Cerebrovascular response to acute metabolic acidosis in humans.
OBJECTIVE
Evaluation of the cerebrovascular response (delta CBV/delta PaCO2) during baseline metabolic conditions and acute metabolic acidosis.


METHODS
15 healthy subjects, 5 m, 10 f, 56 +/- 10 yrs were investigated. For acidification, NH4Cl was given orally. CBV was measured using Near Infrared Spectroscopy (OXYMON) during normo-, hyper- and hypocapnia.


RESULTS
Acute metabolic acidosis was realised: mean delta BE -2.7 mEq.L-1 (p < 0.001) with mean delta PaCO2 -0.2 kPa (p < 0.01). During normo-, hyper- and hypocapnia, CBV values of 3.51, 4.82 and 2.55 mL.100 g-1 were calculated during baseline metabolic conditions and 3.70, 4.86 and 2.63 mL.100 g-1 during acute metabolic acidosis. The CBV/PaCO2 response showed a hockeystick configuration with the point of infliction around normocapnia. delta CBV/delta PaCO2 reactivity from normo- to hypercapnia and from normo- to hypocapnia was calculated; no significant differences in delta CBV/delta PaCO2 were found in both metabolic conditions.


CONCLUSIONS
Cerebrovascular reactivity to CO2 does not alter during acute metabolic acidosis.
van de Ven
Marjo
M
Department of Pulmonology, Rijnstate Hospital Arnhem, PO 9555, 6800 TA Arnhem, The Netherlands.
Colier
Willy N
WN
Kersten
Bregina T
BT
Oeseburg
Berend
B
Folgering
Hans
H
D000138:Acidosis / Q000139:chemically induced / Q000503:physiopathology*; D000208:Acute Disease; D000368:Aged; D000643:Ammonium Chloride / Q000008:administration & dosage; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019265:Spectroscopy, Near-Infrared
D000643:Ammonium Chloride