Poor-grade aneurysmal subarachnoid hemorrhage: relationship of cerebral metabolism to outcome

2004 ◽  
Vol 100 (3) ◽  
pp. 400-406 ◽  
Author(s):  
Asita Sarrafzadeh ◽  
Daniel Haux ◽  
Ingeborg Küchler ◽  
Wolfgang R. Lanksch ◽  
Andreas W. Unterberg
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebral Metabolism ◽  
Univariate Analysis ◽  
High Morbidity ◽  
Low Grade ◽  
High Grade ◽  
Content Type ◽  
Poor Grade ◽  
Fisher Grade ◽  
Fine Print

Object. The majority of patients with poor-grade subarachnoid hemorrhage (SAH), that is, World Federation of Neurosurgical Societies (WFNS) Grades IV and V, have high morbidity and mortality rates. The objective of this study was to investigate cerebral metabolism in patients with low-compared with high-grade SAH by using bedside microdialysis and to evaluate whether microdialysis parameters are of prognostic value for outcome in SAH. Methods. A prospective investigation was conducted in 149 patients with SAH (mean age 50.9 ± 12.9 years); these patients were studied for 162 ± 84 hours (mean ± standard deviation). Lesions were classified as low-grade SAH (WFNS Grades I–III, 89 patients) and high-grade SAH (WFNS Grade IV or V, 60 patients). After approval by the local ethics committee and consent from the patient or next of kin, a microdialysis catheter was inserted into the vascular territory of the aneurysm after clip placement. The microdialysates were analyzed hourly for extracellular glucose, lactate, lactate/pyruvate (L/P) ratio, glutamate, and glycerol. The 6- and 12-month outcomes according to the Glasgow Outcome Scale and functional disability according to the modified Rankin Scale were assessed. In patients with high-grade SAH, cerebral metabolism was severely deranged compared with those who suffered low-grade SAH, with high levels (p < 0.05) of lactate, a high L/P ratio, high levels of glycerol, and, although not significant, of glutamate. Univariate analysis revealed a relationship among hyperglycemia on admission, Fisher grade, and 12-month outcome (p < 0.005). In a multivariate regression analysis performed in 131 patients, the authors identified four independent predictors of poor outcome at 12 months, in the following order of significance: WFNS grade, patient age, L/P ratio, and glutamate (p < 0.03). Conclusions. Microdialysis parameters reflected the severity of SAH. The L/P ratio was the best metabolic independent prognostic marker of 12-month outcome. A better understanding of the causes of deranged cerebral metabolism may allow the discovery of therapeutic options to improve the prognosis, especially in patients with high-grade SAH, in the future.

Clot volume and clearance rate as independent predictors of vasospasm after aneurysmal subarachnoid hemorrhage

2004 ◽  
Vol 101 (2) ◽  
pp. 255-261 ◽  
Author(s):  
Christopher Reilly ◽  
Chris Amidei ◽  
Jocelyn Tolentino ◽  
Babak S. Jahromi ◽  
R. Loch Macdonald
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Clearance Rate ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Quantitative Imaging ◽  
Univariate Analysis ◽  
Ct Scans ◽  
Focal Neurological Deficit ◽  
Content Type ◽  
Fisher Grade ◽  
Fine Print

Object. This study was conducted for two purposes. The first was to determine whether a combination of measurements of subarachnoid clot volume, clearance rate, and density could improve prediction of which patients experience vasospasm. The second was to determine if each of these three measures could be used independently to predict vasospasm. Methods. Digital files of the cranial computerized tomography (CT) scans obtained in 75 consecutive patients admitted within 24 hours of subarachnoid hemorrhage (SAH) were analyzed in a blinded fashion by an observer who used quantitative imaging software to measure the volume of SAH and its density. Clot clearance rates were measured by quantifying SAH volume on subsequent CT scans. Vasospasm was defined as new onset of a focal neurological deficit or altered consciousness 5 to 12 days after SAH in the absence of other causes of deterioration, diagnosed with the aid of or exclusively by confirmatory transcranial Doppler ultrasonography and/or cerebral angiography. Univariate analysis showed that vasospasm was significantly associated with the SAH grade as classified on the Fisher scale, the initial clot volume, initial clot density, and percentage of clot cleared per day (p < 0.05). In multivariate analysis, initial clot volume and percentage of clot cleared per day were significant predictors of vasospasm (p < 0.05), whereas Fisher grade and initial clot density were not. Conclusions. Quantitative analysis of subarachnoid clot shows that vasospasm is best predicted by initial subarachnoid clot volume and the percentage of clot cleared per day.

Delayed neurological deficits detected by an ischemic pattern in the extracellular cerebral metabolites in patients with aneurysmal subarachnoid hemorrhage

2004 ◽  
Vol 100 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Jane Skjøth-Rasmussen ◽  
Mette Schulz ◽  
Soren Risom Kristensen ◽  
Per Bjerre
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Cerebral Metabolism ◽  
Brain Infarction ◽  
Neurological Deficits ◽  
Parent Artery ◽  
Glycerol Concentration ◽  
Microdialysis Probe ◽  
Content Type ◽  
Fine Print

Object. In the treatment of patients with aneurysmal subarachnoid hemorrhage (SAH), early occlusion of the aneurysm is necessary as well as monitoring and treatment of complications following the primary bleeding episode. Monitoring with microdialysis has been studied for its ability to indicate and predict the occurrence of delayed ischemic neurological deficits (DINDs) in patients with SAH. Methods. In 42 patients with aneurysmal SAH microdialysis monitoring of metabolites was performed using a 0.3-µl/minute perfusion flow over several days, and the results were correlated to clinical events and to brain infarction observed on computerized tomography scans. The microdialysis probe was inserted into the territory of the parent artery of the aneurysm. The authors defined an ischemic pattern as increases in the lactate/glucose (L/G) and lactate/pyruvate (L/P) ratios that were greater than 20% followed by a 20% increase in glycerol concentration. This ischemic pattern was found in 17 of 18 patients who experienced a DIND and in three of 24 patients who did not experience a delayed clinical deterioration. The ischemic pattern preceded the occurrence of a DIND by a mean interval of 11 hours. Maximum L/G and L/P ratios did not correlate with the presence of DIND or outcome, and there was no association between the glycerol level and subsequent brain infarction. Conclusions. Microdialysis monitoring of the cerebral metabolism in patients with SAH may predict with high sensitivity and specificity the occurrence of a DIND. Whether an earlier diagnosis results in better treatment of DINDs and, therefore, in overall better outcomes remains to be proven, as it is linked to an efficacious treatment of cerebral vasospasm.

Cerebral circulation and metabolism in the acute stage of subarachnoid hemorrhage

2000 ◽  
Vol 93 (6) ◽  
pp. 1014-1018 ◽  
Author(s):  
Toshiaki Hayashi ◽  
Akifumi Suzuki ◽  
Jun Hatazawa ◽  
Iwao Kanno ◽  
Reizo Shirane ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebral Circulation ◽  
Cerebral Blood Volume ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Cerebral Metabolism ◽  
Aneurysm Rupture ◽  
Acute Stage ◽  
Content Type ◽  
Positron Emission ◽  
Fine Print

Object. The mechanism of reduction of cerebral circulation and metabolism in patients in the acute stage of aneurysmal subarachnoid hemorrhage (SAH) has not yet been fully clarified. The goal of this study was to elucidate this mechanism further.Methods. The authors estimated cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), O2 extraction fraction (OEF), and cerebral blood volume (CBV) preoperatively in eight patients with aneurysmal SAH (one man and seven women, mean age 63.5 years) within 40 hours of onset by using positron emission tomography (PET). The patients' CBF, CMRO2, and CBF/CBV were significantly lower than those in normal control volunteers. However, OEF and CBV did not differ significantly from those in control volunteers. The significant decrease in CBF/CBV, which indicates reduced cerebral perfusion pressure, was believed to be caused by impaired cerebral circulation due to elevated intracranial pressure (ICP) after rupture of the aneurysm. In two of the eight patients, uncoupling between CBF and CMRO2 was shown, strongly suggesting the presence of cerebral ischemia.Conclusions. The initial reduction in CBF due to elevated ICP, followed by reduction in CMRO2 at the time of aneurysm rupture may play a role in the disturbance of CBF and cerebral metabolism in the acute stage of aneurysmal SAH.

Characterization of perioperative seizures and epilepsy following aneurysmal subarachnoid hemorrhage

2003 ◽  
Vol 99 (6) ◽  
pp. 978-985 ◽  
Author(s):  
Chih-Lung Lin ◽  
Aaron S. Dumont ◽  
Ann-Shung Lieu ◽  
Chen-Po Yen ◽  
Shiuh-Lin Hwang ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Predictive Factors ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Neurological Deficits ◽  
Loss Of Consciousness ◽  
Content Type ◽  
Fisher Grade ◽  
The Mean ◽  
Fine Print

Object. The reported incidence, timing, and predictive factors of perioperative seizures and epilepsy after subarachnoid hemorrhage (SAH) have differed considerably because of a lack of uniform definitions and variable follow-up periods. In this study the authors evaluate the incidence, temporal course, and predictive factors of perioperative seizures and epilepsy during long-term follow up of patients with SAH who underwent surgical treatment. Methods. Two hundred seventeen patients who survived more than 2 years after surgery for ruptured intracranial aneurysms were enrolled and retrospectively studied. Episodes were categorized into onset seizures (≤ 12 hours of initial hemorrhage), preoperative seizures, postoperative seizures, and late epilepsy, according to their timing. The mean follow-up time was 78.7 months (range 24–157 months). Forty-six patients (21.2%) had at least one seizure post-SAH. Seventeen patients (7.8%) had onset seizures, five (2.3%) had preoperative seizures, four (1.8%) had postoperative seizures, 21 (9.7%) had at least one seizure episode after the 1st week postoperatively, and late epilepsy developed in 15 (6.9%). One (3.8%) of 26 patients with perioperative seizures (onset, preoperative, or postoperative seizure) had late epilepsy at follow up. The mean latency between the operation and the onset of late epilepsy was 8.3 months (range 0.3–19 months). Younger age (< 40 years old), loss of consciousness of more than 1 hour at ictus, and Fisher Grade 3 or greater on computerized tomography scans proved to be significantly related to onset seizures. Onset seizure was also a significant predictor of persistent neurological deficits (Glasgow Outcome Scale Scores 2–4) at follow up. Factors associated with the development of late epilepsy were loss of consciousness of more than 1 hour at ictus and persistent postoperative neurological deficit. Conclusions. Although up to one fifth of patients experienced seizure(s) after SAH, more than half had seizure(s) during the perioperative period. The frequency of late epilepsy in patients with perioperative seizures (7.8%) was not significantly higher than those without such seizures (6.8%). Perioperative seizures did not recur frequently and were not a significant predictor for late epilepsy.

Decrease in platelet count as an independent risk factor for symptomatic vasospasm following aneurysmal subarachnoid hemorrhage

2005 ◽  
Vol 102 (5) ◽  
pp. 882-887 ◽  
Author(s):  
Yutaka Hirashima ◽  
Hideo Hamada ◽  
Masanori Kurimoto ◽  
Hideki Origasa ◽  
Shunro Endo
Keyword(s):  
Platelet Count ◽  
Subarachnoid Hemorrhage ◽  
Blood Cells ◽  
White Blood Cells ◽  
Experimental Studies ◽  
Content Type ◽  
Symptomatic Vasospasm ◽  
Cell Counts ◽  
Fisher Grade ◽  
Fine Print

Object. Increased platelet consumption is expected in patients with cerebral vasospasm, according to data from clinical and experimental studies. The authors investigated sequential changes in platelet counts in patients with subarachnoid hemorrhage (SAH) and the difference in platelet consumption between patients with and those without symptomatic vasospasm (SV). Variables related to platelet count as well as other clinical and radiological variables were analyzed as independent predictors of SV. Methods. One hundred consecutive patients who had undergone surgery within 48 hours after SAH onset were entered in the study. Clinical and radiological variables and blood cell counts, including red blood cells, white blood cells, and platelets, after SAH were retrospectively examined. Twenty of these variables were entered into univariate and multivariate analyses to determine predictors for SV. After SAH, the platelet count decreased to a minimum and then increased rapidly to levels greater than those recorded on admission. This change was specific to SAH, and platelet consumption was more severe in patients with SV than in those without. There were three independent predictors of SV: a ratio of the lowest platelet count and the admission count greater than 0.7 (odds ratio [OR] 0.322, 95% confidence interval [CI] 0.124–0.834, p = 0.0196) and a history of hypertension (OR 0.338, 95% CI 0.126–0.906, p = 0.0311) were negatively significant (that is, decreases the occurrence of SV), and a Fisher Grade 3 (OR 4.42, 95% CI 1.48–13.2, p = 0.0077) was positively significant (that is, increases the occurrence of SV). Conclusions. The association between a decrease in platelet count and the occurrence of SV indicates the important role of platelets in the pathophysiology of vasospasm following SAH.

Predicting outcome in poor-grade patients with subarachnoid hemorrhage: a retrospective review of 159 aggressively managed cases

1996 ◽  
Vol 85 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Peter D. Le Roux ◽  
J. Paul Elliott ◽  
David W. Newell ◽  
M. Sean Grady ◽  
H. Richard Winn
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Medical Center ◽  
Subsequent Development ◽  
Content Type ◽  
Poor Grade ◽  
Aggressive Management ◽  
Predicting Outcome ◽  
The University ◽  
Fine Print

✓ To determine what factors predict outcome, the authors retrospectively reviewed the management of all 159 poor-grade patients admitted to Harborview Medical Center at the University of Washington who suffered aneurysmal subarachnoid hemorrhage between 1983 and 1993. Favorable outcome (assessed by the Glasgow Outcome Scale) occurred in 53.9% of Hunt and Hess Grade IV, and 24.1% of Grade V patients. Outcome was largely determined by the initial hemorrhage and subsequent development of intractable intracranial hypertension or cerebral infarction. Using multivariate analysis, the authors developed three models to predict outcome. It was found that predicting outcome based only on clinical and diagnostic criteria present at admission may have resulted in withholding treatment from 30% of the patients who subsequently experienced favorable outcomes. It is concluded that aggressive management including surgical aneurysm obliteration can benefit patients with poor neurological grades and should not be denied solely on the basis of the neurological condition on admission.

Low-grade gliomas of the cerebral hemispheres in children: an analysis of 71 cases

1995 ◽  
Vol 82 (4) ◽  
pp. 536-547 ◽  
Author(s):  
Ian F. Pollack ◽  
Diana Claassen ◽  
Qasim Al-Shboul ◽  
Janine E. Janosky ◽  
Melvin Deutsch
Keyword(s):  
Overall Survival ◽  
Univariate Analysis ◽  
Tumor Resection ◽  
Progression Free Survival ◽  
Low Grade ◽  
Free Survival ◽  
Content Type ◽  
Low Grade Gliomas ◽  
Fine Print

✓ Low-grade gliomas constitute the largest group of cerebral hemispheric tumors in the pediatric population. Although complete tumor resection is generally the goal in the management of these lesions, this can prove difficult to achieve because tumor margins may blend into the surrounding brain. This raises several important questions on the long-term behavior of the residual tumor and the role of adjuvant therapy in the management of these lesions. To examine these issues, the authors reviewed their experience in 71 children with low-grade cerebral hemispheric gliomas who were treated at their institution between 1956 and 1991 and assessed the relationship between clinical, radiographic, pathological, and treatment-related factors and outcome. Only seven patients in the series died, one from perioperative complications, five from progressive disease, and one (a child with neurofibromatosis) from a second neoplasm. For the 70 patients who survived the perioperative period, overall actuarial survivals at 5, 10, and 20 years were 95%, 93%, and 85%, respectively; progression-free status was maintained in 88%, 79%, and 76%, respectively. On univariate analysis, the factor that was most strongly associated with both overall and progression-free survival was the extent of tumor resection (p = 0.013 and p = 0.015, respectively). A relationship between extent of resection and progression-free survival was present both in patients with pilocytic astrocytomas (p = 0.041) and those with nonpilocytic tumors (p = 0.037). Histopathological diagnosis was also associated with overall survival on univariate analysis; poorer results were seen in the patients with nonpilocytic astrocytoma compared to those with other low-grade gliomas, such as pilocytic astrocytoma, mixed glioma, and oligodendroglioma (p = 0.021). The use of radiotherapy was not associated with a significant improvement in overall survival (p = 0.6). All three patients who ultimately developed histologically confirmed anaplastic changes in the vicinity of the original tumor had received prior radiotherapy, 20, 46, and 137 months, respectively, before the detection of malignant progression. In addition, children who received radiotherapy had a significantly higher incidence of late cognitive and endocrine dysfunction than the nonirradiated patients (p < 0.01 and 0.05, respectively). The authors conclude that children with low-grade gliomas of the cerebral hemispheres have an excellent overall prognosis. Complete tumor resection provides the best opportunity for long-term progression-free survival. However, even with incomplete tumor excision, long-term progression-free survival is common. The findings in this study do not support the routine use of postoperative radiotherapy after an initial incomplete tumor resection: although irradiation appears to increase the likelihood of long-term progression-free survival, overall survival is not improved significantly, and long-term morbidity may be increased.

Subependymal giant-cell astrocytoma in children

1988 ◽  
Vol 68 (6) ◽  
pp. 880-883 ◽  
Author(s):  
Chung W. Chow ◽  
Geoffrey L. Klug ◽  
Elizabeth A. Lewis
Keyword(s):  
Giant Cell ◽  
Subependymal Giant Cell Astrocytoma ◽  
Low Grade ◽  
High Grade ◽  
Content Type ◽  
Large Numbers ◽  
Aggressive Tumor ◽  
Fine Print ◽  
Giant Cell Astrocytoma

✓ The authors describe five cases of subependymal giant-cell astrocytoma in children in which many clinical, histological, immunohistochemical, and ultrastructural features typical of this tumor were present. However, prominent focal necrosis and mitoses, features usually associated with high-grade tumors, were seen in all cases. Despite the presence of necrosis and mitoses, clinical follow-up studies have revealed a lack of aggressive tumor behavior after surgery alone. The discrepancy between the histological and clinical features in these cases is emphasized so that excessive treatment of a basically low-grade tumor may be avoided. Mast cells were seen in all five cases, often in large numbers.

Relationship between intracranial pressure and other clinical variables in patients with aneurysmal subarachnoid hemorrhage

2004 ◽  
Vol 101 (3) ◽  
pp. 408-416 ◽  
Author(s):  
Gregory G. Heuer ◽  
Michelle J. Smith ◽  
J. Paul Elliott ◽  
H. Richard Winn ◽  
Peter D. Leroux
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Intracranial Pressure ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Clinical Grade ◽  
Icp Monitoring ◽  
Content Type ◽  
Poor Grade ◽  
Symptomatic Vasospasm ◽  
Increased Icp ◽  
Fine Print

Object. Increased intracranial pressure (ICP) is well known to affect adversely patients with head injury. In contrast, the variables associated with ICP following aneurysmal subarachnoid hemorrhage (SAH) and their impact on outcome have been less intensely studied. Methods. In this retrospective study the authors reviewed a prospective observational database cataloging the treatment details in 433 patients with SAH who had undergone surgical occlusion of an aneurysm as well as ICP monitoring. All 433 patients underwent postoperative ICP monitoring, whereas only 146 (33.7%) underwent both pre- and postoperative ICP monitoring. The mean maximal ICP was 24.9 ± 17.3 mm Hg (mean ± standard deviation). During their hospital stay, 234 patients (54%) had elevated ICP (> 20 mm Hg), including 136 of those (48.7%) with a good clinical grade (Hunt and Hess Grades I–III) and 98 (63.6%) of the 154 patients with a poor grade (Hunt and Hess Grades IV and V) on admission. An increased mean maximal ICP was associated with several admission variables: worse Hunt and Hess clinical grade (p < 0.0001), a lower Glasgow Coma Scale (GSC) motor score (p < 0.0001); worse SAH grade based on results of computerized tomography studies (p < 0.0001); intracerebral hemorrhage (p = 0.024); severity of intraventricular hemorrhage (p < 0.0001); and rebleeding (p = 0.0048). Both intraoperative cerebral swelling (p = 0.0017) and postoperative GCS score (p < 0.0001) were significantly associated with a raised ICP. Variables such as patient age, aneurysm size, symptomatic vasospasm, intraoperative aneurysm rupture, and secondary cerebral insults such as hypoxia were not associated with raised ICP. Increased ICP adversely affected outcome: 71.9% of patients with normal ICP demonstrated favorable 6-month outcomes postoperatively, whereas 63.5% of patients with ICP between 20 and 50 mm Hg and 33.3% with ICP greater than 50 mm Hg demonstrated favorable outcomes. Among 21 patients whose raised ICP did not respond to mannitol therapy, all experienced a poor outcome and 95.2% died. Among 145 patients whose elevated ICP responded to mannitol, 66.9% had a favorable outcome and only 20.7% were dead 6 months after surgery (p < 0.0001). According to results of multivariate analysis, however, ICP was not an independent outcome predictor (odds ratio 1.26, 95% confidence interval 0.28–5.68). Conclusions. Increased ICP is common after SAH, even in patients with a good clinical grade. Elevated ICP post-SAH is associated with a worse patient outcome, particularly if ICP does not respond to treatment. This association, however, may depend more on the overall severity of the SAH than on ICP alone.

The effect of nimodipine on cerebral oxygenation in patients with poor-grade subarachnoid hemorrhage

2004 ◽  
Vol 101 (4) ◽  
pp. 594-599 ◽  
Author(s):  
Michael F. Stiefel ◽  
Gregory G. Heuer ◽  
John M. Abrahams ◽  
Stephanie Bloom ◽  
Michelle J. Smith ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Subarachnoid Hemorrhage ◽  
Brain Tissue ◽  
Cerebral Oxygenation ◽  
Content Type ◽  
Poor Grade ◽  
Physiological Variables ◽  
Arterial Blood ◽  
End Tidal ◽  
Fine Print

Object. Nimodipine has been shown to improve neurological outcome after subarachnoid hemorrhage (SAH); the mechanism of this improvement, however, is uncertain. In addition, adverse systemic effects such as hypotension have been described. The authors investigated the effect of nimodipine on brain tissue PO2. Methods. Patients in whom Hunt and Hess Grade IV or V SAH had occurred who underwent aneurysm occlusion and had stable blood pressure were prospectively evaluated using continuous brain tissue PO2 monitoring. Nimodipine (60 mg) was delivered through a nasogastric or Dobhoff tube every 4 hours. Data were obtained from 11 patients and measurements of brain tissue PO2, intracranial pressure (ICP), mean arterial blood pressure (MABP), and cerebral perfusion pressure (CPP) were recorded every 15 minutes. Nimodipine resulted in a significant reduction in brain tissue PO2 in seven (64%) of 11 patients. The baseline PO2 before nimodipine administration was 38.4 ± 10.9 mm Hg. The baseline MABP and CPP were 90 ± 20 and 84 ± 19 mm Hg, respectively. The greatest reduction in brain tissue PO2 occurred 15 minutes after administration, when the mean pressure was 26.9 ± 7.7 mm Hg (p < 0.05). The PO2 remained suppressed at 30 minutes (27.5 ± 7.7 mm Hg [p < 0.05]) and at 60 minutes (29.7 ± 11.1 mm Hg [p < 0.05]) after nimodipine administration but returned to baseline levels 2 hours later. In the seven patients in whom brain tissue PO2 decreased, other physiological variables such as arterial saturation, end-tidal CO2, heart rate, MABP, ICP, and CPP did not demonstrate any association with the nimodipine-induced reduction in PO2. In four patients PO2 remained stable and none of these patients had a significant increase in brain tissue PO2. Conclusions. Although nimodipine use is associated with improved outcome following SAH, in some patients it can temporarily reduce brain tissue PO2.

Sign in / Sign up

Export Citation Format

Share Document