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 + (IPAP = Inspiratory Pressure Support)
  • Note: BiPAP is a brand name of one of the BPAP machines. Both names are often used interchangeably.

Indications

• CHF
• COPD
• Asthma
• OSA
• Pulmonary edema
• Pneumonia

Contraindications

• Obtunded patients
• Uncooperative patients
• Vomiting or inability to protect the airway (aspiration risk)
• Facial trauma or burns
• Facial, esophageal, or gastric surgery
• Poor mask fit

Procedure

1. Prepare intubation equipment in case of BPAP/CPAP failure.
2. Position the patient in a 30-90° upright position.
3. Apply the mask.
   • Select the appropriately-sized mask.
   • Secure it in place by fastening the Velcro straps.
   • Note: Some experts recommend allowing the patient to get used to the mask first, PRIOR TO starting the positive airway pressures.
4. Prepare the patient.
   • Patients will often require frequent coaching throughout this process.
   • In moderately anxious patients, consider a benzodiazepine or Ketamine to assist with patient-ventilator synchrony.
5. Adjust the settings.
   • For BPAP, begin with an IPAP of 8-10 cm H2O and an EPAP of 2-4 cm H2O.
   • Gradually titrate upward IPAP and EPAP 1-2 cm every 5-15 minutes with a goal IPAP 10-16 cm H2O and EPAP of 8-10 cm H2O depending upon patient response.
6. Continue close monitoring.
   • A doctor, nurse, or respiratory therapist should be with the patient at all times during BPAP/CPAP use.

Complications

• Skin irritation
• Nasal bridge pain
• Mucosal dryness
• Eye irritation
• Gastric distention
• Decreased cardiac output
• Barotrauma (rarely)

See Also

Mechanical Ventilation Pages

• Noninvasive ventilation
• Intubation
  • Rapid Sequence Intubation (RSI)
  • Difficult airway algorithm
  • Supraglottic airway
  • Nasal intubation
• Deterioration after intubation
• Ventilation settings
• Ventilation modes
• Ventilator high pressures
• Ventilator associated lung injury (VALI)
• Recruitment maneuver
• Ventilation weaning
• Extubation

References

Authors

Ross Donaldson