|
Respiratory Disturbances
Respiratory disturbances of acid base balance are caused by changes in pulmonary ventilation which result in a change in ECF PCO2. The Henderson-Hasselbalch equation states that, HCO3- to CO2 concentration ratio determines the pH. As the primary event in a disturbance of acid-base balance an increase in PCO2 will cause a decrease in pH and a decrease in PCO2 will cause an increase in pH. The equation also states that disturbances caused by changes in PCO2 can be compensated for by altering the ECF HCO3- concentration.
As noted earlier there are three mechanisms of defense against acid-base imbalance; buffering, pulmonary adjustment of PCO2 and renal adjustment of HCO3- concentration. It is important to recognize that respiratory disturbances are caused by a pulmonary pathology resulting in either hypoventilation or hyperventilation. In either case the malfunctioning lung is the cause of the disturbance (a change in PCO2) and pulmonary compensation is not available.
|
