What Is Mechanical Ventilation?
When a patient has difficulty breathing, a mechanical ventilator assists them by manipulating the pressure in their lungs. Mechanical ventilation typically involves a machine, called a ventilator, to help the patient breathe, as opposed to manual ventilation, which uses a bag valve mask (BVM) that must be operated manually. Mechanical ventilators are designed to provide consistent, automatic breaths with minimal intervention from physicians, nurses, or respiratory therapists. These machines are becoming more common in home, hospital, and pre-hospital settings. Let’s take a closer look at why mechanical ventilation is used and how it works.
The Purpose of Mechanical Ventilation
In a clinical setting, mechanical ventilation keeps a patient stable while the care team treats their underlying conditions, and it is often used to protect airways from pulmonary aspiration or to correct imbalanced blood gases. Mechanical ventilation is not used as a therapeutic measure. Health conditions commonly treated by mechanical ventilation include:
- Acute severe asthma
- Hypotension
- Acute lung injury
- Lung damage
- Apnea
- Neurological diseases
How Mechanical Ventilation Differs from Manual Ventilation
The terms “mechanical ventilation” and “manual ventilation” are sometimes used interchangeably. However, mechanical ventilation properly refers to the use of a specialized machine, called a ventilator, while manual ventilation implies the use of a bag valve mask (BVM).
Typically, manual ventilation is performed by a trained specialist squeezing a BVM to alter the air pressure in the patient’s lung. A BVM is inexpensive compared to a ventilator and does not require electricity to function, making it suitable for rescuers in many different environments and situations. Unfortunately, manual ventilation is subject to human error since the BVM is hand operated.
To avoid human error, many hospitals and EMS providers choose to use ventilators whenever possible. While a specialist will still need to assess a patient’s breathing and provide recommendations regarding the ventilator’s settings, the machine provides a much more consistent, hands-off means of ventilation. A patient on a ventilator still requires ongoing monitoring and assessment, but overall, these machines help give the care team more time to focus on treating the patient’s underlying condition.
Types of Mechanical Ventilation
There are two primary types of mechanical ventilation: negative pressure ventilation (NPV) and positive pressure ventilation (PPV).
Negative pressure ventilation exposes the thorax to sub-atmospheric pressure, which causes breathing by sucking air into the lungs. NPV is largely out of practice, but it still has a few niche uses (such as preparing a donor lung for transplantation).
Positive pressure ventilation delivers either room air or oxygen gas to a patient’s lungs via a tube and is the most common form of ventilation used today. There are two types of positive pressure ventilators: invasive and non-invasive.
An invasive ventilator is used in clinical settings and ventilates the patient via an endotracheal or tracheostomy tube that is inserted into their airway. A non-invasive ventilator can be used in clinical settings or in the home to help patients who experience conditions like COPD or sleep apnea, and uses a face mask, nasal mask, or helmet to ventilate the patient. Hospitals should have both types of ventilator available.
Using Mechanical Ventilation for Patient Transport
A portable ventilator is ideal for keeping patients stable during transport, though not all ventilators are suitable for this purpose. Patients who are attached to a portable ventilator should still have their condition closely monitored by the care team.
Portable ventilators are reliable, lightweight, and come equipped with enough battery life to sustain most patients for the duration of their transport. This makes them easy to maneuver throughout an ICU or similar clinical setting, while also making them appropriate for use within ambulances or air transport.
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Interested in learning about how ventilators can help COVID-19 patients? Check out our COVID-19 resource hub. Or if you’d like to learn more about how to use a ZOLL® ventilator, visit our Z Vent training page.
