What is the appropriate management plan for a patient diagnosed with Acute Respiratory Distress Syndrome (ARDS)?

SOAP Note for Patient with ARDS

Subjective

• Chief Complaint: Progressive dyspnea, tachypnea, and hypoxemia 1
• Onset: Document timing of symptom onset relative to known insult (must be within one week) 1
• Associated Symptoms: Assess for underlying etiology—pneumonia, sepsis, trauma, aspiration, or other precipitating factors 1, 2
• COVID-19 Status: Determine if COVID-19 pneumonia is the underlying cause, as this affects treatment decisions 3

Objective

Vital Signs & Physical Examination

• Respiratory Rate: Document tachypnea 1
• Oxygen Saturation: Measure SpO₂ on current oxygen delivery method 3
• Hemodynamic Status: Assess blood pressure, heart rate, and signs of shock 4
• Mental Status: Document level of consciousness and ability to protect airway 4
• Work of Breathing: Assess for accessory muscle use, paradoxical breathing 4

Laboratory & Diagnostic Studies

• Arterial Blood Gas: Obtain PaO₂/FiO₂ ratio to classify ARDS severity:
  • Mild: 200-300 mmHg
  • Moderate: 100-200 mmHg
  • Severe: <100 mmHg 4, 2
• Chest Imaging: Document bilateral pulmonary opacities 1, 2
• Echocardiography: Assess right ventricular function and rule out cardiac failure as primary cause 3, 4
• Rapid Shallow Breathing Index (RSBI): Calculate if considering NIV (>105 breaths/min/L indicates likely need for intubation) 4

Assessment

Acute Respiratory Distress Syndrome—[Mild/Moderate/Severe] based on PaO₂/FiO₂ ratio

• Underlying etiology: [Specify—pneumonia, sepsis, trauma, etc.]
• Berlin Definition criteria met: acute onset, bilateral opacities, PaO₂/FiO₂ ≤300 mmHg, not fully explained by cardiac failure 4

Plan

Respiratory Support Strategy

For Mild ARDS (PaO₂/FiO₂ 200-300 mmHg):

• Consider high-flow nasal cannula (HFNC) ONLY if: hemodynamically stable, alert, cooperative, SAPS II <34, and pneumonia is NOT the etiology 3, 4
• Start at 30-40 L/min with FiO₂ 50-60% 3
• Proceed to intubation if: deterioration within 1 hour, FiO₂ >70%, flow >50 L/min, or RSBI >105 3, 4
• Contraindications to HFNC: hypercapnia, hemodynamic instability, multi-organ failure, altered mental status 4

For Moderate-to-Severe ARDS or Failed HFNC:

• Proceed to early intubation in a controlled setting 3, 4

Mechanical Ventilation Settings (Lung-Protective Strategy)

Immediately implement the following ventilator parameters:

• Tidal volume: 4-8 mL/kg predicted body weight (NOT actual weight) 3, 4, 5
• Plateau pressure: Maintain ≤30 cmH₂O at all times 3, 4, 5
• PEEP: Use higher PEEP strategy in moderate-to-severe ARDS following ARDS-network PEEP-to-FiO₂ grid 3, 6
• Oxygenation target: SpO₂ 92-96% (NOT higher than 96% to avoid oxygen toxicity), PaO₂ 70-90 mmHg 3, 4
• Monitor for: hemodynamic compromise with higher PEEP 3

Adjunctive Therapies

For Severe ARDS (PaO₂/FiO₂ <100 mmHg):

• Prone positioning: Implement for at least 12 hours per day—this has demonstrated significant mortality reduction 3, 4, 5
• Apply deep sedation and analgesia during prone positioning 4

For Early Severe ARDS:

• Cisatracurium infusion: Consider for 24-48 hours after ARDS onset to improve ventilator synchrony, reduce oxygen consumption, and potentially improve outcomes (RR 0.74 for mortality reduction) 3, 4, 6
• Particularly beneficial when ventilator-patient dyssynchrony persists despite sedation 4

Fluid Management

• Implement conservative fluid strategy: Minimize pulmonary edema while maintaining adequate organ perfusion 3, 4, 5
• Monitor fluid balance carefully—excessive fluid worsens oxygenation, promotes RV failure, and increases mortality 4
• Avoid unnecessary blood product transfusions 3

Treatment of Underlying Cause

• Rapidly identify and treat the underlying etiology—this is the only causal treatment measure 3, 2
• For COVID-19 pneumonia: Administer dexamethasone 3
• For bacterial pneumonia: Appropriate antimicrobials
• For sepsis: Source control and sepsis bundle

Monitoring Requirements

• Continuous monitoring: Oxygen saturation, respiratory mechanics, hemodynamics 3, 4
• Echocardiography: Assess right ventricular function, as RV failure significantly worsens outcomes 3, 4
• Arterial blood gas: At 1-2 hours and 4-6 hours if minimal initial improvement 4
• Daily spontaneous breathing trials: Once condition improves, to reduce duration of mechanical ventilation 4

Advanced Therapies for Refractory Hypoxemia

• Inhaled pulmonary vasodilators: Consider as rescue therapy, but discontinue if no rapid improvement 4
• VV-ECMO: Consider in selected patients with severe ARDS who fail conventional management (protective ventilation, prone positioning, neuromuscular blockade), particularly those with reversible disease 4, 6, 7
• Implement only at centers with ECMO expertise 4

Critical Pitfalls to Avoid

• Do NOT: Use excessive fluid administration, unnecessary blood transfusions, or injurious mechanical ventilation—these aggravate lung injury 3
• Do NOT: Use high-frequency oscillation 5
• Do NOT: Routinely use inhaled nitric oxide 5
• Establish diagnostic protocol: Identify treatable diseases that mimic ARDS, as these require specific therapies 3

Disposition

• ICU admission with continuous monitoring 4
• Consider transfer to ECMO-capable center if refractory hypoxemia develops 4, 7