What are the initial BiPAP (Bilevel Positive Airway Pressure) parameters and how are they set?

BiPAP Parameter Settings and Indications

Initial Pressure Settings

Start with IPAP of 8 cm H₂O and EPAP of 4 cm H₂O for both adult and pediatric patients as the standard initial settings. 1

• These minimum starting pressures apply universally unless specific patient factors warrant adjustment 1
• For patients with elevated BMI, begin with higher initial pressures than these standard values, though exact starting pressures should be determined by body habitus 1, 2
• Maintain a minimum pressure differential of 4 cm H₂O between IPAP and EPAP at all times 1, 2
• The maximum pressure differential should not exceed 10 cm H₂O 1

Maximum Pressure Limits

• Maximum IPAP should be 20 cm H₂O for patients under 12 years of age 1
• Maximum IPAP should be 30 cm H₂O for patients 12 years and older 1, 2
• These limits represent safety thresholds beyond which BiPAP should not be titrated 1

Indications for Switching from CPAP to BiPAP

Switch to BiPAP when the patient is uncomfortable or intolerant of high CPAP pressures, or when obstructive respiratory events persist at 15 cm H₂O of CPAP. 1

• This 15 cm H₂O threshold applies to both adult and pediatric patients 1
• Patient discomfort with high pressures is a valid clinical indication for BiPAP even before reaching the 15 cm H₂O threshold 1
• BiPAP provides lower expiratory pressure, which improves patient tolerance compared to single-level CPAP 1

Titration Algorithm During Sleep Studies

Increase IPAP and/or EPAP by at least 1 cm H₂O increments with intervals no shorter than 5 minutes until obstructive respiratory events are eliminated. 1

Specific Titration Rules:

• Increase both IPAP and EPAP together if ≥2 obstructive apneas are observed in patients ≥12 years 1
• Increase both IPAP and EPAP together if ≥1 obstructive apnea is observed in patients <12 years 1
• Increase IPAP alone (not EPAP) for hypopneas and respiratory effort-related arousals (RERAs) 1
• Continue titration until ≥30 minutes without breathing events is achieved 1
• The goal is complete elimination of apneas, hypopneas, RERAs, and snoring in that order of priority 1

Mode Selection for Different Clinical Scenarios

For Obstructive Sleep Apnea:

• Use spontaneous mode (S mode) where the patient triggers all breaths 1
• This is the standard mode for OSA titration during polysomnography 1

For Patients with Poor Respiratory Drive:

• Use spontaneous-timed mode (ST mode) with a backup respiratory rate 2
• Set backup rate at 10-12 breaths/minute, equal to or slightly less than the patient's spontaneous rate during sleep 2
• Configure inspiratory time to achieve an inspiratory-to-expiratory (I:E) ratio of approximately 1:2 2
• This prevents central apneas and ensures adequate ventilation if spontaneous effort diminishes 2

Common Pitfalls and How to Avoid Them

Pressure Intolerance:

• If the patient awakens and complains pressure is too high, restart at a lower pressure that the patient reports is comfortable enough to allow return to sleep 1
• Do not persist with uncomfortable pressures as this leads to poor adherence 1

Treatment-Emergent Central Apneas:

• If central apneas develop during titration, decrease IPAP or switch to ST mode with backup rate 1
• Central apneas indicate excessive pressure support that is suppressing respiratory drive 1

Inadequate Pressure Increases:

• In split-night studies with limited titration time, consider larger increments of 2 or 2.5 cm H₂O to reach effective pressure more quickly 1
• Standard 1 cm H₂O increments may be too conservative when time is limited 1

COPD Patients:

• BiPAP carries risk of increased work of breathing in spontaneously breathing COPD patients due to intrinsic PEEP 3
• Ensure adequate expiratory time (I:E ratio 1:2) to prevent air trapping and auto-PEEP 2
• EPAP helps offset intrinsic PEEP and improves triggering, reducing perceived effort 4

Pre-Titration Requirements

All patients must receive adequate BiPAP education, hands-on demonstration, careful mask fitting, and acclimatization prior to titration. 1

• Proper mask fitting is essential to minimize leaks that reduce treatment effectiveness 4
• Patient education improves tolerance and adherence to prescribed pressures 1
• Acclimatization allows patients to become comfortable with the sensation of positive pressure 1

Special Considerations for Acute Care Settings

• For aspiration patients or those with acute respiratory failure, evaluate response within 1-2 hours of initiating BiPAP 2
• Inability to maintain SpO₂ >90% despite FiO₂ escalation indicates BiPAP failure requiring intubation 2
• Do not delay intubation if the patient shows signs of deterioration within this narrow window 2
• Patient must be oriented and able to tolerate a well-fitted, non-vented face mask for BiPAP to be appropriate 2