A 56-year-old previously healthy woman with no other past medical history is post-operative day one from an open reduction and internal fixation of a fractured right radius and ulna after a motor vehicle accident. What is one of the primary ways of preventing postoperative pneumonia in this patient?

In-hospital intravenous antibiotics

A 36-year-old man presents to the physician with difficulty in breathing for 3 hours. There is no history of chest pain, cough or palpitation. He is a chronic smoker and underwent elective cholecystectomy one month back. There is no history of chronic or recurrent cough, wheezing or breathlessness. His temperature is 38.2°C (100.8°F), pulse is 108/min, blood pressure is 124/80 mm Hg, and respirations are 25/min. His arterial oxygen saturation is 98% in room air as shown by pulse oximetry. After a detailed physical examination, the physician orders a plasma D-dimer level, which was elevated. A contrast-enhanced computed tomography (CT) of the chest shows a filling defect in a segmental pulmonary artery on the left side. Which of the following signs is most likely to have been observed by the physician during the physical examination of this patient’s chest?

Systolic murmur at the left sternal border

A 23-year-old woman with no significant past medical history currently on oral contraceptive pills presents to the emergency department with pleuritic chest pain. She states that it started today. Yesterday she had a trip and returned via plane. Her temperature is 98°F (36.7°C), blood pressure is 117/66 mmHg, pulse is 105/min, respirations are 14/min, and oxygen saturation is 98% on room air. Physical exam reveals tachycardia, a normal S1 and S2, and clear breath sounds. The patient’s lower extremities are non-tender and symmetric. Chest pain is not reproducible with position changes or palpation but is worsened with deep breaths. Which of the following is the most appropriate next test for this patient?

Ultrasound of the lower extremities

A patient is hospitalized for pneumonia. Gram-positive cocci in clusters are seen on sputum gram stain. Which of the following clinical scenarios is most commonly associated with this form of pneumonia?

Hospitalized adult with development of pneumonia symptoms 2 weeks following a viral illness

Elderly patient who has trouble swallowing and poor dentition

An alcoholic with evidence of empyema and "currant jelly sputum"

An otherwise healthy young adult with a week of mild fatigue, chills, and cough

HIV positive adult with a CD4 count less than 150 and an impaired diffusion capacity

A 63-year-old man undergoes workup for nocturnal dyspnea and what he describes as a "choking" sensation while sleeping. He also endorses fatigue and dyspnea on exertion. Physical exam reveals a normal S1, loud P2, and a neck circumference of 17 inches (43 cm) (normal < 14 inches (< 35 cm)). His temperature is 98.8°F (37°C), blood pressure is 128/82 mmHg, pulse is 86/min, and respirations are 19/min. He undergoes spirometry, which is unrevealing, and polysomnography, which shows 16 hypopneic and apneic events per hour. Mean pulmonary arterial pressure is 30 mmHg. Which of the following complications is this patient most at risk for?

Chronic obstructive pulmonary disease

A 68-year-old man is brought to the emergency department because of fever, progressive weakness, and cough for the past five days. He experienced a similar episode 2 months ago, for which he was hospitalized for 10 days while visiting his son in Russia. He states that he has never fully recovered from that episode. He felt much better after being treated with antibiotics, but he still coughs often during meals. He sometimes also coughs up undigested food after eating. For the last 5 days, his coughing has become more frequent and productive of yellowish-green sputum. He takes hydrochlorothiazide for hypertension and pantoprazole for the retrosternal discomfort that he often experiences while eating. He has smoked half a pack of cigarettes daily for the last 30 years and drinks one shot of vodka every day. The patient appears thin. His temperature is 40.1°C (104.2°F), pulse is 118/min, respirations are 22/min, and blood pressure is 125/90 mm Hg. Auscultation of the lungs shows right basal crackles. There is dullness on percussion at the right lung base. The remainder of the physical examination shows no abnormalities. Laboratory studies show: Hemoglobin 15.4 g/dL Leukocyte count 17,000/mm3 Platelet count 350,000/mm3 Na+ 139 mEq/L K+ 4.6 mEq/L Cl- 102 mEq/L HCO3- 25 mEq/L Urea Nitrogen 16 mg/dL Creatinine 1.3 mg/dL An x-ray of the chest shows a right lower lobe infiltrate. Which of the following is the most likely explanation for this patient's symptoms?

Weak tone of the lower esophageal sphincter

Unrestricted growth of pneumocytes with invasion of the surrounding tissue

Uncoordinated contractions of the esophagus

Formation of a tissue cavity containing necrotic debris

A 19-year-old man is brought to the emergency department 35 minutes after being involved in a high-speed motor vehicle collision. On arrival, he is alert, has mild chest pain, and minimal shortness of breath. He has one episode of vomiting in the hospital. His temperature is 37.3°C (99.1°F), pulse is 108/min, respirations are 23/min, and blood pressure is 90/70 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 92%. Examination shows multiple abrasions over his trunk and right upper extremity. There are coarse breath sounds over the right lung base. Cardiac examination shows no murmurs, rubs, or gallop. Infusion of 0.9% saline is begun. He subsequently develops increasing shortness of breath. Arterial blood gas analysis on 60% oxygen shows: pH 7.36 pCO2 39 mm Hg pO2 68 mm Hg HCO3- 18 mEq/L O2 saturation 81% An x-ray of the chest shows patchy, irregular infiltrates over the right lung fields. Which of the following is the most likely diagnosis?

Acute respiratory distress syndrome

Postoperative respiratory care for USMLE Step 1: High-Yield Surgery Lessons

Post-Op Atelectasis - Lungs Gone Flat

Pathophysiology: Alveolar collapse from airway obstruction (mucus plugs) and shallow breathing (pain, anesthesia), leading to ventilation/perfusion (V/Q) mismatch and hypoxemia.
Timeline: Highest risk 24-48 hours after surgery.
Signs: Fever, tachypnea, tachycardia, ↓ breath sounds, dullness to percussion, tracheal deviation towards the affected side.
Prevention/Tx: Lung expansion is critical.
- 📌 Mnemonic: IS COPE → Incentive Spirometry, Coughing, Opioid minimization, Pain control, Early ambulation.

⭐ Atelectasis is the most common cause of fever on post-op days 1-2 ("Wind").

Chest X-ray: Post-op bibasilar atelectasis with volume loss

Aspiration & Pneumonitis - Wrong Pipe Woes

Aspiration Pneumonitis (Chemical): Acute lung injury from inhaling sterile acidic gastric contents (pH < 2.5).
- Onset: Rapid, within 2-12 hours.
- Sx: Hypoxemia, non-productive cough, respiratory distress.
- Tx: Supportive care (O₂, ventilation). Antibiotics not initially indicated.
Aspiration Pneumonia (Infectious): Lung infection from inhaling colonized oropharyngeal bacteria.
- Onset: Slower, 1-5 days.
- Sx: Fever, productive cough (may be putrid), consolidation.
- Tx: Antibiotics (e.g., Clindamycin).

⭐ Exam Favorite: Infiltrate location varies with patient position during aspiration. Supine: posterior segments of upper lobes or superior segments of lower lobes. Erect: basilar segments of lower lobes (esp. Right Lower Lobe).

Post-Op Pneumonia - Buggy Lung Blues

Onset: Typically >48 hours after surgery.
Pathophysiology: Impaired secretion clearance and aspiration lead to bacterial growth. Atelectasis is a major precursor.
Common Organisms:
- S. pneumoniae, H. influenzae.
- Hospital-Acquired (HAP): Pseudomonas, MRSA, GNRs.
- Aspiration: Anaerobes (e.g., Bacteroides, Prevotella).
Prevention & Rx:
- 📌 Prevention: Pain control, Positioning (head elevation), incentive sPirometry, early amPulation.
- Rx: Empiric broad-spectrum antibiotics, then tailor to cultures.

⭐ Aspiration pneumonia classically affects the right lower lobe (RLL) due to the more vertical angle of the right mainstem bronchus. Suspect anaerobes if foul-smelling sputum or abscess develops.

Pulmonary Embolism - Clot on the Move

Pathophysiology: Obstruction of pulmonary artery, usually from deep vein thrombosis (DVT).
Risk Factors: Virchow's Triad (stasis, hypercoagulability, endothelial injury) - recent surgery, malignancy, immobility.
Presentation: Sudden-onset dyspnea, pleuritic chest pain, tachypnea, tachycardia. Massive PE can cause syncope, hypotension.
Diagnosis: Best initial test is CT Angiogram (CTA). V/Q scan if CTA contraindicated.

CT angiogram showing saddle pulmonary embolism

⭐ ECG Finding: The classic S1Q3T3 pattern (deep S in lead I, Q wave and inverted T in lead III) is highly specific but rarely seen.

Atelectasis is the most common cause of fever in the first 48 hours; prevent with incentive spirometry.

Suspect pulmonary embolism (PE) with sudden-onset dyspnea and pleuritic chest pain.

Postoperative pneumonia typically occurs 3-5 days later, with productive cough and fever.

Aspiration pneumonitis causes acute hypoxemia after potential aspiration during anesthesia induction or emergence.

Major risk factors include smoking, COPD, obesity, and anesthesia time >3 hours.

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