Noninvasive Ventilation Guide

CPAP and BiPAP settings for healthcare professionals

Noninvasive Ventilation Overview

Noninvasive ventilation (NIV) provides ventilatory support without the need for endotracheal intubation. It is delivered through various interfaces such as nasal masks, full face masks, or nasal pillows.

Two primary modes of NIV are:

  • CPAP (Continuous Positive Airway Pressure): Delivers a constant level of positive pressure throughout the respiratory cycle
  • BiPAP (Bilevel Positive Airway Pressure): Provides two distinct pressure levels - higher during inspiration and lower during expiration

NIV has become an essential tool in managing acute and chronic respiratory failure, offering benefits such as:

  • Reduced work of breathing
  • Improved oxygenation and ventilation
  • Preservation of airway defense mechanisms
  • Enhanced patient comfort and communication
  • Reduced risk of ventilator-associated pneumonia

NIV Interface Diagram

CPAP (Continuous Positive Airway Pressure)

Description

CPAP delivers a constant level of positive pressure throughout the respiratory cycle. It does not provide any additional pressure support during inspiration.

Key Characteristics

  • Single pressure level throughout respiratory cycle
  • Improves oxygenation through alveolar recruitment
  • Reduces work of breathing by splinting airways open
  • Patient controls all breathing parameters

Indications

  • Obstructive sleep apnea (chronic use)
  • Cardiogenic pulmonary edema
  • Mild to moderate hypoxemic respiratory failure
  • Post-extubation support

Advantages

  • Simple setup and management
  • Effective for oxygenation problems
  • Well-tolerated by many patients
  • Preserves patient's respiratory drive

Disadvantages

  • Limited assistance with ventilation
  • May increase work of breathing in some patients
  • Not suitable for severe respiratory acidosis
  • Interface leak can reduce effectiveness

Settings to Monitor

  • CPAP level (5-15 cmH2O typically)
  • FiO2 (start high, titrate to SpO2 88-95%)
  • Patient comfort and tolerance
  • Work of breathing
  • Arterial blood gases

BiPAP (Bilevel Positive Airway Pressure)

Description

BiPAP provides two distinct pressure levels: a higher pressure during inspiration (IPAP) and a lower pressure during expiration (EPAP). This pressure differential assists with both oxygenation and ventilation.

Key Characteristics

  • Dual pressure levels (IPAP and EPAP)
  • Provides ventilatory assistance
  • Can improve both oxygenation and CO2 elimination
  • Pressure support = IPAP - EPAP

Indications

  • Acute exacerbation of COPD
  • Acute cardiogenic pulmonary edema
  • Acute hypoxemic respiratory failure
  • Hypercapnic respiratory failure
  • Post-operative respiratory failure

Advantages

  • Assists with both oxygenation and ventilation
  • Reduces work of breathing more effectively than CPAP
  • Better tolerated in patients with increased work of breathing
  • Can be used in patients with mild ventilatory failure

Disadvantages

  • More complex setup than CPAP
  • May cause patient-ventilator dyssynchrony
  • Requires closer monitoring
  • Potential for gastric insufflation

Settings to Monitor

  • EPAP (5-10 cmH2O for oxygenation)
  • IPAP (10-20 cmH2O for ventilation)
  • Pressure support (IPAP - EPAP = 5-15 cmH2O)
  • FiO2 (titrate to SpO2 88-95%)
  • Respiratory rate and pattern
  • Arterial blood gases

Indications and Contraindications

Indications for NIV

  • Acute exacerbation of COPD with respiratory acidosis
  • Acute cardiogenic pulmonary edema
  • Immunocompromised patients with hypoxemic respiratory failure
  • Post-operative respiratory failure (selected cases)
  • Post-extubation support to prevent re-intubation
  • Acute asthma exacerbation (adjunctive therapy)
  • Community-acquired pneumonia with hypoxemia

Absolute Contraindications

  • Cardiac or respiratory arrest
  • Severe hypoxemia (PaO2/FiO2 < 100)
  • Severe acidosis (pH < 7.25)
  • Severe encephalopathy or delirium
  • Hemodynamic instability requiring vasopressors
  • Facial trauma or recent upper airway surgery
  • Inability to protect airway

Relative Contraindications

  • High aspiration risk
  • Severe vomiting or GI bleeding
  • Untreated pneumothorax
  • Severe obesity with restrictive lung disease
  • Non-cooperative patient
  • Excessive secretions with impaired clearance

NIV Settings Guide

Initial Settings

CPAP Initiation

Start with 5 cmH2O CPAP and FiO2 100%, then titrate both parameters

BiPAP Initiation

EPAP 4-5 cmH2O, IPAP 8-10 cmH2O, FiO2 100%, then titrate

Backup Rate (BiPAP-ST)

Set 2-4 breaths per minute below spontaneous rate

Interface Selection

Nasal mask for most patients, full face mask for mouth breathers

Settings Adjustment

Oxygenation Issues

Increase EPAP (CPAP) by 1-2 cmH2O increments, up to 15 cmH2O

Ventilation Issues

Increase IPAP by 2-3 cmH2O increments, maintaining pressure support < 20 cmH2O

FiO2 Titration

Titrate to maintain SpO2 88-95%, reduce to lowest effective level

Patient Discomfort

Check for mask leak, adjust fit, consider pressure relief features

Monitoring Parameters

Clinical Assessment

Work of breathing, respiratory rate, mental status, hemodynamics

Gas Exchange

Arterial blood gases or venous blood gas with SpO2 correlation

Device Monitoring

Leak rate (< 20-25 L/min), tidal volume, respiratory rate

Patient Tolerance

Comfort, mask fit, skin integrity, gastric distension