ICU Infectious Diseases & Sepsis
Septic shock, multidrug-resistant pathogens, VAP, candidemia, and antimicrobial stewardship.
Core Topics
9 topicsVentilator-Associated Pneumonia (VAP)
Quantitative lower tract sampling (ETA vs BAL), rapid multiplex PCR panels and stewardship interpretation, PK/PD extended beta-lactams, 7-day duration, and the SHEA prevention bundle.
Hospital-Acquired Pneumonia (HAP)
Nosocomial pneumonia developing ≥ 48 hours after admission in non-ventilated patients, host and antibiogram MDR risk tailoring, nasal MRSA PCR screening, and 7-day de-escalation.
Multidrug-Resistant (MDR) Pathogens & IDSA AMR Guidance
Molecular resistance mechanisms (ESBL, AmpC, KPC, NDM, OXA-48, DTR-Pseudomonas, CRAB), the MERINO trial, and modern novel beta-lactamase inhibitor therapeutics.
Sepsis
Life-threatening organ dysfunction caused by a dysregulated host response to infection — recognized by an acute rise in SOFA score, not by infection plus fever alone.
Necrotizing Soft Tissue Infections (NSTI)
A surgical source-control emergency: recognize rapidly progressive deep infection, involve surgery immediately, start broad antimicrobials, resuscitate shock, and re-explore until source control is complete.
Immunocompromised & Oncologic Critical Illness
Host immune defects, neutropenic sepsis, acute respiratory failure (PJP/Aspergillus), tumor lysis syndrome, leukostasis, CAR-T CRS/ICANS, and ICU triage.
Candidemia & Invasive Candidiasis
ICU recognition and treatment of candidemia and invasive candidiasis, including source control, repeat cultures, step-down therapy and metastatic infection.
Fulminant C. difficile Colitis
Recognition and rescue management of fulminant C. difficile infection with shock, ileus or toxic megacolon.
Febrile Neutropenia & Neutropenic Sepsis
Time-critical ICU management of fever and organ dysfunction during neutropenia, with early antipseudomonal therapy and source-directed escalation.
Clinical Problems & Bedside Triage
12 guidesNew Tachycardia & Tachyarrhythmias
Algorithmic triage of acute heart rates > 100–150 bpm: stability screen (immediate cardioversion if unstable), narrow vs wide QRS differentiation, Brugada VT rules, and sinus tachycardia etiology search.
Acute Altered Mental Status & ICU Delirium
Systematic neurologic evaluation: immediate metabolic/toxic screening (glucose, hypoxia, hypercapnia), nonconvulsive status epilepticus exclusion, structural CT triage, and CAM-ICU delirium management.
New Fever in the ICU & Suspected Infection
Systematic diagnostic workup of new ICU fever (T ≥ 38.3°C): line and device screening, pulmonary/abdominal/urinary source triage, distinguishing infectious vs non-infectious fever, and rational blood culturing.
Suspected Sepsis & Early Septic Shock
SSC 2026 sepsis recognition and resuscitation: rapid infection-likelihood assessment, timely antimicrobials, individualized initial crystalloids, early norepinephrine, serial perfusion reassessment, and source control.
Persistent Fever Despite Broad-Spectrum Antibiotics
Evaluating unresolved fever after 48–72 hours of antimicrobial therapy: undrained closed-space infection, resistant/fungal pathogens, catheter infections, C. difficile, drug fever, and ICU thrombosis.
Immunocompromised Patient with Fever + Organ Failure
Bedside diagnostic framing and emergency management of acute fever, sepsis, respiratory failure, or oncologic emergency in an immunocompromised host.
New Thrombocytopenia & Coagulopathy in the ICU
Differential diagnosis of acute platelet drops and clotting derangements: 4Ts-based HIT assessment, dynamic disease-specific DIC scoring, recognition of thrombotic microangiopathy/TTP, and targeted replacement or anticoagulant therapy.
Critically Ill Pregnant or Postpartum Patient
Maternal-first stabilization with rapid differentiation of hypertensive, hemorrhagic, thromboembolic, septic, hepatic and cardiac obstetric emergencies.
Persistent Fungemia / New Candidemia
Candida in blood is clinically significant: start appropriate antifungal therapy, document clearance, address intravascular/abdominal sources and determine duration from bloodstream clearance.
Shock with Ileus and Suspected Fulminant C. difficile Colitis
Fulminant CDI with shock, ileus or megacolon requires high-dose enteral vancomycin, IV metronidazole, ileus-directed drug delivery and early surgical rescue planning.
Neutropenic Fever with Organ Dysfunction
Fever during neutropenia with evolving shock, respiratory failure or occult infection.
Pneumonia Not Improving in the ICU
A progressive bedside problem for apparent pneumonia with persistent hypoxemia, fever or shock despite initial therapy.
Physiology Modules & Waveforms
4 conceptsOxygen Consumption
Under normal conditions, VO2 is set by metabolic demand, and the body adjusts oxygen extraction (and, if needed, cardiac output) to meet it — DO2 normally exceeds VO2 several-fold, leaving a wide margin of reserve. Critical illness increases metabolic demand (fever, sepsis, increased work of breathing) while simultaneously threatening the ability to increase DO2 to match, narrowing that reserve. Extraction ratio (VO2/DO2) rises as this margin shrinks, which is reflected clinically as a falling mixed or central venous oxygen saturation (SvO2/ScvO2).
DO2/VO2 Relationship
This produces a two-part relationship: a flat plateau where VO2 is supply-independent, and a steep segment below the critical DO2 threshold where VO2 falls linearly with DO2. The transition point is the critical DO2 — below it, tissues can no longer meet metabolic demand through extraction alone, and anaerobic metabolism begins, producing lactate. The critical threshold isn't fixed; it shifts with metabolic demand, so a febrile, agitated, or septic patient reaches supply-dependency at a higher DO2 than one who is sedated and afebrile.
Contractility
Reduced contractility (from ischemia, sepsis-associated cardiomyopathy, or chronic heart failure) shifts the Frank-Starling curve downward and to the right: for any given preload, stroke volume is lower, and the curve plateaus earlier. Increased contractility (endogenous catecholamines, inotropic drugs) shifts the curve upward. Because contractility is a separate axis from preload, a patient can be both volume-overloaded and have poor contractility at the same time — more fluid won't help, and may worsen congestion, while an inotrope shifts the whole curve rather than just moving along it.
Systemic Vascular Resistance
Blood pressure is the product of cardiac output and SVR (MAP ≈ CO × SVR), so the same blood pressure can arise from very different underlying physiology — a high-CO, low-SVR state (distributive/septic shock) versus a low-CO, high-SVR state (cardiogenic shock). Vasodilation from inflammatory mediators (sepsis, SIRS) or from vasodilating drugs lowers SVR; compensatory sympathetic vasoconstriction, or vasopressor therapy, raises it.
Clinical Reasoning Cases
8 casesSeptic Shock Resuscitation
2026 SSC-aligned fluids, early norepinephrine, dynamic reassessment, and perfusion endpoints
Refractory Septic Shock: Multi-Vasoactive Strategy
Escalating vasopressor requirements after initial resuscitation and source control
Ventilator-Associated Pneumonia Due to DTR Pseudomonas
Susceptibility-directed treatment with newer antipseudomonal beta-lactams
Invasive Candidemia in the Critically Ill
Early echinocandin therapy, source control, clearance cultures, and selective metastatic-focus evaluation
Persistent MRSA Bacteremia
Source-control reassessment and salvage therapy for persistent Staphylococcus aureus bloodstream infection
Fulminant Clostridioides difficile Infection
Antimicrobial therapy, ileus management, early surgery, and selected microbiota rescue
Mixed Septic and Cardiogenic Shock
Sepsis-induced myocardial dysfunction with vasoplegia and low forward flow