What is the initial treatment for a patient with pneumonia presenting in respiratory distress to the emergency room?

Initial Treatment for Pneumonia with Respiratory Distress in the Emergency Department

For patients with pneumonia presenting in respiratory distress to the ER, immediately initiate oxygen therapy, administer empiric antibiotics while still in the ED (β-lactam plus macrolide or fluoroquinolone for ICU-level severity), and assess for need of respiratory support escalation including noninvasive ventilation or intubation based on severity of hypoxemia. 1, 2

Immediate Oxygen Therapy

• Start oxygen therapy at 5 L/min initially, then titrate to target SpO2 ≥90% or PaO2 ≥60 mmHg 1, 2
• Oxygen delivery options include nasal cannula, face mask, high-flow nasal oxygen (HFNO), or noninvasive ventilation depending on severity 1
• Monitor pulse oximetry continuously and obtain arterial blood gas if severe distress or inadequate response 2

Empiric Antibiotic Therapy - Must Be Given in ED

The first antibiotic dose must be administered while the patient is still in the emergency department - this is a critical quality metric 1, 2

For ICU-Level Severity (Respiratory Distress Qualifies):

• Preferred regimen: β-lactam (ceftriaxone 1-2g IV daily OR cefotaxime 1-2g IV q8h) PLUS azithromycin 500mg IV daily 1, 3
• Alternative regimen: β-lactam PLUS respiratory fluoroquinolone (levofloxacin 750mg IV daily) 1
• For penicillin allergy: respiratory fluoroquinolone plus aztreonam 1

Special Considerations for Antibiotic Selection:

• If risk factors for Pseudomonas (structural lung disease, recent hospitalization, broad-spectrum antibiotic use): use antipseudomonal β-lactam (piperacillin-tazobactam 4.5g IV q6h, cefepime 2g IV q8h, or meropenem 1g IV q8h) plus ciprofloxacin or levofloxacin 750mg 1
• If risk factors for MRSA (prior MRSA infection, IV drug use, recent hospitalization): add vancomycin 15-20mg/kg IV q8-12h or linezolid 600mg IV q12h 1
• During influenza season: test for influenza and COVID-19; if positive, add oseltamivir 75mg PO BID 1, 3

Respiratory Support Escalation

Noninvasive Ventilation (NIV):

• Consider NIV trial for patients with hypoxemia or respiratory distress UNLESS they have severe hypoxemia (PaO2/FiO2 <150) with bilateral infiltrates, which requires immediate intubation 1
• NIV is contraindicated if: altered mental status, inability to protect airway, hemodynamic instability, or inability to clear secretions 4, 5
• If NIV is attempted, monitor closely for first 1-2 hours for signs of failure (worsening mental status, increasing work of breathing, persistent hypoxemia) 6

Invasive Mechanical Ventilation:

Immediate intubation is required for: 1, 4, 5

• Severe hypoxemia (PaO2/FiO2 ratio <150) with bilateral infiltrates
• Altered mental status or inability to protect airway
• Severe hypercapnia (PaCO2 >72 mmHg) with acidosis
• Hemodynamic instability despite resuscitation
• Respiratory arrest or agonal breathing

Ventilator Settings if Intubated:

• Use low tidal volume ventilation: 6 mL/kg ideal body weight 1, 4
• Target plateau pressure <30 cmH2O 4
• Set PEEP ≥5 cmH2O, higher (8-15 cmH2O) for moderate-severe ARDS 4
• For severe ARDS (PaO2/FiO2 <150): consider prone positioning >12 hours daily 2, 4
• Consider neuromuscular blockade in first 48 hours for moderate-severe ARDS 2, 4

Hemodynamic Support if Hypotensive

• If hypotension present (MAP <65 mmHg): administer 30 mL/kg isotonic crystalloid in first 3 hours 2
• If hypotension persists after fluid resuscitation: start norepinephrine to maintain MAP ≥65 mmHg 2
• Screen for occult adrenal insufficiency in hypotensive patients after adequate fluid resuscitation 1
• Consider drotrecogin alfa activated within 24 hours for persistent septic shock (though this recommendation is dated and this drug is no longer available) 1

Monitoring Parameters

Monitor continuously: 1, 2

• Vital signs (heart rate, blood pressure, respiratory rate, temperature)
• Pulse oximetry (SpO2)
• Mental status
• Work of breathing

Obtain laboratory studies: 1

• Complete blood count, comprehensive metabolic panel
• Arterial blood gas if severe distress
• Blood cultures before antibiotics (but don't delay antibiotics)
• Lactate level if sepsis suspected
• Procalcitonin and C-reactive protein

Common Pitfalls to Avoid

• Never delay antibiotics to obtain diagnostic studies - give antibiotics in the ED before admission 1, 2
• Don't attempt NIV in patients with altered mental status - they need immediate intubation 4, 5
• Avoid hypotonic crystalloids, starches, or gelatins for resuscitation 2
• Don't use excessive tidal volumes (>6 mL/kg) if patient requires intubation - this worsens lung injury 1, 4
• Don't position patient with affected lung dependent - this worsens shunt and hypoxemia 7