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Amniotic Fluid Embolism
CHAPTER 25
Amniotic Fluid Embolism LEARNING OBJECTIVES
• • • •
Describe the pathophysiology of amniotic fluid embolism. List risk factors for amniotic fluid embolism. Identify clinical presentation of amniotic fluid embolism. Describe a management strategy for amniotic fluid embolism.
Amniotic fluid embolism is a fortunately rare obstetric emergency. However, if mothers are to survive this catastrophic event, clinicians must recognize it quickly and manage it very aggressively.
PATHOPHYSIOLOGY
Amniotic fluid embolism occurs when there is enhanced communication between the amniotic cavity
and maternal circulation. This allows amniotic fluid to enter the maternal circulation where it triggers a systemic inflammatory response (Fig. 25.1). In the first hour, this typically presents as pulmonary hypertension and right ventricular failure. This is followed by left ventricular failure. The resultant hypotension and hypoxemia trigger multisystem organ failure. Concurrent activation of the coagulation cascade results in disseminated intravascular coagulation.1,2
FIG. 25.1 Symptoms of amniotic fluid embolism. Safety Training for Obstetric Emergencies. https://doi.org/10.1016/B978-0-323-69672-2.00025-4 Copyright © 2019 Elsevier Inc. All rights reserved.
157
158
Safety Training for Obstetric Emergencies
TABLE 25.1
Management of Amniotic Fluid Embolism1,2
• • •
Goal MAP is >65 mm Hg Treat hypotension with vasopressors - Norepinephrine 0.05-3.3 mg/kg/min - Dobutamine 2.5-5.0 mg/kg/min Avoid excessive fluid administration If cardiac arrest, follow ACLS algorithms Institute post-arrest hypothermia only if there is no clinical evidence of coagulopathy
Respiratory
• • •
Supplemental oxygen should be titrated to maintain SpO2 at 94e98% Avoid hyperoxia after cardiac arrest (may worsen ischemia-reperfusion injury) Intubation is commonly needed
Coagulopathy
• • •
Aggressive blood replacement (including red blood cells, fresh frozen plasma, cryoprecipitate, and platelets) is critical Consider activating massive transfusion protocol Replacement can be initiated before clinical evidence of coagulopathy
• •
If vaginal delivery is imminent, can proceed with assisted second stage If not, proceed with immediate cesarean
Cardiovascular
Delivery
• •
RISK FACTORS2,3
DIFFERENTIAL DIAGNOSIS
• • • • • • • • •
• • • • • • • •
Multifetal gestation Advanced maternal age Operative delivery Eclampsia Polyhydramnios Cervical laceration Uterine rupture Placenta previa Amnioinfusion
CLINICAL PRESENTATION
Pulmonary embolism Congestive heart failure Myocardial infarction Anaphylaxis Placental abruption Sepsis with hypotension Placental abruption Anesthetic complications
MANAGEMENT1,2 1,2
There are no diagnostic tests or laboratory findings for amniotic fluid embolism. It is a clinical diagnosis based on the following findings: • Sudden, unexplained respiratory distress • Hypotension • Cardiac arrest • Seizure-like activity • Fetal bradycardia • Disseminated intravascular coagulation • Uterine atony
The goals of management are stabilization of the mother and rapid delivery of the fetus (Table 25.1).
REFERENCES
1. Clark SL. Amniotic fluid embolism. Obstet Gynecol. 2014; 123(2 Pt 1):337e348. 2. Society for Maternal-Fetal Medicine, Electronic address, p.s.o, et al. Amniotic fluid embolism: diagnosis and management. Am J Obstet Gynecol. 2016;215(2):B16eB24. 3. Fong A, et al. Amniotic fluid embolism: antepartum, intrapartum and demographic factors. J Matern Fetal Neonatal Med. 2015;28(7):793e798.
CHAPTER 25 Amniotic Fluid Embolism
159
Amniotic Fluid Embolism Simulation MATERIALS NEEDED • Manikin • Laryngoscope • Endotracheal tube • Adult code cart KEY PERSONNEL • Anesthesiologist • Attending obstetrician • Neonatologist • Resident physician (if available in your institution) • Two nurses SAMPLE SCENARIO A 42-year-old G3P2 female at 37 weeks gestation is admitted in active labor. Patient’s pregnancy has been uncomplicated other than idiopathic polyhydramnios. On admission, her cervix is 6 cm dilated. Fetal heart tracing is 135 beats per minute with moderate variability, accelerations, and no decelerations. She is contracting every 5 minutes. Shortly after admission, the patient experiences spontaneous rupture of membranes. She becomes agitated and begins to complain that she cannot breathe. Her respiratory rate climbs to 26 breaths per minute. A pulse oximeter reveals an oxygen saturation of 74%. The patient’s blood pressure is 84/44 mm Hg and pulse is 145 beats per minute. The fetal heart rate is now 100 beats per minute. DEBRIEFING AND DOCUMENTATION • Diagnosis and how it was made • If cardiac arrest occurred, document thoroughly resuscitation • Respiratory interventions-current ventilator settings • Delivery information • Time for decision-to-delivery • Mode of delivery • Infant status • Blood loss • If postpartum hemorrhage occurred, document interventions • Blood products given • Labs ordered • Imaging ordered • Consultants contacted • Communication with patient and family
Simulation Checklist Time Initial response
Recognized emergency Called for help
Team dynamics
Team leader identified Team member roles clearly assigned Considered differential diagnoses
Circulation
Applied blood pressure cuff, cardiac monitor Avoided excessive fluid administration Identified goal MAP of >65 mm Hg Treated of hypotension with vasopressors Confirm adult code cart is readily available EKG ordered
Airway and breathing
Lungs auscultated Supplemental oxygen given FiO2 titrated to keep SpO2 94%e98% Considered need for intubation Pulse ox requested ABG ordered
Pregnancy-related considerations
IV access obtained above diaphragm Left uterine displacement Decision made to proceed with cesarean Prepared for postpartum hemorrhage
Coagulopathy
Considered likelihood of coagulopathy if amniotic fluid embolism Prepared for massive transfusion
Documentation
Persons present Maternal vitals Fetal/neonatal status Interventions Timing of delivery Differential diagnosis Management plan
Communication
Succinctly summarized situation, background, assessment, and recommendations as help arrived Directed communication Closed-loop communication Communication with patient and family
Comments
CHAPTER 25 Amniotic Fluid Embolism
Technical and nontechnical skills in management of amniotic fluid embolism.
161
Amniotic Fluid Embolism LEARNING OBJECTIVES
• • • •
Describe the pathophysiology of amniotic fluid embolism. List risk factors for amniotic fluid embolism. Identify clinical presentation of amniotic fluid embolism. Describe a management strategy for amniotic fluid embolism.
Amniotic fluid embolism is a fortunately rare obstetric emergency. However, if mothers are to survive this catastrophic event, clinicians must recognize it quickly and manage it very aggressively.
PATHOPHYSIOLOGY
Amniotic fluid embolism occurs when there is enhanced communication between the amniotic cavity
and maternal circulation. This allows amniotic fluid to enter the maternal circulation where it triggers a systemic inflammatory response (Fig. 25.1). In the first hour, this typically presents as pulmonary hypertension and right ventricular failure. This is followed by left ventricular failure. The resultant hypotension and hypoxemia trigger multisystem organ failure. Concurrent activation of the coagulation cascade results in disseminated intravascular coagulation.1,2
FIG. 25.1 Symptoms of amniotic fluid embolism. Safety Training for Obstetric Emergencies. https://doi.org/10.1016/B978-0-323-69672-2.00025-4 Copyright © 2019 Elsevier Inc. All rights reserved.
157
158
Safety Training for Obstetric Emergencies
TABLE 25.1
Management of Amniotic Fluid Embolism1,2
• • •
Goal MAP is >65 mm Hg Treat hypotension with vasopressors - Norepinephrine 0.05-3.3 mg/kg/min - Dobutamine 2.5-5.0 mg/kg/min Avoid excessive fluid administration If cardiac arrest, follow ACLS algorithms Institute post-arrest hypothermia only if there is no clinical evidence of coagulopathy
Respiratory
• • •
Supplemental oxygen should be titrated to maintain SpO2 at 94e98% Avoid hyperoxia after cardiac arrest (may worsen ischemia-reperfusion injury) Intubation is commonly needed
Coagulopathy
• • •
Aggressive blood replacement (including red blood cells, fresh frozen plasma, cryoprecipitate, and platelets) is critical Consider activating massive transfusion protocol Replacement can be initiated before clinical evidence of coagulopathy
• •
If vaginal delivery is imminent, can proceed with assisted second stage If not, proceed with immediate cesarean
Cardiovascular
Delivery
• •
RISK FACTORS2,3
DIFFERENTIAL DIAGNOSIS
• • • • • • • • •
• • • • • • • •
Multifetal gestation Advanced maternal age Operative delivery Eclampsia Polyhydramnios Cervical laceration Uterine rupture Placenta previa Amnioinfusion
CLINICAL PRESENTATION
Pulmonary embolism Congestive heart failure Myocardial infarction Anaphylaxis Placental abruption Sepsis with hypotension Placental abruption Anesthetic complications
MANAGEMENT1,2 1,2
There are no diagnostic tests or laboratory findings for amniotic fluid embolism. It is a clinical diagnosis based on the following findings: • Sudden, unexplained respiratory distress • Hypotension • Cardiac arrest • Seizure-like activity • Fetal bradycardia • Disseminated intravascular coagulation • Uterine atony
The goals of management are stabilization of the mother and rapid delivery of the fetus (Table 25.1).
REFERENCES
1. Clark SL. Amniotic fluid embolism. Obstet Gynecol. 2014; 123(2 Pt 1):337e348. 2. Society for Maternal-Fetal Medicine, Electronic address, p.s.o, et al. Amniotic fluid embolism: diagnosis and management. Am J Obstet Gynecol. 2016;215(2):B16eB24. 3. Fong A, et al. Amniotic fluid embolism: antepartum, intrapartum and demographic factors. J Matern Fetal Neonatal Med. 2015;28(7):793e798.
CHAPTER 25 Amniotic Fluid Embolism
159
Amniotic Fluid Embolism Simulation MATERIALS NEEDED • Manikin • Laryngoscope • Endotracheal tube • Adult code cart KEY PERSONNEL • Anesthesiologist • Attending obstetrician • Neonatologist • Resident physician (if available in your institution) • Two nurses SAMPLE SCENARIO A 42-year-old G3P2 female at 37 weeks gestation is admitted in active labor. Patient’s pregnancy has been uncomplicated other than idiopathic polyhydramnios. On admission, her cervix is 6 cm dilated. Fetal heart tracing is 135 beats per minute with moderate variability, accelerations, and no decelerations. She is contracting every 5 minutes. Shortly after admission, the patient experiences spontaneous rupture of membranes. She becomes agitated and begins to complain that she cannot breathe. Her respiratory rate climbs to 26 breaths per minute. A pulse oximeter reveals an oxygen saturation of 74%. The patient’s blood pressure is 84/44 mm Hg and pulse is 145 beats per minute. The fetal heart rate is now 100 beats per minute. DEBRIEFING AND DOCUMENTATION • Diagnosis and how it was made • If cardiac arrest occurred, document thoroughly resuscitation • Respiratory interventions-current ventilator settings • Delivery information • Time for decision-to-delivery • Mode of delivery • Infant status • Blood loss • If postpartum hemorrhage occurred, document interventions • Blood products given • Labs ordered • Imaging ordered • Consultants contacted • Communication with patient and family
Simulation Checklist Time Initial response
Recognized emergency Called for help
Team dynamics
Team leader identified Team member roles clearly assigned Considered differential diagnoses
Circulation
Applied blood pressure cuff, cardiac monitor Avoided excessive fluid administration Identified goal MAP of >65 mm Hg Treated of hypotension with vasopressors Confirm adult code cart is readily available EKG ordered
Airway and breathing
Lungs auscultated Supplemental oxygen given FiO2 titrated to keep SpO2 94%e98% Considered need for intubation Pulse ox requested ABG ordered
Pregnancy-related considerations
IV access obtained above diaphragm Left uterine displacement Decision made to proceed with cesarean Prepared for postpartum hemorrhage
Coagulopathy
Considered likelihood of coagulopathy if amniotic fluid embolism Prepared for massive transfusion
Documentation
Persons present Maternal vitals Fetal/neonatal status Interventions Timing of delivery Differential diagnosis Management plan
Communication
Succinctly summarized situation, background, assessment, and recommendations as help arrived Directed communication Closed-loop communication Communication with patient and family
Comments
CHAPTER 25 Amniotic Fluid Embolism
Technical and nontechnical skills in management of amniotic fluid embolism.
161