Page 49 - Critical Care Nursing Demystified

34 CRITICAL CARE NURSING DeMYSTIFIED

Partially compensated – In this instance, all values are abnormal. The com-
pensating organ system attempts to drive the pH to a more normal level but
is not completely successful.
Example: Partially compensated respiratory acidosis

pH = 7.33, pCO = 55, HCO = 32
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Reason: The pH indicates there is an acidotic state caused. Therefore, we
have a respiratory acidosis. Partial compensation occurs when the renal
absorption of HCO causes the level to be elevated partially neutralizing an
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acidosis. It is not full compensation as the pH is abnormal.
Example: Partially compensated metabolic alkalosis
pH = 7.52, pCO = 48, HCO = 30
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Reason: The pH indicates an alkalosis. Looking at the pCO and the HCO
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shows us that the alkalosis is caused by HCO being retained (metabolic
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alkalosis). The increase in pCO shows us that the lungs are partially com-
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pensating partially by retaining pCO .
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Full or complete compensation – In this type of compensation, the pH Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
remains normal. The pCO and HCO are abnormal. Because the pH remains
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normal, this indicates that one system has been able to fully compensate for
the other.
Example: Fully compensated respiratory acidosis

pH = 7.35, pCO = 55, HCO = 30
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Reason: The pH indicates a normal value; however, if 7.40 is absolutely nor-
mal, 7.35 is slightly acidotic. The nurse must then look at the pCO and
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HCO levels to tell where the acidosis is. In this case, a pCO of 55 shows us
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the acidosis is respiratory. The HCO is alkalotic, so it can not be the primary
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problem. However, it shows that there is a shift in kidney function to fully
compensate for the patient’s acidosis.
Example: Fully compensated metabolic alkalosis

pH = 7.45, pCO = 48, HCO = 30
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Reason: The pH shows that the primary problem is an alkalosis, so the nurse
must look at the value that indicates alkalosis, which is the HCO . This patient’s
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primary problem is a metabolic alkalosis. Since the pH is on the high side of
normal it indicates that this ABG is fully compensated by a change in the
pCO .
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