24.3 Obstetric & Genitourinary Emergencies and the Physiology of Pregnancy

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

24.3 Obstetric & Genitourinary Emergencies and the Physiology of Pregnancy

Key Takeaways Explain This Topic AI

Normal pregnancy produces a compensated respiratory alkalosis with a PaCO2 of about 28 to 32 mmHg, so a PaCO2 of 40 mmHg in a breathless pregnant patient indicates impending respiratory failure.

Magnesium sulfate is given for seizure prophylaxis in preeclampsia with severe features and for treatment of eclamptic seizures, with loss of deep tendon reflexes as the earliest sign of toxicity.

Resuscitative cesarean delivery should begin by about 4 minutes into maternal cardiac arrest, aiming for delivery within 5 minutes, and it improves maternal hemodynamics.

After 20 weeks of gestation, manual left uterine displacement is used during CPR rather than a left lateral tilt, which degrades compression quality.

Obstructed, infected upper urinary tract requires urgent decompression with a ureteral stent or percutaneous nephrostomy; antibiotics alone do not control the source.

Last updated: October 2026

Physiologic Changes That Change ICU Decisions

System Change by the third trimester Implication

Cardiovascular Cardiac output up 30% to 50%, heart rate up 15 to 20 bpm, systemic vascular resistance down, blood pressure slightly lower A "normal" blood pressure of 140/90 mmHg is hypertension; aortocaval compression after 20 weeks reduces venous return when supine

Blood Plasma volume up about 50% with a smaller red cell mass increase: dilutional anemia ; a hypercoagulable state Blood loss is tolerated until late, then decompensation is abrupt; venous thromboembolism risk rises several-fold

Respiratory Minute ventilation up 30% to 50%, PaCO2 about 28 to 32 mmHg with a compensated respiratory alkalosis (bicarbonate around 18 to 22 mEq/L), functional residual capacity down about 20%, oxygen consumption up Rapid desaturation during apnea ; a PaCO2 of 40 mmHg in a dyspneic patient means impending failure; difficult airway from edema and increased Mallampati grade

Renal GFR up about 50%; creatinine normally 0.4 to 0.6 mg/dL A creatinine of 1.0 mg/dL is abnormal

Gastrointestinal Lower esophageal sphincter tone reduced, delayed emptying High aspiration risk: rapid-sequence intubation with cricoid pressure considered, smaller tube sizes for edematous airways

Intubation in pregnancy calls for optimal preoxygenation, a smaller endotracheal tube (6.5 to 7.0 mm), video laryngoscopy, the most experienced operator, and preparation for a difficult airway.

Hypertensive Disorders of Pregnancy

Preeclampsia with severe features : systolic 160 mmHg or more or diastolic 110 mmHg or more, thrombocytopenia, kidney injury, elevated transaminases, pulmonary edema, or new cerebral or visual symptoms. Proteinuria is not required for diagnosis when severe features are present.

Treatment :

Blood pressure control with IV labetalol, hydralazine, or oral immediate-release nifedipine, targeting a systolic below 160 mmHg and a diastolic below 110 mmHg while avoiding precipitous drops that compromise placental perfusion.

Magnesium sulfate (4 to 6 g load, then 1 to 2 g/h) for seizure prophylaxis in severe features, and for treating eclamptic seizures. Monitor reflexes, respirations, and urine output; loss of deep tendon reflexes is the earliest sign of toxicity , and calcium gluconate is the antidote. Reduce the dose in kidney impairment.

Delivery is the definitive treatment; timing depends on gestational age and severity, with corticosteroids for fetal lung maturity when appropriate.

Avoid ACE inhibitors, ARBs, and nitroprusside (fetal cyanide risk).

HELLP syndrome : H emolysis, E levated L iver enzymes, L ow P latelets. Watch for hepatic subcapsular hematoma and rupture, disseminated intravascular coagulation, and acute kidney injury. Treatment is delivery with supportive transfusion; corticosteroids improve laboratory values but not clinical outcomes.

Eclampsia : magnesium is the treatment for seizures (superior to phenytoin and diazepam), with delivery and airway protection. Consider PRES and intracranial hemorrhage if seizures recur or focal signs appear.

Postpartum presentations : preeclampsia and eclampsia can occur up to 6 weeks postpartum, so do not dismiss severe headache or hypertension in a recently delivered patient.

Acute fatty liver of pregnancy : third-trimester nausea, jaundice, hypoglycemia , coagulopathy, and kidney injury; the treatment is urgent delivery and supportive care, including glucose.

Hemorrhage and Other Obstetric Emergencies

Postpartum hemorrhage: the four Ts :

Tone (uterine atony, which is the most common): uterine massage, oxytocin , then misoprostol, methylergonovine (avoid in hypertension), and carboprost (avoid in asthma); tranexamic acid within 3 hours (the WOMAN trial reduced death from bleeding); intrauterine balloon tamponade, uterine artery embolization, compression sutures, and hysterectomy.

Trauma (lacerations, uterine rupture, inversion): repair and reposition.

Tissue (retained placenta, placenta accreta spectrum): removal, with planned multidisciplinary delivery for accreta.

Thrombin (coagulopathy, including amniotic fluid embolism and abruption): targeted blood product therapy with early fibrinogen.

Placental abruption : painful bleeding with a tense uterus, often with disseminated intravascular coagulation and fetal distress.

Amniotic fluid embolism : sudden collapse with coagulopathy (see the nonthrombotic embolism section).

Peripartum cardiomyopathy and pulmonary embolism in pregnancy: the leading cardiovascular causes of maternal death; diagnostic imaging (CT pulmonary angiography or perfusion scanning) should not be withheld because of pregnancy.

Sepsis in pregnancy : chorioamnionitis, endometritis, septic abortion, pyelonephritis (common and often severe), and group A streptococcal infection. Thresholds for ICU admission should be low, given the physiologic reserve masking deterioration.

Cardiac Arrest in Pregnancy

High-quality CPR with hands in the standard position.

Manual left uterine displacement after 20 weeks of gestation (or when the uterus is at or above the umbilicus), rather than a left lateral tilt, which degrades compressions.

Early airway management because of hypoxemia risk and aspiration.

Standard drugs and defibrillation energies ; do not withhold or reduce them.

Resuscitative (perimortem) cesarean delivery : prepare immediately and begin by about 4 minutes if there is no return of spontaneous circulation, aiming to deliver within 5 minutes. It relieves aortocaval compression and improves maternal hemodynamics; it is a maternal resuscitation intervention and is performed where the patient lies, not in an operating room.

Search for specific causes: hemorrhage, amniotic fluid embolism, pulmonary embolism, magnesium toxicity, local anesthetic toxicity (give lipid emulsion), eclampsia, sepsis, and anaphylaxis.

Magnesium toxicity causing arrest is treated with calcium gluconate.

Genitourinary Emergencies

Condition Features Management

Obstructive uropathy with infection Flank pain, fever, sepsis, hydronephrosis from stone, tumor, or stricture Urgent decompression with a ureteral stent or percutaneous nephrostomy plus antibiotics; antibiotics alone do not achieve source control

Emphysematous pyelonephritis Gas in the renal parenchyma, usually in diabetes Antibiotics plus drainage; nephrectomy for extensive disease

Fournier gangrene Necrotizing fasciitis of the perineum; pain out of proportion, crepitus, rapid progression Immediate wide surgical debridement , broad-spectrum antibiotics with clindamycin or linezolid for toxin suppression, and resuscitation

Renal infarction Sudden flank pain with a very high LDH and hematuria, often with atrial fibrillation Anticoagulation; endovascular therapy in selected cases

Renal and bladder trauma Hematuria after blunt or penetrating injury Most renal injuries are managed nonoperatively; intraperitoneal bladder rupture requires surgical repair, extraperitoneal usually catheter drainage

Urinary retention and post-obstructive diuresis Massive diuresis after relief of chronic obstruction Monitor and replace volume and electrolytes; avoid overcorrection

Priapism Ischemic (low-flow) priapism is a compartment syndrome of the penis, often from sickle cell disease or drugs Urgent aspiration and irrigation with phenylephrine; urology involvement

Testicular torsion Acute scrotal pain with a high-riding testis and absent cremasteric reflex Immediate surgical exploration; the window is about 6 hours

Rhabdomyolysis with compartment syndrome Limb pain, pressures above 30 mmHg Fasciotomy, aggressive fluid, monitoring for kidney injury

Note

Two rules from this section recur on examinations: an infected obstructed kidney needs drainage, not just antibiotics , and in pregnancy, a normal PaCO2 is an abnormal finding .