Abstract
The management of critically ill obstetric patients most commonly involves treatment of disease processes that occur as a direct consequence of pregnancy. Although sometimes life-threatening, these conditions are usually reversible. Delivery of the infant often attenuates or ablates the disease process, and the mother typically recovers with supportive and resuscitative measures. Primary obstetric disorders account for 50% to 80% of intensive care unit (ICU) admissions for pregnant patients; approximately 80% of these admissions result from preeclampsia, sepsis, and/or hemorrhage. Trauma accounts for 45% to 50% of all maternal deaths in the United States, and it is the most common nonobstetric cause of maternal death. Other common nonobstetric causes of ICU admission are respiratory failure, endocrine disorders, preexisting autoimmune disease, and thromboembolic disorders. Ethnic minorities and women with low socioeconomic status have the highest rates of morbidity and mortality. Modern medicine has allowed women with complex medical problems such as congenital heart disease and cystic fibrosis to survive into childbearing age, and these patients are at increased risk for complications during pregnancy and have a higher incidence of ICU admission. Among critically ill obstetric patients admitted to an ICU, the most common cause of death is acute respiratory distress syndrome (ARDS), which can complicate both obstetric and nonobstetric disease processes. Critical maternal illness places the fetus at significant risk for morbidity and mortality. Important fetal risk factors include maternal shock, transfusion of blood products, and early gestational age at the time of critical maternal illness.
Keywords
Trauma, Critical care, Resuscitation, Circulation, Ventilation, Injury, Inflammation
Chapter Outline
Trauma during Pregnancy, 1274
Epidemiology, 1274
Complications and Outcomes, 1274
Initial Assessment and Resuscitation, 1276
Traumatic Brain Injury, 1282
Cardiopulmonary Resuscitation, 1283
Management of the Brain-Dead Patient, 1284
Critical Care during Pregnancy, 1284
Stroke, 1284
Status Epilepticus, 1287
Acute Respiratory Distress Syndrome, 1287
Nutrition and Glucose Control, 1290
Transfusion Triggers, 1290
Sepsis, 1290
The Fetus during Critical Maternal Illness, 1294
The management of critically ill obstetric patients most commonly involves treatment of disease processes that occur as a direct consequence of pregnancy. Although sometimes life-threatening, these conditions are usually reversible. Delivery of the infant often attenuates or ablates the disease process, and the mother typically recovers with supportive and resuscitative measures. Primary obstetric disorders account for 50% to 80% of intensive care unit (ICU) admissions for pregnant patients; approximately 80% of these admissions result from preeclampsia, sepsis, and/or hemorrhage ( Box 54.1 ). The estimated ICU admission rate for obstetric patients is 0.5% to 1% in the United States; the mortality rate among this population is 12% to 20%.
Obstetric Causes
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Acute fatty liver of pregnancy
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Amniotic fluid embolism
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Cardiomyopathy
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Chorioamnionitis
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HELLP syndrome
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Hemorrhage
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Pelvic septic thrombophlebitis
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Placental abruption
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Preeclampsia/eclampsia
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Puerperal sepsis
Nonobstetric Causes
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Acute renal failure
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Autoimmune disorders
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Chronic respiratory disease
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Diabetic ketoacidosis
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Drug abuse
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Pneumonia
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Pulmonary thromboembolism
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Trauma
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Urinary tract infection
HELLP, Hemolysis, elevated liver enzymes, low platelet count.
Trauma accounts for 45% to 50% of all maternal deaths in the United States, and it is the most common nonobstetric cause of maternal death. Other common nonobstetric causes of ICU admission are respiratory failure, endocrine disorders, preexisting autoimmune disease, and thromboembolic disorders. Ethnic minorities and women with low socioeconomic status have the highest rates of morbidity and mortality. Modern medicine has allowed women with complex medical problems such as congenital heart disease and cystic fibrosis to survive into childbearing age, and these patients are at increased risk for complications during pregnancy and have a higher incidence of ICU admission. Among critically ill obstetric patients admitted to an ICU, the most common cause of death is acute respiratory distress syndrome (ARDS), which can complicate both obstetric and nonobstetric disease processes.
Critical maternal illness places the fetus at significant risk for morbidity and mortality. Important fetal risk factors include maternal shock, transfusion of blood products, and early gestational age at the time of critical maternal illness.
Trauma During Pregnancy
Epidemiology
Trauma affects 5% to 7% of pregnancies in the United States and is the leading nonobstetric cause of maternal death; as many as 20% of affected women require emergency surgery. It is likely that the reported incidence of maternal trauma is underestimated due to underreporting, especially in cases of domestic violence. Motor vehicle accidents are the most common cause of injury-related maternal death (49% to 70%), followed by domestic violence (11% to 25%) and falls (9% to 23%). Not using a seat belt is a major risk factor for maternal and fetal injury in motor vehicle trauma. Penetrating trauma and burns are less common than blunt mechanisms of injury. The rate of maternal trauma admission to an ICU increases with each trimester: 8% occur in the first trimester, 40% in the second trimester, and 52% in the third trimester. Most women are able to continue their pregnancy at home, but up to 38% are hospitalized until delivery.
Risk factors for maternal trauma include age younger than 25 years, low socioeconomic status, minority race, use of illicit drugs or alcohol, and domestic violence. It is important to remember that any female patient of reproductive age who is a victim of trauma could be pregnant at the time of injury.
Complications and Outcomes
As in the general population, hemorrhagic shock and brain injury are the most common mechanisms of death in pregnant trauma victims. Pelvic and acetabular fractures also pose a significant risk. Injuries and complications that are unique to pregnant trauma victims include uterine rupture, placental abruption, preterm labor, and direct fetal injury. Although rare (0.6% of injuries), uterine rupture is a major threat to the life of both the mother (10% mortality) and the fetus (near 100% mortality). Placental abruption complicates 1% to 5% of minor injuries and 20% to 60% of major trauma and usually occurs from 16 weeks’ gestation onward. Placental abruption can cause major overt and occult hemorrhage and coagulopathy and should be considered as a possible source of bleeding in the unstable pregnant trauma patient. Preterm labor is a common (25%) complication of trauma and can be precipitated even in cases of apparently minor injury. Premature rupture of membranes (PROM) increases the risk for both preterm labor and infection. Amniotic fluid embolism is a rare complication of maternal trauma, but it should be considered as part of the differential diagnosis in patients who are refractory to resuscitation.
Fetal-maternal (transplacental) hemorrhage can occur after trauma and result in maternal isoimmunization with the D antigen of the fetal red blood cell Rhesus protein complex (Rh 0 [D]) in the Rh-negative mother (see Chapter 6 ). The Kleihauer-Betke test is used to identify fetal blood in the maternal circulation after maternal injury. Acid applied to a peripheral maternal blood smear eliminates adult hemoglobin, while fetal hemoglobin is resistant. Subsequent staining lights up the intact fetal cells against a background of pale maternal cells, and the ratio of fetal to maternal cells can be used to calculate the total volume of fetal red blood cells in the maternal circulation. When fetal-maternal hemorrhage is present, treatment with Rh 0 (D) immune globulin (RhoGAM) is generally indicated. In a study performed at the R. Adams Cowley Shock Trauma Center of the University of Maryland, more than 50% of evaluated pregnant trauma victims were positive for fetal-maternal hemorrhage as determined by a positive Kleihauer-Betke test. Essentially all patients with a positive test had uterine contractions, whereas patients with a negative Kleihauer-Betke test did not have contractions. The investigators concluded that the Kleihauer-Betke test was a sensitive and specific predictor of preterm labor in pregnant trauma patients and should be performed in all victims regardless of blood Rh phenotype.
Fetal Trauma and Outcome
The fetal mortality rate after maternal blunt trauma has been reported to range from 3.4% to 38.0%; placental abruption, uterine rupture, maternal shock, and maternal death are the most frequent factors associated with fetal demise ( Box 54.2 ). The risk for direct fetal trauma increases with gestational age because the bony pelvis protects the uterus and fetus before 13 weeks’ gestation. Pregnant women who sustain blunt trauma have a lower risk for bowel injury than nonpregnant patients because the uterus acts as a shield and pushes the abdominal contents into the upper abdomen. Maternal pelvic fractures are associated with uteroplacental injury and fetal skull fractures. Skull fracture is the most common direct fetal injury and has a reported fetal mortality rate of 42%.
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Ejection from vehicle
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Maternal pelvic fracture
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High maternal Injury Severity Score (> 15)
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Maternal death
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Maternal hypotension
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Uterine rupture
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Uterine tenderness
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Placental abruption
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Vaginal bleeding
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Abnormal fetal heart rate pattern
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Amniotic fluid on pelvic examination
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Maternal history of alcohol use
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Maternal history of smoking
The relationship between the Injury Severity Score (ISS) (see later discussion) and fetal outcome is controversial. Some studies have shown a direct relationship between the ISS and the incidence of fetal demise, whereas others have not. Analysis of outcomes from 1075 pregnant trauma victims showed that an ISS of greater than 15 was associated with increased risk for fetal demise. In contrast, a study using data from the state of Washington found no correlation between ISS and pregnancy outcomes. Fetal demise occurred even in women with low ISS. Evidence suggests that decreased serum bicarbonate, an indicator of systemic hypoperfusion, is associated with fetal demise after maternal trauma. Altered maternal mental status and the presence of head trauma have also been linked to adverse fetal outcomes.
It is crucial to preserve maternal cardiac output, blood pressure, and oxygen delivery to optimize maternal recovery and protect fetal well-being. However, fetal loss can occur even if the mother has not incurred serious injuries. Thus, all pregnant women should be evaluated in a medical setting after trauma, regardless of the apparent severity of injury. The fetus remains at risk for delayed complications after maternal discharge from the hospital. Delayed complications include a twofold increase in the risk for preterm delivery and a ninefold increase in the risk for fetal death. Late complications of trauma, such as cerebral palsy, have also been reported in children born to mothers who experienced trauma during pregnancy.
Initial Assessment and Resuscitation
The initial assessment and resuscitation should focus on the mother; it is axiomatic that maternal resuscitation typically facilitates fetal resuscitation. A systematic approach to initial resuscitation and stabilization should be used ( Fig. 54.1 ). Immediate interventions are initiated to identify and treat life-threatening conditions based on the principles of Advanced Trauma Life Support (ATLS). Initial focus should be placed on ensuring adequate airway protection, ventilation (breathing), and circulation (the “ABCs” of resuscitation). Pregnant women experience significant changes in cardiopulmonary and metabolic function that must be considered during resuscitation ( Table 54.1 ).
| Parameter | Effect of Pregnancy | Implications |
|---|---|---|
| Airway | ||
| Functional residual capacity | Decreased by 20% | More rapid oxyhemoglobin desaturation during periods of apnea |
| Oxygen consumption | Increased by 15%–20% | |
| Airway edema | May be present | Tracheal intubation more difficult |
| Lower esophageal sphincter tone | Decreased | Increased risk for aspiration |
| Gastric emptying | Decreased during labor | |
| Breathing | ||
| Diaphragm | Displaced cephalad | Place chest tubes at higher intercostal space |
| Respiratory rate | No change | |
| Tidal volume | Increased 35%–45% | |
| pH | 7.42–7.46, partially compensated respiratory alkalosis | |
| Pa co 2 | 28–32 mm Hg | Reflects normal hyperventilation |
| HCO 3 – | 19–22 mEq/L | Reduced buffering capacity |
| Base deficit | 2–3 mEq/L | |
| Pa o 2 | 100–107 mm Hg | |
| Circulation | ||
| Blood volume | Increased by 40%–50% | Significant blood loss may occur before onset of symptoms and hypotension |
| Cardiac output | Increased by 40%–50% | |
| Heart rate | Increased by 15%–25% | Early diagnosis of hypovolemia more difficult |
| Systolic blood pressure | Decreased by 5–15 mm Hg (more pronounced during mid-pregnancy) | |
| Diastolic blood pressure | Decreased by 5–15 mm Hg (more pronounced during mid- pregnancy) | |
| Hemoglobin | 10–12 g/dL | Physiologic anemia |
| Gravid uterus | Aortocaval compression | Decreased cardiac output in the supine position; left uterine displacement required |
| Other | ||
| Coagulation factors | Increased | Hypercoagulable state |
| BUN, creatinine | Decreased | Abnormal measurements often overlooked a |
| Symphysis pubis/sacroiliac joints | Widened | May alter radiographic interpretations |
a The reported measurements may fall within the normal range for the hospital laboratory, but the measurements may actually be abnormally high for a pregnant patient.
Airway
Airway patency, stabilization, and protection should be ensured as quickly as possible in all critically injured patients, including those who are pregnant. The status of the patient’s airway can be quickly assessed by eliciting a verbal response. The inability to speak is an indication of severely impaired mental status or the inability to move adequate air to mediate phonation, either of which should prompt interventions to secure and protect the airway. Additional means of assessing airway patency include auscultation of the chest, assessment of chest movement, and assessment of air movement at the mouth and nose. Immediate interventions to establish airway patency include head-tilt and jaw-thrust maneuvers, as well as placement of an oral or nasopharyngeal airway to facilitate bag-and-mask ventilation and oxygenation.
It is essential to consider the possibility of cervical spine injury, facial fractures, and skull base injuries. Excessive head-tilt maneuvers can worsen injury if a cervical spine fracture is present. Patients who have sustained severe trauma should be suspected of having a cervical spine injury until proven otherwise. Cervical spine injury must be ruled out by radiographic and physical examination criteria. The cervical spine should be stabilized with a hard collar and in-line stabilization until the severity of injury has been established. In cases of documented cervical spine injury, great care must be taken not to worsen spinal cord injury. A nasopharyngeal airway should not be placed in patients with suspected facial or skull base fractures to avoid further trauma and worsening of preexisting conditions.
Most patients who require interventions to open or support the airway, as just described, will ultimately require tracheal intubation. Indications for tracheal intubation include impaired mental status, airway obstruction, inability to clear secretions or blood from the airway, inadequate spontaneous ventilation, and hypoxemia that is refractory to supplemental oxygen administration. Tracheal intubation of pregnant patients is complicated by changes in respiratory system structure and function (see Table 54.1 ) (see Chapter 29 ). Among the most prominent alterations are airway (including vocal cord) edema, decreased functional residual capacity, and increased oxygen consumption. Airway edema impairs vocal cord visualization, thus complicating laryngoscopy and tracheal intubation. Decreased functional residual capacity and increased oxygen consumption result in more rapid oxyhemoglobin desaturation during periods of apnea. These factors increase the risk for failed tracheal intubation and hypoxemia.
Gastric emptying is normal in pregnant women before the onset of labor. However, lower esophageal sphincter tone is commonly decreased in pregnant women (see Table 54.1 ). Thus, pregnant women are at increased risk for regurgitation and pulmonary aspiration of gastric contents, and similar to all trauma victims, are considered to have a full stomach on arrival in the emergency department or operating room. Therefore, in most cases, rapid-sequence induction of general anesthesia is performed to facilitate tracheal intubation. However, the specific tracheal intubation technique will depend on the practitioner’s skills and resources, as well as on the location of the patient’s injuries. Alternative approaches to rapid-sequence induction include awake tracheal intubation and tracheostomy.
Several factors can complicate tracheal intubation in the trauma patient. The patient may be combative, which complicates awake tracheal intubation strategies. Blood in the airway can also limit the use of a fiberoptic bronchoscope and impair visualization of the glottis when using a standard or video laryngoscope. The presence of facial fractures, direct airway injuries, trauma-induced airway edema, and tracheal deviation can limit access to the airway.
Finally, airway management, including tracheal intubation, is more challenging in the presence of cervical spine injury. If cervical spine injury is present or suspected, it is crucial to avoid flexion, extension, or lateral movement of the neck. The spine is protected using in-line stabilization and/or a hard cervical collar. Airway management devices such as a gum elastic bougie, a video laryngoscope, a lighted intubating stylette, and/or an intubating supraglottic airway (SGA), among others, should be available for use if standard laryngoscopy is difficult or impossible. An SGA such as a laryngeal mask airway can be used to temporarily provide ventilation in cases in which mask ventilation and tracheal intubation have failed, but an SGA will not provide protection from aspiration and should be replaced by a secure airway device as soon as possible. In some cases, cricothyroidotomy or tracheostomy may be necessary to provide a secure airway.
Breathing
Adequate ventilation and oxygenation should be ensured for the benefit of both the mother and the fetus. Supplemental oxygen should be administered immediately, even if the patient is breathing spontaneously. Mechanical ventilation is often necessary after tracheal intubation in patients with respiratory failure and/or hypoxemia. Ventilation can be compromised by trauma-associated factors such as pneumothorax, hemothorax, lung contusion, mediastinal compression, and chest wall injuries. These problems must be identified during the primary survey and treated to optimize ventilation and oxygenation. In women with advanced pregnancy, it may be necessary to place chest tubes more cephalad than normal owing to the cephalad displacement of the diaphragm and intraabdominal structures by the gravid uterus. Pregnant trauma patients should be ventilated to maintain Pa co 2 at a level that is normal for pregnancy (28 to 32 mm Hg) (see Table 54.1 ). Positive end-expiratory pressure (PEEP) may be added to improve oxygenation, if indicated; however, PEEP should be titrated carefully in the hypovolemic patient because it may impair venous return and worsen cardiac output and organ perfusion.
Circulation
Once respiratory stabilization has been achieved, it is essential to assess cardiovascular function and to determine whether the patient is in shock. Two large-bore peripheral intravenous catheters should be placed in the upper extremities to facilitate resuscitation. Central venous access facilitates rapid resuscitation but may be difficult to obtain. Intraosseous cannulation should be considered if it is difficult or impossible to obtain peripheral or central venous access.
Fluid resuscitation should be initiated using crystalloid solution, but blood transfusion should be considered if significant blood loss is apparent or suspected. Left uterine displacement should be initiated immediately to prevent or minimize aortocaval compression by the gravid uterus. The adverse effects of aortocaval compression may be exacerbated during periods of trauma-associated hypovolemia. The use of the pneumatic antishock garment to stabilize fractures or control hemorrhage is relatively contraindicated in pregnant women owing to its adverse effects on venous return.
The hallmark clinical signs of shock are listed in Box 54.3 . The presence of these signs indicates a need for timely and appropriate fluid resuscitation. A rapid assessment of sources of blood loss should be performed. In trauma victims, the most common locations of exsanguinating blood loss are the chest, abdomen, retroperitoneum, long bones, and external sites. In the pregnant trauma patient, placental abruption and uterine rupture are also potential sources of hemorrhage. A brief physical examination will identify fractures of the long bones and external sites of bleeding. Thoracic blood loss and pelvic fractures can be identified by chest and pelvic radiographs, respectively. Focused abdominal sonography in trauma (FAST) or diagnostic peritoneal lavage can be used to identify intra-abdominal bleeding. However, diagnostic peritoneal lavage may be difficult to perform safely in advanced pregnancy. FAST can be rapidly performed to assess the hepatorenal, splenorenal, and pelvic spaces, which are the most common sites of major hemorrhage in trauma patients. FAST can also be used to assess uteroplacental integrity and the presence of intrauterine bleeding. Finally, ultrasonography facilitates assessment of cardiac filling and recognition of cardiac tamponade in patients with thoracic trauma.
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Agitation
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Confusion
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Poor capillary refill
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Mottled appearance
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Cool extremities
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Diaphoresis
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Tachypnea
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Tachycardia
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Weak distal pulses
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Hypotension
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Decreased pulse pressure
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Decreased urine output
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Lactic acidosis
It is important to recognize that pregnant trauma patients may lose a significant amount of blood before the development of hypotension. Pregnant patients have a 40% to 50% increase in blood volume by the third trimester. Classic signs of hypovolemia such as tachycardia, hypotension, and poor capillary refill may not be evident until blood loss approaches 1.5 to 2 liters. Therefore, it is likely that a pregnant trauma victim will have lost significantly more blood volume and oxygen-carrying capacity than a comparable nonpregnant patient when signs of cardiovascular deterioration become evident. Resuscitation should be guided by apparent blood loss to maintain adequate maternal cardiac output and uteroplacental perfusion. Because of the physiologic anemia of pregnancy, oxygen-carrying capacity may be significantly impaired at the time that hypovolemia becomes evident. In addition, maternal perfusion of vital organs is often sustained at the expense of uteroplacental perfusion. Uterine blood flow may decrease by as much as 30% before the mother shows signs of hypovolemia. Therefore, a nonreassuring fetal heart rate (FHR) pattern may be the first sign of significant intravascular volume loss. Fluids should be warmed to minimize the risk for hypothermia, which can contribute to coagulopathy, arrhythmias, and altered drug responses.
Fluid resuscitation.
Current practice supports the use of crystalloid solutions to resuscitate the hypovolemic trauma victim during the early phases of resuscitation. However, the crystalloid versus colloid debate remains to be fully resolved. The Saline versus Albumin Fluid Evaluation (SAFE) did not show any difference in survival in nonpregnant trauma patients randomized to receive resuscitation with colloid or crystalloid, with the exception of patients with head trauma, who had poorer outcomes when resuscitated with albumin. The CRISTAL trial also did not demonstrate differences in 28-day mortality when comparing crystalloid to colloid, but 90-day mortality was lower in patients who received colloid. However, the authors considered the results exploratory and cautioned against conclusions about the efficacy of colloid solutions until further investigations are completed. Colloid solutions are anecdotally preferred in some trauma centers.
Balanced salt solutions (lactated Ringer’s solution, PlasmaLyte) are typically preferred over normal saline in patients without closed head injury. Balanced salt solutions have significant buffering properties and are less likely than normal saline solution to cause hyperchloremic metabolic acidosis during high-volume resuscitation. A 2018 trial showed that use of balanced crystalloids for resuscitation of critically ill patients was associated with a lower incidence of the composite outcome (death, need for renal-replacement therapy, or renal dysfunction) compared with normal saline. Other buffered salt solutions such as Ringer’s ethyl pyruvate and Ringer’s hydroxybutyrate also may have value. Currently, no evidence supports the use of one buffered isotonic crystalloid solution over another.
The use of hypertonic crystalloid solutions such as 3% sodium chloride is controversial; currently no evidence supports their use in pregnant trauma victims. Hypernatremia is a risk in patients resuscitated with hypertonic saline, and some studies have shown increased mortality in patients resuscitated with hypertonic crystalloid solutions. In a 2017 systematic review, Wu et al. did not identify significant survival or complication risk associated with hypertonic saline resuscitation compared with isotonic saline in patients with hemorrhagic shock. Nevertheless, a recent paper by Asehnoune et al. reported improved adjusted 90-day survival in trauma patients with intracranial hypertension treated with continuous hyperosmolar therapy. In general, hypertonic resuscitation does not appear to be beneficial to trauma patients without traumatic brain injury but may benefit patients with traumatic brain injury and elevated intracranial pressure (ICP).
Some practitioners have advocated hypovolemic resuscitation in patients with major hemorrhage after trauma. This technique employs permissive hypotension (systolic blood pressure of 80 to 90 mm Hg) until hemorrhage can be controlled in the operative setting. The underlying premise of hypovolemic (hypotensive) resuscitation is that overresuscitation worsens ongoing blood loss as a result of higher perfusion pressure and dilution of clotting factors. Small boluses of fluids are administered to maintain perfusion in patients without evidence of closed head injury. The use of hypotensive resuscitation is likely detrimental in patients with closed head injury because it is crucial to maintain adequate cerebral perfusion pressure (CPP) in patients with elevated ICP. (CPP is the difference between mean arterial pressure [MAP] and ICP.) No definitive published data support the use of hypotensive resuscitation in pregnant trauma patients. Current guidelines do not support this approach because it may compromise uteroplacental perfusion.
The resuscitative endovascular balloon occlusion of the aorta (REBOA) catheter is a large-vessel occlusion device that is typically deployed into the aorta during periods of severe intraabdominal and pelvic hemorrhage, and is becoming increasingly utilized in cases of major trauma. A proximal pressure transducer is used to titrate balloon inflation to maintain central pressures and limit downstream bleeding as reparative procedures are executed. The device is a less invasive alternative to emergency department thoracotomy and aortic cross-clamping to temporize noncompressible torso hemorrhage. In patients without penetrating thoracic injury, Brenner et al. reported a survival benefit for REBOA compared with patients who received resuscitative thoracotomy. The efficacy of the approach remains to be fully determined in all subsets of trauma patients with hemorrhage; a prospective study of the device is underway. The effectiveness and safety of the REBOA catheter remains to be established in critically injured pregnant patients.
Damage control principles and resuscitation.
The traditional approach to treatment of traumatic life-threatening injuries has been definitive operative repair. However, some patients experience progressive physiologic decline during long surgical procedures and develop severe derangements such as hypothermia, metabolic acidosis, and coagulopathy, a combination that has become known as the deadly triad . These pathologic alterations require rapid and effective treatment to prevent severe morbidity and death. More recently, practitioners have advocated the use of a more targeted surgical approach, termed damage control surgery, which is initiated to control hemorrhage without providing early definitive repair of injuries. Major surgical bleeding is controlled, and the thoracic and abdominal cavities are packed to provide hemostasis. Gastrointestinal diversion is performed, and body cavities are temporarily closed, often using vacuum-type closure systems. Active volume resuscitation is performed using blood products rather than crystalloids, an approach known as damage control resuscitation, to achieve metabolic homeostasis. Once stable hemodynamic and acid-base status, coagulation function, and temperature are achieved, the patient is returned to the operating room for definitive repair of injuries.
Blood products.
All trauma centers should have rapid access to type O, Rh-negative blood for emergency use before type-specific or cross-matched blood is available. Recently, trauma specialists have advocated damage-control resuscitation using packed red blood cells (PRBCs), platelets, and fresh frozen plasma mixed in equal proportions (1 : 1 : 1) (see Chapter 37 ). Several investigators have reported the value of this approach in military practice, and they have specifically observed that this approach results in more effective resuscitation, less coagulopathy, and improved survival than more traditional approaches. Based on experience over the last few years, damage-control resuscitation is also considered to be the optimal strategy for managing civilian patients with exsanguinating trauma. The Pragmatic, Randomized, Optimal Platelet and Plasma Ratios (PROPPR) trial showed that damage-control surgery and balanced blood product resuscitation (1:1:1 ratio) is associated with improved hemostasis at 3 hours after intervention and a decreased incidence of death by exsanguination at 24 hours after injury, although overall mortality at 24 hours and 30 days after injury was not improved compared with patients receiving damage-control surgery with blood products in a 1 : 1 : 2 ratio. Based on current evidence, the Eastern Association for the Surgery of Trauma recommends the use of balanced blood product resuscitation in exsanguinating trauma patients.
Despite implementation of damage-control resuscitation, coagulopathy remains a significant problem for trauma patients requiring large-volume resuscitation. Damage-control resuscitation provides clotting factors via transfused plasma and direct administration of platelets. However, tissue injury and release of endogenous anticoagulants often results in sustained alterations in coagulation. Consequently, some practitioners advocate adopting a goal-directed approach to treat trauma-induced coagulopathy based on viscoelastic monitoring, either with thromboelastography (TEG) or rotational thromboelastometry (ROTEM) (see Chapter 44 ). Gonzalez et al. reported that goal-directed treatment of trauma-associated coagulopathy, compared with standard assessment of coagulation status, was associated with lower mortality and decreased use of plasma and platelets during the acute phase of resuscitation. However, there were limitations associated with the study, and further work is needed to define the benefits of goal-directed treatment of coagulopathy in the trauma patient suffering large-volume hemorrhage.
Secondary Survey
As in all trauma cases, it is crucial to evaluate the mother for significant abdominal, thoracic, orthopedic, and neurologic injuries. A head-to-toe examination should be performed to determine the presence of injuries and the need for intervention. A more detailed evaluation of neurologic function, as well as examination of the head and neck, should be performed. This survey includes examination of posterior structures that may be obscured by the supine position and the presence of a cervical collar. The torso should be examined to identify thoracic and abdominal injuries. The thoracic examination should include chest auscultation, inspection, and palpation. Palpation of the abdomen should be performed to evaluate abdominal tenderness, and a rectal examination should be performed to identify evidence of intraluminal bleeding. The extremities must be examined to identify deformities, and each joint should be manipulated. Distal perfusion of the extremities must be continuously monitored, especially in limbs that show signs of significant injury. This is accomplished by evaluation of distal pulses and capillary refill. In cases of penetrating injury, the sites of entry and exit should be identified. It is especially important to examine carefully the areas that are difficult to access such as the oral cavity, perineum, axilla, scalp, and back. Once the secondary survey has been performed, more targeted assessments of suspected injuries can be performed using radiologic imaging.
Fetal survey.
After initial stabilization of the mother, information about the pregnancy should be gathered through a focused history and physical examination. The history should include the date of the last menstrual period, expected date of delivery, and status of the pregnancy. In cases in which there is uncertainty regarding fetal age, an approximate determination can be made by measuring fundal height. The fetal age is estimated to be 1 week for each centimeter of fundal height above the symphysis pubis. In addition to the assessment of fundal height, the abdominal examination should include an assessment of uterine tenderness and consistency, the presence or absence of uterine contractions, and fetal position and movement.
A pelvic examination should be performed to evaluate cervical dilation and effacement, fetal station, and the presence of amniotic fluid and blood. The FHR is assessed by Doppler auscultation or ultrasonography. If maternal stability permits, ultrasonography facilitates estimation of fetal age and assessment of uteroplacental injury.
If no fetal cardiac activity is identified, fetal resuscitation should not be attempted (see Fig. 54.1 ). In a series of 441 pregnant trauma patients, the absence of a detectable FHR was associated with fetal death in all cases. When an FHR is detected, an assessment of fetal viability should be performed. An estimated gestational age of 23 to 24 weeks and an estimated fetal weight of 500 g are common thresholds for extrauterine fetal viability. The FHR should be monitored in cases in which the fetus is determined to be viable. In cases in which a nonviable fetus is present, the importance of FHR monitoring is unclear. However, alterations in FHR and FHR variability may signal maternal deterioration and serve as a good monitor of the effectiveness of maternal resuscitation.
FHR monitoring is generally performed with external Doppler auscultation, and a tocodynamometer is used to assess uterine contractions. Adverse fetal outcomes are unlikely in cases with a reassuring FHR tracing and no early warning signs of uteroplacental injury (bleeding, abdominal pain). In contrast, an abnormal FHR tracing or evidence of uteroplacental injury (vaginal bleeding, uterine contractions, uterine tenderness, presence of amniotic fluid on vaginal examination) predicts poor fetal outcome in approximately 50% of cases.
Fetal Monitoring
Continuous electronic FHR monitoring is the current standard of care for pregnant trauma victims with a viable fetus. FHR monitoring should be initiated as soon as maternal stabilization allows, because placental abruption can occur early during the course of resuscitation. Continuous electronic FHR monitoring is more sensitive for placental abruption than ultrasonography, physical examination, or Kleihauer-Betke testing. Occasional uterine contractions are common after trauma and are usually not associated with poor fetal outcome. Random uterine contractions usually resolve within a few hours of the accident. However, regular and prolonged uterine contractions (eight contractions per hour for more than 4 hours) are associated with placental abruption, which has a high fetal mortality rate. The diagnosis of placental abruption should trigger immediate cesarean delivery for both fetal and maternal indications; a large percentage of viable fetuses can be rescued if expedited delivery is performed, and placental abruption will exacerbate maternal hemorrhage and coagulopathy. The presence of fetal bradycardia and/or frequent late FHR decelerations should also prompt delivery if the mother is stable and adequately resuscitated.
The ideal duration of FHR monitoring has not been determined. However, a common practice, based on a prospective study of 60 pregnant trauma patients at more than 20 weeks’ gestation, is to monitor the FHR for 4 hours. If maternal-fetal abnormalities are not detected within 4 hours, it is generally considered safe to discontinue FHR monitoring because a normal FHR tracing has a negative predictive value of 100% when combined with a normal maternal physical examination. However, the presence of abnormalities such as vaginal bleeding, spontaneous rupture of membranes, category II and III FHR patterns, persistent uterine contractions, uterine tenderness, abdominal pain, and/or need for maternal analgesia should prompt further FHR monitoring. The sensitivity of ultrasonography for placental abruption ranges from 50% to 80%, but ultrasonography is a safe and effective means of assessing fetal viability, FHR, placental location, gestational age, and amniotic fluid volume. It is particularly valuable in the presence of maternal tachycardia, when it can be difficult to differentiate maternal and fetal heart rates using Doppler auscultation.
Laboratory Studies
Laboratory evaluation in pregnant trauma patients does not differ from the evaluation for nonpregnant patients, with a few exceptions. As for all trauma patients, the laboratory evaluation will be driven by the type and severity of injury. For most patients with significant injury, standard analysis includes a complete blood cell count, coagulation studies, serum electrolyte measurements, blood glucose and lactate levels, liver function tests, arterial blood gas analysis, urinalysis, and toxicology screening, as well as sending a blood sample for typing and cross-matching for compatible blood products ( Box 54.4 ).
