BGOTW #27

Blood Gas of the Week #27

A 14 year, spayed female mix-breed cat is presented for episodes of collapse. The episodes do not seem to be associated with any particular activity or time of day and were first noticed 3 days ago. The first few times the episodes were observed the owners describe the cat appearing suddenly weak, sitting down hard, and panting. These episodes have resolved in less than 60 seconds. Just prior to presentation the cat had a more disturbing (to the owners) event where she vocalized, fell over in lateral recumbency, panted heavily, and urinated on herself. She was still panting after 5 minutes prompting presentation. On examination the cat is thin, has a loud systolic murmur, gallop arrhythmia, and occasional pulse deficits. The remainder of the examination is unremarkable.

T 98.3    P 190    R 38    mm pink    CRT 1.5s     BCS 3/9    Weight 2.7kg   BP 182/96 (123mmHg)

Interpret the blood gas:

 

Step 1: Evaluate the pH

Show More This patient’s pH is 7.31, which is low – this is acidemia. 

 

Step 2: Determine the primary process 

Show More Acidemia can be caused by a high carbon dioxide or low bicarbonate. In this case the pCO2 is low (low pCO2 is alkalosis – this does not match with the pH) and the bicarbonate is normal. Since there pCO2 is not high, and the bicarbonate is not low, this is a mixed acid-base disorder. There is probably more than one thing altering the acid-base status of the patient. 

 

Step 3: Name the process 

Show More (we can’t calculate compensation here because this is a mixed disturbance)

 

Want to learn about reading blood gases? You’ve come to the right place. Every week a new blood gas case will be posted. The scenario will post on Monday and the solution will post on Wednesday.

New to blood gasses? Check out the quick guide to acid-base interpretation here.