Chapter 72
Obstetric and Postobstetric Complications
Chapter 28 describes maternal physiologic adaptations to pregnancy and provides guidelines for the care of pregnant patients who are admitted to the intensive care unit (ICU) for nonobstetric indications. This chapter discusses the management of pregnant patients admitted to the ICU for obstetric indications, including obstetric hemorrhage, preeclampsia or eclampsia, acute fatty liver of pregnancy (AFLP), amniotic fluid embolism, and severe pulmonary edema.
Obstetric Hemorrhage
Antepartum Hemorrhage
Differential Diagnosis
There are multiple causes of antepartum hemorrhage (Table 72.1). Abruptio placenta (separation of the placenta from the uterine wall) and placenta previa (placenta implanted over the uterine cervix) may be associated with substantial maternal blood loss in part because of the inability of fibrinized spiral uterine arteries to vasoconstrict. The dissection of blood between the fetal membranes and the maternal decidua often initiates uterine contractions. These contractions may exacerbate the bleeding and precipitate repeated bleeding episodes.
TABLE 72.1
Selected Causes of Third-Trimester Vaginal Bleeding
| Cause | Risk Factors | Comments |
| Abruptio placenta | Hypertension Cocaine use Trauma | Usually associated with abdominal tenderness and uterine contractions 20% of cases have concealed hemorrhage (no vaginal bleeding) Rarely visualized by ultrasonography |
| Placenta previa | Prior cesarean section | Usually no abdominal tenderness, but uterine contractions are common Ultrasonography confirms diagnosis |
| Uterine rupture | Prior (classic [i.e., via vertical uterine incision]) cesarean section | Acute, persistent, intense abdominal pain |
| Fetal bleeding | Velamentous umbilical cord insertion Vasa previa | Smear of vaginal bleeding demonstrates nucleated red blood cells (i.e., cells of fetal origin) Apt alkali test shows differential resistance of fetal and maternal oxyhemoglobin to sodium hydroxide Ultrasonography to evaluate umbilical cord location |
Laboratory Evaluation
Laboratory evaluation includes a complete blood count (CBC), prothrombin time and partial thromboplastin time, fibrinogen and fibrin degradation (split) product levels, including D-dimer, and a Kleihauer-Betke (KB) stain. A KB stain is an acid elution test that is used to detect fetal hemoglobin in the maternal blood and to calculate the volume of fetomaternal hemorrhage. In an unsensitized Rh-negative mother with antepartum bleeding, Rho immune globulin (RhoGAM) should be given to prevent maternal production of anti-D antibodies. A standard vial (300 mg) of Rho immune globulin provides prophylaxis for a 30-mL fetomaternal hemorrhage. Larger fetomaternal hemorrhages, as calculated by KB stain, require additional Rho immune globulin (10 mg/mL fetal whole blood). If the fetomaternal hemorrhage is calculated to exceed 50 mL, the risk for severe fetal anemia is great, and early delivery must be considered.
Maternal coagulation studies are of critical importance in patients with obstetric hemorrhage because of the risk of disseminated intravascular coagulation (DIC) (Box 72.1). In these patients, the coagulation cascade is activated by the release of large amounts of tissue phospholipids, endotoxin, or both, which produce maternal endothelial damage. Obstetric patients diagnosed with DIC should be aggressively supported with transfusions of plasma or cryoprecipitate and platelets. However, DIC resolves only when the underlying cause of DIC is resolved.
Management
A patient with antepartum obstetric hemorrhage requires continuous fetal heart rate monitoring. “Nonreassuring” fetal heart rate patterns may necessitate emergency delivery. Large-bore intravenous (IV) access should be established, and aggressive volume replacement with crystalloids, blood components, or both should be initiated. In the setting of antepartum obstetric hemorrhage, tocolysis may be considered if the mother and fetus are stable and there is evidence for preterm labor in association with cervical dilatation. Because beta-sympathomimetic tocolytics (terbutaline, ritodrine) produce maternal tachycardia and peripheral vasodilatation, both may mimic signs of continued bleeding. Thus, magnesium sulfate is probably the tocolytic agent of choice. Delivery options are decided based on maternal and fetal clinical conditions, gestational age, and fetal lung maturity.
Postpartum Hemorrhage
Physical Examination and Laboratory Findings
The physical examination and laboratory findings typically allow the physician to identify the cause of postpartum hemorrhage rapidly. Physical examination must include an abdominal and pelvic examination, with visualization of the entire vagina and cervix and palpation of the uterine cavity. Pelvic ultrasonography and a CBC and coagulation profile may assist in diagnostic and therapeutic decisions. The diagnosis of uterine atony is confirmed when brisk vaginal bleeding is encountered after delivery in association with a boggy, flaccid uterus. Retained placenta presents similarly (although often many hours later), and ultrasonography may be used to visualize retained products of conception within the uterine cavity. Because the retained placenta is a nidus for infection, the patient may have an elevated temperature and a tender uterine fundus. Placenta accreta is readily identified by manual exploration of the uterine cavity and finding placenta remaining adherent to the uterine wall. Pelvic examination including manual exploration of the uterine cavity and visualization of the entire lower genital tract allows the physician to identify uterine scar dehiscence, lower genital tract lacerations, and vulvar hematomas readily. Pelvic hematomas may be concealed but can generally be visualized by ultrasonography when suspected in a postpartum patient with a decreasing hemoglobin and hematocrit.
Management
Although postpartum hemorrhage is generally managed medically, if medical techniques fail or a laceration is identified, surgical procedures are indicated (Box 72.2). Central hemodynamic monitoring is indicated if massive volume replacement is needed. Because physiologic intravascular mobilization of extracellular fluid occurs after delivery, fluid replacement therapy places such a patient at increased risk for pulmonary edema.
BOX 72.2 Management of Postpartum Hemorrhage
Bimanual uterine compression (facilitated by an empty bladder)
Intravenous oxytocin (20 units in 1000 mL of crystalloid at a brisk infusion rate)
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