Acid-based homeostasis is fundamental for maintaining life and well-being.
Physiological approach to acid-base balance utilizes the carbonic acid-bicarbonate buffer system.
The system characterizes acids as hydrogen ion donors and bases as hydrogen-ion acceptors.
The carbonic acid-bicarbonate system is critical to maintain homeostasis.
A change in the partial pressure of carbon dioxide causes responses in the bicarbonate concentration and vice versa.
There are four recognize primary acid-base disorders: two are metabolic disorders of acidosis and alkalosis and two are respiratory disorders acidosis and alkalosis.
Hydrgen ion concentration requires tight regulation as changes can alter virtually all protein in membrane functions.
The hydrogen ion concentration in plasma is normally very low at approximately 40 nmol per liter, the pH, is the negative logarithm of the hydrogen ion concentration.
The pH is generally used to indicate acid-based status.
Acidemia and alkalemia refer to states in which the pH is abnormally low as in acidic or abnormally high as in alkaline state.
The process of increasing the hydrogen-ion concentration is called acidosis, in the process in which the hydrogen-ion concentration is decreased is called alkalosis.
The Henderson-hassle black equation determines acid-base values.
Respiratory acid-base disorder occurs when it is caused by primary abnormality in respiratory function and metabolic when the primary change is related to variation in the carbonate concentration.
The initial evaluation of acid-based disorders is a clinical evaluation to provide an understanding of the underlying disorder and includes physical examination to rule out shock, impaired neurologic state, signs of infection with fever, pulmonary status evaluating respiratory rate, cyanosis, Kussmaul respiration, clubbing, vomiting, and diarrhea.
Initial evaluation includes noting underlying medical processes such as pregnancy, metabolic diseases such as diabetes, heart, lungs, kidneys, and liver disorders.
Initial evaluation of acid-base disorders includes noting medications and toxic agents that may affect metabolism.
It is essential to determine the primary acid-base disorder and the secondary response that is present.
pH range that is compatible with life is 7.8-6.8.
There are four major acid-base disturbances, defined as primary acid-based disorders.
The response to acid-based disorders is predictable and can be calculated..
In response to the presence of metabolic acid-base disturbances respiratory rate changes develop rapidly, and a new steady-state PaCO2 is reached within hours.
When persistent respiratory abnormalities exist, metabolic compensation develops slowly and 2 to 5 days are required for the plasma bicarbonate concentration to reach a new steady state level.
Respiratory changes are called acute or chronic and that is dependent on whether a secondary change in the bicarbonate concentration meets criteria.
Mixed acid-based disorder is diagnosed when secondary responses differ from that which would be expected.