How do I set up a BiPAP (Bilevel Positive Airway Pressure) machine?

Setting Up BiPAP: A Comprehensive Guide

BiPAP (Bilevel Positive Airway Pressure) should be set up with initial settings of EPAP 4 cm H₂O, IPAP 8 cm H₂O, and adjusted based on patient response, with the goal of normalizing ventilation and oxygen saturation while ensuring patient comfort. 1

Initial Setup and Equipment Requirements

Required Equipment:

• BiPAP device capable of spontaneous (S), spontaneous/timed (ST), and timed (T) modes
• Appropriate mask interface (nasal, oronasal, or full face)
• Tubing circuit
• Optional: supplemental oxygen, heated humidification

Initial Settings

1. Mode Selection:

   • Start with spontaneous mode for patients who can trigger breaths reliably
   • Use ST mode for patients with central hypoventilation, significant central apneas, low respiratory rate, or muscle weakness 1

2. Pressure Settings:

   • EPAP (Expiratory Positive Airway Pressure): Start at 4 cm H₂O
   • IPAP (Inspiratory Positive Airway Pressure): Start at 8 cm H₂O (providing pressure support of 4 cm H₂O)
   • Pressure support = IPAP - EPAP 1

3. If using ST mode:

   • Set backup rate equal to or slightly less than patient's spontaneous sleeping respiratory rate (minimum 10 breaths/min)
   • Set inspiratory time (IPAP time) to 30-40% of cycle time 1

Titration Process

Adjusting Pressure Support

1. Increase IPAP in 1-2 cm H₂O increments if:

   • Tidal volume remains low (<6-8 mL/kg)
   • SpO₂ remains <90% for >5 minutes
   • PCO₂ remains elevated
   • Respiratory muscle rest has not been achieved 1

2. Increase EPAP in 1-2 cm H₂O increments if:

   • Obstructive events persist (apneas, hypopneas, snoring)
   • Patient has intrinsic PEEP (particularly in COPD patients) 1

Adjusting Backup Rate (in ST mode)

1. Increase backup rate in 1-2 breaths/min increments if:

   • Central apneas persist
   • Ventilation remains inadequate
   • Respiratory rate is inappropriately low 1

2. Calculate appropriate inspiratory time:

   • Cycle time = 60 / respiratory rate (in breaths/min)
   • IPAP time = 30-40% of cycle time
   • For patients with obstructive airways disease: use shorter inspiratory time (~30%)
   • For patients with restrictive disease: use longer inspiratory time (~40%) 1

Advanced Settings and Adjustments

Volume-Targeted BiPAP (if available)

• Initial settings: EPAP = 4 cm H₂O, IPAP min = EPAP + 4 cm H₂O, IPAP max = 25-30 cm H₂O
• Target tidal volume: approximately 8 mL/kg ideal body weight 1

Trigger Sensitivity and Patient Comfort

• Adjust rise time (speed of pressure increase) for patient comfort
• Set appropriate trigger sensitivity to detect patient effort
• Consider pressure relief features if available 1

Adding Supplemental Oxygen

1. Add oxygen if:

   • Awake SpO₂ <88%
   • SpO₂ remains <90% for >5 minutes despite optimized pressure settings 1

2. Start at 1 L/min and increase in 1 L/min increments until SpO₂ >90%

3. Connect oxygen at the mask or via a T-connector between the device outlet and tubing 1

Troubleshooting Common Issues

Mask Leaks

• Refit mask or try different mask type if significant unintentional leak occurs
• Consider chin strap or oronasal mask if mouth leak is present 1

Patient Discomfort

• If patient complains of excessive pressure, temporarily lower settings to allow return to sleep
• Add heated humidification if patient reports dryness or nasal congestion 1

Patient-Ventilator Asynchrony

• Check for delayed triggering or cycling
• Consider adjusting trigger sensitivity, rise time, or inspiratory time
• In severe cases, consider switching to timed mode 1

Special Considerations

For Obstructive Airways Disease

• Use shorter inspiratory time (30% of cycle time)
• Allow adequate expiratory time (I:E ratio of at least 1:2) 1

For Restrictive Disease

• Use longer inspiratory time (40% of cycle time)
• Higher pressure support may be needed 1

For Neuromuscular Disease

• ST mode is typically required
• May need to start with lower pressures (IPAP 8, EPAP 4) and gradually increase based on symptoms and daytime PCO₂ measurements 1

By following this systematic approach to BiPAP setup and titration, you can optimize ventilatory support while ensuring patient comfort and synchrony with the device.