Nomenclature of mechanical ventilation

Nomenclature of Mechanical Ventilation refers to the standardized terminology used to describe the various modes, settings, and parameters of mechanical ventilation. Mechanical ventilation is a life-saving intervention used in critical care settings to assist or replace spontaneous breathing in patients who are unable to maintain adequate ventilation on their own. The nomenclature is essential for ensuring clear communication among healthcare professionals and for the accurate operation of ventilation equipment.

Modes of Mechanical Ventilation

The modes of mechanical ventilation can be broadly categorized into two main types: Invasive Mechanical Ventilation and Non-Invasive Mechanical Ventilation. Within these categories, ventilation modes are further divided based on how the ventilator delivers breaths to the patient.

Invasive Mechanical Ventilation

• Volume-Controlled Ventilation (VCV): Delivers a pre-set volume of air with each breath. The pressure varies depending on the patient's lung compliance.
• Pressure-Controlled Ventilation (PCV): Delivers air until a pre-set pressure is reached. The volume of air delivered can vary.
• Assist-Control Ventilation (ACV): Allows spontaneous breathing, but provides a full assisted breath if the patient's effort falls below a certain threshold.
• Synchronized Intermittent Mandatory Ventilation (SIMV): Provides a combination of mandatory breaths synchronized with the patient's own breathing effort, along with spontaneous breaths.

Non-Invasive Mechanical Ventilation

• Continuous Positive Airway Pressure (CPAP): Maintains a constant level of pressure in the airways to keep them open.
• Bilevel Positive Airway Pressure (BiPAP): Provides two levels of pressure: a higher pressure during inhalation and a lower pressure during exhalation.

Ventilation Settings

Key settings on a ventilator include:

• Tidal Volume (VT): The volume of air delivered with each breath.
• Respiratory Rate (RR): The number of breaths delivered per minute.
• Positive End-Expiratory Pressure (PEEP): A pressure applied at the end of expiration to prevent alveolar collapse.
• FiO2: Fraction of inspired oxygen; the percentage of oxygen delivered to the patient.

Parameters to Monitor

Monitoring parameters are critical for assessing the patient's response to mechanical ventilation and include:

• Peak Inspiratory Pressure (PIP): The highest level of pressure applied to the lungs during inhalation.
• Plateau Pressure: The pressure in the lungs at the end of inhalation, which reflects alveolar pressure.
• Oxygen Saturation (SpO2): The percentage of hemoglobin saturated with oxygen, indicating the oxygen level in the blood.

Complications

Mechanical ventilation, while lifesaving, can be associated with complications such as ventilator-associated pneumonia (VAP), barotrauma, and ventilator-induced lung injury (VILI).

Conclusion

Understanding the nomenclature of mechanical ventilation is crucial for the effective management of critically ill patients. It facilitates precise communication among healthcare providers and ensures the appropriate application of ventilatory support.