A 26 year old female presents with acute onset shortness of breath, central chest pain, tingling in her fingers and around her mouth. She has an important meeting for work scheduled for later in the day. On examination she is tachypneic, oxygen saturation is 99% and ECG is normal. ABG is carried out and reveals the following:
pH = 7.48
PaO2 = 13 kPa
PaCO2 = 3.8 kPa
HCO3 = 25 mmol/L
Which type of acid-base abnormality does the ABG show?
Well done, correct.
Answer:
Step 1:The history suggests a panic attack.
Step 2: PaO2 is normal so the patient is not hypoxic.
Step 3: pH is higher than normal so the patient is alkalotic.
Step 4: PaCO2 is decreased.
Step 5: HCO3 is normal.
Putting the information together and using the ROME mnemonic we come to the conclusion that this is a respiratory alkalosis with no metabolic compensation. Panic attacks lead to hyperventilation and a respiratory alkalosis with normal oxygen saturation.
