Mechanical Ventilation Overview and Types

Mechanical Ventilation Overview

• A mechanical ventilator is a device that offers positive or negative pressure breathing support for extended periods.
• Primarily used for patients with respiratory failure or compromised airways.
• Often involves endotracheal intubation or tracheostomy.

Types of Ventilators

• Positive-pressure ventilators (PPVs): Inflate the lungs by pushing air into them.
  • Volume-cycled ventilators: Deliver a specific volume of air with each breath.
  • Pressure-cycled ventilators: Deliver air until a set pressure is reached.
  • High-frequency oscillatory support ventilators: Provides very high-frequency breaths for better air movement.
  • Noninvasive positive-pressure ventilation (NIPPV): Offers pressure support through masks without intubation.
• Negative-pressure ventilators (NPVs): Achieve lung inflation by drawing the rib cage and abdomen outward.
  • Iron-lung or Tank ventilators: Large sealed cylinders in which patients lie with their heads out.
  • Cuirass ventilator: Smaller version of the iron lung, enclosing only the torso.
  • Exovent ventilator: A modern NPV developed for the COVID-19 pandemic.
  • Jacket ventilator: Also known as a poncho or raincoat ventilator, a lighter version of the iron lung.

Ventilator Modes

• Controlled mechanical ventilation: The ventilator controls all breaths.
• Assist-control (A/C) ventilation: The ventilator provides breaths based on the patient's effort.
• Intermittent mandatory ventilation (IMV): The ventilator provides a set number of breaths, allowing for spontaneous breathing.
• Synchronized intermittent mandatory ventilation (SIMV): Similar to IMV but synchronizes ventilator breaths with patient effort.
• Pressure support ventilation: Assisted breathing with extra pressure added to each breath the patient makes.
• Airway pressure release ventilation: A combination of positive pressure and pressure release for better lung expansion.

Nursing Care Priorities

• Ensuring a patent airway and proper placement of the endotracheal tube.
• Monitoring and managing respiratory status: Lung sounds, oxygen saturation, and end-tidal carbon dioxide levels.
• Managing sedation and pain control: For patient comfort and sync with the ventilator.
• Identifying and handling potential complications: Tube dislodgement, pneumothorax, airway obstruction.
• Preventing complications: Ventilator-associated pneumonia and ventilator-induced lung injury.
• Optimizing ventilator settings: In collaboration with the healthcare team.
• Facilitating weaning protocols and extubation readiness assessments: Along with ongoing patient and family education.

Key Nursing Assessments

• Subjective data:
  • Apprehension, dyspnea, restlessness.
• Objective data:
  • Adventitious breath sounds, diminished lung sounds, abnormal breath sounds, increased or decreased respiratory rate, apnea, ineffective cough, decreased oxygen saturation, increased end-tidal carbon dioxide, difficulty maintaining airway, increased or decreased tidal volume, excessive secretions.

Factors related to Mechanical Ventilation

• Acute respiratory failure
• Noncompliant lung tissue
• Respiratory muscle weakness or paralysis
• Altered oxygen/carbon dioxide ratio
• Decreased energy and fatigue
• Endotracheal intubation
• Stasis of secretions