Critical Care Obstetrics part 51 pps

Trauma in Pregnancy 489 with a GCS of less than 8 had a 19% rate of craniotomy, those with GCS between 8 and 13 had a 9% rate of craniotomy, and victims who presented with a GCS of greater than 13 had a 3% need for craniotomy [19] . Assessment of the patient with trauma in the fashion just described will immediately identify signifi cant cardiovascular or central nervous system dysfunction. The next step in the evalua- tion is to expose ( “ E ” ) the patient. “ Expose ” means completely undressing the patient and examining her from head to toe. The back is examined for entrance or exit wounds, the extremities are briefl y palpated, and any obvious visible injuries are noted. At this stage, the pregnant patient must undergo some prelimi- nary determination of gestational age, the presence or absence of labor, and attempted measurement of fetal heart rate. Because of the potential for both fetal viability and the supine hypotension effects previously described, pregnancies greater than 20 – 24 weeks gestation evoke different management concerns than do gestations at less than the midpoint of pregnancy. Therefore, the crucial primary obstetric assessment of the pregnant trauma victim relates to a basic determination of gestational age of the pregnancy. For the patient undergoing CPR, perimortem cesar- ean section may be necessary. As stated previously, issues regard- ing mechanism of injury, abruption, preterm labor, and aortocaval compression all become important at or after the midpoint of pregnancy. Fetal heart activity may be addressed via direct obtained, must be interpreted in reference to what is normally found during pregnancy. A decreased serum bicarbonate level may be indicative of signifi cant risk for fetal loss. One series reported that initial serum bicarbonate levels were signifi cantly lower (16.4 ± 3.0 mEq/L versus 20.3 ± 2.2 mEq/L) in pregnant major trauma victims in which fetal loss was noted [10] . “ C ” refers to circulation. Pulse quality, blood pressure, and capillary refi ll are basic clinical determinants of the adequacy of perfusion. As mentioned earlier, clinical evaluation of maternal intravascular homeostasis is altered by the underlying physiologic changes of pregnancy. Also, fetal effects from maternal hypovo- lemia are not addressed by basic hemodynamic physical diagnosis [10 – 13] . In any case, because of the ongoing hemorrhage often present in any severely - injured trauma patient, immediate assess- ment and treatment of hypovolemia must be provided. In nearly all trauma cases, a large - bore (14 or 16G) intravenous (IV) access should be established Customarily, patients with multiple trauma should have a large - bore IV inserted in both an upper and lower extremity. Central venous access is not immediately indicated, provided adequate peripheral access can be established. An appropriately sized peripheral IV (14 or 16G) will provide the ability to rapidly instill large amounts of volume. Hypotension in the trauma patient is assumed to be hypovolemia until proven otherwise. Because of the blood volume changes described previ- ously, it is not uncommon for pregnant patients to seemingly “ tolerate ” 1500 – 2000 mL of blood loss with only subtle hemody- namic changes. [1] Splanchnic and uterine blood fl ow may be, but are not always, compromised [12,13] , and deterioration of the patient can develop rapidly with additional blood loss. Initial therapy for hypotension found during the primary survey is the rapid infusion of up to 2000 mL of crystalloid solution and prepa- ration for blood transfusion as necessary. Cardiopulmonary resuscitation in the pregnant trauma victim, discussed in other chapters, is begun if no pulses are palpated. Up to this point in the primary survey, obstetric, and non - obstetric management is very similar. However, at this stage of the resuscitation process, attention to great vessel compression by the gravid uterus must be addressed in pregnancies beyond 20 weeks gestation. In multiple trauma, because of potential verte- bral injury, patients are generally placed on a rigid spinal “ board ” and usual methods for avoiding aortocaval compression (e.g. lateral roll, lateral tilt, etc.) are not possible. Manual lateral dis- placement of the uterus is performed to alleviate aortocaval com- pression. Alternatively, if the gravid trauma patient is on a trauma backboard, the entire board should be tilted 15 ° for stabilization of the vertebral column [6,14] . The letter “ D ” in the sequence stands for “ disability ” . With any trauma, early neurological evaluation is undertaken. A rapid assessment is by the “ A - V - P - U ” method ( a lert; v oice; p ain; u nre- sponsive) [6] . The Glasgow Coma Scale (GCS) can also be used (Table 37.2 ) [15,16] . A GCS of 8 or less may be indicative of signifi cant ongoing neurologic pathology [17,18] . Use of the GCS allows general prognostication regarding the rate of craniotomy. In one non - obstetric study of level one trauma patients, subjects Table 37.2 Glascow Coma Scale. Points Eye - opening response (E - score) Spontaneous (already open and blinking) 4 Opens in response to speech 3 Opens in response to pain (not to face) 2 No response 1 Verbal response (V - score) Oriented and appropriate response 5 Confused response 4 Inappropriate wording 3 Incomprehensible words 2 No response 1 Motor response (M - score) Obeys command 6 Localizes pain 5 Withdraws from pain 4 Flexion response to pain 3 Extension response to pain 2 No response 1 The Glasgow Coma Scale is the sum of scores in the three areas listed. A GCS score > 8 is consistent with coma. Caregivers need to consider intubated patients ’ inability to speak. Referenced in text. Chapter 37 490 assay should be weakly positive, thereby refl ecting some residual “ unused ” RIG. If the follow - up indirect Coombs is negative, additional RIG may be needed [24 – 27] . Finally, even in the absence of detectable fetal cells in the Rh - negative and previously non - immunized trauma victim, administration of a 300 - µ g dose of RIG should be considered anyway, given the signifi cant risk of FMH in the presence of trauma coupled with the relatively small amount of fetal blood required to sensitize the Rh - negative mother [14] . In addition to the use for maternal alloimmuniza- tion evaluation of the Rh - negative patient, FMH may also be a marker for occult or active placental abruption or uterine rupture, albeit less reliably than fetal heart rate monitoring or clinical signs [21,22,57] . Use of the KB test for issues other than RHIG admin- istration testing should generally be for secondary or confi rma- tory evaluation of suspected conditions associated with FMH. Secondary s urvey and t reatment At the conclusion of the primary survey, a second “ top to bottom ” physical assessment is made. This point in the resuscitation is ideal for a more extensive fetal evaluation. Earlier efforts were aimed at: (i) general evaluation of fetal age and presence of life; (ii) ascertainment of the appropriateness of perimortem cesarean section during unsuccessful CPR; (iii) minimizing the effects of uterine compression on maternal resuscitation; and (iv) indirect fetal resuscitation through successful maternal hemodynamic resuscitation. During the secondary survey, however, specifi c fetal investigations are indicated. Identifi cation of vaginal bleed- ing, ruptured fetal membranes, preterm labor, placental abrup- tion, direct uterine or fetal injury, and/or fetal distress are accomplished. Fetal e valuation Fetal injury or death from maternal trauma occurs by several mechanisms. Pearlman and Tintinalla (1990) noted a 41% fetal loss rate with life - threatening maternal injuries and a 1.6% fetal loss rate with non - life - threatening maternal injuries. More recently (2001), Weiss and colleagues, in a review of US birth certifi cate data, demonstrated a rate of fetal death from maternal trauma of 3.7 fetal deaths per 100 000 live births. Motor vehicle accidents were the leading cause of fetal traumatic death (2.3 fetal deaths per 100 000 live births) [28] . Generally, fetal loss is cor- related with the severity of maternal injury; but unfortunately, lethal fetal injury has been encountered in the absence of signifi - cant maternal injury [29] . Placental abruption complicates up to 5% of otherwise minor injuries and up to 50% of major injuries during pregnancy [7,14,29,30] . Placental abruption is also a frequent cause of fetal death from trauma. The relatively inelastic placenta is thought to shear secondary to deformation of the much more elastic myo- metrium. Another possible mechanism is that placental abrup- tion from traumatic injury may be a manifestation of placental fracture or laceration – again from decelerative force and/or direct injury. Uterine tenderness, uterine contractions, vaginal bleeding, and fetal heart rate abnormalities are clinical hallmarks auscultation or through the use of limited brief ultrasound (see FAST evaluation section). However, it should be emphasized that initial management of the pregnant patient should be the same as in the non - pregnant individual. This means that maternal health trumps fetal health. Once the pregnant trauma victim is stabilized, attention can then turn to assessing and managing fetal health. A key point to remember is that the leading cause of fetal mortality in trauma is maternal mortality, and rapid recognition and resuscitation reduce maternal mortality. Investigations At the conclusion of the primary survey, critical resuscitation is under way, major injuries are identifi ed, and a general idea about the status of the pregnancy itself is known. At this juncture in management, diagnostic testing is ordered. Immediate investiga- tions include necessary imaging studies, laboratory evaluation, and ancillary examination. “ Fingers and/or tubes ” should be placed in every orifi ce. Particular attention should be paid to the maternal bladder. Catheterization is undertaken and if gross hematuria is noted on the perineum, consideration of bladder, urethral, ureteral, renal or uterine trauma is essential. Evaluation for ruptured fetal membranes, cervical dilatation, vaginal bleed- ing, and fetal malpresentation is accomplished at this time. Cervical spine and other necessary radiographs are not contrain- dicated in the pregnant trauma victim. If otherwise indicated, pregnant trauma patients with multiple injuries should be con- sidered candidates for chest and cervical vertebral radiographs. Other immediate investigations may include blood gas analysis, complete blood count, coagulation studies, serum electrolytes, and serum glucose determinations. Measurement of fetomaternal hemorrhage (FMH) is also important and especially in Rhesus - negative (Rh - negative) [20] gravidas. The Kleihauer – Betke citric acid elution stain (KB) test can identify as little as 0.1 mL of fetal cells in the maternal circula- tion. The incidence of fetal – maternal hemorrhage is four - to fi vefold higher in pregnant women who have experienced trauma than in uninjured controls. Therefore, 10 – 30% of pregnant trauma cases have some evidence of fetal/maternal admixture of blood [21,22] . Rh - negative gravidas who may be carrying an Rh - positive fetuses need Rh - immune globulin (RIG). In order to calculate the appropriate dose of RIG in the Rh - negative patient with evidence of FMH, Rose et al describe the following formula [23] : number of fetal cells number of adult cells maternal red () × ccell volume fetal cells in maternal circulation= One mL of RIG (300 µ g) is used for each 15 mL of fetal cells or 30 mL of fetal blood detected. The mean volume of FMH is usually less than 15 mL of blood and over 90% exhibit less than 30 mL of FMH. Therefore, in the majority of such patients, 300 µ g of RIG will suffi ce. Measurement of RIG in the maternal circula- tion on the day following administration via indirect Coombs Trauma in Pregnancy 491 often involves the fetal skull and head and is seen in the third trimester in patients with pelvic fractures [29] . This mechanism of injury may be due to the frequent occurrence of engagement of the fetal head within the confi nes of the bony pelvis late in pregnancy [39] . Decelerative injury to the unengaged fetal head may also occur [40] . Very few diagnostic or therapeutic interventions are absolutely contraindicated in the pregnant trauma victim with life - threat- ening injuries. While the effects of high doses of ionizing radia- tion on the fetus may be pronounced, the degree and amount of fetal exposure from routinely obtained conventional or comput- erized tomography (CT) radiography is considerably less. While an absolute lower threshold of safe exposure to ionizing radiation is not known, animal and human data show little or no risk to the fetus from up to 0.1 Gy or more of ionizing radiation [41 – 43] . A single pelvic fi lm delivers less than 0.01 Gy to the fetus. Although fetal exposure is higher with CT scans or pyelography, they should not be avoided if needed to evaluate and treat the mother [29] . Despite the requirement to use fl uoroscopy in conjunction with the technique, angiography may also be relatively benefi cial to the pregnant trauma victim because of its ability to produce hemostasis [44] . As a general guideline for the practitioner, the maximum recommended dose by the National Council on Radiation Protection During Pregnancy is 0.5 cGy. Exposure levels of less than 5 – 15 cGy appear to have a relatively low risk of teratogenicity [43] . Few medications produce harmful fetal effects, and most teratogens impact only early pregnancy. With the supposition that fetal survival and well - being is directly related to maternal survival and well - being, most medically necessary interventions applied to the pregnant trauma victim are indicated for both maternal and fetal well - being. As a general guide, we would rec- ommend an assessment of the risk versus benefi t of medical therapy, and would consult available sources on whatever medi- cations are to be used [45] . Tetanus toxoid administration and tetanus immune globulin are not contraindicated in the gravid trauma victim. Administration should be identical to that for the non - pregnant trauma patient. As stated previously in this chapter, diagnostic ultrasound is not as sensitive as electronic fetal monitoring in the diagnosis of abruption [29,30,35] . Obstetric ultrasound is useful during the secondary evaluation of the pregnant trauma victim for measure- ment of fetal biometric indices, screening for direct trauma, and to aid in the biophysical assessment of the fetus. Volume r esuscitation in p regnancy Volume replacement in pregnancy merits special consideration. By virtue of her young age, and the volume changes inherent in normal pregnancy, the pregnant woman may not exhibit clini- cally signifi cant symptomatology of blood loss until 1500 – 2000 mL is lost. Blood loss greater than 2000 mL often produces rapid maternal deterioration. Because fetal status is a sensitive indicator of maternal hemodynamic homeostasis, fetal compro- mise may occur at maternal blood losses signifi cantly less than of placental abruption. The association of contractions with trau- matic placental abruption has been investigated by Williams (1990) and Pearlman. In the Williams ’ study of pregnant trauma patients placental abruption did not occur in women who did not have uterine contractions, or who had contractions at a frequency of less than 1 every 10 minutes after 4 hours of fetal monitoring. Whereas Pealman found no abruptions in the absence of uterine activity. In patients with more frequent contractions, nearly 20% had placental abruption. Other fetal heart rate abnormalities, such as bradycardia, late decelerations, and tachycardia were also frequently seen in patients who had experienced abruption [31] . Current evidence suggests that a period of continuous fetal moni- toring is usually advisable in most cases of trauma during preg- nancy of greater than 22 – 24 weeks ’ gestation. In those patients that are clinically unstable, prolonged monitoring is usually indi- cated [32] . Finally, placental abruption may be associated with a consumptive coagulopathy and, if so, it will be additive to other trauma - associated coagulopathies [33] . Thus, placental abruption is manifested by the presence of uterine activity within 4 hours of the traumatic event. In effect, the delayed manifestation of placental abruption is highly improbable and is often a delay in diagnosis rather than one of manifestation. The majority of catastrophic events occur much sooner. Patients with regular uterine contractions, or fetal heart rate abnormalities should be monitored until resolution of such fi ndings. In patients without uterine contractions, fetal heart rate abnormalities, or other objective signs or symptoms of abruption it is suggested that a period of 2 – 6 hours of monitoring will suffi ce [32,34] . Electronic fetal monitoring is the preferred method to detect an abruption in the pregnant trauma victim of suffi cient gestational age to warrant fetal monitoring. Ultrasonography is not a sensitive enough modality to diagnose many cases of pla- cental abruption [32,35] . In the woman actively undergoing resuscitation, continuous electronic fetal monitoring of the potentially viable fetus is also a useful indicator of fetal response to and adequacy of resuscita- tion. Fetal heart rate monitoring has been useful for the identifi - cation of maternal hypovolemia [36] . Given the relatively large uteroplacental perfusion requirements during pregnancy, coupled with the poor placental autoregulation in the face of hypotension, the fetoplacental unit often may manifest patho- physiologic alterations in the absence of any obvious maternal manifestations of hypovolemia. The risk of fetal loss is directly related to the degree of maternal hemorrhagic shock [10] . Hence, aggressive volume replacement and shock treatment, coupled with continuous electronic fetal monitoring, is indicated in the gravid trauma victim who is otherwise a candidate for fetal monitoring. The f etal p atient Direct fetal injuries and fractures complicate less than 1% of blunt traumatic injury during pregnancy [37,38] . The uterus of the early pregnant and non - pregnant patient is well protected by the bony pelvis. Direct fetal injury from blunt abdominal trauma Chapter 37 492 Initial resuscitation goals include restoration of maternal vital signs, normalization of fetal heart rate, and resumption of normal urine output. It should be reemphasized that up to a 20% reduc- tion in uteroplacental blood fl ow can occur without changes in maternal blood pressure. Maternal resuscitation should be taken in the context of fetal resuscitation during pregnancy [29,50] . Perimortem c esarean s ection Under normal circumstances, cesarean section in the trauma victim is reserved for the usual obstetric indications and is performed at gestational ages consistent with fetal viability. Unique clinical circumstances may alter these guidelines some- what when perimortem cesarean section is considered during unsuccessful maternal cardiopulmonary resuscitation (CPR). Uterine evacuation may be indicated for either maternal or fetal reasons, or both. The issue of perimortem cesarean section is addressed in other chapters of this text. Katz et al. have reviewed (1986) and recently updated (2005) known reported experience with perimortem cesarean section [51,52] . A modifi ed algorithm for perimortem cesarean section in the face of major trauma is listed in Figure 37.2 . 2000 mL. Fetal heart rate changes may be an early indicator of maternal hypovolemia. Initial treatment of suspected hypovole- mia should consist of rapid infusion of isotonic crystalloid solu- tion (normal saline or lactated Ringer ’ s solution). Blood products should be considered in trauma with ongoing hemorrhage greater than 1000 mL. Type - and Rh - specifi c blood should be available as soon as possible. Until blood is available, isotonic crystalloid solutions is replaced at a rate of 3 cc for each cc of estimated blood loss [6] . While some feel that whole blood may be preferable to packed red blood cells, it is generally not available. Component therapy should not be given empirically, except perhaps in the case of massive exsanguination. Recent experience with the use of recombinant activated factor VII in trauma and massive exsan- guination may make factor VIIa a choice to consider in the resus- citation of diffi cult to control bleeding in pregnant trauma victims [46,47] . Limited pregnancy data suggest effi cacy in HELLP syndrome and uterine rupture [48,49] . Although stabili- zation of the patient is usually recommended prior to surgical treatment, catastrophic traumatic hemorrhage may necessitate concomitant volume and component resuscitation together with immediate surgical control of hemorrhage. CPR in progress Summon pediatric support Bedside cesarean section by or before 5 min of unsuccessful CPR Evacuation of uterus by 5-10 min of unsuccessful CPR Yes Yes Fetal considerations secondary Continue traditional CPR No No Uterine displacement Uterus ≥24 weeks gestation? Fetus alive? Figure 37.2 Perimortem cesarean section. (From Katz VL, Dotters DJ, Droegemueller W. Perimortem cesarean delivery. Obstet Gynecol 1986; 68: 571.) Trauma in Pregnancy 493 attributed to lap belts, restraint systems are still recommended and in most states are mandatory [32] . Available data from crash test dummy simulations of restrained collision during pregnancy suggest that there does not appear to be extraordinary force trans- mission to the pregnant uterus when seat belts are properly placed [32,64,65,66] . Fetal m anifestations of b lunt t rauma The severity of blunt abdominal trauma is associated with the likelihood of placental abruption. Trauma - induced placental abruption is manifested by the appearance of contractions within 4 hours of the traumatic event. The severity of the trauma and mechanism of injury does not directly correlate with the inci- dence or severity of fetomaternal hemorrhage. Relatively minor direct blunt abdominal trauma may infrequently produce placen- tal abruption and/or fetomaternal hemorrhage. Evaluation of the b lunt a bdominal t rauma v ictim Evaluation of the pregnant patient with blunt abdominal trauma is similar to that for the non - pregnant patient. However, and depending on the gestational age, the gravid uterus may alter the typical patterns of injury seen in blunt trauma. For example, bowel injury is less frequent in the pregnant blunt trauma victims when compared to their non - pregnant counterparts [21] ; whereas hepatic and splenic injury are more frequent during pregnancy. In cases of severe blunt abdominal trauma, hemodynamically signifi cant hepatic and/or splenic injuries [9,14] can be seen in up to 25% of victims. Upper abdominal pain, referred shoulder pain, sudden onset of pain, and elevated transaminases suggest hepatic or splenic injury. Abdominal ultrasound is particularly useful in the identifi ca- tion of intraperitoneal fl uid collections secondary to hemorrhage in these cases. Over the last several years, the evaluation of trau- matic blunt abdominal injury has changed to often include the FAST exam ( “ Focused Assessment with Sonography for Trauma ” ) [67,68] . The FAST exam consists of a four - part brief evaluation of the pericardium, perihepatic (RUQ), perisplenic (LUQ), and pelvic regions via ultrasound. Use of the FAST exam, therefore, allows rapid initial bedside assessment for the presence of free fl uid in the abdomen and the presence of a pericardial effusion. In the blunt abdominal and/or chest trauma, FAST examination is a useful screen for the presumptive presence of intra - abdomi- nal hemorrhage, traumatic or non - traumatic pleural effusions, or for corroboration of a suspected hemopericardium. Sensitivity and specifi city in experienced hands demonstrate up to 100% sensitivity and specifi city for the evaluation of abdominal hemor- rhage in the hypertensive blunt trauma victim [69,70] . The use of FAST in the female patient frequently will demon- strate intra - abdominal hemorrhage via a fl uid collection in the pouch of Douglas. FAST examination has been shown to be an effective tool for use during pregnancy. Brown and colleagues (2005) reported on the accuracy of FAST in 102 pregnant trauma victims. Sensitivity and specifi city for the determination of intra - abdominal hemorrhage were 80% and 100%, respectively [71] . Manifestations of t rauma d uring p regnancy Blunt a bdominal t rauma Motor vehicle accidents account for a large portion of severe blunt obstetric trauma. Other lesser causes of blunt abdominal trauma include accidental falls and intentional trauma (violence) [20,22,32,53,54] . During the third trimester of pregnancy, the fetus is more vulnerable to injury due to the thinning of the uterine wall and a reduction in the amniotic fl uid volume. Engagement of the fetal head into the maternal pelvis predisposes the fetus to head trauma associated with pelvic injury [55] . Motor v ehicle a ccidents Passenger restraint systems reduce maternal and fetal injury in motor vehicle accidents (MVAs). In accidents where occupant restraints were not used, the most common cause of fetal death was maternal death [56] . Expulsion from the vehicle and the presence of coexisting head trauma portend poor maternal and fetal outcome. To illustrate, Crosby and Costiloe (1971) noted a 33% mortality in unrestrained gravid automobile accident victims compared to a 5% mortality in those pregnant victims using two - point restraints (traditional lap belt) [56] . The fetal death rate was also lower in the restraint group. The three - point restraint system (lap and shoulder belt) limits “ jack - knifi ng ” of the gravid abdomen during sudden deceleration. Furthermore, Pearlman and associates noted that the proper use of seat belts was the best predictor of maternal and fetal outcome in crashes controlled for severity of collision [57] . In the properly restrained pregnant occupant, placental abruption rather than maternal death was the greatest cause of fetal death. The use of airbags, in conjunction with proper positioning of the mother and correctly placed and used three point restraints afford the best protection to the preg- nant mother and her unborn child. At present, the National Highway Traffi c Safety Administration does not consider preg- nancy as a reason to deactivate the airbags [58] . This is supported by the work of Moorcroft et al. who concluded that, for all frontal impacts, it is safer for the pregnant occupant of an automobile to be properly belted via three - point restraint in a seat in proper apposition to a impact specifi c deployable airbag [59] . In MVAs, the majority of fetal deaths occur in conjunction with relatively minor maternal injury and most are due to placental abruption [32,60 – 62] . Less frequently, fetal death can be associated with fetal skull fracture and intracranial hemorrhage [55] . To protect against fetal injury, the lap belts should be positioned low across the bony pelvis instead of over the mid or upper uterine fundus. Incorrect placement of the lap belt over the uterine fundus could result in an increase in direct force transmission to the uterus during decelerative trauma. Close proximity to airbags markedly increases the transmural forces applied to the maternal abdomen and uterus [59] . The transmission of direct force may result in placental abruption [63] . Shoulder belts should be adjusted for comfort to lie above the gravid uterus and be located between below the breasts [66] . Although fetal injury and death have been Chapter 37 494 of > 500/mm 3 or the detection of bile, gastrointestinal contents or bacteria [74] . Fetal outcome is not adversely affected by the per- formance of a DPL during pregnancy. However, FAST examina- tion often makes DPL a less - used diagnostic modality in pregnant trauma evaluation. Unstable patients with FAST, DPL and/or CT fi ndings may have surgical treatment directed toward the abdomen. Unstable patients with an expanding abdomen should generally not have defi nitive therapy delayed by these evaluative tests. Figure 37.4 outlines a suggested use of FAST, DPL, and CT examinations in blunt abdominal trauma. Maternal volume changes and pregnancy - associated intra - abdominal anatomical alterations may mask signifi cant intra - abdominal injuries. For example, Baerga et al. [75] found that 44% of pregnant abdominal trauma victims who eventually required laparotomy for intra - abdominal pathology were initially asymptomatic. The presence of maternal hypotension (systolic blood pressure < 90 mmHg) and tachycardia may represent late fi ndings. Consequently, the risk of pregnancy loss is much higher in such cases [75] . Rib or pelvic fractures in the pregnant trauma victim should heighten one ’ s suspicion for hepatic, splenic, genitourinary, uterine, or other abdominal injury [1,76] . Uterine rupture may also occur and is more likely in patients with a history of prior cesarean section. In patients without a surgically scarred uterus, uterine rupture often involves the posterior aspect of the uterus [55] . Another leading cause of blunt abdominal trauma is physical abuse during pregnancy. It is estimated that between 1 in 6 and 1 in 10 pregnant women will experience physical or sexual abuse at some time during pregnancy. In addition to blunt abdominal trauma, other injuries commonly occur on the face, neck, and proximal extremities. Serious fetal injury or death may not always be related to the degree of maternal injury from physical abuse. In one analysis of fetal death from maternal injury secondary to interpersonal violence, 5 of 8 fetal deaths occurred in those that otherwise appeared to be minimally injured [76] . Providers must maintain an index of suspicion for physical or sexual abuse during pregnancy [77 – 79] . Traumatic u terine r upture Uterine rupture is a relatively infrequent complication of blunt traumatic injury during pregnancy. The incidence does tend to increase with advancing gestational age and the severity of direct traumatic abdominal force of injury. Most traumatic uterine rupture involves the uterine fundus. Other locations and degrees of uterine injury may be found. At least one case of complete transection of the gravid uterus has been reported as a result of blunt vehicular trauma combined with incorrect seat belt posi- tioning [80] . Principles of management and repair of uterine rupture secondary to trauma are similar to those used in treat- ment of non - traumatic uterine rupture. As reviewed later in this chapter, pelvic fractures as a result of blunt trauma during pregnancy may result in signifi cant retroperitoneal bleeding. Regarding delivery route in a future pregnancy, the past presence Other methods used to assess the presence and severity of intra - abdominal bleeding include CT radiography and diagnostic peritoneal lavage. Hemodynamically stable patients with ultrasound - identifi ed abdominal fl uid may have characterization of the fl uid source and nature through the use of CT scanning [72,73] . The sensitivity and specifi city of abdominal ultrasonog- raphy to detect intraperitoneal fl uid associated with intra - abdominal lesions have been demonstrated to be similar to those seen in non - pregnant individuals. Patients with no intra- peritoneal fl uid visible by ultrasound are usually at low risk of having intra - abdominal lesions requiring immediate operative management. CT radiography scanning may aid diagnosis in less obvious cases. Hemodynamically stable patients with the ultrasound - identifi ed abdominal fl uid may have characterization of the fl uid source and nature through use of CT scanning. Embolization or hepatic lobe resection, coupled with packing and local control may ameliorate hepatic hemorrhage. Splenectomy is generally the preferred treatment for splenic rupture. Other indications for exploratory laparotomy in the pregnant patient with blunt abdominal trauma include hemodynamic instability with sus- pected active bleeding, viscus perforation, infection, and fetal distress in the viable gestation. Direct peritoneal lavage (DPL) may also be used in pregnancy. However, the open technique should nearly always be the method of choice in pregnancy beyond the fi rst trimester of pregnancy. The FAST examination reduces the necessity for DPL (Figure 37.3 ) and its usefulness is limited to cases with confl icting FAST and CT results [71] is markedly reduced [71] . Theoretically the procedure - associated risks of DPL may often be avoided. Its mention here in this chapter is merely for completeness. Criteria for a positive DPL include aspiration of at least 10 mL of gross blood, a bloody lavage effl uent, a serum amylase of > 175 IU/dL, a red blood cell count of > 100 000/mm 3 , a white blood cell count Elevated intracranial pressure herniation Mass effect (severe bleeding) Regained consciousness Meningeal artery laceration loss of consciousness Injury Figure 37.3 Sequence of events associated with acute epidural hemorrhage. Trauma in Pregnancy 495 in the advanced gravida than would occur in non - pregnant victims. Gunshot w ounds Management of gunshot wounds to the pregnant abdomen includes general resuscitation measures outlined previously. Particular attention should be paid to the pathway of the projec- tile. Entry and exit wounds must both be identifi ed. If the missile has not exited the abdomen, radiographic localization aids bullet location and injury prognostication. Gunshot projectiles that enter into the uterus often will remain in utero . Penetrating trauma occurring anteriorly and above the uterine fundus or from the maternal back carries a high risk of extrauterine visceral injuries. Patients in whom the missile entered anteriorly and below the uterine fundus often do not have maternal visceral involvement [83] . Fetal death may be direct or indirect. Most authors recommend abdominal exploration for all extrauterine intra - abdominal gunshot wounds and most intrauterine wounds. Experience from the Middle East confl ict and other reports suggest an individualized approach to intrauterine injuries [9,84] . Awwad and colleagues advocate conservative management in anterior abdominal entry wounds which enter below the uterine fundus [85] . Posterior abdominal wounds, upper abdominal of a pelvic fracture is not an absolute contraindication for vaginal delivery. Provided pelvic architecture is not substantially dis- rupted and the old fracture is not unstable, safe vaginal delivery is often possible. Penetrating a bdominal t rauma The two most common types of penetrating abdominal injury are stab and gunshot wounds. As with blunt trauma, pregnancy often changes the usual manifestations of penetrating abdominal injury. The gravid uterus displaces lower abdominal organs ceph- alad. Therefore, after the fi rst trimester, the gravid uterus is some- what protective of other intra - abdominal organs. Accordingly, reported maternal mortality is lower from abdominal gunshot wounds than it is in non - pregnant adults (3.9% versus 12.5%). Fetal mortality (71%), however, is high [81] . Reported data from abdominal stab wounds were similar in that fetal mortality was high (42%) and maternal mortality was not seen [82] . The reduced maternal mortality, yet high fetal loss, from penetrating abdominal injury are probably due to the gravid uterus shielding other abdominal contents from the force of the penetrating pro- jectile when the impact of the shell or penetrating object is below the uterine fundus [1,29,81,82] . In contrast, upper abdominal penetrating injuries are more likely to produce small bowel injury Hemodynamic assessment Stable Unstable Expanding abdomen (presumed active bleeding) Physical exam unclear FAST evaluation Positive Negative Observation and secondary evaluation CT Radiography FAST evaluation Exploratory laparotomy Positive exam Positive exam Definitive therapy Conflicting results DPL Figure 37.4 Diagnostic abdominal evaluation – blunt trauma, CT. CT, radiograph; FAST, focused assessment with sonography for trauma; DPL, direct peritoneal lavage. Chapter 37 496 of fetal injury, and of both the maternal and fetal prognosis if left undelivered. Other obstetric considerations for delivery also apply in that direct uterine injury to the active uterine segment probably neces- sitates eventual cesarean section as the preferred route of delivery. Injury to the lower uterine segment with delayed delivery prob- ably needs to be approached on an individual case - by - case basis. In cases of direct uterine injury, preterm labor may be treated with tocolytics, although betasympathomimetics and non - steroi- dal anti infl ammatory agents generally should be avoided because of their effects upon maternal hemodynamics and platelet func- tion, respectively [90,91] . From a hemodynamic perspective, magnesium sulfate would probably be the drug of choice for treatment of preterm labor in the circumstance of maternal trauma. General consensus is probably not present regarding preference and/or indicated use of tocolytics for idiopathic preterm labor. Therefore, little non - anecdotal data are available to make an evidence - based recommendation on the use of toco- lytics for the treatment of preterm labor in the pregnant trauma patient. It is obvious to state that maternal instability, non - reas- suring fetal status, or active uterine bleeding are generally con- traindications to tocolytic therapy. Victims of penetrating trauma should receive tetanus prophy- laxis as needed. In the previously immunized patient with no booster within the last 5 years, 0.5 mL of tetanus toxoid is admin- istered. If the patient has not been previously immunized, the toxoid is administered in conjunction with tetanus immuno- globulin at a dose of 500 U intramuscularly [92] . Chest t rauma Thoracic trauma represents a particular challenge to the clinician caring for the pregnant trauma victim. There is a paucity of information regarding thoracic trauma (or its management) during pregnancy. In the United States, chest trauma accounts for 1 in 4 trauma deaths annually. Recognition and stabilization of chest trauma is vital, because less than 10% of blunt chest trauma and less than 30% of penetrating chest injuries require immediate thoracotomy [6,74] . Most cases of thoracic trauma initially respond to non - surgical stabilization. Effective stabiliza- tion ultimately results in improved operative outcome if surgery is required. A basic understanding of the types of chest trauma will help the obstetric member of the trauma team function more effectively in the overall resuscitation of the injured gravida. Classifi cation of c hest t rauma Chest trauma can be classifi ed functionally or mechanistically. Mechanistically, thoracic trauma is subdivided into blunt and penetrating injuries (much like abdominal trauma). More imme- diately important is the recognition of immediately life - threaten- ing chest trauma, with differentiation of life - threatening trauma from potentially serious, but less immediately life - threatening subtypes of chest trauma. In this discussion we will generally divide chest trauma into immediately life - threatening and non - life - threatening subtypes [6,84] . wounds, fetal or maternal compromise, or uterine location of projectile in cases of gunshot wound are not, according to Awwad, optimal for expectant management. We generally advocate surgi- cal exploration of the pregnant intra - abdominal gunshot wound victim, although individualized circumstances may permit a modifi ed approach [86,112] . Stab w ounds Abdominal stab wounds generally are less serious than gunshot wounds. Because of less likelihood for “ collateral damage ” , many pregnant stab wound victims will not have abdominal organ damage that requires surgical repair. Because of the compartmen- talization that occurs with advanced pregnancy, the mechanism of injury changes with abdominal stab wounds during pregnancy. Small bowel involvement is more frequent with upper abdominal stab wounds during pregnancy [10,14] . Also, the upper abdomen is the most frequent site of abdominal stab wounds during pregnancy, comprising some two out of three anterior abdominal penetrating wounds [9] . Because of the propensity for small intestinal injury and the potentially catastrophic effects of diaphragmatic involvement with up to a 66% mortality with thoracic herniation and strangulation of small intestine, most recommend exploration of upper abdominal stab wounds during pregnancy. Depending on the gestational age of the pregnancy, lower abdominal stab wounds during pregnancy may involve the uterus, fetus, uteropelvic vessels, or urinary bladder. An individu- alized approach to management is suggested. FAST evaluation, CT radiography, and possibly DPL are useful to evaluate intra - abdominal bleeding [29] . Amniocentesis and ultrasound may help in the evaluation of intrauterine bleeding. Urinary bladder involvement may be determined by radiographic evaluation [9] . Actual abdominal cavity entry can be determined through direct exploration of the wound or the performance of a wound fi stu- logram [87] . While not all lower abdominal stab wounds need to be explored, a very high index of suspicion for the need to explore the abdomen should be maintained. Direct u terine i njury During exploratory laparotomy for penetrating abdominal trauma, the uterus must be carefully inspected for injury. If direct uterine perforation is noted in the presence of a living term fetus, abdominal delivery is probably warranted. Less extensive uterine or adnexal injury or the presence of intrauterine fetal death does not necessarily dictate emptying of the uterus [88] . Likewise, the uterus should not necessarily be emptied via cesarean section or hysterectomy during surgery for non - uterine injuries. In cases in which direct uterine injury is found and the fetus is alive, prema- ture, but potentially viable, cesarean section may be obvious for fetal or maternal hemorrhage or intrauterine infection [1,9,89] . These are incredibly diffi cult cases and will require an assessment of the risk : benefi t ratio of expectant management versus delivery by cesarean section specifi c to the best estimate of gestational age, Trauma in Pregnancy 497 In addition to trauma, other causes of tension pneumothorax include central line placement, bullous emphysema, and mechan- ical ventilation. Regardless of its etiology, immediate recognition and treatment of a tension pneumothorax or massive hemotho- rax is vital. Needle thoracostomy, performed in the second inter- costal space – mid - clavicular line, will convert a tension pneumothorax to a simple pneumothorax. Defi nitive treatment is by insertion of a thoracostomy tube in the affected hemithorax. For this indication, a thoracostomy tube is usually placed in the fi fth intercostal space (nipple level), anterior to the mid - axillary line [96] . Additional care during pregnancy must be taken, because of the normally elevated diaphragm [1] . Inadvertent abdominal insertion of a chest tube with the resultant diaphrag- matic, hepatic, or splenic injury is potentially more likely during pregnancy. Particular attention to this potentially catastrophic complication must be heeded if additional thoracostomy tubes are placed in locations other than the anterior mid - axillary fi fth intercostal space and especially if such tubes are placed in lower intercostal spaces. To reduce the chance of abdominal placement, consideration should be taken to place the thoracostomy tube at least one interspace higher than usual. Hemothorax Massive hemothorax is initially treated by thoracostomy tube placement as previously described. To facilitate drainage of tho- racic blood, the chest tube should be directed inferiorly (after its insertion in the mid - axillary fi fth intercostal space). Once again, care should be taken to avoid abdominal entry. A large chest tube (i.e. 38 French) is usually recommended. If the initial volume of blood drained from the tube is ≥ 1500 mL, early thoracotomy is probably necessary. Continued loss of 300 mL or more per hour from the chest tube may also indicate the need of a thoracotomy. Other temporizing measures such as volume replacement, trans- fusion, and potential use of cell - saving autotransfusion should be initiated until the patient is evaluated by a qualifi ed thoracic trauma surgeon [94,97,98] . Open p neumothorax Open pneumothorax is often referred to as a “ sucking chest wound ” . If the size of the opening to the hemothorax is near to or greater than the size of the tracheal diameter, physics dictates that air will preferentially enter the chest through the chest wall rather than through the trachea during inspiratory attempts. Consequently, to temporarily restore effective ventilation, a large occlusive dressing is placed upon the open injury. Ultimately, thoracostomy tube placement at a site distal to the thoracic entry wound and surgical repair is required [74] . Cardiac t amponade Cardiac tamponade has been mentioned previously in our discus- sion of tension pneumothorax. Tamponade usually occurs with penetrating injuries, and is less common than tension pneumo- thorax. Catastrophic hypotension and, ultimately, pulseless electrical activity (electromechanical disassociation) result from The primary survey of a trauma patient will identify several types of life - threatening thoracic trauma. When identifi ed, life - threatening injuries require expedient management. Fortunately, many immediately life - threatening injuries can be initially managed by oxygen administration, mechanical ventilation, needle pneumothoracocentesis, or tube thoracostomy (chest tube) placement. Life - threatening chest injuries (Table 37.3 ) include airway obstruction, open pneumothorax, massive hemo- thorax, tension pneumothorax, fl ail chest, cardiac tamponade, and blunt trauma - mediated severe myocardial dysfunction (blunt cardiac injury). Airway m anagement Airway obstruction should be managed initially as described else- where in this text with CPR, and then systematically with early intubation or cricothyroidotomy, if required. Cervical spine pro- tection by neck stabilization and jaw thrust is vital during intuba- tion of any patient with an unevaluated cervical spine. In pregnancy, the additional increased risk of aspiration of gastric contents may necessitate the more aggressive use of endotracheal intubation or surgical airway control. The requirement for oxy- genation and effective pulmonary gas exchange precedes all other aspects of resuscitation [18,93] . Tension p neumothorax Tension pneumothorax develops when a one - way fl ow of gas collects in the pleural space. Intrapleural pressure increases pro- gressively with each inspiration. When intrapleural pressure increases to a level higher than great vessel pressures, hemody- namic instability can result. The clinical diagnosis of a tension pneumothorax is made by a combination of respiratory distress, hypotension, tachycardia, diminished or absent breath sounds, possible jugular venous distention, and tracheal deviation. The differential diagnosis of tension pneumothorax includes massive hemothorax (similar thoracic pathophysiology and treatment) and pericardial tamponade (much less common) [94] . Radiographic confi rmation of a suspected tension pneumothorax is usually only useful for postmortem correlation [95] . Table 37.3 Life - threatening chest injuries. Immediately life threatening Initial treatment * Airway obstruction Airway control Open pneumothorax Injury site control and thoracotomy tube Tension pneumothorax Needle thoracostomy Flail chest Supportive ( ± intubation) Cardiac tamponade Volume therapy and pericardiocentesis Severe myocardiac damage Inotropic support and treatment of dysrhythmias * Qualifi ed consultants should be involved in the care of any chest trauma patient. These treatment recommendations are guidelines. Each case should be individualized. Chapter 37 498 Pulmonary contusion is a very frequent complication of blunt chest trauma [74] . Progressive hypoxemia results from the sec- ondary effects of the contusion. Typically, respiratory failure from pulmonary contusion progresses insidiously and is often not immediately present. A diffuse radiographic injury pattern is characteristic of pulmonary contusion. Careful clinical monitor- ing, frequent blood gas analysis, and a low threshold for intuba- tion and mechanical ventilation in the patient with a severe pulmonary contusion help reduce mortality [8,106,107] . The increased frequency of traumatic diaphragmatic rupture in association with upper abdominal injury during pregnancy needs to be considered in any pregnant chest or upper abdominal trauma victim [14] . Traumatic aortic rupture frequently occurs in conjunction with motor vehicle accidents or falls from great heights [106] . Aortic rupture mechanistically occurs from the relative fi xation of the aorta, thereby reducing its ability to move or fl ex with sudden deceleration. This produces tearing of one or more of the layers of the vessel. The clinical manifestation of aortic rupture is variable and depends on the extent of the rupture. For example, patients with unconfi ned lesions or transections usually exsan- guinate before or shortly after arrival to the hospital, while patients with contained hematomas are more frequently alive at hospital presentation. Diagnosis of the contained aortic rupture may be more diffi cult because it may often be associated with modest hypotension, especially with lesions near the ligamentum arteriosum. Mediastinal widening, obliteration of the aortic knob, or fi rst or second rib fractures may suggest an aortic rupture [97,106,122] . Ultrasound, magnetic resonance imaging, or CT radiography may assist in the diagnosis of aortic rupture, but angiography is the defi nitive diagnostic procedure for trau- matic aortic rupture [6,108] . In the context of trauma manage- ment of the pregnant patient, medically necessary radiographic studies should not be deferred if required for the diagnosis and/ or treatment of maternal life - threatening injuries. Tracheobronchial tree injuries (TBI) may produce sudden airway obstruction. A high clinical index of suspicion, especially in cases of refractory pneumothorax, subcutaneous emphysema, or blast injuries is necessary for timely diagnosis. Operative inter- vention is frequently necessary in patients with TBI [94,108,109] . Esophageal trauma is often an insidious feature of chest trauma. It is usually, but not always, associated with penetrating chest trauma. Esophageal rupture is suspected in any patient with severe epigastric injury, substernal trauma, pneumothorax without chest wall injury, and/or in patients with continued par- ticulate material in their thoracostomy tube drainage. Esophagoscopy or contrast studies confi rm the diagnosis. Death may result directly from hemorrhage or from unrelenting medi- astinitis [6,110,111] . While thoracic trauma should be evaluated by a thoracic spe- cialist familiar with chest trauma management, an understanding of the ramifi cations of potentially lethal chest trauma often will allow the obstetrician to recognize and stabilize the chest trauma victim. cardiac tamponade. Because of non - compliance of the pericardial sac, a relatively small amount of rapidly collected blood will cause hemodynamic compromise. Diagnosis is possible by clinical fea- tures (Becks ’ triad: venous pressure elevation, decreased arterial pressure, and muffl ed heart tones), radiographic examination (enlarged cardiac silhouette), or echocardiography. Unfortunately, as with tension pneumothorax, time is often not available to defi nitively diagnose cardiac tamponade. Pericardiocentesis by a qualifi ed operator is a life - saving temporizing measure. Rapid volume infusion will also often temporarily alleviate the problem. As with thoracostomy tube placement, pericardiocentesis should be undertaken with recognition of the fact that the pregnant patient ’ s diaphragm is normally elevated. Defi nitive treatment of pericardiocentesis is usually by the opening of the pericardium by a qualifi ed thoracic trauma surgeon [99,100] . Flail c hest Flail chest occurs secondary to trauma - mediated separation of a part of the bony chest wall from the remaining thorax. Respiratory failure from pain - induced atelectasis and underlying pulmonary contusion is produced by fl ail chest [101,102] . Paradoxical move- ment of part of the chest during respiration, direct physical exam- ination of the chest and radiographic evaluation lead to the diagnosis of this condition. Intubation and mechanical ventila- tion may be required in the fl ail chest victim with intractable hypoxemia or other injuries [93,94] . Blunt c ardiac i njury Massive chest trauma can produce intrinsic myocardial damage. Myocardial contusion, myocardial ischemia from hypoperfusion, or underlying substance abuse all may cause or contribute to myocardial injury. Because trauma - mediated myocardial injury may not occur per se in association with a contusion itself, the term “ myocardial contusion ” has been supplanted by the more accurate term “ blunt cardiac injury ” (BCI). Although usually diagnosed during the secondary survey, potentially lethal dys- rhythmias can also be noted during the primary survey. These dysrhythmias may be produced by the initial injury or from reperfusion of the injured myocardium. Standard treatment of such dysrhythmias is recommended to reduce the likelihood of malignant degeneration of the rhythm or cardiac arrest [103 – 106] . Patients at a lower risk of life - threatening dysrythmia devel- opment can be determined through the use of ECG screening. A troponin I level of less than 1.5 ng/mL 8 hours after injury is also consistent with stable prognosis [107] . Other t horacic t raumatic i njuries The secondary survey may also uncover evolving life - threatening thoracic injuries, although usually the progression of such inju- ries is less fulminant than when they are diagnosed during the primary survey. Potentially lethal secondary survey injuries include pulmonary or myocardial contusion, aortic esophageal disruption, tracheal or bronchial rupture, and traumatic dia- phragmatic rupture [6] . . Scale is the sum of scores in the three areas listed. A GCS score > 8 is consistent with coma. Caregivers need to consider intubated patients ’ inability to speak. Referenced in text. Chapter. resuscitation reduce maternal mortality. Investigations At the conclusion of the primary survey, critical resuscitation is under way, major injuries are identifi ed, and a general idea about the. evaluation, and ancillary examination. “ Fingers and/or tubes ” should be placed in every orifi ce. Particular attention should be paid to the maternal bladder. Catheterization is undertaken and