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.
• Reduces need for intubation and mortality in acute cardiogenic pulmonary edema and acute COPD exacerbation

CPAP vs. BPAP

Illustration of difference between CPAP and BPAP.

• CPAP = PEEP = EPAP
  • Use for isolated hypoxia
  • Increasing CPAP increases oxygenation
• BPAP = PEEP + (IPAP = Inspiratory Pressure Support)
  • Use for hypoxia and hypoventilation (decreases work of breathing)
  • Increasing IPAP (specifically IPAP-CPAP) increases ventilation
    • 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

Patient on BPAP.

CPAP mask on EMS manikin.

Home CPAP device.

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 low-dose fentanyl, 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
  • Intubation (peds)
• Mechanical ventilation (main)
  • Ventilation modes
  • Initial mechanical ventilation settings
    • Initial mechanical ventilation settings (peds)
  • Adjusting mechanical ventilation settings
    • Deterioration after intubation
    • Lung recruitment maneuver
    • Ventilator high pressures
    • Ventilator associated lung injury
  • Weaning mechanical ventilation
    • Extubation
• Miscellaneous
  • ARDS and EBQ:ARDSnet
  • Airway pressure release ventilation
  • Ideal Body Weight Estimation

External Links

• Merk Manual - How To Do Noninvasive Positive Pressure Ventilation
• NUEM - Non-Invasive Positive Pressure Ventilation in the ED