Critical Care Medicine: Common ICU Conditions — Shock and Sepsis
Pulmonary and Critical Care Medicine · Critical Care Medicine 🎯 Practice these cards
Shock exists whenever systemic tissue perfusion is insufficient to meet cellular ____ needs, forcing cells to switch from aerobic to ____ metabolism.
Shock exists whenever systemic tissue perfusion is insufficient to meet cellular oxygen needs. Early, cells switch from aerobic to anaerobic metabolism and the resulting tissue injury is still reversible; once compensatory mechanisms are exhausted, sustained hypoperfusion progresses to cellular dysfunction and death. Shock is recognized by end-organ hypoperfusion, not by the blood pressure number alone.
Mean arterial pressure is determined by ____ × ____; cool extremities with a narrow pulse pressure point to a ____-output state.
Mean arterial pressure is set by cardiac output and systemic vascular resistance (MAP ≈ CO × SVR). Warm extremities with a wide pulse pressure suggest a high-output (distributive) process, whereas cool extremities with a narrow pulse pressure point to a low-output state (hypovolemic, cardiogenic, or obstructive).
The four primary categories of shock are distributive, ____, ____, and obstructive.
Four primary mechanisms produce shock: reduced circulating volume (hypovolemic), pump failure (cardiogenic), circulatory obstruction (obstructive), and inappropriate vasodilation (distributive); they frequently overlap in the same patient.
Representative causes of distributive shock include ____ (most common), anaphylaxis, vasodilator drugs, and spinal cord injury above ____.
Distributive shock reflects excessive vasodilation and microvascular dysfunction (↓SVR) with normal volume and often increased cardiac output. Causes: sepsis (most common), anaphylaxis, drugs (peripheral vasodilators, nitrates), and spinal cord injury (usually above T4).
Hypovolemic shock results from reduced circulating volume; representative causes include acute ____, GI losses, cutaneous losses from burns, and renal losses from ____.
Hypovolemic shock results from reduced circulating volume (↓preload, ↓stroke volume). Causes include acute blood loss (trauma, GI bleeding, surgery, obstetric, aortic rupture), cutaneous losses (burns, toxic epidermal necrolysis), GI losses (vomiting, diarrhea), and renal losses (diabetic ketoacidosis, hyperglycemic hyperosmolar syndrome, adrenal insufficiency).
Obstructive shock occurs when extracardiac forces impair cardiac output despite normal cardiac function; causes include ____, cardiac tamponade, and ____.
Obstructive shock occurs when extracardiac forces impair cardiac output despite normal cardiac function, and hemodynamics often mimic cardiogenic shock. Causes include pulmonary embolism, cardiac tamponade, tension pneumothorax, constrictive pericarditis, atrial myxoma, and abdominal compartment syndrome. Most causes are rapidly reversible once identified.
Clinical findings of shock include altered mentation, capillary refill time > ____ seconds, serum lactate > ____ mEq/L, and urine output < ____ mL/kg/h.
Common clinical findings in shock: altered mentation, capillary refill time >2 seconds, elevated serum lactate (>3 mEq/L [3 mmol/L]), hypotension (SBP <90 mm Hg or a drop >30 mm Hg from baseline), mottled skin, tachycardia (>100/min), tachypnea (>20/min), and urine output <0.5 mL/kg/h.
Sepsis-3 defines sepsis as life-threatening organ dysfunction caused by a dysregulated ____ response to infection (SOFA score ≥ ____); septic shock additionally requires vasopressors to maintain MAP > 65 mm Hg and lactate > ____ mmol/L despite adequate fluids.
Sepsis-3 defines sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection, operationalized by a SOFA score of 2 or higher (predicting hospital mortality >10%). Septic shock is defined as hypotension requiring vasopressors to maintain MAP >65 mm Hg AND serum lactate >2 mmol/L despite adequate fluid resuscitation; in-hospital mortality then exceeds 40%.
The three qSOFA criteria are respiration rate ≥ ____/min, systolic blood pressure ≤ ____ mm Hg, and ____.
The quick SOFA (qSOFA) score uses three bedside criteria, each worth 1 point: respiration rate ≥22/min, systolic blood pressure ≤100 mm Hg, and altered mental status. A score ≥2 in the setting of known or suspected infection predicts mortality >10% — but qSOFA <2 does not rule out sepsis, and its pooled sensitivity is poor (~65%), so it should not be used as a single screening tool.
Elements of the 1-hour sepsis bundle: obtain ____ cultures, measure serum ____, administer broad-spectrum ____, and begin fluid or vasopressor resuscitation.
The 1-hour sepsis bundle (consolidated in 2018 from the older 3- and 6-hour bundles): obtain blood cultures, measure serum lactate, administer broad-spectrum antibiotics, and begin fluid or vasopressor resuscitation in patients with hypotension or signs of hypoperfusion. The bundle captures the two pillars of sepsis management: supporting organ perfusion and controlling the infection.
When hypotension or lactate ≥4 mmol/L is present, initial sepsis resuscitation is ____ mL/kg of ____ within the first hour.
Current guidance recommends an initial bolus of 30 mL/kg of crystalloid within the first hour when hypotension or lactate ≥4 mmol/L is present; lactate >2 mmol/L should be rechecked within 2-4 hours. Crystalloid is the resuscitation fluid of choice (no clear superiority of colloid). In CLOVERS, an early restrictive fluid strategy with immediate vasopressors was not superior to a liberal strategy (90-day mortality ~14% vs ~15%), favoring individualized resuscitation.
The first-line vasopressor in septic shock is ____; ____ is not recommended except for select patients with clinically significant bradycardia.
Norepinephrine is the first-line vasopressor because it raises systemic vascular resistance without compromising myocardial performance. If insufficient, epinephrine, vasopressin, or dobutamine may be added. Dopamine is not recommended except for select patients with clinically significant bradycardia (more tachyarrhythmia and death than norepinephrine); phenylephrine can lower stroke volume and is reserved for salvage therapy. All patients on vasopressors should have an arterial catheter.
Broad-spectrum antibiotics should be given within the first ____ of suspected sepsis; the typical duration is ____ to ____ days.
Broad-spectrum antibiotics should be given within the first hour of suspected sepsis; in bacterial septic shock, each hour's delay is associated with roughly a 7-8% rise in mortality. In septic shock, combination therapy with at least two antibiotics from different classes is recommended. Typical duration is 7-10 days; the BALANCE trial showed 7 days was noninferior to 14 days for documented bloodstream infection (90-day mortality 14.5% vs 16.1%).
For refractory septic shock, the Surviving Sepsis Campaign recommends hydrocortisone ____ mg/day (maximum ____ mg/day); glucocorticoids have no role in sepsis without ____.
The Surviving Sepsis Campaign recommends hydrocortisone 200 mg/day for refractory septic shock (hemodynamic instability despite fluids and vasopressors), with a maximum of 400 mg/day (SCCM/ESICM 2017); glucocorticoids have no role in sepsis without shock. The SCCM 2024 update conditionally suggests corticosteroids in septic shock, strongly recommends against high-dose short-duration regimens (>400 mg/day hydrocortisone equivalent for <3 days), and strongly recommends them in severe bacterial community-acquired pneumonia.
In critically ill septic patients, the recommended upper glucose target is < ____ mg/dL; tight control at 80-110 mg/dL increases severe ____.
The Surviving Sepsis Campaign recommends an upper glucose limit below 180 mg/dL; tight control targeting 80-110 mg/dL produced higher rates of severe hypoglycemia (<40 mg/dL), sometimes fatal. Patients should receive early oral feeding when possible and early enteral nutrition if oral intake is not feasible; at-risk for malnutrition once ICU stay exceeds 48 hours.
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