Acid-base balance

acid-base balance

n.

The state that exists when acidic and basic ions in solution neutralize each other.

---

Acid-base balance

The condition that exists when the body's carbonic acid-bicarbonate buffer system is in equilibrium, helping to maintain the blood pH at a normal level of 7.35-7.45.

Mentioned in: Blood Gas Analysis, Electrolyte Disorders

---

acid-base balance,

n the balance of acid to base necessary to keep the blood pH level normal (between 7.35 and 7.43).

---

acid-base balance

a state of equilibrium between acidity and alkalinity of the body fluids; called also hydrogen ion (H+) balance because, by definition, an acid is a substance capable of giving up a hydrogen ion during a chemical exchange, and a base is a substance that can accept it. The positively charged hydrogen ion (H+) is the active constituent of all acids.

Most of the body's metabolic processes produce acids as their end products, but a somewhat alkaline body fluid (pH 7.4) is required as a medium for vital cellular activities. Therefore chemical exchanges of hydrogen ions must take place continuously in order to maintain a state of equilibrium. An optimal pH (hydrogen ion concentration) between 7.35 and 7.45 must be maintained; otherwise, the enzyme systems and other biochemical and metabolic activities will not function normally.

Although the body can tolerate and compensate for slight deviations in acidity and alkalinity, if the pH drops below 7.30, the potentially serious condition of acidosis exists. If the pH goes higher than 7.50, the patient is in a state of alkalosis. In either case the disturbance of the acid-base balance is considered serious, even though there are control mechanisms by which the body can compensate for an upward or downward change in the pH. Shifts in the pH of body fluids are controlled by three major regulatory systems which may be classified as chemical (the buffer systems), biological (blood and cellular activity), and physiological (the lungs and kidneys).

Imbalances of the acid-base ratio are discussed under acidosis and alkalosis. Diagnosis and monitoring of either of these conditions are greatly enhanced by periodic determination of the plasma pH and by blood gas analysis.