Study guide
25.2 Post-Cardiac Surgery Critical Care: Bleeding, Tamponade, Low Output & Vasoplegia
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
25.2 Post-Cardiac Surgery Critical Care: Bleeding, Tamponade, Low Output & Vasoplegia
Key Takeaways Explain This Topic AI
Chest tube output above about 300 to 400 mL/h, or 1.5 L in 24 hours, with hemodynamic instability indicates surgical re-exploration rather than more blood products.
Localized postoperative tamponade can occur with a small or loculated collection, so pericardial clot must be excluded by echocardiography even when the chest radiograph looks unremarkable.
Vasoplegic syndrome after cardiopulmonary bypass is treated with vasopressin, with methylene blue and hydroxocobalamin as rescue options for refractory cases.
A sudden cessation of chest tube drainage in a bleeding patient suggests tube obstruction by clot and impending tamponade.
Postoperative atrial fibrillation occurs in roughly a quarter to a third of cardiac surgery patients, peaks on days 2 to 3, and is reduced by perioperative beta-blockade and amiodarone prophylaxis.
Last updated: October 2026
The First Hours: A Systematic Handover
A structured handover covers the operation and bypass details (cross-clamp and bypass times, cardioplegia, difficulty weaning), grafts or valves placed, intraoperative transesophageal echocardiography findings, blood products given, lines and drains, pacing wires and the underlying rhythm, and the planned extubation pathway.
Routine early goals :
Normothermia with controlled rewarming; shivering raises oxygen consumption and causes hypertension.
Blood pressure control to protect anastomoses and suture lines; aortic surgery requires tighter limits.
Fast-track extubation within 2 to 6 hours in uncomplicated patients, using protocols with short-acting sedation. Early extubation reduces pneumonia and ICU stay.
Glucose 140 to 180 mg/dL by infusion.
Transfusion : restrictive thresholds are safe in cardiac surgery (TRICS III supported a threshold around 7.5 g/dL).
Pain control with multimodal analgesia to permit deep breathing and mobilization.
The Postoperative Instability Differential
Cause Discriminating findings Action
Hemorrhage High chest tube output, falling hematocrit, rising lactate, coagulopathy Correct coagulopathy with targeted products and point-of-care testing; re-explore for surgical bleeding
Tamponade Rising filling pressures, narrowing pulse pressure, low output, sudden cessation of chest tube drainage , falling urine output Echocardiography (often transesophageal); urgent re-exploration or sternotomy at the bedside if arresting
Low cardiac output syndrome Low cardiac index with high filling pressures, cool extremities, rising lactate Optimize rate and rhythm, preload and afterload; inotropes; mechanical support if refractory
Vasoplegia Low systemic vascular resistance with normal or high cardiac output Vasopressin, norepinephrine, methylene blue
Graft failure or ischemia New ST changes, regional dysfunction, ventricular arrhythmias Urgent echocardiography, angiography, or return to the operating room
Arrhythmia Atrial fibrillation, bradycardia, complete block Pacing wires, rate control or cardioversion, electrolytes
Right ventricular failure High central venous pressure with a low wedge pressure, poor RV function Inotropes, inhaled pulmonary vasodilators, avoid volume overload
Pneumothorax or hemothorax Unilateral findings, high airway pressures Decompress
Bleeding thresholds for re-exploration vary by institution but commonly include output above about 300 to 400 mL/h for 1 to 2 hours, above 1.5 L in 24 hours, or any output with hemodynamic instability or tamponade. Re-exploration finds a surgical source in about half of cases; the rest are coagulopathic, but evacuating clot still helps. Do not simply transfuse a surgically bleeding patient.
Coagulopathy management uses point-of-care viscoelastic testing: protamine for residual heparin effect, platelets for antiplatelet drug effect or dysfunction, fibrinogen (cryoprecipitate or concentrate), prothrombin complex concentrate for factor deficiency, and tranexamic acid. Desmopressin helps with uremic or aspirin-related platelet dysfunction.
Post-Cardiotomy Vasoplegic Syndrome
Definition : hypotension with a low systemic vascular resistance and preserved or high cardiac output within hours of bypass, often needing escalating vasopressors.
Mechanisms : inflammatory activation during bypass with nitric oxide and cyclic GMP excess, vasopressin depletion, ATP-sensitive potassium channel activation, and preoperative renin-angiotensin blockade.
Risk factors : preoperative ACE inhibitor or ARB use, long bypass times, poor ventricular function, heart failure therapy, and amiodarone.
Therapy ladder :
Norepinephrine and volume optimization.
Vasopressin (0.01 to 0.06 units/min), which is particularly effective because of relative deficiency after bypass.
Methylene blue (1 to 2 mg/kg) inhibits nitric oxide synthase and guanylate cyclase; avoid with serotonergic drugs (serotonin syndrome) and in G6PD deficiency, and note it discolors urine and interferes with pulse oximetry.
Hydroxocobalamin (5 g) is a nitric oxide scavenger used as rescue.
Angiotensin II is an option in vasodilatory shock.
Hydrocortisone for suspected relative corticosteroid insufficiency.
Rhythm Problems and Pacing
Postoperative atrial fibrillation affects roughly a quarter to a third of patients, peaking on days 2 to 3 . Prophylaxis with perioperative beta-blockers (continued unless contraindicated) and amiodarone reduces incidence. Treat with rate control, magnesium and potassium repletion, and cardioversion for instability; anticoagulation decisions weigh stroke risk against fresh surgical bleeding.
Epicardial pacing wires : know the configuration (atrial, ventricular, or both). Use atrial pacing to improve output in sinus bradycardia with preserved conduction, and AV sequential pacing when the atrial contribution matters, particularly in hypertrophied or stiff ventricles.
Complete heart block after valve surgery (especially aortic or tricuspid) can be transient; permanent pacing decisions are made after a period of observation.
Ventricular arrhythmias suggest ischemia, graft failure, electrolyte disturbance, or reperfusion injury.
Other Specific Postoperative Problems
Post-cardiotomy shock requiring mechanical support: intra-aortic balloon pump, Impella, or VA-ECMO. Central cannulation is often used early after sternotomy.
Stroke and delirium : watch for embolic stroke from aortic manipulation or atrial fibrillation; delirium is extremely common and responds to the ABCDEF bundle approach.
Acute kidney injury : multifactorial; avoid nephrotoxins and hypotension, and recognize that a low cardiac output state is often the cause.
Mediastinitis and sternal wound infection : fever, instability of the sternum, and purulent drainage; needs debridement and prolonged antibiotics, with risk factors including diabetes, obesity, and bilateral internal mammary harvesting.
Protamine reaction : hypotension, pulmonary hypertension, and anaphylaxis during or shortly after protamine administration.
Heparin-induced thrombocytopenia : suspect a platelet drop around days 5 to 10 with thrombosis; cardiac surgery itself causes an early, expected postoperative platelet fall that recovers.
Transfusion-related acute lung injury and circulatory overload : distinguish by filling pressures and response to diuresis.
Post-pericardiotomy syndrome : fever, pleuritic pain, and effusion weeks later; treat with NSAIDs and colchicine.
Gastrointestinal complications : mesenteric ischemia after bypass carries very high mortality; a rising lactate with abdominal pain after cardiac surgery warrants urgent imaging.
Phrenic nerve injury from cold cardioplegia or dissection causes diaphragmatic paresis and failure to wean.
Vocal cord paralysis after aortic arch surgery causes aspiration and stridor.