Emergency Delivery and Peripartum Emergencies

122 Emergency Delivery and Peripartum Emergencies



Jeremy B. Branzetti



image      Key Points




• If shoulder dystocia is encountered, attempt the McRoberts maneuver with suprapubic pressure while simultaneously calling for obstetric assistance.


• Practitioners underestimate blood loss in postpartum hemorrhage by as much as 50%.


• Uterine inversion is relatively uncommon but is associated with significant morbidity if not recognized and treated promptly.


• Up to 87% of patients with uterine rupture have no pain, and up to 89% have no vaginal bleeding.


• Perimortem cesarean delivery is indicated in gravid patients if more than 24 weeks pregnant and if arrest continues after 4 to 5 minutes of cardiopulmonary resuscitation.


• The clinical examination of a term pregnant patient is notoriously unreliable.


• Treatment of anaphylactoid syndrome of pregnancy is similar to that for sepsis and disseminated intravascular coagulation and should begin immediately; the diagnosis is one of exclusion, and patients must be treated promptly to survive.




Emergency Delivery



Pathophysiology


During labor the fetus follows a series of stereotypic movements known as the cardinal movements of labor. Although the specifics have little bearing on the emergency physician’s approach to labor, the final movement typically leaves the baby with the occiput anterior (relative to the maternal pelvis) and the head sharply flexed. This position offers the smallest fetal head diameter and is therefore optimal for passage through the pelvis. Any deviation from this position is by definition a malpresentation, and these different presentations are all associated with increasing morbidity and mortality. The overwhelming majority of births, however, will require little physician intervention beyond timely encouragement and vigilance for complications.


For a description of potential malpresentation, along with management recommendations, see www.expertconsult.com



Presenting Signs and Symptoms


Labor is classically heralded by shedding of the mucous plug that was occluding the cervix (the “bloody show”), passage of clear fluid from the vagina from ruptured membranes (the “water breaking”), and contractions. True contractions are organized and detectable by tocometry; tend to increase in pain, frequency, and strength with time; and have associated cervical changes. Braxton-Hicks contractions, commonly called false labor, are characterized by unorganized myometrial activity without cervical changes. Other common symptoms at labor onset include abdominal pain and back pain.


In the emergency department (ED), the majority of patients seen in labor are in the latter part of stage I or stage II.1 Precipitous delivery is a common occurrence because most patients whose labor progresses more slowly will have time to get to their designated obstetric facility.



Differential Diagnosis and Medical Decision Making


For any woman encountered after 20 weeks of pregnancy, labor must be in the differential diagnosis. Although the ultimate differentiation of false labor, or Braxton-Hicks contractions, is made by continuous tocometry, a good history can often make the diagnosis.


For patients with a chief complaint of vaginal bleeding, placental abruption and placenta previa should be considered. When the only complaint is passage of clear fluid from the vagina, premature rupture of membranes (PROM) and preterm premature rupture of membranes (PPROM) should be assumed until proved otherwise.


For an uncomplicated delivery, no diagnostic testing is needed. In those without any prenatal care, a complete blood count and Rh status should be obtained.


For patients complaining of vaginal bleeding, placenta previa or abruption should be assumed. Ultrasound is required to evaluate for previa. It is essential that placenta previa be diagnosed early because vaginal delivery is absolutely contraindicated with this condition. Ultrasound is not useful in ruling out the diagnosis of placental abruption because tococardiographic monitoring in an obstetric suite is required.



Treatment


The major point of triage is during stage I of labor. If care is available in-house, transfer can be accomplished at any point before crowning. If care requires out-of-hospital transfer, it is imperative to establish early and reliable contact with the treating obstetrician to facilitate a safe plan of care.


Even though multiple physical interventions may be necessary with an abnormal delivery, an uncomplicated one typically only requires measures that support smooth fetal passage. Resuscitation equipment should be available immediately. Episiotomies are no longer recommended during routine pregnancies. They should be used sparingly and typically only with complicated deliveries. If shoulder dystocia is encountered, hyperflexion of the maternal hips and knees (McRoberts maneuver) and suprapubic pressure are first-line interventions that resolve most instances of dystocia.


For more information on the management of difficult labor, see www.expertconsult.com


After determination of hemodynamic stability, the next priorities are to determine whether true labor is occurring and the appropriate disposition to achieve optimal medical care. For any patient with a complaint of passage of clear fluid from the vagina without other signs and symptoms of labor (bloody show and regular, progressing, often painful contractions), a sterile speculum examination should be performed before a gloved digital examination to evaluate for PROM.


Once labor is confirmed, the goal is to evaluate the positioning (orientation in space relative to the maternal pelvis) and presentation (body part palpable at the cervix) of the fetus, along with the degree of change in the uterine cervix. This includes assessment of station (level of decent into the pelvis relative to the maternal ischial spines), effacement (degree of cervical thinning), and dilation of the cervical aperture. For the emergency physician, determination of dilation and effacement is the most important part of the examination—a fetus that is still contained within a closed and minimally effaced cervix will probably be transferred to obstetrics whether or not it is vertex (fetal head as the presenting part).


If delivery is imminent, the patient will have to remain in the ED. A gynecologic bed with lithotomy position capability is ideal, and a resuscitation bay with greater accessibility and equipment is recommended. A radiant warmer and appropriate airway equipment should be available. Positioning of the mother may require an approximate 10-degree tilt to the left to prevent uterine pressure on the inferior vena cava and associated hypotension. When crowning occurs, the mother should be instructed to push along with the contractions, with the physician positioned in front of the introitus ready to accept the fetus. As soon as the head is accessible, continuous gentle countertraction should be administered to maintain it in a flexed position. This technique provides control of an explosive delivery, as well as avoidance of the high morbidity associated with fetal neck hyperextension. Though once recommended, the modified Ritgen maneuver has recently been shown to be associated with an increased rate of third-degree lacerations and episiotomy in comparison with a “hands-off” approach.2 Similar rates of perineal tears were found for each modality.


When the head is clear, the fetus rotates 90 degrees. Suction of the fetal mouth and nose should be performed as soon as possible in the setting of meconium staining. Typically, the shoulders will then be delivered, anterior first, without assistance. Mild downward traction on the torso (not lateral flexion of the neck) may be required to assist passage of the anterior shoulder. Once clear, the posterior shoulder is typically delivered spontaneously or with upward traction in a similar manner as just described. At this point the largest fetal diameter has passed, and labor is generally smooth. The cord may be clamped once it is accessible after passage of the fetus. If the cord is tightly wound around the fetus, knotted, or abnormal in any way, it is clamped (typically at 7 and 10 cm) and cut once accessible. When free, the neonate is dried and warmed and its resuscitation needs evaluated. If available, a neonatologist should be present at any ED delivery.


Three classic signs indicate delivery of the placenta: sudden lengthening of the cord, a gush of blood, and a change in the shape of the uterine fundus. Once the fetus is clear, gentle traction on the cord should continue until these signs are seen. After the placenta is delivered, typically within 20 minutes, it is inspected for irregularities that may suggest retained tissue. Manual abdominal massage of the uterine fundus will often assist in uterine contraction. An infusion of oxytocin, typically 20 units in a 1000-mL bag of normal saline infused at about 200 mL/hr, can be administered to hasten separation and assist in contraction of the uterus back into the pelvis.



Follow-Up, Next Steps in Care, and Patient Education


After the placenta is delivered and the neonate is stabilized, the mother should be evaluated for bleeding—the causes and treatment of which are covered next. If hemodynamically stable after the first postpartum hour, the mother may be transferred to the postpartum floor.



Postpartum Hemorrhage



Epidemiology


Hemorrhage is a significant cause of maternal morbidity and is the second most common cause of peripartum deaths (following amniotic fluid embolism). Hemorrhage was a direct cause of more than 18% of 3201 pregnancy-related maternal deaths in the United States from 1991 to 1997.3 Worldwide, hemorrhage has been identified as the single most important cause of maternal death and is responsible for almost half of all postpartum deaths in developing countries.4


Postpartum hemorrhage is the term used to describe excessive blood loss after delivery. Classically, it is defined as more than 500 mL of blood loss in a vaginal delivery or more than 1000 mL of blood loss in a cesarean delivery; however, careful quantitative measures reveal that blood loss in the range of 500 to 1000 mL is actually average for both types of delivery. Of note, practitioners often underestimate blood loss by as much as 50%.5 For the ED physician, the most important causes of hemorrhage in the postpartum period are birth trauma, uterine atony, uterine rupture, and uterine inversion.



Pathophysiology


Separation and delivery of the placenta constitute the third stage of labor. With separation of the placenta, there is also severance of the numerous uterine arteries and veins that carry 600 mL/min of blood through the intervillous space. The most important factor for hemostasis is contraction and retraction of the myometrium to compress and obliterate the open lumens of the vessels.


Uterine atony, the most common cause of postpartum hemorrhage, is the result of a hypotonic uterus after delivery. Factors that lead to uterine overdistention or that interfere with uterine contractility can cause uterine atony and are associated with postpartum hemorrhage. Although it is important to keep these associations in mind, most cases of postpartum hemorrhage occur without any known predisposing factors.


Trauma to the genital tract during labor and delivery (lacerations of the perineum, vagina, vulva, or cervix) is the second most common cause of postpartum hemorrhage. Abnormal placentation (placenta accreta, increta, or percreta) can contribute to postpartum hemorrhage in different ways: (1) an adherent placenta or large blood clots prevent effective contraction of the myometrium, thereby impairing hemostasis at the implantation site, and (2) significant bleeding from the implantation site is more likely with placental separation of abnormally adherent tissue.


Uterine inversion is prolapse of the uterine corpus to or through the cervix. Uterine inversion may be incomplete (inverted but does not go through the cervix) or complete (the fundus protrudes through the cervix). In the more extreme cases, the entire uterus may prolapse out of the vagina. Most cases are acute and occur immediately after delivery and before the cervical ring constricts. If inversion occurs (or is noted) after cervical contraction, the inversion is termed subacute. Chronic inversion takes place weeks after delivery. The majority of cases of uterine inversion occur as a result of traction on the umbilical cord during removal of the placenta. Acute, significant hypotension is common.


Uterine rupture is classified by the degree (complete or incomplete) and cause (spontaneous or traumatic) of the defect. A complete uterine rupture is defined as a full-thickness tear of the uterine wall and overlying serosa; it is associated with life-threatening maternal and fetal compromise. After complete rupture, the uterine contents may escape or partially extrude from the uterus and into the peritoneal cavity. An incomplete uterine rupture is defined as uterine muscle separation with an intact visceral peritoneum (often from uterine scar dehiscence). In an incomplete rupture, hemorrhage frequently extends into the broad ligament, which has a tamponading effect.



Presenting Signs and Symptoms


Peripartum patients may lose a substantial amount of blood before becoming hypotensive or feeling symptomatic. Immediate postpartum hemorrhage should be recognized as a potential complication of a precipitous delivery. The classic clinical manifestation is a woman with sudden massive vaginal bleeding who is tachycardic, pale, and possibly diaphoretic or hypotensive. However, three factors make this classic manifestation flawed. First, an elevated pulse and decreased blood pressure are insensitive indicators until large amounts of blood have been lost. Second, many patients will have steady bleeding that, although moderate in appearance, may escape notice until serious hypovolemia develops. Third, intrauterine, intravaginal, intraperitoneal, and retroperitoneal accumulation of blood can be overlooked.


In a reported case series on uterine inversion, the most common signs were shock and hemorrhage.6 With a complete inversion, the prolapsed uterus may be visible as a large, dark red polypoid mass within the vagina or protruding through the introitus. If the fundus remains within the vagina, the diagnosis may be suspected because of dimpling, indentation, or absence of the uterine fundus on abdominal examination or because a mass is palpated in the cervix on bimanual examination. Establishing the diagnosis of incomplete inversion can be quite difficult; severe hypotension, postpartum hemorrhage, and subtle abnormalities on abdominal examination may be the only clues.


Uterine rupture is also a difficult clinical diagnosis and should be considered in any patient with unexplained peripartum hemorrhage or hypotension. The classic findings of uterine rupture are “ripping” or “tearing,” suprapubic pain and tenderness, absence of fetal heart sounds, recession of the presenting parts, and vaginal hemorrhage. Signs and symptoms of hypovolemic shock and hemoperitoneum may follow. This classic manifestation is actually rare; 87% of patients with uterine rupture have no pain and 89% have no vaginal bleeding. Pain is also an unreliable finding because of the altered response to noxious intraperitoneal stimuli by a stretched abdominal wall. Fetal distress is the most consistent finding (80% to 100%), with fetal bradycardia being the most common sign.7 Most reports of uterine rupture describe patients with normal blood pressure or even elevated blood pressure without tachycardia. Abnormal maternal vital signs are late indicators of severe hemorrhage. The most important risk factor for uterine rupture is a previous uterine scar; other factors are listed in Box 122.1.



Box 122.1 Risks for Uterine Rupture



Surgery or Procedure




Previous cesarean delivery (most common by far—1 in 125 subsequent pregnancies)


Previous uterine rupture


Previous myomectomy incision (1 in 40 subsequent pregnancies)


External or internal version


Breach extraction


Forceful uterine pressure during delivery



Trauma or Environmental




Trauma


Cocaine use



Structural Anomaly




Congenital fetal or uterine anomaly


Previous invasive molar pregnancy


Uteroplacental abnormalities: adenomyosis or placenta increta or percreta



Pregnancy Related




Silent rupture in a previous pregnancy


Persistent, intense contractions (spontaneous or iatrogenic)


High parity (1 in 100 subsequent pregnancies); grand multiparity (>7) increases the risk for rupture 20-fold8


In vitro fertilization



Differential Diagnosis and Medical Decision Making


Postpartum hemorrhage is a sign, not a diagnosis; it is important to consider the cause of the postpartum hemorrhage because it will often direct the treatment. The key to identifying the cause of postpartum hemorrhage is the physical examination. Because uterine atony is the most common cause of postpartum hemorrhage, accurate assessment of uterine tone is essential. To assess uterine tone, a hand is placed on the anterior wall of the uterus (over the fundus) to palpate it. If a soft, boggy, or very large uterus is felt, the diagnosis of uterine atony is established. At this point, management of uterine atony should be a priority over inspection for secondary causes of bleeding. If a firm, contracted uterus is felt, a search for other causes should be initiated promptly.


Without palpation or visualization of a frankly prolapsed uterus, it may be difficult to differentiate uterine inversion from severe atony. Heavy bleeding may make visualization of the cervix impractical. In addition, accurate abdominal palpation for a uterine fundus may be impossible in an obese patient. Depending on factors such as patient stability, resources, and diagnostic uncertainty, ultrasonography or laparotomy may be necessary. In stable patients in whom the diagnosis is uncertain and resources are available, prompt ultrasound scanning may be helpful.9 Ultrasonography may be able to identify retained products or clot in the uterus, but manual exploration is still needed. Ultrasound can also help detect peritoneal free fluid suggestive of uterine rupture. In selected circumstances in stable patients, a computed tomography scan can be useful in making the diagnosis in those with postpartum hemorrhage (retroperitoneal hematoma). If the accompanying hemorrhage or shock is sufficiently alarming to require immediate exploration, the correct diagnosis may be established only at laparotomy.


Although congenital coagulation defects may be relatively rare, consumptive, dilutional, and disseminated intravascular coagulopathies are important considerations. Depletion of platelets and soluble clotting factors after blood loss and subsequent crystalloid and packed red blood cell replacement is difficult to distinguish clinically from disseminated intravascular coagulopathy. Placental abruption, amniotic fluid embolism, HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count), and intrauterine demise are pregnancy-related risk factors for disseminated intravascular coagulation. Initial laboratory studies include a complete blood count, coagulation studies, disseminated intravascular coagulation panel, liver function tests, and basic metabolic panel.



Treatment


The most important aspects of managing postpartum hemorrhage are obtaining hemostasis and treating shock, including supplemental oxygen, placement of two large-bore intravenous (IV) lines, hemodynamic monitoring, and volume replacement. In addition, blood should be typed and crossmatched and 4 to 6 units of packed red blood cells should be available. Consultation with the obstetrics service should be arranged. Along with the initial resuscitation, bimanual massage and IV oxytocin should be initiated (Fig. 122.1 and Table 122.1). A Foley catheter should be placed.


image

Fig. 122.1 Algorithm for postpartum hemorrhage management strategies.


ABCs, Airway, breathing, and circulation; AFE, amniotic fluid embolism; CT, computed tomography; CV, cardiovascular; DIC, disseminated intravascular coagulation; IR, interventional radiology; OB, obstetrics; OR, operating room; UI, uterine inversion; UR, uterine rupture.



Table 122.1 Medications

image

If the placenta has been delivered, manual uterine exploration may reveal uterine rupture or retained products or clots (which should be removed manually to improve uterine contraction). If the placenta is still in place and bleeding is ongoing, the placenta should be removed if a distinct cleavage plane is palpated on exploration. If an indistinct cleavage plane is revealed, the diagnosis of placenta accreta is likely. In this case the placenta should not be removed in the ED. Bimanual uterine compression should continue, with the goal being to stabilize patients until they can be taken to the operating room.


Trauma to the genital tract can be diagnosed by careful inspection of the labia, vagina, and cervix for laceration or hematoma. Noncomplex (first or second degree), easily accessible lacerations can be repaired with absorbable suture. Cervical lacerations and third- and fourth-degree lacerations should be repaired by an obstetrician. Temporary hemostasis may be achieved by direct pressure or, in the case of cervical lacerations, by gentle application of ring forceps to the bleeding point.


Retroperitoneal hematoma is a potentially life-threatening condition that may be manifested as hypotension, cardiovascular shock, or flank pain. Once a diagnosis is made, treatment should be supportive until the obstetrician, interventional radiology, or the operating room is available.


First-line interventions for atony are part of the initial management of postpartum hemorrhage—namely, initiation of bimanual uterine compression, IV oxytocin, and clearing of products of conception and clots from the uterus. If bleeding persists after the initial interventions, additional uterotonic medications should be given (see Table 122.1). The choice of agent may be influenced by the side effect profile, but the best drug is probably the agent that is the most quickly available in the ED. Interventional radiology may be beneficial because embolization may control the bleeding. In any case, temporizing measures may be required until definitive intervention (Table 122.2).


Table 122.2 Temporizing Measures for Hemostasis of Postpartum Hemorrhage











































METHOD PROCEDURE COMMENTS
Uterine packing Layer sterile gauze within the uterus, with the distal end going out through the os May adhere to the uterine wall and removal required; does not allow monitoring of ongoing bleeding; start prophylactic antibiotics
Balloon tamponade   If available and time allows, use bedside ultrasonography to confirm that the balloon is beyond the internal os before inflation to avoid damage to the cervical canal; give prophylactic antibiotics and continue oxytocin infusion
Foley catheter Insert a large bulb catheter (24 French) into the uterus
Instill with 80-100 mL of saline
Pack the vagina to avoid expulsion of the catheter		 Multiple catheters may be needed (in a sterile overbag), which makes the inner lumen difficult to monitor
SOS Bakri balloon Insert into the uterus
Instill 300-500 mL of saline through the stopcock
Pack the vagina		 Best option if available; allows direct measurement of ongoing bleeding via the open inner lumen; developed for postpartum hemorrhage; balloon conforms to the shape of the uterine cavity
Sengstaken-Blakemore tube Cut off the distal (“stomach”) end of the tube
Insert inside the uterine cavity
Infuse 75-300 mL of saline
Pack the vagina to avoid expulsion of the tube		 Does not conform to the shape of the uterine cavity; with the end cut off, proximal bleeding can be monitored through the lumen; may be available from the gastrointestinal department laboratory if not available in the emergency department
Rusch catheter Using a 60-mL bladder syringe, inflate the balloon via the drainage port with 150-500 mL of saline
Pack the vagina to avoid expulsion of the tube		 Urologic catheter used for bladder stretching; may be available in the urology department
Condom catheter Slide the condom over the end of the Foley catheter and tie it off with string to close the end
Inflate with 250-500 mL of saline and clamp the end
Pack the vagina to avoid expulsion of the tube		 A sterile rubber catheter is fitted with a condom
Vaginal packing Pack the vagina with a blood pressure cuff placed inside a sterile glove
Increase pressure to 10 mm Hg above systolic blood pressure		 Various techniques have been described; concern for bleeding proximal to the vaginal pack
Noninflatable antishock garment Begin application at the ankles and progress sequentially up to the abdomen Adjust the panels if any discomfort or dyspnea; contraindicated in women with heart failure or mitral stenosis

Uterine tamponade with sterile gauze and balloon tamponade are commonly used temporizing measures. Uterine balloon tamponade has been described with large Foley catheters, Sengstaken-Blakemore tubes, condom catheters, sterile gloves, and Rusch urologic catheters, as well as with catheters specifically designed to be used for uterine tamponade in patients with postpartum hemorrhage (SOS Bakri tamponade balloon).10



Uterine Inversion


Management of uterine inversion has two important components: treatment of hemorrhagic shock and immediate repositioning of the uterus (Fig. 122.2). Resuscitation should be initiated immediately and continued while attempts are made to reposition the uterus manually. If oxytocin is being infused, it should be stopped once uterine inversion is suspected.


image

Fig. 122.2 Algorithm for uterine inversion management strategies.


ABCs, Airway, breathing, and circulation; IV, intravenous; OB, obstetrics; UI, uterine inversion.


The success of nonsurgical replacement depends on completion before the myometrium regains its tone. The reported rate of successful immediate reduction is between 40% and 80%.11 If initial measures are delayed or fail to relieve the condition, the inversion may progress to the point at which operative treatment or even hysterectomy is necessary.


The most common nonsurgical replacement method is a variation of the Johnson maneuver.12 The prolapsed uterus is cupped in the operator’s palm, and firm upward pressure is applied to move the uterus up through the cervix along the natural curve of the pelvis toward the umbilicus until it is in place. Usually when the inverted mass is pushed upward, the uterus automatically reverts, with the fundus returning to its anatomic position. If the placenta has not separated, it should not be removed.


If initial repositioning is unsuccessful, myometrial relaxation with pharmacologic agents should be attempted. Magnesium sulfate, terbutaline, and nitroglycerin (attractive because of its easy availability and short half-life) are the agents most commonly used (see Table 122.1).13 Attempts at manual repositioning of the uterus should continue.


After successful reduction, the uterus should be supported for several minutes to allow the ligaments to return to their original state while uterotonics are administered. If magnesium sulfate was administered as a tocolytic, calcium gluconate can be given to reverse the tocolytic effect. Fluid and blood replacement and manual uterine massage should be maintained until the uterus is well contracted and the bleeding has stopped. Antibiotics should be started as soon as practical. Uterotonics are continued for at least 24 hours.


If all other efforts have failed to reposition the inverted uterus, operative intervention is required. If the uterus was repositioned with the placenta attached, manual removal can be attempted once the use of relaxants is stopped. Uterotonics should be initiated, and if the placenta cannot be removed easily, it should be left in place.



Uterine Rupture


Initial management of uterine rupture differs and is based on the stability of the patient and fetus. Because the results of examination are normal in most patients with uterine rupture and because fetal distress is the most common finding, initial management will probably be the same as that for other causes of acute fetal distress—urgent delivery.


The physician should consult obstetrics on an emergency basis, ensure adequate IV access, notify the blood bank, and alert the neonatal team to be ready for intensive care newborn resuscitation. If these resources are not available in the hospital, arrangements should be made for immediate transfer.


For unstable patients, prompt, aggressive resuscitation is an important temporizing measure until definitive surgical repair is performed. Fetal morbidity almost invariably occurs because of catastrophic hemorrhage, fetal anoxia, or both. In a study of 99 cases of uterine rupture, the best fetal outcomes were noted when surgical delivery was accomplished within 17 minutes from the onset of fetal distress.7

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Jun 14, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Emergency Delivery and Peripartum Emergencies

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