What is the most appropriate next step for a patient with Guillain-Barré Syndrome (GBS) presenting with bilateral lower extremity weakness, decreased sensation, and significantly decreased forced vital capacity (FVC)?

Immediate Intubation and Mechanical Ventilation for Guillain-Barré Syndrome with Respiratory Compromise

The most appropriate next step for this patient with Guillain-Barré Syndrome is immediate intubation and mechanical ventilation due to her critically low forced vital capacity of 600 mL (10 mL/kg), which indicates impending respiratory failure. 1

Clinical Assessment and Rationale

This 35-year-old woman presents with classic features of Guillain-Barré Syndrome (GBS):

• Recent diarrheal illness 2 weeks ago (common antecedent infection)
• Progressive ascending weakness starting with numbness/tingling
• Decreased reflexes
• Sensory deficits

The critical finding necessitating immediate action is her severely compromised respiratory function:

• Forced vital capacity (FVC) of 600 mL in a 60 kg patient = 10 mL/kg
• According to the "20/30/40 rule" established by the American Academy of Neurology, vital capacity < 20 mL/kg is a critical threshold indicating need for mechanical ventilation 1
• Her FVC is significantly below this threshold at only 10 mL/kg

Decision Algorithm for Respiratory Management in GBS

1. Assess respiratory parameters:

   • Vital capacity < 20 mL/kg → Proceed to intubation
   • Maximum inspiratory pressure < 30 cmH₂O → Proceed to intubation
   • Maximum expiratory pressure < 40 cmH₂O → Proceed to intubation
   • Single breath count ≤ 19 → Consider intubation

2. Clinical factors increasing urgency for intubation:

   • Rapid disease progression (present in this case)
   • Bulbar dysfunction
   • Bilateral facial weakness
   • Dysautonomia

3. Avoid waiting for classical signs of respiratory distress:

   • Dyspnea, tachypnea, and use of accessory muscles occur too late 2
   • Emergency intubation can lead to life-threatening complications 3
   • Elective intubation based on objective measurements is safer

Why Other Options Are Not Appropriate First Steps

• Intravenous immunoglobulin (IVIG): While IVIG is a first-line immunotherapy for GBS, addressing the immediate respiratory failure takes precedence. IVIG should be initiated after the patient is stabilized on mechanical ventilation 1

• Plasmapheresis: Like IVIG, plasma exchange is an appropriate immunotherapy but addressing respiratory failure is the priority 1

• High-dose intravenous corticosteroids: Not recommended for GBS as they show no benefit and may have negative effects 1

• Lumbar puncture: While useful for diagnosis (showing albuminocytologic dissociation), it is not the priority in a patient with impending respiratory failure 1

Post-Intubation Management

After securing the airway:

• Initiate immunotherapy with either IVIG (0.4 g/kg/day for 5 days) or plasma exchange (4-5 exchanges over 1-2 weeks) 1
• Consider early tracheostomy, as delayed tracheostomy (≥14 days after intubation) is associated with increased risk of ventilator-associated pneumonia 4
• Implement preventive measures for complications:
  • Pressure ulcers
  • Hospital-acquired infections
  • Deep vein thrombosis 1

Monitoring During ICU Stay

• Continue respiratory monitoring
• Watch for dysautonomia (blood pressure fluctuations, heart rate abnormalities)
• Assess for pain and manage appropriately with gabapentinoids as first-line agents 1
• Monitor for bulbar dysfunction and swallowing difficulties
• Begin planning for rehabilitation early

The patient's presentation with rapidly progressive weakness, sensory deficits, and critically low forced vital capacity mandates immediate airway protection through intubation before proceeding with specific GBS treatment.