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The National Center for Injury Prevention and Control guidelines for field triage recommends a 4-level approach to determine the need for care at a high-level trauma center. Level 1 consists of measuring vital signs and consciousness level. If initial assessment reveals an abnormal Glasgow coma scale (<13), SBP less than 90 mm Hg, respirations greater than 29 or less than 10/min or if ventilation is needed, transport to a level I trauma center is indicated. Level 2 involves assessing the anatomy of injury. Penetrating injuries, chest wall instability, more than or equal to 2 proximal long bone fractures, crushed or pulseless extremity, amputation proximal to wrist or ankle, pelvic fracture, open/depressed skull fracture or paralysis, all require high-level trauma care. Level 3 involves determining the mechanism of injury and evidence of high-energy impact. Patients with fall greater than 20 feet (2 stories), auto versus pedestrian collision, motorcycle crash, or high-risk auto crash (intrusion into car frame, ejection from vehicle, death within same compartment, or vehicle telemetry data consistent with high risk of injury) are candidates for transport to a level 1 trauma facility. Finally, level 4 takes into account special or system considerations. Examples include older adults, children, burns, bleeding disorders, and others. Pregnancies beyond 20 weeks belong in this category. Ultimately, the EMS provider can advise transport to a high-level trauma center if he or she judges it to be appropriate.58
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Pregnant women should be transported in the usual manner, taking care to position them with a 15-degree left lateral tilt, thus reducing aortocaval compression from the gravid uterus. If spinal injury is suspected, the rigid board can be tilted, or the uterus can be manually displaced leftward. Military antishock trousers (MAST) or a pneumatic antishock garment (PASG) have been used to support BP while transporting hypotensive patients with intra-abdominal trauma. However, their use is relatively contraindicated during pregnancy.20 High-flow oxygen should be administered via non-rebreather mask with reservoir. Intubation should not be attempted in the prehospital stage in most cases. Supraglottic devices such as laryngeal mask airway may provide an alternative in the prehospital setting, or in the event of intubation failure.59
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Activation of Trauma Team
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Recent articles question routine high-level trauma evaluation of pregnant women. A 3-year prospective study reported only 3% of 317 patients with minor trauma had a positive KB test, and only 1 of them had an abruption. The 49 cases (19%) with abruption, PTB, or LBW, could not be predicted based on maternal or injury characteristics or their OB evaluation. These authors argued against extensive evaluation after minor trauma.60 Another study evaluated 352 cases and compared trauma activation based on pregnancy only with activation based on other physiologic, mechanistic, and anatomic (OPMA) criteria. In this comparison, 52% of cases were “pregnancy only" and 42% were OMPA. Overall, 94% of injured pregnant women less than 20 weeks were discharged home. No patients in the “pregnancy-only” group were admitted to the trauma service. There were no maternal deaths, but 4 fetal deaths were reported and abruption was diagnosed in only 2%. Surprisingly, 3 cesareans were performed in the “pregnancy only" group. These authors’ opined that trauma team activation based solely on pregnancy resulted in over-triage and a possible misuse of resources.61 Clearly, more research is needed in this important area.
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The typical trauma team is composed of emergency department (ED) and/or trauma physicians and nurses, as well as anesthesia personnel. Many trauma centers advocate simultaneous (not sequential) evaluation of the injured pregnant patient by the trauma and OB team.62 An OB physician and nurse should be on standby for secondary assessment, once the patient is stabilized and the initial evaluation is complete. Neonatal equipment, as well as team members able to perform emergent delivery and neonatal resuscitation should be immediately available.
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Injury Scoring Systems
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Literature is conflicting regarding the ability of trauma scores to predict adverse pregnancy outcomes. Although high injury scores are often associated with high rates maternal or fetal death, low injury scores do not exclude fetal death or other complications. A review of 30 pregnant trauma patients was one of the first to show that the Revised Trauma Score (RTS) did not correlate well with obstetric complications.63 Subsequently, the ISS was evaluated to identify a cutoff to predict poor OB outcomes. In general, a score of 16 or more denotes a severe injury. Records from 294 injured pregnant women with abruption or fetal death revealed ISS ranging from 1 to 34, but most scores were low. Placental abruption occurred in 7%, intrauterine fetal death (IUFD) in 3%, and 3 maternal deaths were reported. A high ISS did not predict abruption or fetal death reliably. However, low ISS scores were nevertheless associated with adverse pregnancy outcomes.64
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In contrast, 68 patients with an ISS greater than or equal to 12 had an overall fetal mortality of 65%. Blood loss, ISS, abruption, and DIC were all predictors of fetal death.65 Also, 271 pregnant patients with blunt abdominal trauma were evaluated and risk factors for fetal death included ISS greater than 9, maternal ejection from vehicle, motorcycle or pedestrian collision, maternal death, maternal tachycardia, lack of restrains, and abnormal FHR.33 Other studies also support the role of ISS, including a report of 294 women, where maternal age, first trimester, elevated lactate, and high ISS were significant risk factors for poor fetal outcome.2 Similarly, a study of 1195 pregnant trauma patients reported independent risk factors for fetal loss included ISS greater than 15, GCS less than or equal to 8, or Adjusted Injury Score greater than or equal to 3 for the head, abdomen, thorax or lower extremities.4 Some institutions provide prolonged observation for those with high injury scores, but there is no consensus.
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Approach to the Patient
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The initial assessment should take only a few minutes. The ABCDE framework allows for a complete, yet efficient exam and is no different from nonpregnant patients. (See Fig. 18-1.) It is important to stabilize mother first, only then turning attention to the pregnancy and fetus.
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After initial stabilization, evaluate for specific maternal injuries and assess fetal well-being. Physical examination for the pregnant trauma patient should include all the same elements as for nonpregnant women, in additional to attention to issues pertaining to pregnancy. Adjunctive laboratory tests should focus on injury patterns related to mechanism of injury, patient complaints, or suspicious findings on exam. A secondary survey includes an early vaginal and rectal examination, with attention to dilation and effacement of the cervix. If vaginal bleeding is present in the second or third trimester, cervical examination should be deferred until sonography excludes placenta previa. Gestational age can be initially estimated by fundal height and is confirmed by bedside ultrasonography. EFM should be performed for at least 4 to 6 hours for patients at viability and beyond. One should not avoid or delay necessary exams due to concerns about fetal radiation exposure. In major trauma, the evaluation usually includes radiographs of chest and other areas as indicated (pelvis, neck, extremities, etc). In nearly all cases, ultrasound (US) is performed, but computed tomography (CT) is also frequently done.
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Electronic fetal monitoring (EFM) is one of the most sensitive clinical tools for detecting placental abruption after trauma. Continuous EFM is more sensitive in detecting placental abruption than ultrasonography, KB testing, or physical examination. Among women with contractions occurring every 10 minutes or more, the risk of abruption is as high as 20%.44 EFM should be a routine part of a trauma evaluation when the fetus is viable (≥23 weeks’ gestation), for at least 4 to 6 hours. Abnormal findings such as contractions more than 6 times per hour or a category II FHR pattern (fetal tachycardia, FHR decelerations, or decreased FHR variability) are potential indicators of higher fetal risk. In this case, continuous monitoring should be extended to 24 to 48 hours. Cesarean delivery should be considered if a category III FHR pattern is identified, or as medically indicated.66
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Standard laboratory tests for female trauma patients include complete blood count (CBC), basic metabolic panel (BMP) (electrolytes and glucose), type and cross, prothrombin time/partial thromboplastin time (PT/PTT), fibrinogen, Kleihauer-Betke (KB), toxicology screen, and urinalysis (and human chorionic gonadotropin (HCG) if needed). If indicated, arterial blood gas testing should be done if respiratory function is compromised.
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Be aware that normal ranges for laboratory results are based on nonpregnant persons. Notable pregnancy-related changes to common test results include: mildly elevated WBC and physiologic anemia. Arterial pH is increased and serum bicarbonate is decreased, as is arterial PCO2. Maternal fibrinogen levels are increased; in fact, the most sensitive laboratory indicator of abruption is a decreased fibrinogen content. Although some studies question its use, a positive KB test (>0.01% fetal RBC in the maternal circulation) has been associated with PTL by some authors. (Table 18-2)
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Focused assessment with sonography in trauma (FAST) is performed at the bedside to identify intraperitoneal fluid or pericardial fluid, indicating major organ injury. Bedside US also estimates gestational age, FHR, amniotic fluid volume, and placental position.67 FAST can detect many, but not all abdominal or placental injuries. FAST was evaluated in 102 pregnant blunt abdominal trauma patients. FAST identified 4 of 5 patients who went to surgery, but placental injury was missed in one case. Of interest, 96% required no ionizing radiation and 0% required DPL.68 Overall, the sensitivity of FAST to detect intra-abdominal injury in pregnancy is 60% to 80% and the specificity is 94% to 100%.69 Ultrasound (US) plays a limited role in detecting placental abruption. The appearance depends on the size and location of the bleed and the time between abruption and US examination. Acute abruption has a hyperechoic or isoechoic appearance compared to the placenta, but becomes hypoechoic within 1 to 2 weeks.41 In fact, US had a sensitivity of only 24% and negative prediction value of only 53% in diagnosing abruption after trauma in one study.70 Importantly, pregnancy information gained by US identifies pregnancies that otherwise would receive radiation exposure. At one center, 11% of trauma patients had incidental pregnancy (8% newly diagnosed). Gestational age was earlier and fetal mortality was higher in this group of women. The mean initial radiation exposure for all trauma patients was 4.5 rads in 85% seen at that center.71
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Computed Tomography (CT)
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Although ultrasound is more suited for triage of unstable patients, CT is more sensitive than ultrasound to detect organ injury, retroperitoneal hemorrhage, or small amounts of fluid. Multidetector CT (MDCT) is fast, readily available, and facilitates immediate surgery, if needed. CT is the modality of choice for trauma patients; this is also true for pregnant women with suspected intra-abdominal injury. Abdominopelvic CT use during pregnancy increased 22% per year (per 1000 deliveries) from 1998 to 2005, and was used most often to evaluate appendicitis (58%). The average fetal dose from abdominopelvic CT was 24.8 mGy (range 6.7-56 mGy, but 1 examination exceeded 50 mGy). Using a pitch less than 1 and more than 1 series acquisition was associated with a dose of greater than 30 mGy. Thus, attention to technical aspects of image acquisition is important in mitigating potential fetal risk.72 A survey of 183 radiology residencies confirmed preference of CT over MRI for evaluating trauma during pregnancy in all trimesters (75%-88% vs 4%-5%).73
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Case series suggest that CT may also have a high detection rate for placental abruption. Among pregnant trauma patients, 61 CT studies cited an accuracy of 96% to predict delivery in less than or equal to 36 hours. However, the small number of cases studied and limited clinical details considered preclude definitive conclusions.74 In another study, 44 CT scans from pregnant abdominal trauma patients yielded sensitivity and specificity for abruption of 100% and 80%, respectively. The authors speculated that a high false positive rate could be related to differences in experience in interpreting normal placental appearance.75 Differentiating normal versus abnormal placental appearance was further explored in a study of 176 pregnant trauma patients with CT scans. Abruption was identified by CT in 61 patients (35%), when viewed by examiners blinded to other clinical data. Intraoperative findings correlated with CT findings in relation to placental perfusion defect. When placental enhancement decreased to less than 50%, clinical signs of abruption reached statistical significance, and the likelihood of delivery due to abruption increased as placental enhancement decreased below 25% to 50% on CT.76 While results are encouraging, more study is needed in this area.
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Counseling Patients About Risks of Ionizing Radiation
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Population-based risks of pregnancy include a 3% risk of spontaneous birth defects, 15% risk of spontaneous abortion, and 1% to 2% risk of mental retardation. The potential for congenital malformations, fetal growth problems, mental retardation, or childhood cancer after in utero ionizing radiation exposure is a concern, but the risks are comparatively small when taken in the context of other aspects of trauma care. Radiation exposure exceeding 0.1 Gy (10 rads) within 2 weeks from conception is associated with high risk for pregnancy wastage, but no increased risk if the embryo survives (ie, the effect appears to be all-or-none). The risk for teratogenesis is highest during the period of organogenesis (2-7 weeks postconception) and early fetogenesis (8-15 weeks postconception). Problems could include microcephaly, microphthalmia, mental retardation, growth restriction, cataracts, and others. Exposure to ionizing radiation during the later fetal period (16 weeks postconception and beyond) may increase the risks for fetal loss, mental retardation, and growth restriction. The radiation dose which may cause birth defects is thought to be approximately 0.05 to 0.15 Gy (5-15 rad). A 2-view chest films delivers a fetal dose of less than 0.0001 Gy (0.01 rad), while a typical pelvic CT delivers about 0.02 to 0.05 Gy (2-5 rads), which are well below the threshold for congenital malformations, but may increase the risk of cancer from a background rate of 0.3% to as high as 1% to 6%.77 A simple, qualitative dose assessment has been suggested for providers, in order to determine when a more formal quantitative assessment is needed. Doses are estimated at 2 mGy per exposure for radiographs, 5 mGy per slice for CT, and 10 mGy per minute of fluoroscopy time (when conceptus is in the field). The authors suggest a formal radiation exposure calculation by a medical physicist when the provisional calculation exceeds 10 mGy.78
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Examples of Protocols and Algorithms
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Many hospitals have established protocols for evaluation of pregnant trauma patients. Important elements of standardized care plans include establishing the viability and gestational age of pregnancy and triaging women into risk categories based on injury and obstetric characteristics.
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Practice management guidelines were published in 2010 by the Eastern Association for the Surgery of Trauma (EAST) regarding the diagnosis and management of injury in the pregnant patient. Their recommendations are summarized as follows:
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The best initial treatment is optimum resuscitation of the mother and early fetal assessment.
Keep the patient tilted left side down 15 degrees to prevent aortocaval compression
All female patients of childbearing age should have a β-human chorionic gonadotropin (β-HCG) screen and be shielded for x-rays when possible
Concern about ionizing radiation exposure should not prevent medically indicated x-ray procedures from being performed, but other imaging should be considered instead of x-rays when possible.
Obstetric consult should be considered in all cases of injury in pregnant patients.
All pregnant women greater than 20 weeks’ gestation who suffer trauma should have cardiotocographic monitoring for a minimum of 6 hours. Monitoring should be continued and further evaluation should be carried out if uterine contractions, nonreassuring FHR pattern, vaginal bleeding, significant uterine tenderness or irritability, serious maternal injury, or rupture of the amniotic membranes is noted.
Kleihauer-Betke analysis should be performed in all pregnant patients greater than 12 weeks’ gestation.
Perimortem cesarean section should be considered in any moribund pregnant woman at greater than or equal to 24 weeks’ gestation. Perimortem cesarean delivery must occur within 20 minutes of maternal death but ideally should start within 4 minutes of maternal arrest. Fetal neurologic outcome is related to delivery time after maternal death.79
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A proposed algorithm for evaluation and management of trauma in pregnancy is shown in Fig. 18-2. A basic approach to obstetric management is detailed below. Decisions about route and timing of delivery should be based on usual obstetric considerations within the context of treatment plans for other maternal injures.
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Brief observation (4-6 hours) is sufficient if
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Maternal trauma is minor.
Mother is hemodynamically stable.
Primary evaluation is negative.
FAST-US is negative for intra-abdominal fluid.
No obstetric complaints are found.
Fewer than 6 contractions per hour occur.
It is category I FHR pattern.
Examination and laboratory data are normal.
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Prolonged observation (24-48 hours, with continuous EFM) strongly advised if
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Multiple or severe maternal injuries occur.
Mother is hemodynamically unstable.
Obstetric symptoms present (regular contractions, vaginal bleeding, vaginal leakage, pain).
Contractions greater than 6 per hour occur during first 4 to 6 hours.
FHR pattern on EFM is abnormal.
Examination is abnormal (eg, fundal tenderness, cervical dilatation ≥2 cm).
Laboratory data are abnormal (eg, +KB, abnormal fibrinogen).
Imaging studies are abnormal (eg, FAST US, abnormal OB ultrasound, short CL, abnormal CT).
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All eligible Rh-negative patients should receive Rh immune globulin (RhIG) 300 μg IM within 72 hours of an episode of trauma, in order to prevent maternal sensitization. For women with a positive KB test, additional RhIG can be administered, with an additional 300 μg for each 30 mL of fetal RBCs in the maternal circulation. For Rh-negative women with confirmed (FMH), additional RhIG may be needed. To estimate the volume of fetal blood loss into the maternal circulation, several formulae exist, but the basic equation is as follows45:
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Tetanus is a rare, potentially fatal disease caused by the anaerobe, Clostridium tetani. Wounds that are crushed, devitalized, or contaminated with dirt or rust are considered to be tetanus-prone. Open fractures, punctures, and abscesses are also associated, but severity of the wound does not determine the risk. All wounds should be cleaned and debrided, if necessary.
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Tetanus toxoid should be given if the last booster was more than 10 years prior for clean, minor wounds, or more than 5 years prior for all other wounds. If the history of tetanus immunization is unknown or less than 3 prior doses, tetanus toxoid (Td) is indicated. Tetanus toxoid (Tdap may be used), but a single dose of Tdap should be provided in place of one Td booster if the patient has not previously received Tdap. Passive immunization with Tetanus immune globulin is indicated (≥250 IU) in persons with other than clean, minor wounds and a history of no, unknown, or less than 3 previous tetanus toxoid doses. Tetanus immune globulin can only help remove unbound tetanus toxin. It cannot affect toxin bound to nerve endings. Part of the tetanus immune globulin (TIG) dose should be infiltrated around the wound. Intravenous immunoglobulin (IVIG) contains tetanus antitoxin and may be used if TIG is not available.80
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Cardiopulmonary Resuscitation and Perimortem Cesarean
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Aspects of CPR During Pregnancy
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In rare cases, pregnant women may have life-threatening injuries requiring cardiopulmonary resuscitation (CPR) and advanced cardiovascular life support (ACLS) procedures. There should be no delay in administering CPR, but there are several modifications for pregnant patients which may improve resuscitation efforts. The woman’s torso should be tilted 15 to 30 degrees from the left lateral position. Alternatively, a wedge can be placed under the woman’s right side, or one rescuer can kneel next to the woman’s left side and gently displace the gravid uterus laterally. There are no modifications in defibrillation dose or pad position. If possible, remove any fetal or uterine monitors prior to delivering a shock. The airway should be secured early, using continuous cricoid pressure before and during intubation attempts. The endotracheal tube (ETT) may need to be 0.5 to 1 cm smaller in diameter than that used for a nonpregnant woman of similar size, due to airway edema. If possible, use an exhaled CO2 detector to confirm ETT placement. Reduce ventilation volumes, since the mother’s diaphragm is elevated by the gravid uterus. Follow usual ACLS guidelines for medications used in ACLS protocols. Although vasopressors decrease uterine blood flow, there are no alternative agents or regimens. Consider potentially reversible causes of cardiac arrest when approaching the gravid patient. In addition to the same causes seen in nonpregnant patients, one must consider other factors such as magnesium toxicity, eclampsia, acute coronary syndromes, aortic dissection, pulmonary embolism, stroke, amniotic fluid embolism, and drug overdose.81 CPR and ACLS are discussed in further detail elsewhere in this textbook.
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Cesarean delivery can be life-saving for both mother and fetus. Survival rates and the risks for long-term impairment depend on the gestational age and the interval from cardiac arrest to delivery. The recommendation to perform perimortem cesarean delivery (PMCD) within 4 minutes of maternal cardiac arrest was first made in 1986.82 A follow-up study of 38 cases of PMCD resulted in 34 surviving infants, including 3 sets of twins and 1 set of triplets. Eleven women were delivered within 5 minutes, and 6 within 15 minutes, but 7 were delivered over 15 minutes after maternal arrest. PMCD likely improves results of maternal resuscitation. PMCD preceded return of maternal pulse and blood pressure in 12 of 18 cases where specifics could be reviewed and 8 other mothers showed an overall improvement after PMCD. Among 20 cases with “resuscitatable” causes for cardiac arrest, 13 mothers recovered and were later discharged in good condition.83 Alleviating vena cava compression and improving ventilation by emptying the gravid uterus may account for the beneficial effects of PMCD. A review of all reported cases of cardiac arrest in 1980 to 2010 yielded 94 cases, with 54% who survived to hospital discharge. PMCD was beneficial to the mother in 32% of cases and not harmful in any case. In-hospital arrest and PMCD within 10 minutes of arrest were associated with better maternal outcomes. Neonatal survival was only associated with in-hospital cardiac arrest.84
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Team Drills and Simulation Training for CPR and PMCD
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Team drills and simulations can provide insight into performance issues or gaps in knowledge and skills. For example, transporting a gravid patient with cardiac arrest decreases the quality of CPR. Among 26 teams of 2 providers performing CPR on a mannequin, only 32% were able to correctly perform chest compressions when CPR was done while transporting versus 93% when stationary. Interruptions were common and tidal volume was suboptimal when CPR was done during transport.85 Simulation followed by oral debriefing was also studied in 25 anesthesiology residents. They simulated care for maternal cardiac arrest due to magnesium toxicity and preeclampsia. Although general aspects were performed well, OB-related interventions were performed poorly. Features of OB care, including uterine displacement, cricoid pressure, treatment of magnesium toxicity, and initiation of PMCD by 4 minutes, were all suboptimal. Oral debriefing highlighted and addressed gaps in knowledge about adaptations to ACLS for pregnant women.86
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Simulations also demonstrate an advantage to PMCD being performed in the labor room. A trial involving 15 teams simulated PMCD in the labor room versus transporting to the operating room (OR). The median time to incision was 4:25 when PMCD was in the labor room, versus 7:53 after going to the OR. (Only 57% of labor room teams and 14% of OR teams achieved delivery within 5 minutes.) Faster were times to defibrillation, NICU contact and maternal intubation were also seen when remaining in place.87 Recently, simulation training for PMCD was described using a model for a gravid uterus, where residents were expected to perform PMCD and resuscitate the newborn. Debriefing followed the scenario, including indications and technique for PMCD. All participants strongly agreed that the session enhanced learning more than lectures and readings alone.88 Indeed, advanced staff training about maternal CPR and PMCD appears to affect patient outcomes. Data from the Netherlands over a 15-year period showed that 55 women had cardiac arrest, of whom 12 underwent PMCD. The Managing Obstetric Emergencies and Trauma (MOET) course was initiated in 2004; subsequent practice patterns indicate increasing use of PMCD. Prior to the MOET course, 4 PMCS were done (0.36/y) compared with 8 cases after (1.6/y). Eight of 12 women treated with PMCD regained cardiac output, with 2 maternal and 5 neonatal survivors.89