Aportaciones de la monitorización intraoperatoria de la presión titular de oxígeno en neurocirugía vascular

Abstract

This doctoral thesis consists of four articles that provide new and relevant information about cerebrovascular diseases obtained from intraoperative monitoring of tissue oxygen pressure (PtiO2) using Clark-type polarographic probes. The studies that comprise this thesis are listed below._x000D_ • [Detection of episodes of ischemic tissue hypoxia by means of the combined intraoperative neurophysiologic monitoring with the tissue oxygenation monitoring in aneurysm surgery]. Arikan F, Vilalta J, Minoves T, Moncho D, Vilalta A, Noguer M, Ibarra B, Sahuquillo J. Neurosurgery (Astur). 2008 Apr; 19 (2): 113-20. Spanish. ISSN: 1130-1473PMID: 18500409._x000D_ • Intraoperative monitoring of brain tissue oxygenation during arteriovenous malformation resection. Arikan F, Vilalta J, Noguer M, Olive M, Vidal-Jorge M, J. J Neurosurg Sahuquillo Anesthesiol. 2014 Oct; 26 (4): 328-41. DOI: 10.1097 / ANA. 0000000000000033. PMID: 24492516_x000D_ • [Intraoperative monitoring of oxygen tissue pressure: Applications in vascular neurosurgery]. Arikan F, Vilalta J, Torne R, Chocron I, Rodriguez-Tesouro A, Sahuquillo J. Neurosurgery (Astur). 2014 Nov-Dec; 25 (6): 275-85. DOI: 10.1016 / j.neucir.2014.03.003. Epub 2014 June 14. Spanish. PMID: 24934513_x000D_ • Rapid resolution of brain ischemic hypoxia after cerebral revascularization in moyamoya disease. Arikan F, Vilalta J, Torne R, Noguer M, Lorenzo-Bosquet C, Sahuquillo J. Neurosurgery. In press. Accepted on October 27, 2014. DOI: 10.1227 / NEU.0000000000000609 PMID: 25584958._x000D_ These studies provide the clinically relevant information outlined below._x000D_ 1. Monitoring PtiO2 allows for immediate and reliable detection of ischemic cerebral hypoxia caused by surgical technique and may be used to develop strategies to manage this condition._x000D_ 2. Continuous monitoring of PtiO2 can be used to quickly and reliably detect situations of intraoperative cerebral ischemic hypoxia and establish therapeutic strategies to resolve it. Continuous intraoperative monitoring of PtiO2 is a useful tool for reducing ischemic complications._x000D_ 3. The PtiO2/PaO2 ratio is a better index than absolute PtiO2 because it detects hypoxia when absolute values are artifactually high due to increased PaO2 (e.g. patients under mechanical ventilation). The lower reference threshold indicative of tissue hypoxia for the PtiO2/PaO2 ratio is 0.10. The upper reference threshold indicative of tissue hyperoxia for PtiO2/PaO2 is 0.35._x000D_ 4. PtiO2 / PaO2 ratios obtained in healthy subjects show that oxygen in the brain is heavily regulated and that the relationship between PaO2 and PtiO2 in the normal brain reaches a plateau._x000D_ 5. The findings of other authors are confirmed by the finding that many patients with AVM present clinically well-tolerated hypoxia in the brain around the nidus. AVMs can cause changes in oxygenation and metabolism in remote areas of the ipsilateral cerebral hemisphere._x000D_ 6. Many patients with AVM have a hypoxic pattern around the malformation nidus and/or the distant brain. These hypoxic patterns reverse after resection of the AVM._x000D_ 7. Intraoperative monitoring of PtiO2 is a safe and reliable method to determine brain oxygenation status and patency of bypass in patients undergoing surgery for cerebral revascularization. Tissue hypoxia is almost constant in patients with moyamoya disease and those with a reduction of cerebral perfusion reserve._x000D_ 8. Direct superficial temporal artery to middle cerebral artery bypass revascularization produces a rapid and sustained increase in PtiO2 and achieves values consistent with normoxia.

Date of Award	27 Mar 2015
Original language	Spanish
Supervisor	Juan Sahuquillo Barris (Director) & Jordi Vilalta Castan (Director)