ADVANCING YOUR PRACTICE Managing hyperemesis gravidarum Anne M. Lamondy, RN,C, MSN Hyperemesis gravidarum, or excessive nausea and vomiting that persists beyond the 20th week of pregnancy, causes weight loss of more than 5% of prepregnancy body weight, dehydration, metabolic acidosis from starvation, alkalosis from loss of hydrochloric acid, and hypokalemia. The cause of hyperemesis gravidarum isn't known, but its effects—decreased placental blood flow, decreased maternal blood flow, and acidosis—can threaten the health of mother and fetus. Dehydration can also cause preterm labor. This is where you come in: By administering I.V. fluid and nutritional support to the mother, you can help minimize the risk of perinatal morbidity and mortality. Severe malnutrition during the first trimester can lead to spontaneous abortion or teratogenic effects; during the second trimester, it can contribute to low-birth weight and poor neurologic development. Prolonged fetal exposure to stress and malnutrition may also be linked to development of chronic diseases later in life, such as diabetes and heart disease. Intravenous fluids can correct dehydration, electrolyte deficiencies, and acid-base imbalances brought on by hyperemesis gravidarum. This therapy is introduced in stages, depending on the severity of the patient's dehydration and the amount of fluid resuscitation needed. Initial I.V. therapy consists of a crystalloid solution, such as dextrose, 0.9% sodium chloride solution, or lactated Ringer's solution (which can correct some potassium and calcium deficits). The patient may also need electrolyte, mineral, or water-soluble vitamin replacement based on her serum levels. Reestablishing normal fluid and electrolyte levels often relieves nausea and vomiting. Encourage the patient to eat, and tell her to avoid going for a long period without eating. Advise her to eat when she feels hungry, starting with small, frequent low-fat meals. She should avoid drinking fluids with meals. Antiemetics may be used with I.V. fluids to shorten therapy or lessen the severity of symptoms. The medication regimen should be tailored to the patient's symptoms. For example, vomiting is best treated with prochlorperazine or promethazine HCl, but reflux should be treated with an antireflux medication such as ranitidine. Administer antiemetics I.V. or rectally as ordered; avoid the I.M. route due to slower medication absorption and the potential need for repeated administration, as well as the muscle atrophy that accompanies malnourishment, which may cause repeated injections to be painful. Dosing on a schedule is more effective than p.r.n. dosing. The health care provider will discontinue I.V. fluids when episodes of nausea and vomiting decrease and the patient can eat and drink enough to assure appropriate weight gain and fetal growth, stable electrolyte and fluid balance, and a positive nitrogen balance. If these goals aren't met or maintained, however, she may need to be admitted to the hospital for continued I.V. fluids and total parenteral nutrition (TPN). Watch for these complications Monitor your patient for these two rare but serious neurologic complications of hyperemesis gravidarum: Wernicke’s encephalopathy and central pontine myelinolysis. Wernicke's encephalopathy is caused by a deficiency in thiamine, a vitamin essential for carbohydrate metabolism. This risk can be reduced by ensuring that I.V. thiamine is added to fluids containing glucose. Signs and symptoms of Wernicke's encephalopathy include diplopia, nystagmus, disorientation, delusions, uncoordinated movements, and gait ataxia. Central pontine myelinolysis, which is caused by rapid reestablishment of normal sodium levels in a severely hyponatremic patient, is characterized by confusion, horizontal gaze paralysis, spastic quadriplegia, and delirium leading to brain damage or death. This complication can occur simultaneously with Wernicke's encephalopathy. If your patient needs TPN Because of the inherent risks associated with TPN and central venous access, TPN should be used as a last resort after the risks and benefits have been reviewed with the patient. On average, patients with hyperemesis gravidarum need TPN for 33 days, but some may need it from early pregnancy through delivery. During therapy, assess maternal and fetal status frequently. Closely monitor maternal serum glucose levels, especially in the first trimester because hyperglycemia is associated with congenital malformations. Lactic acidosis, a very rare complication of TPN, can occur if the patient doesn't get appropriate vitamin supplementation. A patient with hyperemesis gravidarum is at especially high risk for catheter-related thromboembolism because of the elevated coagulation factors associated with pregnancy and dehydration contributing to venous stasis. Administering TPN, a hypertonic solution, can injure blood vessel walls, increasing the risk of thrombosis. Administer TPN through a central venous access device, such as a peripherally inserted central catheter, with the tip in the vena cava. Monitoring your patient on TPN Standard TPN should be adjusted (by a perinatologist and a nutritionist) to meet the mother's increased needs for calories, fluids, carbohydrates, amino acids, lipids, and micronutrients. The recommended fluid intake is 30 mL/kg/day. But if she's vomiting, she'll need more fluid to balance losses. The dextrose in the TPN solution is the mother's principle energy source, providing 50% to 60% of her total calories. Monitor her blood glucose closely and keep it between 70 and 120 mg/dL—hyperglycemia is associated with fetal complications such as excessive birth weight. Remember that pregnancy causes insulin resistance, so insulin supplementation, including in the TPN solution, may be required. Monitor your patient for complications of vascular access, such as catheter occlusion, air embolus, and infection. Monitor her intake and output. Patient may be NPO until vomiting has resolved. She may be very weak and require assistance with hygiene and mouth care. Monitor her weight—she should be gaining between 0.5 and 1 pound per week in the second and third trimesters. If she's not gaining enough, work with the nutritionist to change the TPN formula to a higher-calorie and protein formula. If your patient is gaining weight too rapidly, evaluate her for fluid overload or preeclampsia. Follow your facility's protocol for monitoring lab studies and determining if the TPN formula needs modification. For example, ketones in the urine indicate the patient needs more glucose as an energy source. Nitrogen balance studies, done on 24-hour urine collections, assess the adequacy of protein intake. Markers of visceral protein status are albumin, prealbumin, transferrin, or retinol-binding protein. Measurement of electrolytes and lipids also help validate that the mother's nutritional status is improving. Fetal assessment criteria that will confirm an improved intrauterine environment are increasing fundal height, fetal heart tones, and periodic fetal ultrasounds for growth. Support the mother and family emotionally during this trying time. A private room in a quiet area, away from extra noise and food odors, may also help your patient get extra rest. Happy endings By using a multidisciplinary approach and combination therapy that includes nutritional support, medications, education, and emotional support, you can help your patient with hyperemesis gravidarum feel better and deliver a healthy baby. References Bertram CE, Hanson MA. Prenatal programming of postnatal endocrine responses by glucocorticoids. Reproduction. 124(4):459-467, October 2002. Eliakim R, et al. Hyperemesis gravidarum: A current review. American Journal of Perinatology. 17(4):207-218, 2000. Folk JJ, et al. Hyperemesis gravidarum: Outcomes and complications with and without total parenteral nutrition. Journal of Reproductive Medicine. 49(7):497-502, July 2004. Pillitteri A. Maternal and Child Health Nursing: Care of the Childbearing and Childrearing Family, 4th edition. Philadelphia, Pa., Lippincott Williams & Wilkins, 2003. Source: Nursing2007. February 2007.