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.
- Pulmonary edema
- 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
- Prepare intubation equipment in case of BPAP/CPAP failure.
- Position the patient in a 30-90° upright position.
- 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.
- 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.
- 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.
- Continue close monitoring.
- A doctor, nurse, or respiratory therapist should be with the patient at all times during BPAP/CPAP use.
- Skin irritation
- Nasal bridge pain
- Mucosal dryness
- Eye irritation
- Gastric distention
- Decreased cardiac output
- Barotrauma (rarely)
- Noninvasive ventilation
- Mechanical ventilation (main)