Surgical Critical Care: Non-Invasive Ventilation (NIV)

Non-Invasive Ventilation (NIV)

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

Non-Invasive Positive Pressure Ventilation (NIPPV)

Continuous Positive Airway Pressure (CPAP)

  • Mechanism:
    • Provides a Continuous Positive Pressure (Similar to PEEP)
  • Benefit: Increases Recruitment of Collapsed Alveoli to Keep Open – Maximizes Oxygen Transfer

Bilevel Positive Airway Pressure (BPAP)

  • Mechanism:
    • Provides a Continuous Positive Pressure (Similar to CPAP)
    • Provides Additional Higher Pressure on Inspiration
  • Settings:
    • Expiratory Positive Airway Pressure (EPAP) – Low Pressure (PEEP)
    • Inspiratory Positive Airway Pressure (IPAP) – High Pressure (Pressure Support)
  • Benefit (Over CPAP): Reduces Work of Breathing During Inspiration
  • *BiPAP is a Specific Brand-Name Type of BPAP, Often Used Incorrectly to Refer to BPAP

Indications

  • Acute Respiratory Failure from COPD or CHF
  • Possibly Acute Hypoxic Respiratory Failure of Other Causes (Data to Support is Less Robust)
  • *CPAP is Also Used Overnight in the Chronic Management for Patients with 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
    • Aspiration Risk
    • Facial Trauma
    • Recent Upper GI Anastomosis
    • Bowel Obstruction
    • Bullous Lung Disease/Emphysema
    • Massive Hemoptysis/Hematemesis
    • Hemodynamic Instability (Decreases Venous Return)

BPAP 1

Non-Invasive Negative Pressure Ventilation (NINPV)

Basics

  • Mechanism:
    • Sub-Atmospheric Pressure is Applied to the Trunk to Generate the Negative-Pressure for Inspiration
    • Passive Elastic Recoil of the Lung Induces Exhalation
  • Widely Used During the Polio Epidemic of the 1950’s
  • Rarely Used in Modern Practice Outside of Select Situations

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 & 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 & 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 & Abdomen
    • Most Common form of NINPV Used Today

Modern Uses

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

Iron Lung 2

References

  1. Heilman J. Wikimedia Commons. (License: CC BY-SA-4.0)
  2. Sgerbic. Wikimedia Commons. (License: CC BY-SA-4.0)