Noninvasive ventilation

Background

Mechanism of Action

• Augments inspiratory/expiratory pressures throughout a spontaneous respiratory cycle.
  • Recruits compressed alveoli to reduce atelectasis.
  • Prevents small airway collapse during inspiration.
  • Counteracts intrinsic PEEP (Positive End Expiratory Pressure).
  • Decreased both preload and afterload in heart failure exacerbations.
  • Improves lung compliance and V/Q matching.
  • Decreases the work of breathing.

CPAP vs. BPAP

• CPAP = PEEP = EPAP
• BPAP = PEEP + (pressure support = IPAP)
  • Note: BiPAP is a brand name of one of the BPAP machines. Both names are often used interchangeably.

Indications

1. CHF
2. COPD
3. Asthma
4. OSA
5. Pulmonary edema
6. Pneumonia

Contraindications

1. Obtunded patients
2. Uncooperative patients
3. Vomiting or inability to protect the airway (aspiration risk)
4. Facial trauma or burns
5. Facial, esophageal, or gastric surgery
6. Poor mask fit

Settings

1. Failure of oxygenation
   1. Pulmonary Edema, PNA
   2. Start PEEP 5 (up to 15)
      1. Recruits alveoli
      2. Improves V/Q mismatch
      3. Decreases preload/afterload
2. Failure of ventilation
   1. Asthma, COPD
      1. When tire out unable to move air
   2. Need inspiratory pressure support
   3. Start pressure support 5 (up to 15)
   4. Consider PEEP 2-3 to overcome the mask

See Also

• Ventilation (Main)
• Ventilation (Settings)
• Ventilation (Weaning)
• Ventilation (Management)

Source

EMcrit Podcast 19