An arterial blood gas analysis is used by doctors to measure the partial levels of carbon dioxide, oxygen and the pH in a blood sample. This test can help monitor several conditions that can cause serious health complications. Steps Look at the pH number on your results. If the pH level is below 7.35, then the condition of acidosis is present, indicating a buildup of carbonic acid in the blood.[1] If the pH level is above 7.45, then the condition of alkalosis is present, which indicates a buildup of bicarbonate (bases) in the blood.[2] The pH level in a healthy human should be between 7.35 to 7.45. Your body is constantly striving to keep pH in balance. 2.Examine the PCO2 number on your report.[3] This number is the amount of carbon dioxide in the blood. It is the respiratory component in acid-base balance.[4] It is measured in millimeters of mercury (mmHg). The normal level for PCO2 is between 35 to 45 mmHg.[5] The condition of respiratory alkalosis is present if the PCO2 number is below 35 mmHg. This means there is too little carbon dioxide in the blood. A person with this condition can be breathing very fast (hyperventilating). The condition of respiratory acidosis is present if the PCO2 number is above 45 mmHg. There is too much carbon dioxide in the blood. A person with this condition can be confused or restless and have a low heart rate. 3. Check your blood gas report for the bicarbonate (HCO3) level. It is the renal component in the acid-base balance. The normal level for these ions is between 24 to 26 milliEquivalents Per Liter (mEq/L).[6] An HCO3 level is below 24 mEq/L indicates metabolic acidosis. The body cannot produce enough bicarbonates to keep up with the carbonic acid in the blood. It can be caused by many conditions including dehydration and kidney disease. An HCO3 level above 26 mEq/L indicates metabolic alkalosis. There are too many bicarbonates in the blood. A common cause is hyperventilation, but it is also seen in many other conditions including Cushing's disease and long term steroid therapy. 4. Determine whether there is compensation for the pH imbalance. Generally, the pulmonary and renal systems compensate for each other to return the pH to normal. The lungs will compensate for metabolic instability by changing CO2 excretion and the kidneys will compensate for the respiratory instability by altering bicarbonate retention and H+ secretion.[7] To look for compensation in respiratory acidosis (↓ pH, ↑ CO2), look at the HCO3values. There is compensation when the HCO3level is increased (excess hydrogen is excreted in the urine in exchange for bicarbonate ions, therefore making the blood more alkaline). However, in respiratory alkalosis (↑pH, ↓CO2), there is compensation when the HCO3level is decreased (the renal excretion of bicarbonate increases to retain the hydrogen ions, therefore, making the blood more acidic). To look for compensation in metabolic acidosis (↓pH, ↓HCO3), look at the PaCO2levels. There is compensation when the PaCO2level is decreased (due to hyperventilation, thereby raising the blood's pH value, making it more alkaline.) However, in metabolic alkalosis (↑pH, ↑HCO3), there is compensation when the PaCO2 level is increased (due to hyperventilation, therefore decreasing the blood's pH value, making it more acidic) 5. Inspect the PO2 number in your blood gas test results. This is the amount of oxygen that is dissolved in the blood. The normal PO2 level should be between 80 to 100 mmHg. If they are below limits, there is evidence of hypoxemia, therefore, no compensation is done to restore the pH balance. 6. Finally, evaluate the diagnosis of your ABG reading. The readings of the blood gas test results will help you make a diagnosis Source
Good article....the is a error in the explanation of compensated metabolic alkalosis...the correct explanation should read there is an increase in the pCO2 due to HYPOVENTILATION and not HYPERVENTILATION....should also keep in mind states where mixed can result and short explanation on increased anion gap causing metabolic acidosis....overal good explanation and if am wrong please correct and keep posting awesome review material....
