Second and Third Trimester Obstetric Emergencies
Slide 1: Life-Threatening Hemorrhagic Emergencies
Postpartum hemorrhage is the leading preventable cause of maternal mortality worldwide and demands immediate recognition. 1
Immediate Management Protocol:
- Administer oxytocin 5-10 IU via slow IV or IM injection immediately at shoulder release or postpartum as first-line prophylaxis 1, 2, 3
- If bleeding continues despite oxytocin, give tranexamic acid 1 gram IV within 1-3 hours of bleeding onset (NNT: 276 to prevent one maternal death) 1, 2, 3
- Critical pitfall: Delaying tranexamic acid beyond 3 hours significantly reduces effectiveness 1, 2, 3
Essential Resources Required:
- Large-bore IV catheters (14-16 gauge) 4
- Fluid warmers and forced-air body warmers 1, 3
- Rapid infusion devices 1, 3
- Massive transfusion protocol with 1:1:1 ratio of packed RBCs:FFP:platelets 3
- Maintain maternal temperature >36°C as clotting factors function poorly at lower temperatures 3
Slide 2: Hypertensive Emergencies - Severe Preeclampsia/Eclampsia
Severe preeclampsia and eclampsia represent acute neurological and cardiovascular emergencies requiring immediate blood pressure control and seizure prophylaxis. 1
Immediate Treatment:
- Administer magnesium sulfate as first-line therapy for eclamptic seizures 1, 2, 3, 5
- Initiate antihypertensive treatment immediately to prevent intracranial hemorrhage 2, 3
- Coordinate immediately with emergency services for rapid response 1, 2
Magnesium Sulfate Administration:
- Dilute 50% solution to 20% or less prior to IV infusion 5
- Monitor patellar reflexes before each dose; if absent, hold additional doses until reflexes return 5
- Therapeutic serum levels: 3-6 mg/100 mL (2.5-5 mEq/L) 5
- Reflexes diminish at >4 mEq/L; respiratory paralysis risk at 10 mEq/L 5
- Have injectable calcium salt immediately available to counteract magnesium toxicity 5
Critical Warning:
- Careful blood pressure monitoring required when combining nifedipine with IV magnesium sulfate due to risk of excessive hypotension 6
- Continuous administration beyond 5-7 days can cause fetal hypocalcemia, skeletal demineralization, and osteopenia 5
Slide 3: Maternal Cardiac Arrest - The 4-Minute Rule
Emergency cesarean delivery must be performed within 4 minutes of cardiac arrest onset if the uterus is palpable at or above the umbilicus (≥20 weeks gestation) to optimize maternal and fetal survival. 7, 1, 2, 3
Immediate Resuscitation Protocol:
- Initiate standard ACLS with continuous manual leftward displacement of gravid uterus by designated team member 7, 2
- Without left uterine displacement, cardiac massage yields only 10% of normal pregnancy cardiac output 7
- Left lateral tilt position reduces external cardiac massage efficacy 7
- Provide oxygen supplementation to maintain maternal saturation >95% 4
Critical Time Windows:
- No maternal survival reported after 15 minutes of resuscitation 7
- No fetal survival reported after 30 minutes 7
- Objective: Extract neonate within 5 minutes of resuscitation onset 7
- Do not transport to operating room; perform at bedside with rudimentary aseptic conditions 7
Gestational Age Assessment:
- Uterus palpable at pubic symphysis = 12 weeks 7
- Uterus palpable at umbilicus = 20 weeks (may occur 15-19 weeks) 7
- Uterus palpable at xiphisternum = 36 weeks 7
Slide 4: Amniotic Fluid Embolism (AFE)
AFE presents with sudden cardiovascular collapse, respiratory distress, and coagulopathy—use cognitive aid checklists focusing on ABC principles. 1, 2, 3
Clinical Presentation:
- 70% occur during labor, 11% after vaginal delivery, 19% during cesarean delivery 7
- Prodrome: anxiety, mental status changes, agitation, sensation of doom 7
- Rapid progression to cardiac arrest with pulseless electrical activity, asystole, or ventricular arrhythmias 7
- Fetal monitoring shows decelerations, loss of variability, terminal bradycardia 7
Immediate Management:
- Secure airway immediately if respiratory distress and seizure activity occur to prevent aspiration 1, 2, 3
- Designate timekeeper to call out times at 1-minute intervals 3
- Transfer to ICU immediately given multi-system involvement with respiratory failure, neurological compromise, and coagulopathy 1
Hemodynamic Phases:
- Early phase: acute right ventricular failure (confirm with bedside transthoracic echo) 7
- Second phase: left ventricular failure with cardiogenic pulmonary edema 7
- Treat right ventricular failure with inotropes (dobutamine or milrinone) 7
- Decrease pulmonary afterload with inhaled nitric oxide or prostacyclin 7
- Consider norepinephrine to maintain blood pressure; avoid excessive fluid resuscitation 7
Coagulopathy Management:
- Activate massive transfusion protocols 7
- Avoid prostaglandin F2α and ergometrine in patients with respiratory distress 1, 3
- Aggressive treatment of uterine atony and search for anatomic bleeding sources 7
Slide 5: Delivery-Related Emergencies
Imminent Delivery Assessment:
- Systematically assess: multiparity, history of previous rapid/non-hospital delivery, regular painful contractions, urge to push 1, 2
- Perform cervical examination before contacting receiving obstetric team to optimize triage 1, 2
Shoulder Dystocia:
- Position patient for McRoberts maneuver if anticipated 1, 2
- Occurs when fetal shoulders fail to deliver after head emerges 1
Obstructed Labor:
- Assess for cephalopelvic disproportion before augmentation—occurs in 25-30% of active phase arrest cases 1, 2
- Oxytocin augmentation is first-line treatment with 92% success rate for vaginal delivery when cephalopelvic disproportion absent 1, 2
Impacted Fetal Head at Cesarean:
- Prevention: manual vaginal disimpaction, fetal pillow 3
- Management: assistant pushing head up from vagina, reverse breech extraction, tocolysis 3
Slide 6: Placental Emergencies
Placental Abruption:
- Do not delay management pending ultrasound confirmation—ultrasound is not sensitive for diagnosis 4
- Clinical diagnosis based on: vaginal bleeding, uterine tenderness, sustained contractions, abnormal fetal heart rate 4
- Defer speculum/digital vaginal examination at ≥23 weeks until placenta previa excluded by ultrasound 4
Placenta Accreta Spectrum:
- Leave placenta in situ if abnormal attachment evident 3
- Consider ureteric stent placement and urologic surgeon involvement if bladder invasion suspected 3
- Avoid forced placental removal with suspected accreta 3
- Coordinate with receiving facility before transport; stabilize with temporizing maneuvers 3
Slide 7: Trauma in Pregnancy
Primary Survey Modifications:
- Every female of reproductive age with significant injuries considered pregnant until proven otherwise 4
- Insert nasogastric tube in semiconscious/unconscious patients to prevent aspiration 4
- Maintain oxygen saturation >95% for adequate fetal oxygenation 4
- Insert thoracostomy tube 1-2 intercostal spaces higher than usual 4
Aortocaval Compression Management:
- After mid-pregnancy, manually displace gravid uterus off inferior vena cava or use left lateral tilt 4
- Secure spinal cord when using left lateral tilt 4
- Do not inflate abdominal portion of military anti-shock trousers—reduces placental perfusion 4
Transfusion Protocol:
- Transfuse O-negative blood to Rh-negative mothers until cross-matched blood available 4
- Give anti-D immunoglobulin to all Rh-negative pregnant trauma patients 4
- Perform Kleihauer-Betke test to determine need for additional anti-D doses 4
Fetal Monitoring:
- All viable pregnancies (≥23 weeks) undergo electronic fetal monitoring for at least 4 hours 4
- Admit for 24-hour observation if: uterine tenderness, significant abdominal pain, vaginal bleeding, sustained contractions (>1/10 min), ruptured membranes, abnormal fetal heart rate, high-risk mechanism, fibrinogen <200 mg/dL 4
Perimortem Cesarean:
- Perform no later than 4 minutes following maternal cardiac arrest for viable pregnancies (≥23 weeks) to aid maternal resuscitation and fetal salvage 4
Slide 8: Diagnostic Imaging and Radiation Safety
Radiographic Studies:
- Do not defer or delay radiographic studies including abdominal CT due to fetal radiation concerns 4
- Fetal risk from radiation depends on gestational age and dose received 7
- Gadolinium-based contrast agents can be considered when maternal benefit outweighs potential fetal risks 4
Ultrasound Applications:
- Focused abdominal sonography for trauma (FAST) should be considered for detecting intraperitoneal bleeding 4
- Abdominal CT may be considered as alternative to diagnostic peritoneal lavage when intra-abdominal bleeding suspected 4
- Urgent obstetrical ultrasound when gestational age undetermined and delivery anticipated 4
- All admitted patients with viable pregnancy monitored >4 hours should have obstetrical ultrasound prior to discharge 4
Slide 9: Venous Thromboembolism in Pregnancy
Diagnosis:
- Pregnancy predisposes to VTE 8
- D-dimer levels have low specificity in pregnancy 8
- Ventilation-perfusion scan preferred over CT pulmonary angiography in some situations to reduce breast radiation 8
Treatment:
- Low-molecular-weight or unfractionated heparins form mainstay of treatment 8
- Vitamin K antagonists, oral factor Xa inhibitors, and direct thrombin inhibitors not recommended in pregnancy 8
Slide 10: Airway Management Considerations
Equipment Requirements:
- Have immediately available: rigid laryngoscope blades, videolaryngoscopic devices, endotracheal tubes of assorted sizes 3
- Consider neuraxial techniques over general anesthesia when possible 3
- Use aspiration prophylaxis 3
- Critical pitfall: Underestimating physiological changes of pregnancy complicates airway management during emergency cesarean 1
Pregnancy-Specific Changes:
- Rapid desaturation with apnea due to increased oxygen consumption and decreased functional residual capacity 7
- Increased risk of aspiration due to delayed gastric emptying and decreased lower esophageal sphincter tone 4
Slide 11: System-Level Preparedness
Pre-Event Planning (Four Critical Steps):
- Educate staff about management of cardiac arrest in pregnancy 7
- Identify contact details to mobilize entire maternal cardiac arrest response team; ensure availability of equipment for cesarean delivery and neonatal resuscitation 7, 3
- Stock drugs commonly available in obstetric units including oxytocin and prostaglandin F2α 7
- Make decisions about fetal viability in collaboration with obstetrician, neonatologist, and family 7
Team Coordination:
- Establish direct contact between on-call obstetrician and emergency medical services 1, 2, 3
- Ensure immediate availability of basic and advanced life-support equipment in labor and delivery units 1, 2
- Lack of standardized approaches to emergency obstetric care contributes to poor maternal outcomes 2
Transfer Protocols:
- Transfer to maternity facility when injuries neither life- nor limb-threatening and fetus viable (≥23 weeks) 4
- Transfer to emergency room when fetus <23 weeks or non-viable 4
- Transfer to trauma unit regardless of gestational age when injury is major 4
Slide 12: Simulation Training and Education
Training Recommendations:
- Simulation training on obstetrical emergencies suggested for emergency medicine teams 7
- Particularly important: breech delivery, twin pregnancies, shoulder dystocia, ineffective uterine contractions 7
- Emergency obstetric training essential for all personnel managing deliveries 2, 3
- Educate all staff about pregnancy-specific resuscitation modifications 2, 3
Evidence Limitations:
- Practically no literature on simulation training for emergency medicine teams on obstetrical emergencies 7
- Rare studies assessed only learner satisfaction and knowledge acquisition 7
- More evidence exists for positive impact on obstetrical teams regarding confidence, knowledge, and skills 7
Slide 13: Additional Medical Emergencies
Acute Respiratory Distress Syndrome:
- ARDS occurs more frequently in pregnancy 8
- Permissive hypercapnia, plateau pressure limits, and prone positioning may not be acceptable in late pregnancy 8
Genital Tract Infections:
- Chorioamnionitis 8
- Group A streptococcal infection causing toxic shock syndrome 8
- Polymicrobial infection with streptococci, staphylococci, Clostridium perfringens causing necrotizing vulvitis or fasciitis 8
Other Conditions:
Domestic Violence:
- Every woman who sustains trauma should be questioned specifically about domestic or intimate partner violence 4
- Carefully document fetal well-being in cases involving violence for legal purposes 4
Slide 14: Non-Obstetric Abdominal Emergencies
Acute Appendicitis:
- Most common abdominal emergency in pregnancy (1 in 500-700 pregnancies) 9
- Best treated by laparoscopic appendectomy 9
Acute Calculous Cholecystitis:
- Best treated by laparoscopic cholecystectomy from first trimester through early third trimester 9
Intestinal Obstruction:
- Medical treatment is first-line approach, same as non-pregnant patients 9
Acute Pancreatitis:
- Rare, usually from trans-ampullary passage of gallstones 9
- Usually resolves with medical treatment 9
- Elevated recurrence risk justifies laparoscopic cholecystectomy in 2nd trimester, endoscopic sphincterotomy in 3rd trimester 9
General Principles:
- Surgery necessary in 0.2-2% of pregnancies 9
- Refer to specialized centers with surgical, obstetrical, and neonatal care available 9
- Surgical intervention increases risk of premature labor 9
- Clinical presentations may be atypical due to pregnancy-associated anatomical and physiologic alterations 9
Slide 15: Critical Pitfalls Summary
Time-Sensitive Errors:
- Failure to recognize 4-minute window for perimortem cesarean leads to poor maternal and fetal outcomes 1
- Delaying tranexamic acid beyond 3 hours reduces effectiveness 1, 2
Technical Errors:
- Failing to maintain left uterine displacement during resuscitation perpetuates aortocaval compression 1
- Not having hemorrhage management resources immediately available delays critical interventions 1
- Underestimating physiological changes of pregnancy complicates airway management 1
Clinical Judgment Errors:
- Avoiding forced placental removal with suspected accreta 3
- Not using prostaglandins in patients with respiratory distress or cardiovascular disease 3
- Tachycardia as unreliable indicator of ruptured ectopic pregnancy 10