How a Ventilator is used to Deliver Oxygen to a Patient with a Breathing difficulty

A ventilator is used on patients who go into respiratory failure and cannot maintain breathing for some reasons. Respiratory failure occurs when the body’s metabolic needs are not met. If this is not corrected, then the patient will have laboured breathing, resulting into a cardiac arrest. When this limit is crossed or about to be crossed, the patient has to be intubated – which is a process of having a tube placed in the trachea (windpipe) so that the ventilator can be linked to it. The ventilator works by pushing air in and out of the lungs. The ventilator simulates breathing. The amount of oxygen and air can be adjusted during each breath and even the number of breaths per minute. The ventilator machine can even monitor lung mechanics such as:

• Compilation
• Resistance in airway

The ventilator is used till the patient breathes himself in the normal way.

Positive pressure ventilators generate the inspiratory flow by applying positive pressure (greater than atmospheric) to the airways

During the inspiration, the inspiratory flow delivery system creates a positive pressure into the patient circuit and the exhalation control system closes the outlet to the atmosphere. During the expiratory phase, the inspiratory flow delivery system stops the positive pressure at the exhalation system and opens the valves to allow the exhaled air to the atmosphere.

Positive pressure ventilators are used in treating a wide range of pulmonary disorders in patients. Positive pressure ventilators operate either in mandatory or spontaneous mode.

In spontaneous breath delivery, the ventilator responds to the patient’s effort to breathe independently. Therefore the patient can control the volume and rate of respiration. Spontaneous breath delivery is used for those patients who are on their way to full recovery but are not completely ready to breathe from the atmosphere without mechanical assistance. Mandatory breath delivery system is used for patients who are incapable of breathing on their own.

Learn more about these: ventilator resources

Generally, most ventilators employ positive pressure during inspiration to inflate the lungs with a mixture of gases (air, oxygen). Expiration is normally passive however under certain conditions pressure may have to be applied during the expiratory phase in order to improve arterial oxygen pressure.

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