Monitoring of brain tissue oxygenation during aneurysm surgery: prediction of procedure-related ischemic events

Object. The aim of this study was to evaluate the feasibility of monitoring brain tissue oxygenation (PO2) during aneurysm surgery for the detection of procedure-related ischemia. Methods. Between 1997 and 1998, PO2 was monitored prospectively in a cohort of 40 patients (42 recordings) during aneurysm surgery in the anterior circulation within the vascular territory of the aneurysm-bearing artery. The position of the probe used to measure oxygenation levels was verified on computerized tomography (CT) scanning on the 1st postoperative day. Because of the mislocation of one probe and the malfunction of another, data from only 38 patients (40 recordings) were suitable for analysis. Relative changes from baseline to absolute nadir values of intraoperative PO2 were correlated with simultaneously recorded somatosensory evoked potentials (SSEPs), and cardiovascular and ventilatory parameters. The frequency of ischemic events was evaluated with the aid of CT on the 1st postoperative day as a substitute parameter for intraoperative ischemia. Clinical outcome was evaluated 30 days postoperatively based on the Glasgow Outcome Scale. Except for three, all patients underwent surgery for treatment of a symptomatic aneurysm. Mean baseline PO2 was 23.9 mm Hg (range 2–67.2 mm Hg) before clip application. A relative decrease in PO2 (20% decrease in value compared with baseline) occurred in 12 patients and was a sensitive indicator for the risk of ischemia during temporary arterial occlusion, but was less predictive of nonocclusive ischemia (sensitivity 0.5; positive predictive value [PPV] 0.42; p > 0.05). Results of receiver operating characteristic analysis demonstrated a postclipping PO2 nadir of 15 mm Hg as a dichotomizing threshold for the prediction of ischemia. This threshold rendered an improved sensitivity (0.9) and PPV (0.56) for procedure-related ischemia (p = 0.0003). The results of utility analysis revealed this monitoring parameter to be clinically diagnostic. Only PO2 monitoring, and not SSEP at the tibial nerve, was predictive of ischemia within the anterior cerebral artery territory. Conclusions. Using 15 mm Hg as a dichotomizing threshold, intraoperative PO2 monitoring enables one to identify patients at risk for procedure-related ischemia during aneurysm surgery and surpasses SSEP monitoring. This newly defined threshold based on intraoperative PO2 monitoring provides a basis for studies on treatments for procedure-related ischemia during aneurysm surgery.

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Measurement of brain tissue oxygenation performed using positron emission tomography scanning to validate a novel monitoring method

Journal of Neurosurgery ◽

10.3171/jns.2002.96.2.0263 ◽

2002 ◽

Vol 96 (2) ◽

pp. 263-268 ◽

Cited By ~ 76

Author(s):

Arun K. Gupta ◽

Peter J. Hutchinson ◽

Tim Fryer ◽

Pippa G. Al-Rawi ◽

Dot A. Parry ◽

...

Keyword(s):

Positron Emission Tomography ◽

Brain Injury ◽

Brain Tissue ◽

Tissue Oxygenation ◽

Emission Tomography ◽

Brain Tissue Oxygenation ◽

Content Type ◽

Positron Emission ◽

Pet Scans ◽

Fine Print

Object. The benefits of measuring cerebral oxygenation in patients with brain injury are well accepted; however, jugular bulb oximetry, which is currently the most popular monitoring technique used has several shortcomings. The goal of this study was to validate the use of a new multiparameter sensor that measures brain tissue oxygenation and metabolism (Neurotrend) by comparing it with positron emission tomography (PET) scanning. Methods. A Neurotrend sensor was inserted into the frontal region of the brain in 19 patients admitted to the neurointensive care unit. After a period of stabilization, the patients were transferred to the PET scanner suite where C15O, 15O2, and H215O PET scans were obtained to facilitate calculation of regional cerebral blood volume, O2 metabolism, blood flow, and O2 extraction fraction (OEF). Patients were given hyperventilation therapy to decrease arterial CO2 by approximately 1 kPa (7.5 mm Hg) and the same sequence of PET scans was repeated. For each scanning sequence, end-capillary O2 tension (PvO2) was calculated from the OEF and compared with the reading of brain tissue O2 pressure (PbO2) provided by the sensor. In three patients the sensor was inserted into areas of contusion and these patients were eliminated from the analysis. In the subset of 16 patients in whom the sensor was placed in healthy brain, no correlation was found between the absolute values of PbO2 and PvO2 (r = 0.2, p = 0.29); however a significant correlation was obtained between the change in PbO2 (ΔPbO2) and the change in PvO2 (ΔPvO2) produced by hyperventilation in a 20-mm region of interest around the sensor (ρ = 0.78, p = 0.0035). Conclusions. The lack of correlation between the absolute values of PbO2 and PvO2 indicates that PbO2 cannot be used as a substitute for PvO2. Nevertheless, the positive correlation between ΔPbO2 and ΔPvO2 when the sensor had been inserted into healthy brain suggests that tissue PO2 monitoring may provide a useful tool to assess the effect of therapeutic interventions in brain injury.

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Continuous monitoring of regional cerebral blood flow during temporary arterial occlusion in aneurysm surgery

Journal of Neurosurgery ◽

10.3171/jns.2001.95.3.0402 ◽

2001 ◽

Vol 95 (3) ◽

pp. 402-411 ◽

Cited By ~ 43

Author(s):

Claudius Thomé ◽

Peter Vajkoczy ◽

Peter Horn ◽

Christian Bauhuf ◽

Ulrich Hübner ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Cerebral Artery ◽

Regional Cerebral Blood Flow ◽

Arterial Occlusion ◽

Aneurysm Surgery ◽

Regional Cerebral Blood ◽

Anterior Circulation ◽

Content Type ◽

Fine Print

Object. Temporary arterial occlusion (TAO) during aneurysm surgery carries the risk of ischemic sequelae. Because monitoring of regional cerebral blood flow (rCBF) may limit neurological damage, the authors evaluated a novel thermal diffusion (TD) microprobe for use in the continuous and quantitative assessment of rCBF during TAO. Methods. Following subcortical implantation of the device at a depth of 20 mm in the middle cerebral artery or anterior cerebral artery territory, rCBF was continuously monitored by TD microprobe (TD-rCBF) throughout surgery in 20 patients harboring anterior circulation aneurysms; 46 occlusive episodes were recorded. Postoperative radiographic evidence of new infarction was used as the threshold for failure of occlusion tolerance. The mean subcortical TD-rCBF decreased from 27.8 ± 8.4 ml/100 g/min at baseline to 13.7 ± 11.1 ml/100 g/min (p < 0.0001) during TAO. The TD microprobe showed an immediate exponential decline of TD-rCBF on clip placement. On average, 50% of the total decrease was reached after 12 seconds, thus rapidly indicating the severity of hypoperfusion. Following clip removal, TD-rCBF returned to baseline levels after an average interval of 32 seconds, and subsequently demonstrated a transient hyperperfusion to 41.4 ± 18.3 ml/100 g/min (p < 0.001). The occurrence of postoperative infarction (15%) and the extent of postischemic hyperperfusion correlated with the depth of occlusion-induced ischemia. Conclusions. The new TD microprobe provides a sensitive, continuous, and real-time assessment of intraoperative rCBF during TAO. Occlusion-induced ischemia is reliably detected within the 1st minute after clip application. In the future, this may enable the surgeon to alter the surgical strategy early after TAO to prevent ischemic brain injury.

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Anosmia following operation for cerebral aneurysms in the anterior circulation

Journal of Neurosurgery ◽

10.3171/jns.1990.72.6.0864 ◽

1990 ◽

Vol 72 (6) ◽

pp. 864-865 ◽

Cited By ~ 30

Author(s):

Kjeld Dons Eriksen ◽

Torben Bøge-Rasmussen ◽

Christian Kruse-Larsen

Keyword(s):

Intracranial Aneurysms ◽

Cerebral Aneurysms ◽

Olfactory Nerve ◽

Aneurysm Surgery ◽

Anterior Circulation ◽

Widespread Occurrence ◽

Content Type ◽

High Incidence ◽

Ruptured Intracranial Aneurysms ◽

Fine Print

✓ Damage to the olfactory nerve during frontotemporal approach to the basal cisternal region has not previously been investigated in a quantified manner. In this retrospective study of 25 patients operated on for ruptured intracranial aneurysms via the frontotemporal route, 22 patients suffered postoperatively from anosmia ipsilateral to the side of surgery. This complication most often goes unrecognized by the patient as well as the physician, and attention should be drawn to it because of its widespread occurrence. This investigation demonstrates a high incidence of anosmia (24 (88.9%) of 27 surgical sides) occurring ipsilateral to the frontotemporal approach in aneurysm surgery. Recovery after traumatic anosmia has been recorded up to 5 years after injury.1 Nevertheless, the authors believe that the damage is permanent when lasting 35 months or longer.

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Brain tissue oxygenation monitoring supplementary to somatosensory evoked potential monitoring for aneurysm surgery. Initial clinical experience

Neurological Research ◽

10.1179/016164102101200528 ◽

2002 ◽

Vol 24 (6) ◽

pp. 555-562 ◽

Cited By ~ 6

Author(s):

Andrea Szelényi ◽

Carla S. Jung ◽

Holger Schön ◽

Volker Seifert

Keyword(s):

Brain Tissue ◽

Clinical Experience ◽

Evoked Potential ◽

Tissue Oxygenation ◽

Somatosensory Evoked Potential ◽

Aneurysm Surgery ◽

Brain Tissue Oxygenation ◽

Evoked Potential Monitoring ◽

Oxygenation Monitoring ◽

Initial Clinical Experience

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Effects of hyperbaric oxygen therapy on cerebral oxygenation and mitochondrial function following moderate lateral fluid-percussion injury in rats

Journal of Neurosurgery ◽

10.3171/jns.2004.101.3.0499 ◽

2004 ◽

Vol 101 (3) ◽

pp. 499-504 ◽

Cited By ~ 64

Author(s):

Wilson P. Daugherty ◽

Joseph E. Levasseur ◽

Dong Sun ◽

Gaylan L. Rockswold ◽

M. Ross Bullock

Keyword(s):

Brain Injury ◽

Redox Potential ◽

Brain Tissue ◽

Mitochondrial Function ◽

Cerebral Oxygenation ◽

Brain Tissue Oxygenation ◽

Content Type ◽

Fluid Percussion ◽

Lateral Fluid Percussion ◽

Fine Print

Object. In the current study, the authors examined the effects of hyperbaric O2 (HBO) following fluid-percussion brain injury and its implications on brain tissue oxygenation (PO2) and O2 consumption (VO2) and mitochondrial function (redox potential). Methods. Cerebral tissue PO2 was measured following induction of a lateral fluid-percussion brain injury in rats. Hyperbaric O2 treatment (100% O2 at 1.5 ata) significantly increased brain tissue PO2 in both injured and sham-injured animals. For VO2 and redox potential experiments, animals were treated using 30% O2 or HBO therapy for 1 or 4 hours (that is, 4 hours 30% O2 or 1 hour HBO and 3 hours 100% O2). Microrespirometer measurements of VO2 demonstrated significant increases following HBO treatment in both injured and sham-injured animals when compared with animals that underwent 30% O2 treatment. Mitochondrial redox potential, as measured by Alamar blue fluorescence, demonstrated injury-induced reductions at 1 hour postinjury. These reductions were partially reversed at 4 hours postinjury in animals treated with 30% O2 and completely reversed at 4 hours postinjury in animals on HBO therapy when compared with animals treated for only 1 hour. Conclusions. Analysis of data in the current study demonstrates that HBO significantly increases brain tissue PO2 after injury. Nonetheless, treatment with HBO was insufficient to overcome injury-induced reductions in mitochondrial redox potential at 1 hour postinjury but was able to restore redox potential by 4 hours postinjury. Furthermore, HBO induced an increase in VO2 in both injured and sham-injured animals. Taken together, these data demonstrate that mitochondrial function is depressed by injury and that the recovery of aerobic metabolic function may be enhanced by treatment with HBO.

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