Intraoperative monitoring of brain tissue oxygenation during arteriovenous malformation resection.
BACKGROUND
In normal perfusion pressure breakthrough (NPPB) it is assumed that following arteriovenous malformation (AVM) resection, vasoparalysis persists in the margins of the lesion and that a sudden increase in cerebral blood flow (CBF) after AVM exclusion leads to brain swelling and postsurgical complications. However, the pathophysiology NPPB remains controversial.The aim of our study was to investigate the oxygenation status in tissue surrounding AVMs and in the distant brain using intraoperative monitoring of cerebral partial pressure of oxygen (PtiO(2)) to achieve a better understanding of NPPB pathophysiology.


METHODS
Patients with supratentorial AVMs were monitored intraoperatively using 2 polarographic Clark-type electrodes. To establish reference values, we also studied PtiO(2) in a group of patients who underwent surgery to treat incidental aneurysms.


RESULTS
Twenty-two patients with supratentorial AVMs and 16 patients with incidentally found aneurysms were included. Hypoxic pattern was defined as PtiO(2)≤15 mm Hg and/or PtiO(2)/PaO(2) ratio ≤0.10. Tissue hypoxia was detected in 63.6% of the catheters placed in the perinidal area and in 43.8% of catheters placed in a distant area. AVM excision significantly improved oxygenation both around the AVM and in the distant area.


CONCLUSIONS
The PtiO(2)/PaO(2) ratio is a better indicator than absolute PtiO(2) in detecting tissue hypoxia in mechanically ventilated patients. Intraoperative monitoring showed tissue hypoxia in the margins of AVMs and in the distant ipsilateral brain as the most common finding. Surgical removal of AVMs induces a significant improvement in the oxygenation status in both areas.
Departments of *Neurosurgery †Neurosurgery and Neurotraumatology Research Unit (UNINN) ‡Anesthesiology, Vall d'Hebron University Hospital, Vall d'Hebron Research Institute, Universitat Autonoma de Barcelona, Barcelona, Spain.
Fuat
F
Arikan
Jordi
J
Vilalta
Montserrat
M
Noguer
Montserrat
M
Olive
Marian
M
Vidal-Jorge
Juan
J
Sahuquillo
D000328:Adult; D000368:Aged; D001921:Brain / Q000378:metabolism* / Q000601:surgery; D004566:Electrodes; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis*; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D010100:Oxygen / Q000378:metabolism*; D011446:Prospective Studies
D010100:Oxygen