A 68-year-old retired teacher is brought to the acute care clinic by his wife due to 48 ho… — USMLE Step 2 CK

A $68$ -year-old retired teacher is brought to the acute care clinic by his wife due to $48$ hours of worsening breathlessness and a change in his chronic cough. He notes his sputum has become thick and yellow-green, and he is coughing up a larger volume than usual. His medical history includes moderate chronic obstructive pulmonary disease and essential hypertension. On triage, his temperature is $37.6^\circ$ C ( $99.7^\circ$ F), blood pressure is $158/92$ mm Hg, pulse is $114$ /min, and respiratory rate is $28$ /min. Pulse oximetry shows an oxygen saturation of $85\%$ on ambient air.

Physical examination reveals a barrel-shaped chest. Lung auscultation demonstrates globally decreased breath sounds with prominent expiratory wheezing and a significantly prolonged expiratory phase. Cardiac examination reveals a regular rhythm, rapid rate, and no murmurs or gallops. The jugular veins are not distended, and there is no lower extremity edema.

An arterial blood gas analysis performed on room air demonstrates:

Parameter	Value
pH	$7.27$
PaCO $_2$	$66$ mm Hg
PaO $_2$	$50$ mm Hg
HCO $_3^-$	$29$ mEq/L

A portable chest radiograph shows flattened diaphragms and increased retrosternal airspace, without focal opacities or cardiomegaly.

He is immediately provided with supplemental oxygen via Venturi mask (targeting a saturation of $90\%$ - $92\%$ ), nebulized short-acting bronchodilators, and systemic glucocorticoids.

Which of the following are appropriate additional steps in the management of this patient's acute condition? (Select $2$ answers)

Initiate noninvasive positive pressure ventilationCevap
Administer a five-day course of oral azithromycinCevap
C
Administer a bolus of intravenous furosemide
D
Administer empiric intravenous vancomycin and cefepime
E
Initiate a continuous infusion of sodium bicarbonate

Cevap

The correct management steps are to initiate noninvasive positive pressure ventilation (NPPV) and to administer a five-day course of oral azithromycin.

The patient is experiencing an acute exacerbation of chronic obstructive pulmonary disease (AECOPD), characterized by increased dyspnea, sputum volume, and sputum purulence. Arterial blood gas analysis reveals an acute-on-chronic respiratory acidosis (pH

7.27

, PaCO

_2

66

mm Hg, with an elevated bicarbonate indicating baseline metabolic compensation). Noninvasive positive pressure ventilation (NPPV) is strongly indicated for patients with AECOPD who have respiratory acidosis (pH <

7.35

and PaCO

_2

45

mm Hg), as it decreases mortality, reduces the need for intubation, and improves respiratory parameters. Additionally, antibiotic therapy is indicated for AECOPD patients who exhibit all three cardinal symptoms (increased dyspnea, sputum volume, and purulence) or those requiring mechanical ventilation. A macrolide (like azithromycin), a second- or third-generation cephalosporin, or doxycycline is the appropriate targeted therapy; broad-spectrum coverage is not routinely required absent specific risk factors for Pseudomonas aeruginosa or MRSA.

Adım Adım Çözüm

Identify the primary clinical syndrome based on the patient's presentation and history.

The patient has an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) characterized by the three cardinal symptoms: increased dyspnea, increased sputum volume, and increased sputum purulence.

Recognizing the syndrome and its severity determines the need for specific interventions such as targeted antibiotics and ventilatory support.

Analyze the arterial blood gas (ABG) results to determine the acid-base status.

The ABG shows an acute-on-chronic respiratory acidosis (pH

7.27

, PaCO

_2

66

mm Hg) alongside severe hypoxemia.

The presence of significant respiratory acidosis (pH <

7.35

) in the setting of AECOPD is a strong indication for noninvasive positive pressure ventilation (NPPV) to improve alveolar ventilation.

Evaluate the indications for antibiotic therapy and select the appropriate antimicrobial spectrum.

Antibiotics are indicated due to the presence of all three cardinal symptoms and the need for mechanical ventilatory support. A macrolide (azithromycin) provides the appropriate coverage.

Targeted antibiotic therapy reduces the risk of treatment failure in severe AECOPD while strictly adhering to antimicrobial stewardship principles by avoiding unnecessary broad-spectrum agents.

Anahtar Kavram

Patients with a severe COPD exacerbation complicated by acute respiratory acidosis require noninvasive positive pressure ventilation (NPPV). Additionally, those with three cardinal symptoms (or those requiring mechanical ventilation) should receive targeted antibiotic therapy, typically a macrolide, cephalosporin, or doxycycline.

Soru

Cevap

Adım Adım Çözüm

Anahtar Kavram

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