Noninvasive Ventilation (CPAP/BiPAP)

Noninvasive Ventilation (CPAP/BiPAP)

David Ray Velez, MD

Table of Contents

Definitions
Non-Invasive Positive Pressure Ventilation (NIPPV)
Non-Invasive Negative Pressure Ventilation (NINPV)

Definitions

Non-Invasive Ventilation (NIV): Ventilatory Support Delivered without Endotracheal Intubation or Tracheostomy

Non-Invasive Positive Pressure Ventilation (NIPPV): NIV Delivered Through the Use of Positive Pressure Via Nasal or Face Mask

  • Two Types: CPAP or BPAP

Non-Invasive Negative Pressure Ventilation (NINPV): NIV Delivered Through the Use of Negative Pressure Applied to the Trunk

Non-Invasive Positive Pressure Ventilation (NIPPV)

Non-Invasive Positive Pressure Ventilation (NIPPV): Noninvasive Ventilatory Support Delivered Through the Use of Positive Pressure Via Nasal or Face Mask
  • Two Types: CPAP or BPAP
Continuous Positive Airway Pressure (CPAP)
  • Mechanism: Provides a Continuous Positive Pressure (Similar to PEEP)
  • Effects:
    • Increased Alveolar Recruitment (Prevents Collapse to Maximize Oxygen Transfer)
    • Increased Functional Residual Capacity (FRC)
    • Increased Compliance
  • Common Initial Settings: 4-10 cm H2O
Bilevel Positive Airway Pressure (BPAP)
  • Mechanism: Provides a Continuous Positive Pressure (Similar to CPAP) with an Additional Higher Pressure on Inspiration
  • Settings:
    • Expiratory Positive Airway Pressure (EPAP): Lower Continuous Pressure (PEEP)
    • Inspiratory Positive Airway Pressure (IPAP): Higher Inspiratory Pressure (Pressure Support)
  • Benefit (Over CPAP): Reduces Work of Breathing During Inspiration
  • Common Initial Settings (IPAP/EPAP): 10/4 to 20/10 cm H2O
  • *Note: BiPAP ® is a Specific Brand-Name Type of BPAP, Often Used to Refer to BPAP
Indications
  • Best Outcomes are Shown in COPD Exacerbations and Acute Cardiogenic Pulmonary Edema
  • May Use in Acute Hypoxic Respiratory Failure of Other Causes (Data to Support is Less Robust)
  • CPAP Used Overnight in the Chronic Management of Obstructive Sleep Apnea (OSA)
Contraindications
  • Absolute Contraindications:
    • Need for Emergent Intubation (Unable to Protect Airway, Cardiopulmonary Arrest, or Severe Respiratory Distress) – The Only Absolute Contraindication
  • Relative Contraindications:
    • Copious Secretions
    • High Aspiration Risk
    • Facial Trauma
    • Recent Upper GI Anastomosis
    • Bowel Obstruction
    • Bullous Lung Disease/Emphysema
    • Massive Hemoptysis/Hematemesis
    • Hemodynamic Instability (Decreases Venous Return)
Complications
  • Mask Discomfort – Most Common
  • Skin Rash/Hypersensitivity
  • Pressure Ulcers to Face
  • Aerophagia
  • Aspiration
  • Pneumothorax
  • Pneumocephalus
  • Pneumomediastinum
  • Increased Intrathoracic Pressure Can Decrease Venous Return (Preload) and Cardiac Output
  • Patient-Ventilator Dyssynchrony with BPAP
    • Failure to Trigger Causing Inadequate Gas Exchange and Increased Work of Breathing

BiPAP

Non-Invasive Negative Pressure Ventilation (NINPV)

Non-Invasive Negative Pressure Ventilation (NINPV): Noninvasive Ventilatory Support Delivered Through the Use of Negative Pressure Applied to the Trunk

*Primarily of Historical Interest: Widely Used During the Polio Epidemic of the 1950’s and Rarely Used in a Modern Practice

Mechanism

  • Sub-Atmospheric Pressure is Applied to the Trunk to Generate the Negative-Pressure for Inspiration
  • Passive Elastic Recoil of the Lung Induces Exhalation

Comparison to Modern Positive Pressure Ventilation Systems

  • Similar Lung Perfusion
  • Advantages:
    • More Physiologic Mechanism
    • Ventilation is More Evenly Distributed with Better Oxygenation
    • Avoids Intubation
    • May Decrease Sedation Requirements
    • Increased Systemic Venous Return
  • Disadvantages:
    • Less Portable
    • Harder to Initiate
    • Can Exacerbate Obstructive Sleep Apnea Causing Collapse of the Extra-Thoracic Upper Airway During Inspiration
    • Less Protection of the Airway from Aspiration
    • Increased Left Ventricular Afterload

Types

  • Tank Ventilation (“Iron Lung”/Cabinet Ventilator)
    • The Entire Body, Except the Head is Enclosed with an Air-Tight Seal Around the Neck
    • Bulky and Heavy with Virtually No Portability
    • Rarely Used Today, More of a Historical Interest
  • Biphasic Cuirass Ventilation (BCV/Turtle Shell/Tortoise Shell)
    • Rigid Shell that Only Encloses the Chest and Abdomen
    • Essentially a More Compact Form of the Tank Ventilator
  • Jacket Ventilation (Pulmo-Wrap/Poncho-Wrap)
    • Impermeable Nylon Jacket Suspended by a Rigid Chest Piece Covering the Chest and Abdomen
    • Most Common form of NINPV Used Today

Modern Uses

  • Respiratory Failure from Neuromuscular Disorders
  • Central Apneas
  • Pediatric Intensive Care

Iron Lung