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Arterial Blood Gasses

Arterial Blood Gasses
pH 6.94 (7.35-7.45)
PCO2 13 mmHg (32-46)
PO2 150mmHg (74-135)
HCO3- 3 mEq/L (21-29)
O2 Saturation 98% (92-96)
Base excess -27 mEq/L (-2-+2)


Instructor's Notes:

Three key diagnostic indicators of an acid-base imbalance are the pH, PCO2, and HCO3-. The pH tells the physician if the blood is too acidic, too alkaline, or normal. A pH below the normal range indicates the patient's blood is acidic. This can be a very serious condition leading to coma and death.  HCO3is an indication of how much "base" is present in the blood. HCO3- is regulated by the kidneys. The low bicarbonate value (HCO3-) indicates the acidosis is caused by a metabolic problem rather than respiratory.  The pCO2 is an indicator of how much "acid" is in the patient's blood. pCO2 is regulated by the respiratory system. In this case, the respiratory system is trying to compensate by rapid breathing (hyperventilation) to get rid of acidic CO2. The pCO2 values are low because of this compensatory mechanism. Acid-Base imbalances are complex and will not be dealt with in any detail here. It is important for the student to understand that the patient is hyperventilating to compensate for a life-threatening acidic condition.