Acid-base imbalance
| Acid–base imbalance | |
|---|---|
| Classification and external resources | |
| Specialty | endocrinology |
| ICD-10 | E87.2-E87.4 |
| ICD-9-CM | 276.2-276.4 |
| MeSH | D000137 |
| PaO2 | Arterial oxygen tension, or partial pressure |
|---|---|
| PAO2 | Alveolar oxygen tension, or partial pressure |
| PaCO2 | Arterial carbon dioxide tension, or partial pressure |
| PACO2 | Alveolar carbon dioxide tension, or partial pressure |
| PvO2 | Oxygen tension of mixed venous blood |
| P(A-a)O2 | Alveolar-arterial oxygen tension difference. The term formerly used (A-a DO2) is discouraged. |
| P(a/A)O2 | Alveolar-arterial tension ratio; PaO2:PAO2 The term oxygen exchange index describes this ratio. |
| C(a-v)O2 | Arteriovenous oxygen content difference |
| SaO2 | Oxygen saturation of the hemoglobin of arterial blood |
| SpO2 | Oxygen saturation as measured by pulse oximetry |
| CaO2 | Oxygen content of arterial blood |
| pH | Symbol relating the hydrogen ion concentration or activity of a solution to that of a standard solution; approximately equal to the negative logarithm of the hydrogen ion concentration. pH is an indicator of the relative acidity or alkalinity of a solution |
Acid–base imbalance is an abnormality of the human body's normal balance of acids and bases that causes the plasma pH to deviate out of the normal range (7.35 to 7.45). In the fetus, the normal range differs based on which umbilical vessel is sampled (umbilical vein pH is normally 7.25 to 7.45; umbilical artery pH is normally 7.18 to 7.38). It can exist in varying levels of severity, some life-threatening.
An excess of acid is called acidosis or acidaemia and an excess in bases is called alkalosis or alkalemia. The process that causes the imbalance is classified based on the cause of the disturbance (respiratory or metabolic) and the direction of change in pH (acidosis or alkalosis). This yields the following four basic processes:
The presence of only one of the above derangements is called a simple acid–base disorder. In a mixed disorder more than one is occurring at the same time. Mixed disorders may feature an acidosis and alkosis at the same time that partially counteract each other, or there can be two different conditions affecting the pH in the same direction. The phrase "mixed acidosis", for example, refers to metabolic acidosis in conjunction with respiratory acidosis. Any combination is possible, except concurrent respiratory acidosis and respiratory alkalosis, since a person cannot breathe too fast and too slow at the same time...
The traditional approach to the study of acid–base physiology has been the empirical approach. The main variants are the base excess approach and the bicarbonate approach. The quantitative approach introduced by Peter A Stewart in 1978 is newer.
There are numerous reasons that each of the four processes can occur (detailed in each article). Generally speaking, sources of acid gain include:
...
Wikipedia