by "Grog" (Alan W. Grogono), Professor Emeritus, Tulane University Department of Anesthesiology
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Classical Acid-Base Examples

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Classical Examples:

Acute Respiratory
1. Acidosis || 2. Alkalosis

Chronic Respiratory
3. Acidosis || 4. Alkalosis

Metabolic
5. Acidosis || 6. Alkalosis

Combined
7. Acidosis || 8. Alkalosis

Complex Examples
    Case 9   ||   Case 10  

  Case 11   ||   Case 12  


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11. Metabolic Acidosis with Respiratory Depression.

A road traffic accident has caused multiple injuries to both legs of this man. The metabolic acidosis due to ischemic lactic acid release. In response the patient was hyperventilating and initially had a respiratory alkalosis.

Treatment with morphine depressed the ventilation and the PCO2 rose from the typical value of 28 mmHg to an apparently normal PCO2 of 40 mmHg.

If these acid-base results were reviewed with no knowledge of the patient's history, this would appear to be a case of pure metabolic acidosis. However, metabolic acidosis typically elicits hyperventilation in partial compensation. A pure metabolic acidosis, therefore, implies the probability that there is, as in this case, respiratory depression - a respiratory acidosis moving the patient in a more acid direction than expected.

Acid-Base Zones

Classical Zones

The diagram shows the position of the principal zones. These zones are based on the review of the literature described by Schlichtig, Grogono, and Severinghaus. The arrows indicate typical acidosis and alkalosis. The labels in the black circles correspond to the legend in the table below.

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Acidosis  Slope
AR   Acute Respiratory Acidosis:  Delta SBE = 0 
CR   Chronic Respiratory Acidosis:   Delta SBE = 0.4 x Delta PCO2
M   Metabolic Acidosis:  Delta PCO2 = 1.0 x Delta SBE
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Alkalosis  Slope
AR   Acute Respiratory Alkalosis:  Delta SBE = 0 
CR   Chronic Respiratory Alkalosis:     Delta SBE = 0.4 x Delta PCO2
M   Metabolic Alkalosis:   Delta PCO2 = 0.6 x Delta SBE



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Acid-Base Tutorial
Alan W. Grogono
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