Mechanical Ventilation Overview

Mechanical Ventilation

• Mechanical ventilation (MV) is a technique that uses an external device to move gas to and from the lungs.
• MV helps manage gas exchange and acid-base balance by controlling:
  • Inspired oxygen (FIO2)
  • Minute volume (VE)
  • Pressure
  • Volume
  • I:E ratio
  • Positive end-expiratory pressure (PEEP)
• MV works by applying tidal volumes to improve functional residual capacity (FRC).
• MV supports respiration when there's an increased ventilatory demand.
• MV goals:
  • Decrease work of breathing
  • Improve oxygenation
  • Improve carbon dioxide clearance
  • Maintain arterial blood gases (ABG) within normal range
  • Improve distribution of inspired gases

Indications for MV

• Increased work of breathing due to airway obstruction.
• Impending or existing respiratory failure.
• Acute head injuries in sedated patients.
• Control ventilation in critically ill patients like those in coma, Guillain-Barré Syndrome (GBS).
• Inspiratory muscle weakness.
• Hypercarbia, hypoxia, and clinical deterioration.
• Post-surgical conditions

Intubation Methods

• A patient can be connected to a ventilator via an endotracheal tube (ET) or tracheostomy tube (TT).
• ET placement involves inserting a tube through the nose or mouth, through the larynx, and into the trachea.
• TT provides an airway directly into the second or fourth tracheal rings.
• TT is shorter and more comfortable, offering less resistance to airflow.
• TT is suitable for long-term ventilation.
• TTs may be cuffed for MV or to prevent aspiration.
• TTs are uncuffed when patients have competent glottis function.

Indications for Intubation

• To protect the airway from aspiration, especially in patients with a loss of gag/cough reflex (Glasgow Coma Scale score ≤ 9).

Decannulation of Tracheostomy

• The first step involves replacing the cuffed TT with an uncuffed tube.
• The tube can be removed when the patient has a satisfactory cough with minimal secretions.
• After tube removal, the patient is taught how to hold a sterile dressing over the stoma when coughing.

Mechanical Ventilation

• A technique that uses an external device to move gas towards and from the lungs.
• Regulates gas exchange and acid-base balance by manipulating:
  • Inspired oxygen (FIO2)
  • Minute volume (VE)
  • Pressure
  • Volume
  • I: E ratio (Inspiration to expiration ratio)
  • PEEP (Positive End-Expiratory Pressure)
• Improves functional residual capacity (FRC) by applying tidal volumes.
• Provides respiratory support for increased ventilatory demands.

Goals of Mechanical Ventilation

• Decrease work of breathing, allowing respiratory muscles to rest.
• Improve oxygenation.
• Enhance carbon dioxide clearance.
• Maintain arterial blood gases (ABG) within normal ranges.
• Improve the distribution of inspired gases.

Indications for Mechanical Ventilation

• Increased work of breathing due to airway obstruction.
• Impending or existing respiratory failure.
• Acute head injuries with sedation.
• Controlling ventilation in critically ill patients (coma, Guillain-Barré syndrome).
• Inspiratory muscle weakness.
• Hypercarbia, hypoxia, and clinical deterioration.
• Post-surgical conditions.

Intubation Methods

• Endotracheal tube: Placed through the nose or mouth, into the larynx and trachea.
  • Provides a temporary airway and helps to protect it from aspiration.
• Tracheostomy Tube: Inserted directly into the 2nd or 4th tracheal ring, bypassing the upper airway.
  • Provides a more comfortable and less resistant airway for long-term ventilation.
  • Can be cuffed to prevent aspiration or for mechanical ventilation.
  • Can be uncuffed if the patient has intact glottis function.

Indications for Intubation

• To protect the airway from aspiration, especially for patients with decreased gag/cough reflex (Glasgow Coma Scale (GCS) < 9).

Decannulation of Tracheostomy

• First, the cuffed tracheostomy tube is replaced with an uncuffed tube.
• Removal of the tube occurs when:
  • The patient demonstrates satisfactory cough effectiveness.
  • Minimal secretions are present.
• Post-removal, patients are trained to cover the stoma with a sterile dressing while coughing.