N D Kitchen

The National Institute of Neurology and Neurosurgery, Tlalpam, The Federal District, Mexico

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Publications (149)467.32 Total impact

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    ABSTRACT: Introduction. Idiopathic normal pressure hydrocephalus (iNPH) is a shunt- reversible syndrome of the elderly. Shunt management is aimed at achieving a balance between clinical improvement and the complications associated with overdrainage. Although clinical improvement occurs at low pressure, these benefits may be negated by the increase in complication rates observed at lower pressures. The addition of gravity-switch devices has been shown to reduce over drainage problems even at a low valve pressure setting. At our centre the Miethke proGAV is used and commonly lowered below 5 cmH2O to gain further clinical improvement. Object. To determine whether lowering the opening pressure to below 5cmH2O using the proGAV valve in iNPH patients results in a) improved clinical features; and b) no significant increase in complication rates. Methods. A retrospective case series of iNPH patients was undertaken with 24 patients who had the proGAV shunt system inserted with an initial opening pressure of 5cmH2O. Exclusion criteria were secondary NPH, shunt system other than proGAV inserted, no valve adjustment to below 5cmH2O and inadequate follow-up. Outcome measures were clinical improvement (gait, cognition and urinary continence) and complications (subdural haematoma, low-pressure symptoms and valve damage). Results. Patients underwent a total of 29 adjustments to below 5cmH2O. The mean valve opening pressure after the first adjustment was 2.5cmH2O and the mean opening pressure after the second adjustment was 1cmH2O. Overall, outcome after adjustment included 26% no change, 48% improvement and 26% deterioration clinically. One patient (4%) suffered traumatic subdural haematoma that resolved with increasing valve pressure to 20cmH2O. There was no valve damage or low-pressure symptoms after adjustment. Conclusion. This study found that lowering the opening pressure of the proGAV shunt system to below 5cmH2O results in clinical improvement and does not significantly increase the complication rate in iNPH patients.
    British Journal of Neurosurgery 08/2014; · 0.86 Impact Factor
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    ABSTRACT: The design and operation of a facility in which a magnetic resonance imaging (MRI) scanner is incorporated into a room used for surgical or endovascular cardiac interventions presents several challenges. MR safety must be maintained in the presence of a much wider variety of equipment than is found in a diagnostic unit, and of staff unfamiliar with the MRI environment, without compromising the safety and practicality of the interventional procedure. Both the MR-guided cardiac interventional unit at Kings College London and the intraoperative imaging suite at the National Hospital for Neurology and Neurosurgery are single-room interventional facilities incorporating 1.5 T cylindrical-bore MRI scanners. The two units employ similar strategies to maintain MR safety, both in original design and day-to-day operational workflows, and between them over a decade of incident-free practice has been accumulated. This article outlines these strategies, highlighting both similarities and differences between the units, as well as some lessons learned and resulting procedural changes made in both units since installation.J. Magn. Reson. Imaging 2014. © 2014 Wiley Periodicals, Inc.
    Journal of Magnetic Resonance Imaging 02/2014; · 2.57 Impact Factor
  • Ahmed K Toma, Neil D Kitchen, Fergus Robertson
    British Journal of Neurosurgery 12/2013; · 0.86 Impact Factor
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    ABSTRACT: Preoperative embolization of meningiomas remains contentious, with persisting uncertainty over the safety and efficacy of this adjunctive technique. To evaluate the safety of presurgical embolization of meningiomas and its impact on subsequent transfusion requirement, with respect to the extent of embolization and technique used. 117 consecutive patients between 2001 and 2010 were referred for embolization of presumed intracranial meningioma prior to surgical resection. Glue and/or particles were used to devascularize the tumor in 107 patients, all of whom went on to operative resection. The extent and nature of embolization-related complications, degree of angiographic devascularization, and the intraoperative blood transfusion requirements were analyzed. Mean blood transfusion requirement during surgery was 0.8 units per case (range 1-14 units). Blood transfusion was significantly lower in patients whose meningiomas were completely, angiographically devascularized (P= .035). Four patients had complications as a direct result of the embolization procedure. These included intratumoral haemorrhage in two, sixth cranial nerve palsy in one, and scalp necrosis requiring reconstructive surgery in a further patient. The complication rate was 3.7%. No relationship between the embolic agent and the degree of devascularization was observed. Achieving a complete devascularization resulted in a lower blood transfusion requirement, considered an indirect measure of operative blood loss. This series demonstrates that pre-operative meningioma embolization is safe and may reduce operative blood loss. We present distal intratumoral injection of liquid embolic as a safe and effective alternative to more established particle embolization techniques.
    Neurosurgery 09/2013; · 2.53 Impact Factor
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    ABSTRACT: Object The aim of this study was to design a checklist with a scoring system for reporting on studies of surgical interventions for trigeminal neuralgia (TN) and to validate it by a review of the recent literature. Methods A checklist with a scoring system, the Surgical Trigeminal Neuralgia Score (STNS), was devised partially based on the validated STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) criteria and customized for TN after a literature review and then applied to a series of articles. These articles were identified using a prespecified MEDLINE and Embase search covering the period from 2008 to 2010. Of the 584 articles found, 59 were studies of interventional procedures for TN that fulfilled the inclusion criteria and 56 could be obtained in full. The STNS was then applied independently by 3 of the authors. Results The maximum STNS came to 30, and was reliable and reproducible when used by the 3 authors who performed the scoring. The range of scores was 6-23.5, with a mean of 14 for all the journals. The impact factor scores of the journals in which the papers were published ranged from 0 to 4.8. Twenty-four of the studies were published in the Journal of Neurosurgery or in Neurosurgery. Studies published in neurosurgical journals ranked higher on the STNS scale than those published in nonneurosurgical journals. There was no statistically significant correlation between STNS and impact factors. Stereotactic radiosurgery (n = 25) and microvascular decompression (n = 15) were the most commonly reported procedures. The diagnostic criteria were stated in 35% of the studies, and 4 studies reported subtypes of TN. An increasing number of studies (46%) used the recommended Kaplan-Meier methodology for pain survival outcomes. The follow-up period was unclear in 8 studies, and 26 reported follow-ups of more than 5 years. Complications were reported fairly consistently but the temporal course was not always indicated. Direct interview, telephone conversation, and questionnaires were used to measure outcomes. Independent assessment of outcome was only clearly stated in 7 studies. Only 2 studies used the 36-Item Short Form Health Survey to measure quality of life and 4 studies reported on the severity of preoperative pain. The Barrow Neurological Institute pain questionnaire was the most commonly used outcome measure (n = 13), followed by the visual analog scale. Conclusions Similar to the STROBE criteria that provide a checklist of items that should be included in reports of observational studies in general, the authors' suggested checklist for the STNS could help editors and reviewers ensure that quality reports are published, and could prove useful for colleagues when reporting their results specifically on the surgical management of TN. It would help the patient and clinicians make a decision about selecting the appropriate neurosurgical procedure.
    Neurosurgical FOCUS 09/2013; 35(3):E3. · 2.49 Impact Factor
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    ABSTRACT: Early surgical series of shunt insertion for idiopathic normal-pressure hydrocephalus reported a low rate of short-term improvement with a relatively high rate of mortality and morbidity; subsequently shunt insertion was recommended for patients in whom there is favourable risk-to-benefit ratio. Bibliographic search for studies that objectively assessed the outcome following shunt insertion in idiopathic normal-pressure hydrocephalus was done; the aim was to estimate the outcome of shunt insertion in terms of improvement rates and associated mortality and morbidity. A total of 64 studies of 3,063 patients were reviewed. Positive improvement following shunt insertion was reported in an average of 71 % of patients with an average 1 % mortality. Results from studies published in the last 5 years showed 82 % improvement following shunt insertion, mortality of 0.2 %, and combined common complications rate of 8.2 %. When patients are properly selected, shunt insertion is a safe and effective management of idiopathic normal-pressure hydrocephalus with a prolonged positive outcome.
    Acta Neurochirurgica 08/2013; · 1.55 Impact Factor
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    ABSTRACT: Intracranial germinoma is most commonly found in the pineal and suprasellar regions. The medulla oblongata and fourth ventricle are rare sites of primary germinoma, with only 12 previous patients reported, all from the Far East. To our knowledge, we report the first patient from Europe. A 25-year-old female of Afro-Caribbean origin presented with several weeks of worsening migraines, dizziness, tachycardia and veering to the right whilst walking. MRI revealed a lesion in the fourth ventricle, which was treated with surgical debulking and post operative radiotherapy. Two months following completion of radiotherapy, MRI showed almost complete resolution of the enhancing disease within the primary tumour area and no intraspinal pathological enhancement. This patient highlights the importance of considering germinoma in the differential diagnosis of all medullary masses with extension into the fourth ventricle irrespective of geographic location.
    Journal of Clinical Neuroscience 07/2013; · 1.25 Impact Factor
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    ABSTRACT: The incidence of oligometastases to the brain in good performance status patients is increasing due to improvements in systemic therapy and MRI screening, but specific management pathways are often lacking. We established a multi-disciplinary brain metastases clinic with specific referral guidelines and standard follow-up for good prognosis patients with the view that improving the process of care may improve outcomes. We evaluated patient demographic and outcome data for patients first seen between February 2007 and November 2011. The clinic was feasible to run and referrals were appropriate. 87% of patients referred received a localised therapy during their treatment course. 114 patients were seen and patient numbers increased during the 5 years that the clinic has been running as relationships between clinicians were developed. Median follow-up for those still alive was 23.1 months (6.1-79.1 months). Primary treatments were: surgery alone 52%, surgery plus whole brain radiotherapy (WBRT) 9%, radiosurgery 14%, WBRT alone 23%, supportive care 2%. 43% received subsequent treatment for brain metastases. 25%, 11% and 15% respectively developed local neurological progression only, new brain metastases only or both. Median overall survival following brain metastases diagnosis was 16.0 months (range 1--79.1 months). Breast (32%) and NSCLC (26%) were the most common primary tumours with median survivals of 26 and 16.9 months respectively (HR 0.6, p=0.07). Overall one year survival was 55% and two year survival 31.5%. 85 patients died of whom 37 (44%) had a neurological death. Careful patient selection and multi-disciplinary management identifies a subset of patients with oligometastatic brain disease who benefit from aggressive local treatment. A dedicated joint neurosurgical/ neuro-oncology clinic for such patients is feasible and effective. It also offers the opportunity to better define management strategies and further research in this field. Consideration should be given to defining specific management pathways for these patients within general oncology practice.
    Radiation Oncology 06/2013; 8(1):156. · 2.11 Impact Factor
  • Matthew A Kirkman, Huma Sethi, Neil D Kitchen
    Acta Neurochirurgica 06/2013; · 1.55 Impact Factor
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    ABSTRACT: Introduction. The flow diverting stent (FDS) is a relatively new endovascular therapeutic tool specifically designed to reconstruct the parent artery and divert blood flow along the normal anatomical course and away from the aneurysm neck and dome. Methods. Retrospective review of prospectively built clinical and imaging database of patients treated with FDS at the National Hospital for Neurology and Neurosurgery, Queen Square, London, UK was done. Results. Between 18/03/2008 and 10/11/2011, 80 patients underwent 84 FDS insertion procedures for various indications. Mean duration of clinical follow-up was 11.3 ± 9.3 months and of imaging follow-up was 10.6 ± 9.3 months. Sixty-seven had anterior circulation aneurysms while 17 had posterior circulation aneurysms. Seven (8.3%) patients died (two probably not related, giving a procedure-related mortality of 5.9%), eight had permanent new deficit (9.5%), 20 had transient deficit (23%) and 49 (58%) had no complications. There was a trend towards bad outcome with larger posterior circulation aneurysms. Angiographic follow-up showed 38% cure rate at 6 months and 61% at 12 months. Conclusion. FDS should only be used following multidisciplinary discussion in selected patients. Further data is required regarding long-term safety, efficacy and indications.
    British Journal of Neurosurgery 05/2013; · 0.86 Impact Factor
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    ABSTRACT: The past decade has seen significant changes to the face of neurosurgical training in the United Kingdom, driven in part by an increasing focus on patient safety and the introduction of Modernising Medical Careers and the European Working Time Directive (EWTD). Recent reforms to neurosurgical training over the past few years have resulted in creation of an 8-year 'run-through' training programme. In this programme, early years (ST1 and ST2) trainees often lack dedicated time for elective theatre lists and outpatient clinics. Further, any time spent in theatre and clinics is often with different teams. Here we describe a training model for early years trainees at the National Hospital for Neurology and Neurosurgery, who are given the responsibilities traditionally associated with a more senior trainee including dedicated weekly theatre and clinic time under the supervision of a single consultant, in addition to out of hours experience. The advantages and considerations for implementing this model are discussed, including the benefit of guidance under a single consultant in the early stages of training, along with key educational concepts necessary for understanding its utility. We feel that this is an effective model for junior neurosurgical training in the EWTD era, expediting the trainee's development of key technical and non-technical skills, with potentially significant rewards for patient, trainee and trainer. National implementation of this model should be considered.
    British Journal of Neurosurgery 05/2013; · 0.86 Impact Factor
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    ABSTRACT: BACKGROUND: Angiogram negative sub-arachnoid haemorrhage (SAH) is generally considered to have a more benign course than SAH of known cause. There is also variability from centre to centre as to what proportion of angiogram negative SAH patients undergo repeat Digital Subtraction Angiography (DSA). We performed a retrospective study looking at the last four years' of SAH patients at our institution in order to ascertain the clinical course, the nature and results of repeat imaging. METHODS: Retrospective analysis of clinical records and imaging of all patients presenting to our institution with non-traumatic SAH between April 2008 and February 2012 was performed. Results were analysed for presenting grades, blood distribution, complications, outcomes, repeat imaging modalities and findings. RESULTS: 459 patients with proven non-traumatic SAH of which 50 (11%) had no vascular cause identified on their initial angiogram were identified. The blood distribution was perimesencephalic in 17, non-perimesencephalic in 23, and 10 patients were computed tomography (CT) Negative with a positive lumbar puncture. Eight (16%) patients were complicated by hydrocephalus and 2 (4%) were complicated by vasospasm. Eight patients (16%) underwent repeat cranial DSA with a high suspicion in a multi-disciplinary team setting. None of the repeat angiograms showed an underlying aetiology for the SAH. 76% of patients had a Glasgow Outcome Score of 5 at 6 months. There were no rebleeds. CONCLUSIONS: While generally more benign, angiogram negative subarachnoid haemorrhage can have a complicated clinical course. In our experience repeat DSA should be reserved for cases in which there is significant suspicion of occult vascular lesion. However, evidence-based guidelines are needed to aid the development of management protocols for angiogram-negative SAH and ensuring optimal patient outcomes.
    Clinical neurology and neurosurgery 02/2013; · 1.30 Impact Factor
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    ABSTRACT: BACKGROUND:: Preoperative embolization of meningiomas remains contentious, with persisting uncertainty over the safety and efficacy of this adjunctive technique. OBJECTIVE:: To evaluate the safety of presurgicalembolization of meningiomas and its impact on subsequent transfusion requirement, with respect to the extent of embolization and technique used. METHODS:: 117 consecutive patients between 2001 and 2010 were referred for embolization of presumed intracranial meningioma prior to surgical resection. Glue and/or particles were used to devascularize the tumor in 107 patients, all of whom went on to operative resection. The extent and nature of embolization-related complications, degree of angiographic devascularization, and the intraoperative blood transfusion requirements were analyzed. RESULTS:: Mean blood transfusion requirement during surgery was 0.8 units per case (range 1-14 units). Blood transfusion was significantly lower in patients whose meningiomas were completely, angiographicallydevascularized (P= .035). Four patients had complications as a direct result of the embolization procedure. These included intratumoral haemorrhage in two, sixth cranial nerve palsy in one, and scalp necrosis requiring reconstructive surgery in a further patient. CONCLUSION:: The complication rate was 3.7%. No relationship between the embolic agent and the degree of devascularization was observed. Achieving a complete devascularization resulted in a lower blood transfusion requirement, considered an indirect measure of operative blood loss. This series demonstrates that pre-operative meningiomaembolization is safe and may reduce operative blood loss. We present distal intratumoral injection of liquid embolic as a safe and effective alternative to more established particle embolization techniques.
    Neurosurgery 02/2013; · 2.53 Impact Factor
  • JOURNAL OF NEUROSURGERY; 01/2013
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    ABSTRACT: OBJECTIVE: Capillary hemangioma in the cranial cavity is rare. This report presents two additional cases with onset of symptoms in relation to pregnancy and provide a systematic review summarizing clinical experience to date. METHODS: Case reports were compiled retrospectively. Patient 1: A 28 year old woman presented with a simple partial seizure associated with left-sided visual distortions which progressed to a secondary generalised tonic clonic seizure. Imaging revealed a contrast-enhancing lesion in the right temporal region adjacent to the transverse sinus, with vasogenic edema and scalloping of the inner table. Angiographic appearance suggested the correct diagnosis. Patient 2: A 41 year-old woman presented with progressive visual disturbance 6 months after giving birth to her second child. Subtle symptoms of headache and visual disturbance had commenced during pregnancy. Non-contrasted imaging displayed a homogenous tumor with surrounding vasogenic edema in the occipital region. The publications on PubMed and Science Citation Index were reviewed systematically. RESULTS: Complete surgical excision was performed in both patients. Neuropathological examination confirmed benign capillary hemangioma consisting of a mesh-work of capillary sized and larger feeder vessels in both instances. The systematic review was based on 20 publications and clinical, radiological and surgical features together with the management were summarized. CONCLUSION: At follow-up, symptoms had disappeared and MRI confirmed complete removal in both patients. Intracranial capillary hemangioma is rare and treatment is empirical. Review of limited published reports suggested that surgery is the most commonly used treatment and that complete excision appears most likely to prevent further recurrence.
    World Neurosurgery 12/2012; · 1.77 Impact Factor
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    ABSTRACT: OBJECTIVE: As inspired oxygen availability falls with ascent to altitude, some individuals develop high-altitude headache (HAH). We postulated that HAH results when hypoxia-associated increases in cerebral blood flow occur in the context of restricted venous drainage, and is worsened when cerebral compliance is reduced. We explored this hypothesis in 3 studies. METHODS: In high-altitude studies, retinal venous distension (RVD) was ophthalmoscopically assessed in 24 subjects (6 female) and sea-level cranial magnetic resonance imaging was performed in 12 subjects ascending to 5,300m. Correlation of headache burden (summed severity scores [0-4] ≤24 hours from arrival at each altitude) with RVD, and with cerebral/cerebrospinal fluid (CSF)/venous compartment volumes, was sought. In a sea-level hypoxic study, 11 subjects underwent gadolinium-enhanced magnetic resonance venography before and during hypoxic challenge (fraction of inspired oxygen = 0.11, 1 hour). RESULTS: In the high-altitude studies, headache burden correlated with both RVD (Spearman rho = 0.55, p = 0.005) and with the degree of narrowing of 1 or both transverse venous sinuses (r = -0.56, p = 0.03). It also related inversely to both the lateral + third ventricle summed volumes (Spearman rho = -0.5, p = 0.05) and pericerebellar CSF volume (r = -0.56, p = 0.03). In the hypoxic study, cerebral and retinal vein engorgement were correlated, and rose as the combined conduit score fell (a measure of venous outflow restriction; r = -0.66, p < 0.05 and r = -0.75, p < 0.05, respectively). INTERPRETATION: Arterial hypoxemia is associated with cerebral and retinal venous distension, whose magnitude correlates with HAH burden. Restriction in cerebral venous outflow is associated with retinal distension and HAH. Limitations in cerebral venous efferent flow may predispose to headache when hypoxia-related increases in cerebral arterial flow occur. ANN NEUROL 2012;
    Annals of Neurology 11/2012; · 11.19 Impact Factor
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    ABSTRACT: There is no level I evidence to indicate whether placement of a shunt is effective in the management of idiopathic normal pressure hydrocephalus (INPH), because no trial has as yet compared the placement of a shunt versus no shunt in a randomized controlled manner. We started recruiting patients into a prospective double-blind randomized controlled study aiming to provide class I evidence supporting or refuting the role of surgical management in INPH. Inclusion criterion was the diagnosis of probable INPH plus objective improvement of walking speed following 72 h of extended lumbar drainage. Patients with concomitant Alzheimer's disease or vascular dementia were excluded. All patients included in the trial were to have a shunt placed with proGAV(®) adjustable valve. Patients were randomly assigned into two groups: group A was to have the shunt immediately adjusted to function, and group B was to have the shunt valve adjusted to the highest setting for 3 months then adjusted to function. Assessment of gait, cognitive function, and urinary symptoms were done before shunt insertion and at 3 months. Primary end point was to be an improvement in gait. Secondary end points were improvement in mental function or urinary function and incidence of complications. Final results are expected mid 2011.
    Acta neurochirurgica. Supplement 01/2012; 113:21-3.
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    ABSTRACT: Current theories of the pathophysiology of normal pressure hydrocephalus suggest the classical symptoms are a consequence of disruption of normal frontal function. We present the case of a 70-year-old patient with an isolated, frontal dilatation of his lateral ventricles in the presence of a complete triad as supportive of these theories.
    Acta Neurochirurgica 11/2011; 154(4):769-72; discussion 772. · 1.55 Impact Factor
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    ABSTRACT: The workup of patients with suspected subarachnoid hemorrhage (SAH) presenting late is complicated by a loss of diagnostic sensitivity of computed tomography (CT) brain imaging and cerebrospinal fluid (CSF) bilirubin levels. In this prospective longitudinal study of CSF ferritin levels in SAH, serial CSF samples from 14 patients with aneurysmal SAH requiring extraventricular drainage (EVD) were collected. The control group comprised 44 patients presenting with headache suspicious of SAH. Nine patients underwent a traumatic spinal tap. CSF ferritin levels were significantly higher in the patients with SAH compared with controls (P < .0001). The upper reference range of CSF ferritin is 12 ng/mL, and there was no significant difference between the traumatic and normal spinal taps (mean, 9.0 ng/mL vs 3.9 ng/mL; P = .59). CSF ferritin levels increased after SAH, from an average of 65 ng/mL on day 1 to 1750 ng/mL on day 11 (P < .01). Both the Fisher and Columbia CT scores were significantly correlated with CSF ferritin level. The increase in CSF ferritin level after SAH and possibly may provide additional diagnostic information in patients with suspected SAH who present late to the clinic.
    Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 11/2011; 20(6):489-93.
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    ABSTRACT: BACKGROUND: Nitric oxide (NO) is a compound with both protective and damaging effects on neurons. Quantification of NO metabolites in humans is limited by sample contamination with blood. In vivo cerebral microdialysis may offer an alternative approach as sampling of extracellular fluid (ECF) adjacent to neurons becomes possible. We investigate the prognostic value of brain ECF NO metabolites in patients with traumatic brain injury (TBI). METHODS: A prospective case cohort of 195 ECF samples collected from 11 cases over 4 days following TBI was collected. Nitrate and nitrite concentrations ([NO( x )]) were quantified using a vanadium-based colorimetric assay. RESULTS: Early ECF [NO( x )] (<48 h post TBI) were significantly higher in non-survivors (median 59.2 μmol/l, n = 7) compared to survivors (23.3 μmol/l, n = 4) (P = 0.04). Late (48-96 h) ECF [NO( x )] remained higher in non-survivors (47.9 μmol/l) compared to survivors (23.0 μmol/l) but this was not significant (P = 0.29). Receiver operator characteristic analysis shows an optimized cutoff level for ECF [NO( x )] of 26.5 μmol/l measured <48 h post TBI for predicting non-survival (sensitivity 100%, specificity 75%). CONCLUSION: Early ECF NO( x ) concentrations are of prognostic value after TBI. ECF NO( x ) may be a useful biomarker for treatment trials targeted at nitric oxide metabolism.
    Neurocritical Care 10/2011; · 3.04 Impact Factor

Publication Stats

2k Citations
467.32 Total Impact Points

Institutions

  • 2002–2013
    • The National Institute of Neurology and Neurosurgery
      Tlalpam, The Federal District, Mexico
  • 2005–2011
    • UCL Eastman Dental Institute
      Londinium, England, United Kingdom
  • 2000–2011
    • University College London
      • Institute of Neurology
      Londinium, England, United Kingdom
    • Queen Mary, University of London
      Londinium, England, United Kingdom
  • 2008
    • University of Southampton
      • Clinical Neurosciences
      Southampton, ENG, United Kingdom
  • 2006
    • The Bracton Centre, Oxleas NHS Trust
      Дартфорде, England, United Kingdom
  • 1998
    • Philips
      Eindhoven, North Brabant, Netherlands