For every acute increase of 10 mmHg in PaCO 2, pH will decrease 0.08and HCO 3 will increase 1 mEq These changes are not considered "compensation", by the kidneys. Technically, it is a buffering, rather than a compensation.

For every acute decrease of 10 mmHg in PaCO 2, pH will increase 0.08 and HCO 3 will decrease 2 mEq. These changes are not considered "compensation", by the kidneys. Technically, it is a buffering, rather than a compensation.

For every chronic increase* of 10 mmHg in PaCO 2, the kidneys will respond by increasing the HCO 3 4 mEq/L. This will decrease the pH to only 0.03 below normal. This is compensation - when one body system responds to counteract the abnormal changes resulting from other body system. * It takes the kidneys, 2- 3 days to maximally compensate for changes in the respiratory CO 2 levels.

For every chronic decrease* of 10 mmHg in PaCO 2, the kidneys will respond by lowering the HCO 3 5 mEq/L. This will raise the pH to only 0.03 above normal. This is compensation - when one body system responds to counteract the abnormal changes resulting from other body system. * It takes the kidneys, 2- 3 days to maximally compensate for changes in the respiratory CO 2 levels.

For every decrease of 1 mEq/L of HCO 3, pH will decrease 0.015, and the PaCO 2 will decrease 1.2 mmHg. When the kidneys are responsible for an acidosis or alkalosis, the lungs are quick to respond (within minutes) to compensate by either blowing off, or retaining CO 2 (remember: think of CO 2 as an acid) to try and help minimize the metabolic change. Due to the quickness of the lungs to respond, there is never really any functional distinction between acute vs chronic metabolic alkalosis.

For every increase of 1 mEq/L of HCO 3, pH will increase 0.015, and the PaCO 2 will increase 0.7 mmHg. (Note: the PaCO 2 change can be highly variable. See section on metabolic alkalosis). When the kidneys are responsible for an acidosis or alkalosis, the lungs are quick to respond (within minutes) to compensate by either blowing off, or retaining CO 2 (remember: think of CO 2 as an acid) to try and help minimize the metabolic change. Due to the quickness of the lungs to respond, there is never really any functional distinction between acute vs chronic metabolic alkalosis.

Determining Compensation Expected changes for every 10 mmHg change in PaCO 2 : ConditionAcuteChronic Respiratory AcidosispH ↓ by 0.08 HCO 3 - ↑ by 1 pH ↓ by 0.03 HCO 3 - ↑ by 4 Respiratory AlkalosispH ↑ by 0.8 HCO 3 - ↓ by 2 pH ↑ by 0.3 HCO 3 - ↓ by 5

Determining Compensation Expected changes for every 1 mEq/L change in HCO 3 -: ConditionExpected Change Metabolic AcidosispH ↓ PaCO 2 ↓ 1.2 Metabolic AlkalosispH ↑ PaCO 2 ↑ 0.7