Acid-Base Physiology - Examples for 9.6
Case History  24 : A man with a leaking aneurysm


Clinical Details
A 63 year old man presented to a private hospital with significant pain in his right side. A CT scan confirmed the clinical assessment of a leaking abdominal aneurysm. Previous health was good. Initial pathology results included Hb 142 g/l, Na+ 137, K+ 3.8 Cl- 103, bicarbonate 23, urea 5.1 and creatinine 0.10 mmol/l. He was transferred to a public hospital for surgery. Arterial blood gases were collected midway through the procedure (with FIO2
1.0 & end-tidal pCO2 37mmHg):

Arterial Blood Gases




50 mmHg


476 mmHg



 The patientís previous health was good so all the acid base changes would be expected to be acute. Consideration of the clinical circumstances strongly support a metabolic acidosis (due to lactic acidosis related to poor perfusion) and a respiratory acidosis (due to inadequate alveolar ventilation).

Immediate management is to significantly increase the minute ventilation to decrease the arterial pCO2. This will result in a rapid improvement in the acidaemia and also and more significantly improve the intracellular acid-base state towards normal.

Firstly, initial clinical assessment (on the first gas results):

To be completed in the future when I update these remaining Cases to the new format.

Secondly, the acid-base diagnosis: 
1. pH: A significant acidaemia indicates that an acidosis is present
2. Pattern:
The pattern of an elevated pCO2 and              bicarbonate level means a mixed acidosis must be present.
3. Clues:  
4. Compensation:  
5. Formulation:  
6. Confirmation: 

Finally, the Clinical Diagnosis:




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