weaning off ventilator And how to do it

weaning off ventilator, The respiratory center, located in the lower part of the brain, involuntarily controls breathing, which, in general, is automatic. Breathing continues during sleep and even when unconscious. A person can also control breathing according to need, for example during speech, when singing or voluntarily containing it.

The brain, the aorta and the carotid arteries have small sensory organs that analyze the blood and detect levels of oxygen and carbon dioxide. Normally, a high concentration of carbon dioxide is the most powerful stimulus to breathe more deeply and more frequently. Conversely, when the concentration of carbon dioxide is low, the brain decreases the frequency and depth of breathing. The respiratory rate of the adult during rest is about 15 breaths (inhalations) and exhalations (exhalations) per minute.

weaning off ventilator

Respiratory muscles

The lungs do not have their own skeletal muscles. The work of respiration is mainly performed by the diaphragm and, to a lesser extent, the intercostal, cervical and abdominal muscles.

The diaphragm, a laminar dome-shaped muscle that separates the thoracic cavity from the abdomen, is the most important muscle for inhalation or inspiration. The diaphragm adheres to the base of the sternum, the lower edge of the rib cage and the spine. As the diaphragm contracts, the length and diameter of the chest cavity increase so that the lungs expand. The intercostal muscles participate in breathing helping to mobilize the rib cage.

The process of exhalation or expiration is usually passive when efforts are not being made. The elasticity of the lungs and the wall of the rib cage, which opens energetically during inspiration, allows them to recover their resting position and expel air from the lungs when the respiratory muscles relax. Therefore, when a person is at rest, no effort is required to exhale. During intense exercise, however, certain muscles participate in expiration. The abdominal muscles are the most important in that situation. These muscles contract, raise the abdominal pressure and push the relaxed diaphragm against the lungs, with which the air is expelled.

The muscles used in breathing can be contracted only if the nerves that connect them to the brain are intact. In some neck or back injuries, the spinal cord can be severed, thus breaking the connection of the nervous system between the brain and muscles, so that the affected person can die if not receiving artificial ventilation.

Function that the diaphragm plays in breathing
When the diaphragm contracts and moves downward, the chest cavity enlarges, reducing the pressure inside the lungs. To equalize the pressure, air enters inside. When the diaphragm relaxes and returns to its position, the elasticity of the lungs and the chest wall pushes the air out of the lungs.

Apnea
Apnea, apnoea, or apnœa is a technical term for suspension of external breathing.

During apnea there is no movement of the muscles of respiration and the volume of the lungs initially remains unchanged.

Depending on the patency (openness) of the airways there may or may not be a flow of gas between the lungs and the environment; gas exchange within the lungs and cellular respiration is not affected.

Apnea can be voluntarily achieved (i.e., “holding one’s breath”), drug-induced (e.g., opiate toxicity), mechanically induced (e.g., strangulation), or it can occur as a consequence of neurological disease or trauma.

Mechanism Under normal conditions, humans cannot store much oxygen in the body.

Apnea of more than approximately one minute’s duration therefore leads to severe lack of oxygen in the blood circulation.

Permanent brain damage can occur after as little as three minutes and death will inevitably ensue after a few more minutes unless ventilation is restored.

However, under special circumstances such as hypothermia, hyperbaric oxygenation, apneic oxygenation (see below), or extracorporeal membrane oxygenation, much longer periods of apnea may be tolerated without severe consequences.

Untrained humans cannot sustain voluntary apnea for more than one or two minutes.

The reason for this is that the rate of breathing and the volume of each breath are tightly regulated to maintain constant values of CO2 tension and pH of the blood.

In apnea, CO2 is not removed through the lungs and accumulates in the blood.

The consequent rise in CO2 tension and drop in pH result in stimulation of the respiratory centre in the brain which eventually cannot be overcome voluntarily.

Note: The above text is excerpted from the Wikipedia article “Apnea”, which has been released under the GNU Free Documentation License.

To know what might be affecting your ability to breathe properly, it is first helpful to understand what normal breathing is like.

Breathing is automatic

It may sound simple, but it is important to realize that breathing is not something we should remember to do consciously. It is a reflex controlled by neurons in the brain and spine.

The upper and lower airways

The respiratory system consists of two parts: the upper airway and the lower airway.

Superior airway

Lower airway

The lower airway is protected by the thoracic cavity, which also contains the heart and lungs.

The respiratory process

The respiratory process starts with the effort you make (from the chest) to get air into the body.

When breathing, the air that enters through the nose cleans, warms and moistens. Then it goes through the throat to the windpipe and down to the bronchi in the lungs.

When inhaling and exhaling, the thorax and the ribs expand and contract to allow the entry and exit of air.

Abnormal respiration

As you can imagine, the daily act of breathing can become very difficult if you have a respiratory condition that affects the muscles, nerves, reflexes or organs that intervene in breathing.

The respiratory center, located in the lower part of the brain, involuntarily controls breathing, which, in general, is automatic. Breathing continues during sleep and even when unconscious.

A person can also control breathing according to need, for example during speech, when singing or voluntarily containing it. The brain, the aorta and the carotid arteries have small sensory organs that analyze the blood and detect levels of oxygen and carbon dioxide.

Normally, a high concentration of carbon dioxide is the most powerful stimulus to breathe more deeply and more frequently. Conversely, when the concentration of carbon dioxide is low, the brain decreases the frequency and depth of breathing. The respiratory rate of the adult during rest is about 15 breaths (inhalations) and exhalations (exhalations) per minute.

Respiratory muscles

The lungs do not have their own skeletal muscles. The work of respiration is mainly performed by the diaphragm and, to a lesser extent, the intercostal, cervical and abdominal muscles.

The diaphragm, a laminar dome-shaped muscle that separates the thoracic cavity from the abdomen, is the most important muscle for inhalation or inspiration. The diaphragm adheres to the base of the sternum, the lower edge of the rib cage and the spine. As the diaphragm contracts, the length and diameter of the chest cavity increase so that the lungs expand. The intercostal muscles participate in breathing helping to mobilize the rib cage.

The process of exhalation or expiration is usually passive when efforts are not being made. The elasticity of the lungs and the wall of the rib cage, which opens energetically during inspiration, allows them to recover their resting position and expel air from the lungs when the respiratory muscles relax.

Therefore, when a person is at rest, no effort is required to exhale. During intense exercise, however, certain muscles participate in expiration. The abdominal muscles are the most important in that situation. These muscles contract, raise the abdominal pressure and push the relaxed diaphragm against the lungs, with which the air is expelled.

The muscles used in breathing can be contracted only if the nerves that connect them to the brain are intact. In some neck or back injuries, the spinal cord can be severed, thus breaking the connection of the nervous system between the brain and muscles, so that the affected person can die if not receiving artificial ventilation.