Sepsis
What is the first line pressor for septic shock?
This non invasive modality is used when myocardial perfusion imaging is inconclusive and anatomical assessment is needed.
Coronary CT angiography
Hypoxemia that does not correct with 100% FiO₂ suggests this mechanism.
Shunt
A 56-year-old man with sepsis develops acute hypoxemic respiratory failure. ABG on 100% FiO₂ shows PaO₂ 60 mmHg. Chest X-ray reveals bilateral infiltrates, and echocardiogram shows normal LV function. He is intubated and placed on volume control ventilation. Which of the following is the most appropriate initial tidal volume setting?
A. 8 mL/kg predicted body weight
B. 6 mL/kg predicted body weight
C. 10 mL/kg actual body weight
D. Tidal volume adjusted to maintain pCO₂ < 40 mmHg
E. 7 mL/kg actual body weight
6 mL/kg predicted body weight
Explanation: Lung-protective ventilation with low tidal volumes (6 mL/kg predicted body weight) is standard in ARDS to reduce barotrauma and mortality (based on the ARDSNet trial).
What is the most common EKG finding in someone with a PE?
Sinus tachycardia
What are the criteria for septic shock under the Sepsis 3 Guidelines?
Hypotension, need for vasopressors, serum lactate > 2mmol/L.
In a patient with LBBB, this type of stress imaging is preferred to reduce false positives.
Pharmacologic nuclear stress testing (e.g., with adenosine or regadenoson).
A low PaO₂ with normal A-a gradient and high PaCO₂ suggests this mechanism of hypoxemia.
Hypoventilation
In ARDS, this ventilator setting is adjusted to prevent alveolar collapse and improve oxygenation, but excessive levels may reduce cardiac output.
Positive end-expiratory pressure (PEEP)
Intermediate-risk PE patients can be further risk stratefied by what tests?
TTE (RV strain) and biomarkers (troponin and BNP)
The APROCCHSS trial investigated hydrocortisone plus what other medication which demonstrated a 6% absolute reduction in 90-day mortality (43% vs 49.1%)?
Fludrocortisone
What are the contraindications for using adenosine in a stress test?
Seizure history and severe bronchospastic airway disease.
A patient with severe hypoxemia, an elevated A-a gradient, and minimal response to supplemental O₂ has a normal chest X-ray. TTE with bubble shows late appearance of bubbles in the left atrium. This suggests what type of shunt?
intrapulmonary shunt
A PaO₂/FiO₂ ratio less than this value is required to diagnose ARDS according to the Berlin definition.
300 mmHg
This clinical prediction tool uses age, vital signs, and oxygen saturation to classify PE patients into five risk classes that predicts 30-day mortality
Pulmonary Embolism Severity Index (PESI) score
ProCESS, ARISE, and ProMISe trials evaluated EGDT versus usual care in sepsis. What was the common conclusion of these three multicenter RCTs
That EGDT did not reduce 90-day mortality compared to usual care, leading to its removal from guidelines.
A 70-year-old man with a history of coronary artery disease and chronic atrial fibrillation is scheduled for ischemia evaluation. What stress test is a poor choice for this patient and why?
Dobutamine stress test.
Rationale: Atrial fibrillation, which causes variable ventricular response, reduces test accuracy as well as increased risk of other arrhythmias with beta agonists.
A scuba diver surfaces rapidly and develops dyspnea and confusion. ABG shows a widened A-a gradient. What mechanism of hypoxemia is most likely at play, and what condition explains the clinical scenario?
V/Q mismatch due to air embolism (decompression sickness)
A 74-year-old man with a history of myasthenia gravis presents with increasing shortness of breath and weakness. ABG shows pH 7.32, PaCO₂ 54 mmHg, and PaO₂ 68 mmHg on room air. Vital capacity is 10 mL/kg.
What is the most appropriate next step?
A. Trial of BiPAP
B. Observation and repeat ABG in 6 hours
C. Intubation for impending respiratory failure
D. High-flow nasal cannula
E. Intravenous steroids
Neuromuscular respiratory failure, a vital capacity <15 mL/kg and hypercapnia indicate impending respiratory collapse. Early intubation prevents crash intubation.
This 2024 RCT compared large-bore mechanical thrombectomy to catheter-directed thrombolysis in intermediate-risk PE, showing better win-ratio outcomes with MT?
The PEERLESS trial
The CLASSIC and CLOVERS trials challenged traditional "fluid-first" resuscitation. What did these studies suggest about fluid-sparing strategies versus liberal fluid use in early septic shock?
No significant mortality difference, but potential benefit in reducing fluid overload and complications with conservative strategies.
This electrocardiographic finding during an exercise stress test is most specific for myocardial ischemia.
What is horizontal or downsloping ST-segment depression ≥1 mm?
A patient with a widened A-a gradient and platypnea-orthodeoxia likely has this mechanism of hypoxemia
Intracardiac (PFO) or intra pulmonary shunt ( AVMs, hepatopulmonary syndrome).
Usually platypnea-orthodeoxia is seen in pulmonary shunts given gravity increases blood flow to the bases of the lungs, where these shunts are often located, aggravating the shunting of deoxygenated blood and worsening hypoxemia.
A 40-year-old man with severe ARDS remains hypoxemic despite high PEEP and FiO₂ of 1.0. PaO₂ remains <55 mmHg. The team is considering next steps.
Which of the following is the most evidence-based next step?
A. Increase tidal volume
B. Start prone positioning
C. Add corticosteroids
D. ECMO immediately
E. Reduce PEEP and monitor
Start prone positioning
Explanation: Prone positioning improves oxygenation and mortality in patients with severe ARDS and refractory hypoxemia (PROSEVA trial). It should be considered before ECMO.
In the FLARE/FLASH studies, this parameter decreased immediately post-thrombectomy and remained lower at 3 months.
The right ventricle/left ventricle (RV/LV) ratio