Reaction Respiratory alkalosis

Arts. If for some reason, CO2 is not removed from the lungs rapidly enough, the mass action system will back up, the hydrogen ion will not be removed by reaction with HCO, , and the blood pH will fall. This condition is called respiratory acidosis. On the contrary, if CO, is removed from the lungs faster than it arrives, the blood pH will rise. Such a condition is called respiratory alkalosis. 

Respiratory alkalosis is caused by hyperventilating—breathing rapidly and deeply. Hysteria, anxiety, or prolonged crying may result in hyperventilation in which too much carbon dioxide is exhaled, which disturbs the blood s normal carbon dioxide/carbonic acid ratio. According to Le Chatelier s principle, Reaction 15.6 (written again below) shifts to the right as it attempts to restore the equilibrium ... 

The dominant feature in this patient s acid-base disorder is an alkalosis as the [H" ] is low. The bicarbonate concentration is in keeping with the presence of a metabolic alkalosis, which is the dominant disorder in this case. The PCO is increased which may be partially due to a compensatory reaction to the alkalosis. However, the increase in PCO., is in excess of that associated with this degree of alkalosis. The patient had a long-standing history of respiratory disease. 

The need for a better measure of the metabolic component of an acid-base disorder. At first sight, w e might think that the deviation of the standard bicarbonate from the value for normal blood is all the information that we need about the non-respiratory component of an acid- base disorder. However, the change in standard bicarbonate underestimates the non-respiratory component of the acid base disorder. To illustrate this, consider uncompensated metabolic alkalosis, produced by the addition of alkali, such as sodium hydroxide, to the blood. Each of the buffer acids in the blood (protein buffer acid and CO2) buffers some of the added alkali as shown in the two chemical reactions in Table 4.2A. Protein buffer acid combines with some of the alkali to yield water and protein buffer base CO2 from metabolism combines with most of the rest of the alkali to yield bicarbonate. The result is an increase in concentration both of non-bicarbonate buffer base Pr and of bicarbonate. 

The reverse of alkalosis is a condition known as acidosis. This condition is often caused by a depletion of HCO ions from the blood, which can occur as a result of kidney dysfunction. The kidney controls the excretion of HCO j" ions. If there are too few HCO j" ions in solution, the forward reaction is favored and H3O+ ions accumulate, which lowers the blood s pH. Acidosis can also result from the body s inability to expel CO2, which can occur during pneumonia, emphysema, and other respiratory disorders. Perhaps the single most common cause of acidosis is uncontrolled diabetes, in which acids normally excreted in the urinary system are instead retained by the body. 

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