90 Hyperemesis gravidarum
Overview/pathophysiology
Nausea and vomiting are common symptoms of unknown cause in the first trimester of pregnancy. Although mildly or moderately distressing, they do not cause metabolic imbalance. Hyperemesis gravidarum is a rare condition of excessive vomiting in pregnancy that causes weight loss of 5% or more from prepregnancy weight, dehydration, electrolyte imbalance, acidosis from starvation, and alkalosis from loss of hydrochloric acid. This condition usually begins during the first trimester, after which vomiting becomes intractable and may last throughout the entire pregnancy. The cause is unknown, but theories include rising estrogen and human chorionic gonadotropin levels (hCG), displacement of the gastrointestinal (GI) tract, decreased motility caused by an increase in progesterone, decrease in motilin levels, and psychogenic factors. Affected women may face multiple disruptions of work, family, and social responsibilities because of the debilitating nature of the condition and repeated hospitalization. Goals of treatment include control of nausea and vomiting, correction of dehydration, restoration of electrolyte balance, and maintenance of adequate nutrition to optimize maternal and fetal/newborn outcomes.
Health care setting
Patients are often treated on an outpatient basis with oral medications, home intravenous (IV) infusion therapy to replace fluids and electrolytes, or total parenteral nutrition. Approximately 1% of women who develop hyperemesis gravidarum require multiple hospitalizations.
Assessment
The first priority of care is to determine severity of the nausea and vomiting problem in patients who can no longer retain solids or liquids as well as the degree of dehydration and weight loss. Laboratory studies are prescribed to identify electrolyte imbalances. Patients may exhibit a low-grade fever, increased pulse rate, decreased blood pressure, weakness, dry skin, cracked lips, and poor skin turgor. Patients may appear extremely fatigued and listless with a possible loss of 5%-10% of total body weight, be constipated as a result of dehydration, and have a markedly decreased urinary output with ketonemia (presence of ketones in the blood). Women with diabetes who have hyperemesis need to be monitored closely to maintain glycemic control and avoid ketoacidosis. See “Diabetes in Pregnancy,” p. 619.
Gastrointestinal:
GI motility is reduced because of increased progesterone and decreased motilin levels. “Normal” nausea and vomiting of pregnancy usually has an onset between 4 and 6 wk, peaks at about the 12th wk, and resolves between 16 to 20 wk. Hyperemesis usually begins in the first trimester but may extend throughout the entire pregnancy.
Fluid and electrolyte imbalance:
With the inability to maintain adequate fluids for hydration and solids for fuel and nutrients, the body experiences an imbalance of the elements necessary for health maintenance, which can lead to maternal ketosis.
Cardiopulmonary:
The patient may experience one or all of the following: tachycardia, hypotension, postural changes, and tachypnea.
Complications—fetal:
With prolonged dehydration and maternal weight loss, fetal intrauterine growth restriction (IUGR) and low birth weight may be seen.
Physical assessment:
The pregnant patient with hyperemesis looks debilitated and is ill. She is extremely fatigued and pale. A thorough systems assessment is needed to rule out other causes of severe nausea and vomiting, such as gastroenteritis, cholecystitis, pyelonephritis, GI ulcers, or a molar pregnancy (intrauterine benign or neoplastic mass of grapelike vesicles of trophoblastic cells—the embryonic cells that form the chorion).
Diagnostic tests
Urine chemistry:
The most important initial laboratory test is urine dipstick measurement of ketonuria (or a specimen may be sent for microscopic urinalysis). Ketones are present with cellular starvation and dehydration from prolonged vomiting.
Complete blood count (CBC):
With dehydration, there likely will be evidence of hemoconcentration (i.e., elevated red blood cell and hematocrit levels).
Serum chemistry:
Azotemia (increased blood urea nitrogen [BUN]) is seen with salt and water depletion. Serum creatinine will be elevated because of changes in renal function caused by dehydration. Hyponatremia and hypokalemia also may be present because of fluid loss.
Liver enzymes:
Slight elevations of aspartate aminotransferase and alanine aminotransferase reverse with IV fluid hydration, adequate nutrition, and cessation of vomiting.
Obstetric ultrasound:
Ultrasound is used to evaluate a normal intrauterine pregnancy versus a molar pregnancy, presence of multiple gestation, fetal growth for IUGR, and amniotic fluid volume/amniotic fluid index (AFI).
Results for CBC, electrolyte panel, laboratory tests for liver enzymes and bilirubin levels, and kidney function:
Help to rule out the presence of underlying diseases previously listed.
Nursing diagnoses:
Risk for electrolyte imbalance
related to excessive gastric losses and reduced intravascular and intercellular fluid occurring with nausea and vomiting
Desired Outcome: Within 24 hr after initiation of treatment, patient begins to show signs of adequate hydration, as evidenced by decreased emesis, balanced intake and output, and improvement in acid-base balance and electrolyte status.
| ASSESSMENT/INTERVENTIONS | RATIONALES |
|---|---|
| Assess characteristics of the patient’s nausea/vomiting: frequency, duration, and severity; amount and color of vomitus; accompanying symptoms (abdominal pain, diarrhea, dyspepsia [a vague feeling of discomfort or bloating after eating]); and precipitating factors. Reassess q8h or as indicated. | This comprehensive initial assessment provides a basis for nursing interventions/teaching and a subsequent comparison for changes. |
| Assess for signs of dehydration: dry mucous membranes, poor skin turgor, decreased blood pressure (BP), increased pulse, possible low-grade fever, and increases in urine specific gravity, BUN, and hematocrit. | With fluid losses, blood and urine become concentrated, circulating blood volume decreases, BP may decrease, and the heart rate increases to compensate. |
| Assess for signs of electrolyte imbalance q8h (muscle weakness, cramps, irritability, irregular heartbeats), and monitor results of prescribed laboratory studies. | Potassium and magnesium are lost with prolonged vomiting. Muscles, including the myocardium, are weakened by loss of these electrolytes. Severe potassium loss impacts the kidneys’ ability to concentrate urine. |
| Initiate and monitor IV hydration while keeping the patient NPO (nothing by mouth) for 48 hr, as prescribed by the health care provider. | This approach aids in resting GI motility, resolving dehydration, and improving electrolyte balance caused by intractable vomiting. |
| Administer parenteral nutrition as prescribed by the health care provider. Secure assistance of the hyperalimentation team to manage patient’s nutrition. | Total nutritional needs can be met with parenteral nutrition, thereby helping ensure adequate fetal growth and preventing maternal malnutrition. |
| Encourage patient to take approximately 100 mL (e.g., in 1 oz portions qh) of liquid between each meal and avoid fluids with meals. | This measure prevents dehydration between meals, overdistension of the stomach during meals, allowing more space for caloric foods, and may prevent nausea. |
Nursing diagnosis:
Imbalanced nutrition: less than body requirements
related to inability to ingest, digest, and absorb sufficient nutrients and calories because of prolonged vomiting
Desired Outcome: Within 1 wk of diagnosis, patient increases her nutritional intake and demonstrates improvement in her acid-base balance, electrolytes, and nutritional status.
| ASSESSMENT/INTERVENTIONS | RATIONALES |
|---|---|
| Assess for signs of starvation q8h (e.g., jaundice, bleeding from mucous membranes, and ketonuria). | Insufficient nutrition may cause hypothrombinemia, depleted vitamin C and B complexes, and ketosis. |
| Initiate and titrate enteral (nasogastric feeding) or hyperalimentation (parenteral nutrition by Intravascular therapy) as prescribed by the health care provider and agency protocols. | These are effective methods with which to administer nutrients and hydration when oral ingestion of food and fluids is not possible. |
| Start patient on oral intake when acute nausea resolves, beginning as prescribed with clear liquids (broth and bland juices) and advancing to solid foods as tolerated. | Because an individual tolerates liquids and foods differently it is important to gradually test which food(s) and pattern of eating is better tolerated. |
| Suggest alternative dietary patterns (e.g., frequent small and dry meals, six or more per day, followed by clear liquids). | Small, frequent, dry meals may reduce nausea and vomiting from a distended stomach. |
| Suggest eating meals with the highest protein/calorie intake when the nausea is the least problematic, possibly within 30 min to 1 hr after taking medication for nausea and vomiting. | When the meal providing the most nutrition is consumed at the time the patient is most likely to retain it, the patient may be able to absorb higher protein and nutrient levels necessary for pregnancy. |
| Suggest that patient drink high-protein supplemental beverages. | Liquids may be easier to tolerate than solid foods. |
| As indicated, suggest that the patient avoid food odors and foods that are greasy, highly spiced, rich, or overly sweet. | These measures prevent stimulating the gag reflex or increasing acid reflux. However, because some patients prefer salty and spicy foods, patient should try anything that is appealing and that she believes she will be able to keep down. |
| Encourage patient to stay upright for 2 hr after eating. | This prevents esophageal spasms that can be caused by reflux of acid and food into the esophagus. Gravity aids in facilitating movement of food through the esophagus to the stomach and into the small intestine. |
| Administer prescribed therapies for nausea, e.g., ginger or ginger syrup; antiemetic medications such as pyridoxine (vitamin B6) (Cochrane Review), metoclopramide (Reglan), or promethazine (Phenergan). | These therapies are known to decrease nausea and may enable the patient to ingest and retain fluid and food nutrients, vitamins, proteins, carbohydrates, and fats from oral intake. |
| Refer for acupuncture as prescribed by the health care provider to stimulate the median nerve at the P6 point, or encourage patient to wear an acupressure wristband. | Acupuncture at this site acts on the GI system. Many women report less nausea and vomiting with the wristband. |
| Assess weight at admission (or initial encounter), and document daily morning weight on the same scale. Compare with prepregnant weight, and monitor continued weight loss or gain. | Weight changes indicate progress with treatment and resolution of the condition or severity of losses and risk of maternal and fetal malnutrition. |
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