Critical Care Obstetrics part 51 pps

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 b

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 treatassess-ment 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

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

Verbal response (V - score)

Oriented and appropriate response 5

Motor response (M - score)

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

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 evaluaalloimmuniza-tion 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 manifestaabrup-tion 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 incontrain-dicated,

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 cellsmaternal red )

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 administracircula-tion via indirect Coombs

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

resuscitation 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

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 solusolu-tion) 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 5min

of unsuccessful CPR

Evacuation of uterus

by 5-10min 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.)

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 collecca-tions 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

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

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

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

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 immeimme-diately life - threaten-ing chest trauma, with differentiation of life - threatenthreaten-ing 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,

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 tendiscus-sion 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 pneumohemo-thorax, 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

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 ventilaintuba-tion 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]