We have an interesting case of a girl with a haemoglobin of 24g/L.
She has a normal oxygen dissociation curve and so far no
explanation for her markedly elevated hemoglobin. She is needle
phobic and difficult to approach.
Her arterial blood gas sample gave the following results
pH 7.24
pO2 109mmHG
pCO2 57mmHg
Base Excess -3
One possibility is that the acute respiratory acidosis is due to
breath holding. In which case my question is how long do you need
to hold your breath to produce these changes? The other
possibility is that the high haemoglobin is having a direct
measurement effect on the true value of pCO2 and pH or there is
an in vivo effect. Is either of these two possibilities likely. I know
that the haemoglobin concentration will effect the total amount of
carbon dioxide carried in blood but I assumed this would not effect
pCO2.
Breath holding is my favoured explanation but I would appreciate
others views.
Dr G.Michael Addison
Royal Manchester Children's Hospital
Pendlebury
Manchester M27 4HA
United Kingdom
Tel 0161-727-2250(AM)or 0161-220-5342(PM)
FAX 0161-727-2249
Email [log in to unmask]
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