I note with interest your hyperventilating patient (pH 7.72; pO2 133 mmHg).
My guess is that we do not see many of these results because they are
treated (calmed and re-breathing with the ubiquitous paper bag) prior to
having blood gases performed. I can share some results from a patient
hyerventilating in hospital as follows:
pH 7.77 (7.37-7.43)
pO2 140 (80-100, mmHg)
pCO2 10 (36-44, mmHg)
HCO3 15 (23-33, mmol/L)
Sat 99 (94-98, %)
The results were repeated twice over the night with very similar results
and were reported as being on room air. Being a keen registrar at the time
I assumed that the patient was on oxygen to reach that value, but I should
have noted the very low CO2. This patient was breathing room air but had a
tracheostomy allowing very efficient hyperventilation with reduced dead
space. I have assumed it was not possible to reach these values with a
normal upper-airway but the patient described comes very close.
Thank you for the case.
Graham Jones
Staff Specialist in Chemical Pathology
St Vincents Hospital, Sydney
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