Although the body produces a large amount of acids and there are wide variations in dietary intake of acids or alkali, pH of the arterial blood and interstitial fluid normally ranges between 7.35 and 7.45 despite. The widest range of the pH values compatible with life is from 6.8 to 7.8.
There are three processes available for maintaining the concentration of hydrogen ion within normal limits.
1. Buffer system.
2. Reduction of carbonic acid by elimination of CO2 via pulmonary ventilation.
3. Reduction of noncarabonic acid by renal elimination.
Types of acid-base abnormalities.
«Acidemia» and «alkalemia» refer to blood hydrogen concentration and therefore to the pH of the blood. «Acidosis» and «alkalosis» refer to the mechanism by which a given acid-base disturbance is reached. «Primary» refers to the initiating process of acid-base disturbance, while «secondary» refers to a compensatory process. Mixed acidbase disturbances are combinations of two or more primary acid-base disturbances.
Acidosis can be defined as an abnormal condition or process caused by the bodily accumulation of acid or loss of base sufficient to decrease pH below 7,35 in the absence of compensatory changes.
Alkalosis is an abnormal condition or process caused by the accumulation of base or the loss of acids sufficient to raise pH above 7,45 in the absence of compensatory changes.
Respiratory acidosis or alkalosis refers to conditions of abnormally high or low arterial CO2 tention respectively. Metabolic acidosis refers to a disturbance that leads to the accumulation of involative carbonic acid in the extracellular fluid or to the loss of HCO3- from the extracellular fluid. Metabolic alkalosis refers to an imbalance characterized by a loss of noncarbonic acid or a gain of HCO3- by the extracellular fluid.