title: Microdialysis in cisterna magna during cerebral air embolism in swine.
abstract: Arterial gas embolism may occur as a consequence of lung rupture, decompression sickness, following operative procedures or as accidental infusion of gas during various diagnostic procedures. It can lead to severe morbidity or even death. Microdialysis is a technique that has been extensively used for evaluating localized changes in the brain. The microdialysis probe is only capable of measuring changes in the immediate adjacent tissue. In arterial gas embolism the changes are multifocal. Thus a probe located in the cerebral cortex will not detect the total amount of damage. We used microdialysis in the cisterna magna of 9 anaesthetized pigs to study the diffuse injury following arterial gas embolism. After injection of 5.0 mL of air in the internal carotid artery, we found a significantly increased lactate-pyruvate ratio in the cerebrospinal fluid, lasting for 2 hours. This indicates anaerobic metabolism. Mean levels of glycerol were significantly increased, indicating membrane disruption. Glutamate levels were also elevated, although not significantly. The injection of air affected carotid flow. Flow in the carotid artery of the side of injection decreased significantly, but returned to baseline in 1 hour. Flow in the contralateral carotid was increased, but not significantly. We conclude that massive air embolism causes ischemia and reduced blood flow in the brain that can be detected in the cisterna magna.
authors.affiliation: Department of Physiology and Biomedical Engineering, Norwegian University of Science and Technology.
authors.forename: C
authors.initials: C
authors.lastname: Medby
authors.forename: H
authors.initials: H
authors.lastname: Rø
authors.forename: S
authors.initials: S
authors.lastname: Koteng
authors.forename: R
authors.initials: R
authors.lastname: Juul
authors.forename: B K
authors.initials: BK
authors.lastname: Krossnes
authors.forename: A O
authors.initials: AO
authors.lastname: Brubakk
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply; D002946:Cisterna Magna; D004618:Embolism, Air / Q000134:cerebrospinal fluid*; D005260:Female; D018698:Glutamic Acid / Q000134:cerebrospinal fluid; D005990:Glycerol / Q000134:cerebrospinal fluid; D020766:Intracranial Embolism / Q000134:cerebrospinal fluid*; D019344:Lactic Acid / Q000134:cerebrospinal fluid; D008297:Male; D017551:Microdialysis / Q000379:methods*; D019289:Pyruvic Acid / Q000134:cerebrospinal fluid; D013552:Swine
chemical_list: D019344:Lactic Acid; D018698:Glutamic Acid; D019289:Pyruvic Acid; D005990:Glycerol