The brain adapts to swelling by shunting blood and cerebrospinal fluid and by shifting sodium from the brain cells to extracellular areas. If the brain volume expands by more than 5%, your patient will develop cerebral herniation unless treated promptly.

Signs of trouble

Early symptoms of hyponatremic encephalopathy include nausea, vomiting, headache, and lethargy. If the condition isn't treated, the patient may develop muscular twitching, generalized seizures, coma, and respiratory arrest.

Postoperative hyponatremia can affect any patient but is much more serious in women of childbearing age. Premenopausal women who develop hyponatremic encephalopathy are about 25 times more likely to have permanent brain damage or die, compared with men and postmenopausal women.

Researchers believe that physiologic responses are one factor-in premenopausal women, estrogen stimulates ADH release and antagonizes the brain's ability to adapt to swelling. In men, androgens suppress ADH release and enhance the brain's ability to adapt to swelling.

Age is another factor. Although skull size remains constant in adulthood, brain volume declines progressively with age, allowing more room for brain expansion. That means younger women are at greater risk.

Also, the amount of cerebrospinal fluid increases with age, especially in men. This allows older individuals, especially men, to more effectively adapt to brain swelling by temporarily shunting cerebrospinal fluid out of the brain to decrease brain mass. The more fluid a person has to shunt, the more potential he has to adapt to brain swelling.

A tragedy unfolds

Let's take a closer look at Ms. Glover's case and what you can do to prevent this type of situation from happening in your unit.

Ms. Glover's admission assessment was normal; her serum sodium level was 142 mEq/liter. She stood 5 feet 1 inch and weighed 97 pounds (44.1 kg).

In the postoperative unit, a nurse misinterpreted an I.V. fluid order, and Ms. Glover was started on an infusion of 1 liter of D5W with 20 mEq of potassium chloride at 125 ml/hour. (She was to have received 5% dextrose in 0.45% sodium chloride solution, not plain DSW.) At 3 p.m., her indwelling urinary catheter was removed.

At 8:30 p.m., Ms. Glover was awake, her vital signs were stable, her abdomen was flat, and her abdominal wound was dry. The nurse offered her the bedpan, but she said she didn't need it.

At 9:30 p.m., Ms. Glover reported nausea and was given a dose of antiemetic medication. At 12:30 a.m., according to the chart, she was still nauseated, but it was too soon to repeat the antiemetic. At 1:45 a.m., she was still nauseated and was given another dose of antiemetic. A second liter bag of DsW with 20 mEq of potassium chloride was started at 2:30 a.m.