Understanding Mechanical Ventilation : A Comprehensive Guide

Mechanical ventilation is a form of treatment used to help the patient in breathing or actually will breathe for the patient if he/she is unable to do so on their own.^{(1, 2, 3)} A person can be on a ventilator during surgery or in cases where the lungs aren’t functioning as they should.⁽¹⁾ The function of mechanical ventilation is keeping the airways open, eliminating carbon dioxide and delivering oxygen to the body.

Mechanical ventilation is not responsible for directly treating any diseases; it is more of an aid or help in stabilizing the patient while medications and other treatments help in fighting the illness and helping the body to recover.

It is a machine which helps the patient in breathing similarly to how crutches help in supporting the weight. The ventilator completely or partially helps in supporting the function of the lungs. The functions of the ventilator are:⁽⁴⁾

• Removing carbon dioxide from the lungs.
• Giving oxygen to the lungs.
• Provides ample pressure so the alveoli or the small air sac present in the lungs do not collapse.
• The settings on the ventilator can be adjusted as per the requirement of the patient.

Mechanical ventilation and intubation are commonly done together; however, they both are different. Intubation is where a tube is inserted down the throat into the trachea.⁽⁵⁾ This tube then will be connected to a ventilator. In some cases, the patient is not intubated and instead a face mask is used to connect the patient to the ventilator.

Noninvasive Ventilation:⁽⁶⁾ In this type of ventilation, a face mask is used instead of a tube to connect the patient to the ventilator. The mask is held firmly in place with the help of straps. The ventilator propels the air into the lungs. Other types of noninvasive ventilation are devices which can be used at home, such as BiLevel positive airway pressure or CPAP.

Invasive Mechanical Ventilation:⁽⁶⁾ In this type of ventilation, there is a tube in the airway which is then connected to a ventilator. This tube can go through the neck (tracheostomy) or through the mouth (intubation).

Mechanical respiration or ventilation is needed during the following scenarios:

• During surgery when general anesthesia is used, the patient cannot breathe sufficiently on its own.
• In case of a medical emergency where the airway is blocked or if the breathing is impaired.
• When suffering from certain forms of lung infections or conditions.
• In case of certain types of brain conditions or injuries where the communication between the body (including lungs) and the brain is impaired, which results in not being able to breathe properly.
• In case of certain conditions, which cause excessive carbon dioxide (hypercapnia) to accumulate in the blood or if there is insufficient oxygen (hypoxemia).
• To prevent accidental aspiration, where the fluids get into the lungs.
• Some of the conditions which need mechanical ventilation are: pneumonia, coma, stroke, anaphylaxis, traumatic brain injury, acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD) and COVID-19 and other respiratory illnesses.

The amount of time a patient needs mechanical ventilation depends on the cause of it and it can be hours to days to weeks and in some rare cases even months or years. Most of the times, the patient will need mechanical ventilation for as little time as possible. The doctor will assess the patient’s ability to breathe without its support and decide the duration of mechanical ventilation and when to wean off.

In case the patient needs to be on a ventilator for about a couple of weeks or more, then the doctor will likely change the patient from an endotracheal tube to a tracheostomy where a tube is inserted via the neck into the airways

The procedure of invasive mechanical ventilation is as follows:⁽⁷⁾

The patient is given medication for sedation so the patient can relax and not move unnecessarily or fidget. An endotracheal tube is inserted down the throat and trachea, which is the airway leading to the lungs. The tube is then attached to the ventilator, which will assist in breathing. This patient will be kept on the ventilator until the medical team deems it safe for the patient to breathe on their own again.

All these steps can vary depending on patient to patient and their specific condition.

When the patient is on the ventilator, the doctors will do other necessary procedures for preventing and treating complications. These can consist of: monitoring, giving medications, suctioning, bronchoscopy, mobilization, giving fluids and nutrition.

Other Machines: Additional machines can be connected to the patient to assess how the body is functioning. This can consist of: heart rate, blood pressure, oxygen levels and respiratory rate.

Suctioning is done to keep the airways clear and this is an important step. This is done by inserting a catheter into the breathing tube, which will then remove mucus.

Investigations: Blood tests and chest X-rays can be done to look at the lungs and find out the oxygen and carbon dioxide levels in the blood.

Medications in aerosolized from are given via breathing tube. These medications act better when they are inhaled directly into the lungs or airways. Intravenous medicine may also be given as needed. Nutrition in liquid form is given when the patient is on ventilator as patient cannot consume anything when intubated.  The liquid food is given via the tube which is then passed through the nose and into the stomach. Intravenous fluids are also given to the patient.

Mobilization means where the patient is made to sit up regularly and in some cases is also encouraged to get up and walk.

Bronchoscopy is done to check the airways in the lungs. This is done by inserting a small, lighted camera via the breathing tube and into lungs. Samples of tissue or mucus can also be taken for testing.

The patient is kept on ventilator in an intensive care unit (ICU) and is closely monitored by the doctors and other staff who are specially trained for caring the patients requiring mechanical ventilation.

When the patient is on a ventilator, the doctor will try to keep the patient awake as much as possible, while making sure that he/she is comfortable and relaxed.

Medications are given for this purpose as needed. The patient can be awake, but can also feel confused, sleepy or not completely comprehending of what is going on.

In some cases, depending on the patient’s illness, the doctor will keep the patient deeply sedated so the patient is not disturbed and the body can recover. The arms of the patient might be restrained for preventing any self-injury, such as pulling on the tube when waking up.

The doctors will perform tests to assess if the patient can breathe on their own and then decide whether he/she can be taken off the ventilator. The endotracheal tube is not removed when doing these tests. As the condition of the patient improves and the patient can breathe on their own, the doctor will remove the endotracheal tube and then take the patient off mechanical ventilation.

There may be soreness of the throat or mouth; and hoarseness of the voice after removing the endotracheal tube.

The removal of the ET tube is known as extubation after which the patient can be kept on other devices for assisting in breathing, such as oxygen masks or noninvasive ventilation using a mask. In some cases, depending on the condition the patient can be intubated again and shifted back on mechanical ventilation.

The advantages of mechanical ventilation are:

• The patient does not have to exert himself when trying to breathe and the body can recover and heal in the mean time.
• The mechanical ventilation helps in providing all the oxygen needs of the patient and also removes carbon dioxide.
• It helps in keeping the airways open.
• The mechanical ventilator also applies pressure to prevent small sacs of the lungs from collapsing.

Despite all the care taken to prevent or avoid complications there might be a few risks mechanical ventilation carries, such as:^(8,9)

Bacterial Infections: The bacteria can easily enter the lungs via the ET tube and cause infections like VAP or ventilator-associated pneumonia. Antibiotics are used for treating this infection.

Lung damage can occur from the pressure exerted from the ventilator.

Collapsed lung can also occur if an area of the lung is weak, then it can develop a hole, resulting in pneumothorax which is collapsing of the lungs.

Changes in the heart and blood flow occur by being on a ventilator. If there are problems in the functioning of the heart, then there is reduction in the blood pressure or increase in the heart rate. This results in reduced oxygen in the blood despite there being sufficient oxygen present in the lungs.

In cases where the patient is unable to come off the ventilator or needs to be put on a ventilator for prolonged period of time, then the doctor will remove the tube from the mouth and insert in into the neck via a small incision.

Unnecessary suffering can occur as the mechanical ventilation can prolong the dying process in cases where the likelihood of the patient recovering from their condition is nil. Keeping such patients on ventilators just prevents death and cause lot of unnecessary suffering. Ask your doctor for guidance in making these tough decisions about mechanical ventilation in such cases.

The amount of time needed to get off the mechanical ventilation depends on the cause of and the duration of which the patient was on it. The doctor will guide the family members in terms of expectations and how to take care of the patient after being weaned off the mechanical ventilation.

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