Hyperventilation impairs brain function in acute cerebral air embolism in pigs.
OBJECTIVE
To evaluate, in a model of cerebral air embolism (CAE), the effects of ventilation-induced hypocapnia and hyperoxemia on intracranial pressure (ICP), cerebral perfusion pressure (CPP), brain oxygen (PbrO(2)), brain carbon dioxide (PbrCO(2)), brain pH (brpH) and levels of brain glucose and lactate.


METHODS
Prospective animal study in a university medical center.


METHODS
Fifteen Landrace/Yorkshire pigs.


METHODS
In 15 anesthetized pigs ICP, PbrO(2), PbrCO(2) and brpH were measured with multi-parameter sensors, and brain glucose and lactate by microdialysis. All these parameters were recorded for 2 h after injection of air into the internal carotid artery. Nine animals were hyperventilated (PaCO(2 )+/-25 mmHg) and hyperoxygenated (FiO(2) 1.0) and six animals were normoventilated (PaCO(2)()+/-40 mmHg with an FiO(2) 0.4) and served as controls. RESULTS. In the treatment group the ICP rose from 8+/-1 to 52+/-6 mmHg, which was similar to that in the control group (12+/-1 to 57+/-8 mmHg). At the end of the 2-h study period, there were no significant differences in PbrO(2), PbrCO(2) and brpH between the two groups. The decreased brain glucose and increased brain lactate reached severe pathological values in both groups by the end of the 2-h study period.


CONCLUSIONS
Hypocapnia and hyperoxemia in acute CAE did not improve pathological functional brain parameters compared with normoventilated controls. Similarly, the pathological changes in brain glucose/lactate could also not be improved by hypocapnia and hyperoxemia.
van Hulst
Robert A
RA
Department of Anesthesiology, Erasmus Medical Center, PO Box 1738, 3000 DR Rotterdam, The Netherlands.
Haitsma
Jack J
JJ
Lameris
Thomas W
TW
Klein
Jan
J
Lachmann
Burkhard
B
D000818:Animals; D001794:Blood Pressure; D001921:Brain / Q000378:metabolism*; D004618:Embolism, Air / Q000628:therapy*; D005260:Female; D006339:Heart Rate; D006931:Hyperbaric Oxygenation / Q000009:adverse effects*; D020766:Intracranial Embolism / Q000628:therapy*; D007427:Intracranial Pressure; D008297:Male; D013552:Swine