Examples of ventilation in the following topics:
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- Ventilation is the rate at which gas enters or leaves the lung.
- Ventilation is generally expressed as volume of air times a respiratory rate.
- Minute ventilation (VE):
The amount of air entering the lungs per minute.
- The three types of ventilation are mathematically linked to one another, so changes in one ventilation rate can cause the change of the other.
- Alveolar ventilation is the most important type of ventilation for measuring how much oxygen actually gets into the body, which can initiate negative feedback mechanisms to try and increase alveolar ventilation despite the increase in dead space.
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- This condition is often fatal, usually requiring mechanical ventilation and admission to an intensive care unit.
- Ventilation is usually delivered through oro-tracheal intubation, or tracheostomy whenever prolonged ventilation (≥2 weeks) is deemed inevitable.
- However, mechanical ventilation may constitute a risk factor for the development, or the worsening, of ARDS.
- Aside from the infectious complications arising from invasive ventilation with tracheal intubation, positive-pressure ventilation directly alters lung mechanics during ARDS.
- This adds up to the impaired oxygenation which is the central problem of ARDS, as well as to respiratory acidosis, which is often caused by ventilation techniques such as permissive hypercapnia which attempt to limit ventilator-induced lung injury in ARDS.
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- Ventilation is the rate at which gas enters or leaves the lung.
- In respiratory physiology, ventilation rate is the rate at which gas enters or leaves the lung.
- There are several different terms used to describe the nuances of the ventilation rate.
- Minute Ventilation (VE): The amount of air entering the lungs per minute.
- Dead Space Ventilation (VD): The amount of air per unit of time that doesn't reach the alveoli.
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- Their increased ventilation rate will remove too much carbon dioxide from their body.
- In cases of acidosis, feedback will increase ventilation to remove more carbon dioxide to reduce the hydrogen ion concentration.
- Conversely, vomiting removes hydrogen ions from the body (as the stomach contents are acidic), which will cause decreased ventilation to correct alkalosis.
- In cases where oxygen intake is too low, feedback increases ventilation to increase oxygen intake.
- A more detailed example would be that if a person breathes through a long tube (such as a snorkeling mask) and has increased amounts of dead space, feedback will increase ventilation.
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- While a severe ventilation–perfusion mismatch indicates severe lung disease, minor imbalances can be corrected by maintaining air flow that is proportional to capillary blood flow, which maintains the balance of ventilation and perfusion.
- In response, the arteries being supplied by the constricted airway undergo vasocontriction, reducing the flow of blood into those alveoli so that the perfusion doesn't become much greater relative to the decreased ventilation (a type of ventilation–perfusion mismatch called a shunt).
- Ventilation adjusts from changes in PACO2.
- When airflow becomes higher relative to perfusion, PACO2 decreases, so the bronchioles will constrict in order to maintain to the balance between airflow (ventilation) and perfusion.
- External respiration is a result of partial pressure gradients, alveolar surface area, and ventilation and perfusion matching.
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- Carbon dioxide is produced constantly as the body's cells respire, and this CO2 will accumulate rapidly if the lungs do not adequately expel it through alveolar ventilation.
- Acute respiratory acidosis occurs when an abrupt failure of ventilation occurs.
- This failure in ventilation may be caused by depression of the central respiratory center by cerebral disease or drugs, inability to ventilate adequately due to neuromuscular disease (e.g., myasthenia gravis, amyotrophic lateral sclerosis, Guillain-Barré syndrome, muscular dystrophy), or airway obstruction related to asthma or chronic obstructive pulmonary disease (COPD) exacerbation.
- During acute respiratory alkalosis, the person may lose consciousness where the rate of ventilation will resume to normal.
- Respiratory alkalosis may be produced accidentally (iatrogenically) during excessive mechanical ventilation.
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- Carbon dioxide is produced constantly as the body's cells respire, and this CO2 will accumulate rapidly if the lungs do not adequately expel it through alveolar ventilation.
- Acute respiratory acidosis occurs when an abrupt failure of ventilation occurs.
- This failure in ventilation may be caused by depression of the central respiratory center by cerebral disease or drugs, inability to ventilate adequately due to neuromuscular disease (e.g., myasthenia gravis, amyotrophic lateral sclerosis, Guillain-Barré syndrome, muscular dystrophy), or airway obstruction related to asthma or chronic obstructive pulmonary disease (COPD) exacerbation.
- During acute respiratory alkalosis, the person may lose consciousness where the rate of ventilation will resume to normal.
- Respiratory alkalosis may be produced accidentally (iatrogenically) during excessive mechanical ventilation.
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- The time period is variable, but usually expressed in breaths per minute because it that time period allows for estimation of minute ventilation.
- Tidal volume multiplied by the respiratory rate is minute ventilation, which is one of the most important indicators of lung function.
- In an average human adult, the average respiratory rate is 12 breaths per minute, with a tidal volume of .5 liters and a minute ventilation of 6 liters per minute, though these numbers vary from person to person.
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- Acid–base imbalances that overcome the buffer system can be compensated in the short term by changing the rate of ventilation.
- Distinguish between buffer solutions, ventilation, and renal function as buffer systems to control acid-base balance
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