Introduction
Artificial ventilation refers to the exchange of gases in the body by ventilation, external respiration, and internal respiration. It is achieved through manual insufflation of the lungs through mouth-to-mouth resuscitation or mechanical devices. However, artificial ventilation through mechanical devices is more effective in providing pulmonary ventilation.
What Is Artificial Ventilation?
Artificial ventilation is also called artificial respiration. This process stimulates or assists breathing for persons who are unable to breathe or have difficulty breathing. The complete exchange of gases happens via external respiration, internal respiration, and pulmonary ventilation. Artificial ventilation is achieved with mouth-to-mouth resuscitation or by using mechanical devices. Mouth-to-mouth resuscitation is a part of cardiopulmonary resuscitation (CPR). It is done for drowning individuals and in opiate overdose.
What Are the Types of Artificial Ventilation?
There are two types of artificial ventilation, positive pressure ventilation and negative pressure ventilation.
Positive Pressure Ventilation
Positive pressure ventilation involves the delivery of air or a mixture of oxygen and other gases into the lungs. It forces air into the lungs and delivers oxygen to the alveoli (air sacs) in the lungs. Positive pressure ventilators may be pressure-controlled, volume-controlled, or dual control.
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Continuous Positive Airway Pressure (CPAP) - It delivers constant and steady air pressure for patients with sleep apnea. It uses mild pressure to open the airway for patients with breathing problems during sleep. CPAP machine comprises a mask that fits the mouth, a tube that connects the mask to the motor, and a motor that pumps air into the tube.
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Automatic Positive Airway Pressure (APAP) - It automatically changes air pressure according to the breathing requirement of the patient. It is used for patients with sleep apnea.
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Bilevel Positive Airway Pressure (BiPAP) - Bilevel positive airway pressure delivers more air pressure during inhalation and reduced air pressure during exhalation. It is used in chronic obstructive lung disease (COPD) and obstructive or central sleep apnea. It has a timer to program the number of breaths per minute.
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Non-invasive Ventilation (NIV) - NIV is a technique of providing ventilation without using artificial airways.
Negative Pressure Ventilation
A negative pressure ventilator applies negative air pressure to the entire body below the neck, expands the lungs, and initiates inhalation of air. In addition, the negative pressure reduces and compresses the lungs for exhalation. There are different negative pressure ventilators, but they are of little use in the current scenario.
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Iron Lung - The first negative pressure ventilator, a tank ventilator. It is a large, sealed horizontal cylinder in which the patient lies down with the head protruding from one end of the cylinder. An air pump lowers and raises the air pressure in continuous alterations and causes the patient’s chest to rise and fall to stimulate inhalation and exhalation through the patient’s nose and mouth, which are outside the cylinder.
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Cuirass Ventilator - It is also known as chest shell, turtle shell, or tortoiseshell ventilator. It consists of a small shell attached to the patient’s chest with a strap to create negative pressure. They are easy to wear and suitable for home use.
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Exovent - is a newly developed ventilator responding to COVID (coronavirus disease). The patient lies on the internal mattress inside the event, and the cover is placed over the entire body and arms and fitted with neck and hip seals. This delivers negative air pressure.
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Jacket Ventilator - It is a poncho or raincoat ventilator. It has an inner metal or plastic framework covered with an anorak-like jacket. It seals around the neck, arms, and thighs. The air is intermittently evacuated to provide Ventilation.
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Pulmotor - It is a positive and negative pressure ventilator that uses pressure from a tank of compressed oxygen and a valve system to force air into the patient’s airway using alternative positive and negative pressure. But it is considered dangerous by some medical professionals. As a result, it is not used due to the risk of barotrauma (damage to the body tissues due to the continuous changes in the air pressure) and vomiting.
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Hayek Oscillator - is a versatile ventilator with a lightweight, flexible, airtight chest enclosure with a soft seal around the chest and abdomen that rests on a backplate or a loose cushion. This ventilator is attached to a piston pump to provide a baseline and high-frequency negative pressure.
Airway Devices Used in Artificial Ventilation:
The following airway devices are used to provide artificial ventilation:
- Endotracheal Intubation - The endotracheal tube is inserted into the patient’s airway through the nose or the mouth. A laryngoscope visualizes the vocal cords and upper part of the airway while inserting the tube. It supports breathing in conditions like pneumonia, emphysema, heart failure, lung collapse, or trauma.
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Tracheostomy Tube - A curved plastic tube inserted through an opening created in front of the neck to reach the trachea (airway). It is used in emergencies when endotracheal intubation cannot be done. It is also used in trauma, head and neck surgeries, and long-term Ventilation.
What Are the Indications of Artificial Ventilation?
Artificial Ventilation is required in conditions like:
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Pneumonia.
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Acute asthma.
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Chronic obstructive pulmonary disease (COPD).
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Acute respiratory distress syndrome (ARDS).
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Collapsed lung or severe lung injury.
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Cardiovascular diseases.
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Coma.
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Airway obstruction.
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Protection of airway.
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Suctioning of secretions.
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Respiratory failure.
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During surgical procedures under anesthesia.
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Viral infections like influenza, severe acute respiratory syndrome (SARS), and coronavirus disease (COVID).
What Are the Uses of Mechanical Ventilation?
There are 23 operating modes of mechanical ventilation. The uses of mechanical ventilation include the following;
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It allows the respiratory muscles to rest.
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It provides adequate oxygen and removes carbon dioxide.
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It stabilizes the airway and prevents aspiration.
What Are the Complications of Artificial Ventilation?
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Trauma to mouth, nose, vocal cords, or trachea during intubation.
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Lung injury leading to lung collapse. Trauma due to excess air pressure (barotrauma), trauma due to extra volume (volutrauma).
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Ventilator-associated pneumonia due to bacterial and viral infections.
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Oxygen toxicity due to increased oxygen.
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Sepsis.
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Inability to wean from the ventilator.
Conclusion
Mechanical ventilation is an effective treatment strategy for respiratory disorders. Continuous advancements and computer feedback systems help to meet the individual requirements of artificial ventilation. In addition, improvements in mechanical ventilation technologies optimize patient-ventilator interactions and outcomes.
