What is the appropriate management plan for a patient with respiratory failure?

SOAP Note for Patient with Respiratory Failure

Subjective

• Chief complaint: Document degree of dyspnea, ability to speak in full sentences, and duration of symptoms 1
• Symptom severity: Assess work of breathing by asking about use of accessory muscles and ability to complete activities 2
• Past medical history: Specifically inquire about COPD, asthma, neuromuscular disease, chest wall deformity, heart failure, or obstructive sleep apnea 3
• Smoking history and recent infections: Critical for determining etiology and prognosis 4
• Goals of care: Document patient wishes regarding intubation and invasive mechanical ventilation at presentation 3

Objective

• Vital signs: Respiratory rate (concerning if >30/min), heart rate, blood pressure, oxygen saturation, mental status 1, 2
• Physical examination:
  • Work of breathing: accessory muscle use, paradoxical breathing, ability to speak
  • Auscultation: wheezing, crackles, diminished breath sounds
  • Cardiovascular: signs of fluid overload or shock
  • Neurological: level of consciousness (drowsiness/confusion indicates impending failure) 2
• Arterial blood gas (ABG): Mandatory before initiating treatment to classify Type I (hypoxemic: PaO₂ <60 mmHg with normal/low PaCO₂) versus Type II (hypercapnic: PaCO₂ >45 mmHg with respiratory acidosis) 1, 2
• Chest X-ray: Obtain to identify pneumonia, pulmonary edema, pneumothorax, but do not delay treatment in severe cases 1, 4
• ECG: Rule out ST-elevation myocardial infarction and assess for arrhythmias 3

Assessment

Type of respiratory failure (based on ABG):

• Type I (Hypoxemic): PaO₂ <60 mmHg with normal or low PaCO₂ 2
• Type II (Hypercapnic): PaCO₂ >45 mmHg with pH <7.35 3

Severity classification for hypercapnic failure:

• pH 7.30-7.35: Moderate acidosis - manage on respiratory ward with specialist support 3
• pH 7.25-7.30: Severe acidosis - requires HDU/ICU level care 3
• pH <7.25: Critical acidosis - requires ICU with immediate intubation capability 3

Underlying etiology: COPD exacerbation, pneumonia, cardiogenic pulmonary edema, ARDS, neuromuscular disease, etc. 4

Plan

Immediate Management (First 30 minutes)

For Type II (Hypercapnic) Respiratory Failure:

1. Controlled oxygen therapy: Target SpO₂ 88-92% immediately using Venturi mask or nasal cannula 3, 1

   • Recheck ABG after 1-2 hours to ensure adequate oxygenation without worsening hypercapnia 1, 4

2. Optimal medical therapy (before considering NIV):

   • Nebulized bronchodilators: Albuterol 2.5 mg via nebulizer every 4-6 hours 4, 5
   • Systemic corticosteroids: Prednisolone 30-40 mg daily for COPD exacerbations 4
   • Antibiotics if indicated: For purulent sputum or requiring mechanical ventilation (5-7 day course) 4

3. Non-invasive ventilation (NIV): Initiate when pH <7.35 and PaCO₂ >6.5 kPa persist despite optimal medical therapy 3, 1

   • Start with IPAP 10-12 cmH₂O, EPAP 4-5 cmH₂O, gradually increase as tolerated 1
   • Use full-face mask initially for better seal 3, 1
   • Maximize NIV hours in first 24 hours (aim for near-continuous use with breaks for meals/medications) 1, 4
   • Recheck ABG at 1-2 hours, then 4-6 hours if initial improvement minimal 1, 4
   • If pH and PaCO₂ worsen or fail to improve after 4-6 hours on optimal NIV settings, proceed to invasive mechanical ventilation 1

For Type I (Hypoxemic) Respiratory Failure:

1. High-flow nasal oxygen (HFNO): Preferred initial therapy at 40-60 L/min targeting SpO₂ 94-98% 2, 6

   • Superior to conventional oxygen therapy for reducing mortality (ARD -15.8%) 2
   • Better tolerated than NIV in pure hypoxemic failure 2

2. Escalation if HFNO fails (SpO₂ <90% despite HFNO):

   • Consider NIV with CPAP/BiPAP, particularly for cardiogenic pulmonary edema 2
   • Prepare for invasive mechanical ventilation if non-invasive support fails 2

Location of Care

• pH >7.30: Respiratory ward with trained NIV staff and clear escalation protocols 3
• pH 7.25-7.30: HDU or ICU 3
• pH <7.25 or severe hypoxemia (PaO₂/FiO₂ <100): ICU with immediate intubation capability 3, 2

Monitoring

• Continuous pulse oximetry for at least 24 hours 1, 4
• Serial ABGs: At 1-2 hours after any intervention, then every 4-6 hours until stable 1, 4
• Clinical parameters every 1-2 hours: Respiratory rate, heart rate, blood pressure, mental status, work of breathing 1
• ROX index (SpO₂/FiO₂ ÷ respiratory rate) if using HFNO: >4.88 at 2 hours predicts success; <3.85 at 12 hours predicts failure 6

Invasive Mechanical Ventilation Criteria

Proceed to intubation when:

• NIV failure: worsening pH/PaCO₂ after 4-6 hours despite optimal settings 1
• Cardiovascular instability or shock 7
• Severely impaired mental status or inability to protect airway 7
• Respiratory arrest imminent or apnea 7
• Contraindications to NIV: severe facial trauma, fixed upper airway obstruction, inability to clear secretions 3

Ventilator settings for invasive ventilation:

• Tidal volume 6 mL/kg ideal body weight 1, 2
• Plateau pressure <30 cmH₂O 1, 2
• Appropriate PEEP based on oxygenation needs 1

Documentation Requirements

• Individualized treatment plan at initiation including specific escalation criteria and intubation thresholds 1, 2
• Code status and goals of care discussion documented, particularly regarding invasive ventilation 3
• Consultation with ICU if pH <7.30 or high risk of NIV failure 3

Disposition Planning

• Before discharge: Check ABG on room air, perform spirometry if COPD, arrange early follow-up <30 days 4
• Referrals: Consider home NIV service for neuromuscular disease, chest wall deformity, or morbid obesity with recurrent hypercapnic failure 1
• Patient education: Provide warning card regarding controlled oxygen therapy for future presentations 3

Common Pitfalls to Avoid

• Do not delay NIV while waiting for chest X-ray in severe acidosis 3
• Do not use excessive oxygen - hypercapnic patients require controlled oxygen at 88-92% saturation 3
• Do not persist with failing NIV - worsening pH/respiratory rate after 4-6 hours mandates escalation 1
• Do not use NIV in acute asthma exacerbations - proceed directly to invasive ventilation if needed 3
• Severe acidosis (pH <7.25) does not preclude NIV trial but requires ICU setting with immediate intubation capability 3