Study guide
4.4 Nonthrombotic Embolism (Air, Fat, Amniotic Fluid, Tumor, Septic) & Acute Chest Syndrome
ABIM Critical Care Medicine Study Guide Exam
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1 Chapter 1: Exam Orientation: Format, Blueprint & Study Strategy
1.1 ABIM Critical Care Medicine Exam: Format, Blueprint & Study Strategy
2 Chapter 2: Acute Respiratory Failure & ARDS
2.1 ARDS Definition, Pathophysiology & Phenotypes 2.2 Lung-Protective Mechanical Ventilation 2.3 Refractory ARDS: Prone Positioning, Neuromuscular Blockade & VV-ECMO
3 Chapter 3: Obstructive Airways, Pulmonary Vascular & Pleural Emergencies
3.1 Severe Asthma & COPD Exacerbations in the ICU 3.2 Massive & Submassive Pulmonary Embolism 3.3 Pulmonary Hypertension & Right Ventricular Failure in the ICU 3.4 Massive Hemoptysis, Complex Pleural Effusions & Thoracic Drainage
4 Chapter 4: Airway, Parenchymal & Nonthrombotic Pulmonary Emergencies
4.1 Airway Management, Upper-Airway Obstruction & Artificial-Airway Complications 4.2 Diffuse Alveolar Hemorrhage, Interstitial Lung Disease, Pulmonary Vasculitis & Noncardiogenic Edema 4.3 Severe Community-Acquired & Viral Pneumonia 4.4 Nonthrombotic Embolism (Air, Fat, Amniotic Fluid, Tumor, Septic) & Acute Chest Syndrome
5 Chapter 5: Mechanical Ventilation Modes, Dyssynchrony & Liberation
5.1 Mechanical Ventilator Modes & Advanced Breath Delivery 5.2 Patient-Ventilator Dyssynchrony & Waveform Analysis 5.3 Ventilator Liberation, Spontaneous Breathing Trials & Post-Extubation Support
6 Chapter 6: Shock Syndromes & Hemodynamic Principles
6.1 Shock Classification, Cellular Pathophysiology & Biomarkers 6.2 Hemodynamic Monitoring: Arterial Lines, CVP & Pulmonary Artery Catheter 6.3 Dynamic Assessment of Fluid Responsiveness & Resuscitation Targets
7 Chapter 7: Vasoactive Therapies & Mechanical Circulatory Support
7.1 Vasopressors & Inotropes: Pharmacology & Clinical Titration 7.2 Temporary Mechanical Circulatory Support: IABP, Impella & TandemHeart 7.3 Venoarterial ECMO (VA-ECMO) & Differential Hypoxemia 7.4 Post-Cardiac Arrest Care, Targeted Temperature Management & Neuroprognostication
8 Chapter 8: Acute Kidney Injury & Renal Replacement Therapy
8.1 KDIGO AKI Classification, Etiologies & Diagnostic Evaluation 8.2 Continuous Renal Replacement Therapy (CRRT) vs Intermittent Hemodialysis 8.3 Indications & Timing for RRT in Critical Illness: AKIKI & STARRT-AKI
9 Chapter 9: Electrolyte, Acid-Base & Endocrine Emergencies
9.1 Severe Dysnatremias: Hyponatremia, Hypernatremia & Osmotic Demyelination 9.2 Potassium, Calcium, Magnesium & Phosphate Disorders 9.3 Complex & Mixed Acid-Base Disorders: Boston vs Copenhagen vs Stewart 9.4 Endocrine Crises: DKA, HHS, Thyroid Storm, Myxedema Coma & Adrenal Crisis
10 Chapter 10: Glycemic Control, Hyperammonemia, Pituitary & Adrenal Disorders
10.1 ICU Glycemic Control & Severe Hypoglycemia 10.2 Non-Hepatic Hyperammonemia & Metabolic Encephalopathy 10.3 Pituitary Emergencies, Adrenal Excess & Critical Illness-Related Corticosteroid Insufficiency
11 Chapter 11: Acute Coronary Syndromes & Cardiac Arrhythmias
11.1 Acute Coronary Syndromes & Mechanical Complications of Myocardial Infarction 11.2 Critical Tachyarrhythmias: Atrial Fibrillation with RVR, VT & VF 11.3 Critical Bradyarrhythmias, Conduction Blocks & Temporary Cardiac Pacing
12 Chapter 12: Acute Heart Failure, Valvular & Pericardial Emergencies
12.1 Acute Decompensated Heart Failure & Cardiogenic Pulmonary Edema 12.2 Acute Valvular Regurgitation & Prosthetic Valve Emergencies 12.3 Pericardial Tamponade & Acute Aortic Syndromes
13 Chapter 13: Myocardial Disease, Hypertensive & Cardiac Device Emergencies
13.1 Fulminant Myocarditis, Stress & Peripartum Cardiomyopathy, and Hypertrophic Cardiomyopathy 13.2 Hypertensive Emergencies & Ruptured Abdominal Aortic Aneurysm 13.3 Implanted Cardiac Devices, LVAD Emergencies & Electrical Storm
14 Chapter 14: Sepsis & Systemic Infectious Diseases
14.1 Sepsis-3 Definitions & Surviving Sepsis Campaign 2026 Guidelines 14.2 Refractory Septic Shock & Adjunctive Therapies 14.3 Multidrug-Resistant Pathogens & Antimicrobial Stewardship in the ICU
15 Chapter 15: ICU-Acquired & Severe Focal Infections
15.1 Hospital-Acquired & Ventilator-Associated Pneumonia 15.2 Central Line-Associated Bloodstream Infections & Catheter-Associated UTIs 15.3 Intra-Abdominal Sepsis, Necrotizing Soft Tissue Infections & CNS Infections
16 Chapter 16: Focal, Special-Host & Systemic Infections
16.1 CNS Infections Beyond Bacterial Meningitis: Encephalitis, Brain Abscess & Epidural Abscess 16.2 Infections in the Immunocompromised Host, Tropical & Bioterror Infections 16.3 Infective Endocarditis, Device Infections & Other Focal Cardiovascular Infections 16.4 Antimicrobial Pharmacokinetics, Allergy, Toxicity & Infection Prevention 16.5 Gastrointestinal & Hepatobiliary Infections: Fulminant C. difficile, Typhlitis, CMV Colitis & Abscesses
17 Chapter 17: Neurocritical Care & Coma
17.1 Coma, Altered Mental Status & Acute Delirium in the ICU 17.2 Status Epilepticus & Non-Convulsive Status Epilepticus 17.3 Acute Ischemic Stroke & Intracranial Hemorrhage
18 Chapter 18: Cerebrovascular Syndromes, Encephalopathy & Withdrawal States
18.1 Cerebral Venous Sinus Thrombosis, PRES & Reversible Cerebral Vasoconstriction Syndrome 18.2 Alcohol & Sedative Withdrawal, Wernicke Encephalopathy & Drug-Induced Encephalopathy
19 Chapter 19: Intracranial Hypertension & Neuromuscular Weakness
19.1 Intracranial Pressure Monitoring, Cerebral Perfusion & Tiered ICP Management 19.2 Acute Neuromuscular Respiratory Failure, ICU-Acquired Weakness & Brain Death Determination
20 Chapter 20: Traumatic Brain Injury, Spinal Cord Injury & Toxin-Mediated Paralysis
20.1 Traumatic Brain Injury Management & Paroxysmal Sympathetic Hyperactivity 20.2 Acute Spinal Cord Injury, Neurogenic Shock & Autonomic Dysreflexia 20.3 Toxin-Mediated Paralysis & Neuromuscular Crises: Botulism, Tetanus, Tick Paralysis & Myasthenic Crisis
21 Chapter 21: Gastrointestinal, Hepatic & Abdominal Emergencies
21.1 Acute Upper & Lower Gastrointestinal Bleeding in the ICU 21.2 Acute Liver Failure & Severe Acute Pancreatitis 21.3 Abdominal Compartment Syndrome & Acute Mesenteric Ischemia
22 Chapter 22: Luminal GI Emergencies & Complications of Cirrhosis
22.1 Esophageal, Gastric & Bowel Emergencies: Perforation, Obstruction, Ogilvie Syndrome & Colonic Ischemia 22.2 Complications of Cirrhosis: Alcohol-Associated Hepatitis, Hepatorenal Syndrome & Pulmonary Vascular Syndromes
23 Chapter 23: Trauma, Burns & Perioperative Critical Care
23.1 Polytrauma Resuscitation, Damage Control & Massive Transfusion 23.2 Severe Burn Injury, Inhalation Injury & Environmental Emergencies 23.3 Perioperative Critical Care for High-Risk Surgical Patients
24 Chapter 24: Thoracic Trauma, Environmental Injury & Obstetric Critical Care
24.1 Thoracic Trauma: Flail Chest, Pulmonary Contusion, Great Vessel & Tracheobronchial Injury 24.2 Environmental Injury: Drowning, Diving, Altitude, Heat, Cold, Electrical & Radiation 24.3 Obstetric & Genitourinary Emergencies and the Physiology of Pregnancy
25 Chapter 25: Transplantation, Donor Management & Post-Cardiac Surgery Care
25.1 Solid Organ Transplant Recipients & Deceased Donor Management 25.2 Post-Cardiac Surgery Critical Care: Bleeding, Tamponade, Low Output & Vasoplegia
26 Chapter 26: Hematologic Emergencies, Toxicology, Critical Ultrasound & ICU Liberation
26.1 Hematologic Emergencies in the ICU: HIT, DIC, TMA & Anticoagulant Reversal 26.2 Critical Care Toxicology, Toxidromes & Specific Antidotes 26.3 Critical Care Point-of-Care Ultrasound (POCUS) 26.4 ICU Liberation, Analgosedation, Goals of Care & Critical Care Ethics
27 Chapter 27: Transfusion Medicine, Hematologic & Oncologic Disorders
27.1 Transfusion Medicine: Products, Thresholds, Reactions & Apheresis 27.2 Red and White Cell Disorders, Hemoglobinopathies, Factor Deficiencies & Hypercoagulable States 27.3 Oncologic Emergencies, Hematopoietic Cell Transplant Complications & Cellular Therapy Toxicity
28 Chapter 28: Clinical Pharmacology, Adverse Drug Reactions & Specific Poisonings
28.1 Pharmacokinetic Principles, Dose Adjustment & Drug Interactions in Critical Illness 28.2 Adverse Drug Reactions: Anaphylaxis, Severe Cutaneous Reactions & Hyperthermic Syndromes 28.3 Specific Poisonings: Sodium-Channel Blockers, Lithium, Valproate, Theophylline, Iron, Sulfonylureas & Methemoglobinemia
29 Chapter 29: Ethics, Research Methods, Administration & Abdominal Ultrasound
29.1 Advance Care Planning, Nonbeneficial Treatment, Informed Consent & Confidentiality 29.2 Critical Care Research Methods, Statistics, IRB Oversight & Quality Improvement 29.3 Abdominal, Vascular & Procedural Point-of-Care Ultrasound
4.4 Nonthrombotic Embolism (Air, Fat, Amniotic Fluid, Tumor, Septic) & Acute Chest Syndrome
Key Takeaways Explain This Topic AI
Venous air embolism during central line insertion or removal causes sudden hypoxemia, hypotension, and a fall in end-tidal CO2; stop air entry, give 100% oxygen, and place the patient left side down.
Fat embolism syndrome appears 24 to 72 hours after long-bone or pelvic fracture with hypoxemia, confusion, and petechiae over the axillae, conjunctivae, and upper chest.
Amniotic fluid embolism causes sudden hypoxemia and cardiovascular collapse during labor or soon after delivery, followed by consumptive coagulopathy that needs early fibrinogen replacement.
Lemierre syndrome is internal jugular vein septic thrombophlebitis, usually from Fusobacterium necrophorum after pharyngitis, with septic pulmonary emboli.
Acute chest syndrome is a new infiltrate in sickle cell disease with fever or respiratory findings; exchange transfusion is indicated for rapid progression or worsening hypoxemia despite simple transfusion.
Last updated: October 2026
Venous and Arterial Air Embolism
Sources include:
Central venous catheter insertion or removal, especially with the patient upright or inspiring.
Disconnected lines.
Pressurized infusions and hemodialysis circuits.
Sitting-position neurosurgery, laparoscopy, and penetrating chest trauma.
Barotrauma during mechanical ventilation.
Rapid entry of a few milliliters per kilogram of air can obstruct the right ventricular outflow tract (an "air lock").
Presentation : sudden dyspnea, hypoxemia, hypotension, a sudden fall in end-tidal CO2 (dead space), a "mill-wheel" murmur, and acute right ventricular strain. Arterial gas embolism reaches the brain or coronaries through a patent foramen ovale or across the pulmonary bed. It presents with stroke-like deficits, seizures, or myocardial ischemia.
Management :
Stop the entry : clamp or occlude the line, cover the site with an occlusive dressing, and flood the field with saline.
Give 100% oxygen to wash out nitrogen and shrink the bubbles.
Position : left lateral decubitus with head down (the Durant maneuver) for venous air embolism, to keep air in the right atrial apex away from the outflow tract. The evidence is limited, and positioning must not delay resuscitation.
Aspirate through a catheter already positioned in the right atrium, if one is present.
Start CPR if the patient arrests; chest compressions can break up an air lock.
Arrange hyperbaric oxygen for arterial gas embolism with neurological or cardiac deficits.
Prevention : place jugular and subclavian catheters with the patient head down, remove them supine or head down during exhalation or Valsalva, apply an occlusive dressing, and keep the patient supine briefly afterward.
Fat Embolism Syndrome
Fat embolism syndrome follows long-bone (especially femoral) or pelvic fractures and intramedullary reaming. Less common causes are orthopedic surgery, liposuction, pancreatitis, and bone marrow necrosis in sickle cell disease. Fat globules lodge in capillaries and release free fatty acids that cause endothelial injury.
Timing : 24 to 72 hours after the injury.
Classic triad :
Respiratory distress with hypoxemia (often an ARDS-like picture).
Neurological changes, from confusion to coma.
A petechial rash over the axillae, conjunctivae, oral mucosa, and upper chest (present in a minority).
Supporting findings : thrombocytopenia, anemia, retinal hemorrhages, fat globules in urine or sputum, and a "starfield" pattern of diffuse punctate diffusion restriction on brain MRI. Diagnosis is clinical (Gurd and Wilson criteria).
Management : supportive, with lung-protective ventilation and hemodynamic support. Early fracture fixation , within about 24 hours, lowers the incidence. Routine corticosteroids are not recommended for treatment.
Amniotic Fluid Embolism
Amniotic fluid embolism occurs during labor, cesarean delivery, or within about 30 minutes after delivery . It presents with:
Sudden hypoxemia, hypotension, or cardiac arrest.
Often seizures or altered mental status.
Disseminated intravascular coagulation with massive hemorrhage .
The mechanism is an anaphylactoid reaction with acute pulmonary hypertension and right ventricular failure, followed by left ventricular failure. There is no confirmatory test; it is a clinical diagnosis of exclusion.
Management :
High-quality CPR with manual left uterine displacement .
Perimortem (resuscitative) cesarean delivery if there is no return of circulation by about 4 minutes, aiming to deliver within 5 minutes. This also improves maternal hemodynamics.
A massive transfusion protocol with early fibrinogen replacement (cryoprecipitate or concentrate).
Right ventricular support with inhaled pulmonary vasodilators, dobutamine or milrinone, and norepinephrine.
VA-ECMO at capable centers.
Tumor Embolism
Microscopic tumor emboli most often come from:
Breast, gastric, lung, and prostate cancer.
Hepatocellular and renal cell carcinoma.
They cause subacute, progressive dyspnea and pulmonary hypertension with right heart failure , while CT pulmonary angiography is often normal or shows only subtle peripheral changes. Pulmonary tumor thrombotic microangiopathy, classically from gastric adenocarcinoma, adds fibrocellular intimal proliferation and rapid deterioration. Cytology of blood aspirated through a wedged pulmonary artery catheter can show malignant cells. The prognosis is poor. Large tumor emboli can arise from renal cell carcinoma extending up the IVC, or from atrial myxoma.
Septic Pulmonary Emboli
Sources :
Right-sided endocarditis (people who inject drugs, typically S. aureus ).
Infected central catheters or pacemaker leads.
Pelvic septic thrombophlebitis.
Lemierre syndrome : septic thrombophlebitis of the internal jugular vein after pharyngitis or a peritonsillar abscess, usually from Fusobacterium necrophorum . It presents with neck pain and swelling, persistent fever, and septic emboli.
Imaging : multiple peripheral nodules of varying age that cavitate , often with a feeding-vessel sign.
Treatment :
Prolonged antibiotics; for Lemierre syndrome, a beta-lactam such as ampicillin-sulbactam or a carbapenem, or metronidazole combined with a cephalosporin.
Source control (catheter removal, drainage, or valve surgery when indicated).
Anticoagulation for Lemierre thrombus is individualized.
Acute Chest Syndrome in Sickle Cell Disease
Definition : a new pulmonary infiltrate involving at least one complete lung segment, plus fever, chest pain, tachypnea, wheezing, cough, or hypoxemia.
Triggers :
Infection (atypical bacteria and respiratory viruses).
Fat embolism from bone marrow infarction .
Hypoventilation from rib infarction or opioids.
Surgery and anesthesia.
The syndrome can progress within hours to severe respiratory failure.
Management :
Oxygen for hypoxemia.
Analgesia balanced against hypoventilation.
Incentive spirometry, which also prevents the syndrome during vaso-occlusive crises.
Empiric cephalosporin plus macrolide .
Bronchodilators for wheeze.
Avoid fluid overload.
Simple transfusion when the hemoglobin has fallen about 1 g/dL or more below baseline.
Exchange transfusion for rapid progression:
Oxygen saturation below 90% despite supplemental oxygen.
Increasing respiratory distress.
Spreading infiltrates.
A falling hemoglobin despite simple transfusion.
The aim is to reduce hemoglobin S to below about 30% without raising total hemoglobin above about 10 g/dL, which increases viscosity.