When referring specifically to the pH, the terms acidosis and alkalosis should be avoided. Acidosis can be either metabolic or respiratory. These qualifiers should always be used when we use the terms alkalosis or acidosis. Alkalosis should always be either metabolic alkalosis or respiratory alkalosis. This is similar to reading back what is said to confirm its understanding. This might be seemingly unnecessary much of the time but essential to avoid confusion, misunderstanding and occasionally contentions discussion. The only terms that can be used alone are acidemia and alkalemia. These refer to pH.
Sometimes an ambiguous phrase is used by someone who does not recognize it confusing nature. Sometimes a person’s mistake is covered with a condescending attitude. Some people might expect multiple meanings from a variable term to be clear from the context of the discussion. This is an unreliable assumption. It is best if these discussions are avoided. We could say “be nice” or do some training such as “crew resource management” or CRM. In addition to not using the terms acidosis and alkalosis to describe the pH of body fluids we shouldn’t use them without a qualifier. This can be either metabolic or respiratory. If a qualifier is not used, either metabolic acidosis, metabolic acidosis, respiratory acidosis or respiratory alkalosis there will eventually be confusion. It can lead to discord between individuals. Arrogance often complicates this misunderstanding. Those who expect others to know what is meant when they use the term ambiguously sometimes behave arrogantly and ignorantly. These people are what is known as an expert. The the expert uses their immediate and instant bravado to demonstration their confident assertions. We could liken such individuals to familiar barnyard animals and their argument to odorous barnyard obstructions. It is best to avoid such discussions. Acidosis and alkalosis should be used only with modifiers except by experts who know that everybody else is an idiot.
This does not imply that there is primary metabolic acidosis. If we meant that we would add the modifier primary. We determine that from the clinical assessment not the blood gasses. Not at least if you need to think on your feet in the clinical environment.
The terms metabolic acidosis and metabolic alkalosis do not indicate that these conditions are the primary disturbance or the results of compensation. This implication is removed in the new paradigm. Metabolic acidosis is just a statement of the current state of bicarbonate, that is low. Metabolic alkalosis is also a statement of the current state of bicarbonate, that is high. Modifiers have to be added to say primary or secondary.
Similar to the situation with metabolic states these terms do not specify primary or compensatory, not in the new paradigm. If we want to specify that we use the modifiers primary and compensatory.
Sometimes we can use the terms acidosis and alkalosis as a process.
An
acidosis is a process producing hydrogen ion and a lower pH.
An
alkalosis is a process consuming hydrogen ion and raises the pH.
If we use the term acidosis as a process we still must use include the modifier, metabolic or respiratory.
How do we know if these processes are active. Is the pH on the way down or on the way up? We cannot determine this from a single blood gas.
We can use clinical assessment to determine this.
These changes in terminology have profound implications for the concepts of acid base terminology. For instance a metabolic acidosis means that there is or has been a process producing metabolic acids. This is reflected in the level of HCO3-. This does not mean that the pH is abnormally low. That is acidemia which is different from acidosis.
The
severity of a metabolic acidosis is based on the HCO3- level and not
the pH.
The severity of a respiratory acidosis, is based on the
arterial PaCO2- and not the pH
H+
Hydrogen Ion H+
Ph Negative log of H+
pO2 Partial pressure
of Oxygen
PaO2 Partial Pressure of Oxygen in Arterial Blood
pCO2
Partial pressure of Carbon Dioxide pCO2
PaCO2 Partial Pressure
of Carbon Dioxide in Arterial Blood
HCO3− Bicarbonate ion