Respiratory compensation is the modulation by the
brainstem respiratory centers, which involves altering
alveolar ventilation
Breathing (or ventilation) is the process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen.
All aerobic creatures need oxygen for cellular ...
to try and bring the plasma
pH back to its normal value (7.4) in order to keep the
acid-base balance in the body. It usually occurs within minutes to hours and is much faster than
renal compensation Renal compensation is a mechanism by which the kidneys can regulate the plasma pH. It is slower than respiratory compensation, but has a greater ability to restore normal values.
In respiratory acidosis, the kidney produces and excretes ammonium ...
(takes several days), but has less ability to restore normal values.
In
metabolic acidosis
Metabolic acidosis is a serious electrolyte disorder characterized by an imbalance in the body's acid-base balance. Metabolic acidosis has three main root causes: increased acid production, loss of bicarbonate, and a reduced ability of the kidneys ...
,
chemoreceptors
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...
sense a deranged
acid-base balance with a plasma
pH of lesser than normal (<7.4). The chemoreceptors send afferent fibers to the brainstem respiratory centers. The
brainstem respiratory centers increase alveolar ventilation (
hyperventilation
Hyperventilation is irregular breathing that occurs when the rate or tidal volume of breathing eliminates more carbon dioxide than the body can produce. This leads to hypocapnia, a reduced concentration of carbon dioxide dissolved in the blood. ...
) so that
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
() can be breathed off, resulting in an increase of plasma pH.
The amount of respiratory compensation in metabolic acidosis can be estimated using
Winters' formula
Winters' formula, named after Dr. R.W. Winters, is a formula used to evaluate respiratory compensation when analyzing acid-base disorders in the presence of metabolic acidosis. It can be given as:
P_ = (1.5 \times HCO_\sgn) + 8 \pm 2,
where â ...
. Hyperventilation due to the compensation for metabolic acidosis persists for 24 to 48 hours after correction of the acidosis, and can lead to respiratory alkalosis.
This compensation process can occur within minutes.
In
metabolic alkalosis
Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35–7.45). This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct resu ...
,
chemoreceptors
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance (endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorecept ...
sense a deranged
acid-base balance with a plasma
pH of greater than normal (>7.4). The chemoreceptors send afferent fibers to the brainstem respiratory centers. The
brainstem respiratory centers decrease alveolar ventilation (
hypoventilation
Hypoventilation (also known as respiratory depression) occurs when ventilation is inadequate (''hypo'' meaning "below") to perform needed respiratory gas exchange. By definition it causes an increased concentration of carbon dioxide (hypercapnia ...
) to create a rise in arterial
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
() tension, resulting in a decrease of plasma pH.
However, as there is limitation for decreasing respiration, respiratory compensation is less efficient at compensating for metabolic alkalosis than for acidosis.
The
respiratory brainstem centers can only compensate for metabolic acid-base disturbances (
metabolic acidosis
Metabolic acidosis is a serious electrolyte disorder characterized by an imbalance in the body's acid-base balance. Metabolic acidosis has three main root causes: increased acid production, loss of bicarbonate, and a reduced ability of the kidneys ...
and
metabolic alkalosis
Metabolic alkalosis is a metabolic condition in which the pH of tissue is elevated beyond the normal range (7.35–7.45). This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate, or alternatively a direct resu ...
).
Renal compensation Renal compensation is a mechanism by which the kidneys can regulate the plasma pH. It is slower than respiratory compensation, but has a greater ability to restore normal values.
In respiratory acidosis, the kidney produces and excretes ammonium ...
is needed to balance respiratory acid-base syndromes (
respiratory acidosis
Respiratory acidosis is a state in which decreased ventilation (hypoventilation) increases the concentration of carbon dioxide in the blood and decreases the blood's pH (a condition generally called acidosis).
Carbon dioxide is produced continuou ...
and
respiratory alkalosis
Respiratory alkalosis is a medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35–7.45) with a concurrent reduction in arterial levels of carbon dioxide. This condition is one of the four primary di ...
). The kidneys can compensate for both, respiratory and metabolic acid-base imbalances.
References
{{Renal physiology
Acid–base disturbances