Critical Care Medicine: Principles of Critical Care — Respiratory and Hemodynamic Support
Pulmonary and Critical Care Medicine · Critical Care Medicine 🎯 Practice these cards
The three conditions prompting ICU admission for respiratory insufficiency are acute ____ respiratory failure, acute ____ (ventilatory) failure, and ____ impairment.
Admission to the ICU for respiratory insufficiency is driven by one of three conditions: acute hypoxemic respiratory failure (a shunt problem — treat with FiO2 plus PEEP), acute hypercapnic/ventilatory failure (a pump problem — treat with ventilatory support), or upper airway impairment (obstruction or inability to protect the airway — secure the airway).
Patients receiving oxygen therapy should generally be kept at SpO2 ≤ ____%, and oxygen should not be started at all in acute MI or stroke when SpO2 is ≥ ____%.
Supplementing oxygen to patients whose saturation is already 96% or higher may increase mortality; patients on oxygen should generally be kept at SpO2 ≤96%, and oxygen should not be started in acute MI or stroke when SpO2 ≥93%. Exceptions genuinely needing higher targets: carbon monoxide poisoning, cluster headache, sickle cell crisis, and pneumothorax.
The UK-ROX trial compared a conservative SpO2 target of about ____% (range 88–92%) with usual care in mechanically ventilated ICU adults and found no difference in ____-day mortality.
UK-ROX, the largest oxygen-target trial to date (~16,500 mechanically ventilated ICU adults), compared a conservative SpO2 target of about 90% (range 88–92%) with usual care (typically ≥96%) and found no difference in 90-day mortality (35.4% vs 34.9%) or ICU length of stay; a 2026 meta-analysis reached the same conclusion. A middle-range SpO2 of 92–96% is reasonable — avoid sustained hyperoxia.
In COPD, NPPV reduces intubation most clearly for moderate respiratory acidosis (pH ____), while severe acidosis (pH < ____) generally requires intubation; every patient on NPPV must be reevaluated within ____ hours.
In COPD exacerbations, NPPV reduces intubation and shortens stay most clearly for moderate respiratory acidosis (pH 7.25–7.35), while severe acidosis (pH <7.2) generally requires intubation. NPPV is a time-limited trial: every patient must be monitored and reevaluated within 2 hours, and delayed intubation in failing patients increases mortality.
____ control ventilation delivers a set tidal volume regardless of patient effort; in ____ support the patient triggers and cycles every breath; SIMV should NOT be used as a ____ mode.
Volume control delivers a set tidal volume regardless of patient effort, compliance, or resistance (guarantees minute ventilation; safety). Pressure support lets the patient trigger and cycle every breath (comfort, synchrony; used for spontaneous breathing trials). SIMV guarantees a minimum rate with spontaneous breaths between but should NOT be used for weaning — liberation is driven by daily readiness assessment and SBTs.
Lung-protective ventilation targets tidal volumes around ____ mL/kg of ideal body weight with the end-inspiratory plateau pressure kept at or below ____ cm H2O.
Lung-protective ventilation delivers the lowest effective tidal volume (~6 mL/kg of ideal body weight) and keeps the end-inspiratory plateau pressure ≤30 cm H2O, using PEEP to prevent cyclical end-expiratory alveolar collapse (atelectrauma) and overdistension (volutrauma).
An SBT can be performed when FiO2 ≤ ____%, PEEP ≤ 5–8 cm H2O, pH > ____, and hemodynamics are stable; passing requires at least ____ minutes without respiratory distress, SpO2 <90%, or RR >35/min.
Perform an SBT when the cause of respiratory failure has improved, FiO2 ≤40% and PEEP ≤5–8 cm H2O, pH >7.25, and hemodynamics are stable. Use low pressure support (≤8 cm H2O) or a T-piece for 30 minutes to 2 hours; passing requires at least 30 minutes without distress, SpO2 <90%, RR >35/min, new arrhythmia, tachycardia, or blood pressure instability. Pairing daily SBTs with daily awakening reduces ventilation time and mortality.
Patients with risk factors for post-extubation stridor (e.g., intubation > ____ days) should undergo a cuff-leak test; an absent cuff leak implies a roughly ____% risk of stridor.
Patients with risk factors for post-extubation stridor (intubation >7 days, traumatic intubation, large tube, prior stridor, head/neck surgery) should have a cuff-leak test — deflate the cuff and assess for air passing around the tube. An absent cuff leak implies a ~30% risk of post-extubation stridor, and extubation should be delayed until the cause is treated.
A PICC can dwell for days to ____ and is contraindicated in current or pending ____; intraosseous access should be removed within ____ hours of placement.
A PICC (days to 1 year) is used for caustic medications and central access, carries low pneumothorax risk, but is contraindicated in current or pending dialysis. Tunneled catheters and ports are for >6 weeks (ports have the lowest infection risk). Intraosseous devices provide emergent access when IV access cannot be obtained and should be removed within 24 hours. For rapid volume resuscitation, a short wide-bore peripheral IV is the route of choice.
A MAP of ____ mm Hg is considered the threshold for adequate organ perfusion in most patients; targeting higher pressures (80–85 mm Hg) in septic shock has ____ improved mortality.
A mean arterial pressure of 65 mm Hg is considered the threshold for adequate organ perfusion in most people, and targeting higher pressures (80–85 mm Hg) in septic shock has not improved mortality. An arterial line is useful when systolic pressure falls below 90 mm Hg, when vasoactive infusions require frequent measurements, or when cuff readings are unreliable.
Per the SSC 2026 guidelines, ____ is the first-line vasopressor in septic shock; ____ should be added as its dose escalates for catecholamine sparing; ____ is added if MAP remains inadequate despite both.
The 2026 Surviving Sepsis Campaign guidelines reaffirm an initial MAP target of 65 mm Hg, allow vasopressors to be started through a peripheral line, keep norepinephrine first-line (strong recommendation over dopamine, epinephrine alone, and selepressin), add vasopressin as norepinephrine doses escalate for catecholamine sparing, and add epinephrine if MAP remains inadequate despite norepinephrine plus vasopressin; terlipressin is suggested against.
____ is a pure α1 agonist that may depress cardiac output via reflex bradycardia; ____ is an inotrope (not a vasopressor) and the first choice for cardiogenic shock without hypotension.
Phenylephrine is a pure α1 agonist that raises SVR; it is used when norepinephrine is contraindicated (tachyarrhythmias) or first-line drugs fail, but may depress cardiac output via reflex bradycardia. Dobutamine is an inotrope (β1/β2), not a vasopressor — it is the first choice for cardiogenic shock without hypotension and an add-on in distributive shock with depressed cardiac function.
Distributive shock shows ____ cardiac output and ____ SVR, whereas cardiogenic, hypovolemic, and obstructive shock all show ____ cardiac output with increased SVR.
Shock is classified by primary physiologic derangement: distributive (low SVR/vasodilation — compensatory high CO, low filling pressures; sepsis, anaphylaxis, neurogenic, adrenal crisis), cardiogenic (pump failure — low CO, high SVR, elevated filling pressures), hypovolemic (low preload — low CO, high SVR, low filling pressures), and obstructive (extracardiac flow obstruction — low CO, high SVR, elevated filling pressures). Types are not mutually exclusive.
ICU-acquired weakness develops in ____% to 100% of critically ill patients; the most prevalent form is likely critical illness ____; bedside evaluation uses the ____ muscle scale, with electromyography as the gold standard.
Between 25% and 100% of critically ill patients develop muscle weakness — critical illness polyneuropathy (axonal), critical illness myopathy, critical illness neuromyopathy (perhaps the most prevalent form), or nonspecific ICU-acquired weakness. Risk factors include sepsis, multisystem organ failure, severe illness, prolonged immobility, and hyperglycemia. Failure to wean from the ventilator is often the first clue; bedside evaluation uses the MRC muscle scale, EMG is the gold standard, and it is a diagnosis of exclusion.
As many as ____% to 80% of critical care survivors develop long-term cognitive impairment; one year after critical illness its severity resembles mild ____ disease, with ICU ____ as a major predictor.
As many as 30% to 80% of critical care survivors develop long-term cognitive impairment; one year after critical illness, the level of impairment is similar in severity to mild Alzheimer disease. The development and duration of delirium during the ICU stay appear to be major predictors, reinforcing delirium prevention and early mobilization as core ICU therapies.
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