Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where J. Claude Hemphill is active.

Publication


Featured researches published by J. Claude Hemphill.


Stroke | 2001

The ICH Score A Simple, Reliable Grading Scale for Intracerebral Hemorrhage

J. Claude Hemphill; David C. Bonovich; Lavrentios Besmertis; Geoffrey T. Manley; S. Claiborne Johnston

BACKGROUND AND PURPOSE Intracerebral hemorrhage (ICH) constitutes 10% to 15% of all strokes and remains without a treatment of proven benefit. Despite several existing outcome prediction models for ICH, there is no standard clinical grading scale for ICH analogous to those for traumatic brain injury, subarachnoid hemorrhage, or ischemic stroke. METHODS Records of all patients with acute ICH presenting to the University of California, San Francisco during 1997-1998 were reviewed. Independent predictors of 30-day mortality were identified by logistic regression. A risk stratification scale (the ICH Score) was developed with weighting of independent predictors based on strength of association. RESULTS Factors independently associated with 30-day mortality were Glasgow Coma Scale score (P<0.001), age >/=80 years (P=0.001), infratentorial origin of ICH (P=0.03), ICH volume (P=0.047), and presence of intraventricular hemorrhage (P=0.052). The ICH Score was the sum of individual points assigned as follows: GCS score 3 to 4 (=2 points), 5 to 12 (=1), 13 to 15 (=0); age >/=80 years yes (=1), no (=0); infratentorial origin yes (=1), no (=0); ICH volume >/=30 cm(3) (=1), <30 cm(3) (=0); and intraventricular hemorrhage yes (=1), no (=0). All 26 patients with an ICH Score of 0 survived, and all 6 patients with an ICH Score of 5 died. Thirty-day mortality increased steadily with ICH Score (P<0.005). CONCLUSIONS The ICH Score is a simple clinical grading scale that allows risk stratification on presentation with ICH. The use of a scale such as the ICH Score could improve standardization of clinical treatment protocols and clinical research studies in ICH.


Neurocritical Care | 2011

Critical Care Management of Patients Following Aneurysmal Subarachnoid Hemorrhage: Recommendations from the Neurocritical Care Society’s Multidisciplinary Consensus Conference

Michael N. Diringer; Thomas P. Bleck; J. Claude Hemphill; David K. Menon; Lori Shutter; Paul Vespa; Nicolas Bruder; E. Sander Connolly; Giuseppe Citerio; Daryl R. Gress; Daniel Hänggi; Brian L. Hoh; Giuseppe Lanzino; Peter D. Le Roux; Alejandro A. Rabinstein; Erich Schmutzhard; Nino Stocchetti; Jose I. Suarez; Miriam Treggiari; Ming Yuan Tseng; Mervyn D.I. Vergouwen; Stefan Wolf; Gregory J. Zipfel

Subarachnoid hemorrhage (SAH) is an acute cerebrovascular event which can have devastating effects on the central nervous system as well as a profound impact on several other organs. SAH patients are routinely admitted to an intensive care unit and are cared for by a multidisciplinary team. A lack of high quality data has led to numerous approaches to management and limited guidance on choosing among them. Existing guidelines emphasize risk factors, prevention, natural history, and prevention of rebleeding, but provide limited discussion of the complex critical care issues involved in the care of SAH patients. The Neurocritical Care Society organized an international, multidisciplinary consensus conference on the critical care management of SAH to address this need. Experts from neurocritical care, neurosurgery, neurology, interventional neuroradiology, and neuroanesthesiology from Europe and North America were recruited based on their publications and expertise. A jury of four experienced neurointensivists was selected for their experience in clinical investigations and development of practice guidelines. Recommendations were developed based on literature review using the GRADE system, discussion integrating the literature with the collective experience of the participants and critical review by an impartial jury. Recommendations were developed using the GRADE system. Emphasis was placed on the principle that recommendations should be based not only on the quality of the data but also tradeoffs and translation into practice. Strong consideration was given to providing guidance and recommendations for all issues faced in the daily management of SAH patients, even in the absence of high quality data.


Stroke | 2004

Hospital Usage of Early Do-Not-Resuscitate Orders and Outcome After Intracerebral Hemorrhage

J. Claude Hemphill; Jeffrey Newman; Shoujun Zhao; S. Claiborne Johnston

Background and Purpose— Do-not-resuscitate (DNR) orders are commonly used after severe stroke. We hypothesized that there is significant variability in how these orders are applied after intracerebral hemorrhage and that this influences outcome. Methods— From a database of all admissions to nonfederal hospitals in California, discharge abstracts were obtained for all patients with a primary diagnosis of intracerebral hemorrhage who were admitted through the emergency department during 1999 and 2000. Characteristics included whether DNR orders were written within the first 24 hours of hospitalization. Case-mix–adjusted hospital DNR use was calculated for each hospital by comparing the actual number of DNR cases with the number predicted from a multivariable model. Outcome (in-hospital death) was evaluated in a separate multivariable model adjusted for individual and hospital characteristics. Results— A total of 8233 patients were treated in 234 hospitals. The percentage of patients with DNR orders varied from 0% to 70% across hospitals. Being treated in a hospital that used DNR orders 10% more often than another hospital with a similar case mix increased a patient’s odds of dying during hospitalization by 13% (P <0.001). Patients treated in the quartile of hospitals with the highest adjusted DNR use were more likely to die, and this was not just because of individual patient DNR status. Conclusions— In-hospital mortality after intracerebral hemorrhage is significantly influenced by the rate at which treating hospitals use DNR orders, even after adjusting for case mix. This is not due solely to individual patient DNR status, but rather some other aspect of overall care.


Critical Care Medicine | 2011

Hypertonic saline versus mannitol for the treatment of elevated intracranial pressure: a meta-analysis of randomized clinical trials.

Hooman Kamel; Babak B. Navi; Kazuma Nakagawa; J. Claude Hemphill; Nerissa U. Ko

Objectives:Randomized trials have suggested that hypertonic saline solutions may be superior to mannitol for the treatment of elevated intracranial pressure, but their impact on clinical practice has been limited, partly by their small size. We therefore combined their findings in a meta-analysis. Data Sources:We searched for relevant studies in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, and ISI Web of Knowledge. Study Selection:Randomized trials were included if they directly compared equiosmolar doses of hypertonic sodium solutions to mannitol for the treatment of elevated intracranial pressure in human subjects undergoing quantitative intracranial pressure measurement. Data Extraction:Two investigators independently reviewed potentially eligible trials and extracted data using a preformed data collection sheet. Disagreements were resolved by consensus or by a third investigator if needed. We collected data on patient demographics, type of intracranial pathology, baseline intracranial pressure, osms per treatment dose, quantitative change in intracranial pressure, and prespecified adverse events. Our primary outcome was the proportion of successfully treated episodes of elevated intracranial pressure. Data Synthesis:Five trials comprising 112 patients with 184 episodes of elevated intracranial pressure met our inclusion criteria. In random-effects models, the relative risk of intracranial pressure control was 1.16 (95% confidence interval, 1.00–1.33), and the difference in mean intracranial pressure reduction was 2.0 mm Hg (95% confidence interval, −1.6 to 5.7), with both favoring hypertonic saline over mannitol. A mild degree of heterogeneity was present among the included trials. There were no significant adverse events reported. Conclusions:We found that hypertonic saline is more effective than mannitol for the treatment of elevated intracranial pressure. Our meta-analysis is limited by the small number and size of eligible trials, but our findings suggest that hypertonic saline may be superior to the current standard of care and argue for a large, multicenter, randomized trial to definitively establish the first-line medical therapy for intracranial hypertension.


Neurology | 2009

Prospective validation of the ICH Score for 12-month functional outcome

J. Claude Hemphill; Mary Farrant; Terry A. Neill

Background: The ICH Score is a commonly used clinical grading scale for outcome after acute intracerebral hemorrhage (ICH) and has been validated for 30-day mortality, but not long-term functional outcome. The goals of this study were to assess whether the ICH Score accurately stratifies patients with regard to 12-month functional outcome and to further delineate the pace of recovery of patients during the first year post-ICH. Methods: We performed a prospective observational cohort study of all patients with acute ICH admitted to the emergency departments of San Francisco General Hospital and UCSF Medical Center from June 1, 2001, through May 31, 2004. Components of the ICH Score (admission Glasgow Coma Scale score, initial hematoma volume, presence of intraventricular hemorrhage, infratentorial ICH origin, and age) were recorded along with other clinical characteristics. Patients were then assessed with the modified Rankin Scale (mRS) at hospital discharge, 30 days, and 3, 6, and 12 months post-ICH. Results: Of 243 patients, 95 (39%) died during initial acute hospitalization. The ICH Score accurately stratified patients with regard to 12-month functional outcome for various dichotomous cutpoints along the mRS (p < 0.05). Many patients continued to improve across the first year, with a small number of patients becoming disabled or dying due to late events unrelated to the initial ICH. Conclusions: The ICH Score is a valid clinical grading scale for long-term functional outcome after acute intracerebral hemorrhage (ICH). Many ICH patients improve after hospital discharge and this improvement may continue even after 6 months post-ICH.


Critical Care Medicine | 2009

Brain tissue oxygen tension is more indicative of oxygen diffusion than oxygen delivery and metabolism in patients with traumatic brain injury

Guy Rosenthal; J. Claude Hemphill; Marco D. Sorani; Christine Martin; Diane Morabito; Walter Obrist; Geoffrey T. Manley

Objectives:Despite the growing clinical use of brain tissue oxygen monitoring, the specific determinants of low brain tissue oxygen tension (Pbto2) following severe traumatic brain injury (TBI) remain poorly defined. The objective of this study was to evaluate whether Pbto2 more closely reflects variables related to cerebral oxygen diffusion or reflects cerebral oxygen delivery and metabolism. Design:Prospective observational study. Setting:Level I trauma center. Patients:Fourteen TBI patients with advanced neuromonitoring underwent an oxygen challenge (increase in Fio2 to 1.0) to assess tissue oxygen reactivity, pressure challenge (increase in mean arterial pressure) to assess autoregulation, and CO2 challenge (hyperventilation) to assess cerebral vasoreactivity. Interventions:None. Measurements and Main Results:Pbto2 was measured directly with a parenchymal probe in the least-injured hemisphere. Local cerebral blood flow (CBF) was measured with a parenchymal thermal diffusion probe. Cerebral venous blood gases were drawn from a jugular bulb venous catheter. We performed 119 measurements of Pao2, arterial oxygen content (Cao2), jugular bulb venous oxygen tension (P&OV0413;o2), venous oxygen content (C&OV0413;o2), arteriovenous oxygen content difference (AVDO2), and local cerebral metabolic rate of oxygen (locCMRO2). In multivariable analysis adjusting for various variables of cerebral oxygen delivery and metabolism, the only statistically significant relationship was that between Pbto2 and the product of CBF and cerebral arteriovenous oxygen tension difference (AVTO2), suggesting a strong association between brain tissue oxygen tension and diffusion of dissolved plasma oxygen across the blood-brain barrier. Conclusions:Measurements of Pbto2 represent the product of CBF and the cerebral AVTO2 rather than a direct measurement of total oxygen delivery or cerebral oxygen metabolism. This improved understanding of the cerebral physiology of Pbto2 should enhance the clinical utility of brain tissue oxygen monitoring in patients with TBI.


Neurocritical Care | 2006

Prognostic significance of angiographically confirmed large vessel intracranial occlusion in patients presenting with acute brain ischemia.

Wade S. Smith; Jack W. Tsao; Martha E. Billings; S. Claiborne Johnston; J. Claude Hemphill; David C. Bonovich; William P. Dillon

IntroductionIndependent predictors of outcome for ischemic stroke include age and initial stroke severity. Intracranial large-vessel occlusion would be expected to predict poor outcome. Because large-vessel occlusion and stroke severity are likely correlated, it is unclear if largevessel occlusion independently predicts outcome or is simply a marker for stroke severity.MethodsA consecutive series of patients with suspected stroke or transient ischemic attack were imaged acutely with computed tomography angiography (CTA). CTAs were reviewed for intracranial large-vessel occlusion as the cause of the stroke. Baseline National Institutes of Health Stroke Scale (NIHSS) score, discharge modified Rankin score, and patient demographics were abstracted from hospital records. Poor neurological outcome was defined as modified Rankin score exceeding 2.ResultsSeventy-two consecutive patients with acute ischemic stroke were imaged with CTA. The median (range) time from stroke symptom onset to CT imaging was 183 minutes (25 minutes to 4 days). Median NIHSS score was 6 (1–32) and intracranial large-vessel occlusion was found in 28 (38.9%) patients. Fifty-six percent of patients had a good neurological outcome. In multivariate logistic regression analysis, two variables predicted poor neurological outcome: baseline NIHSS score (OR 1.21,95% CI[1.07–1.37]) and presence of intracranial large-vessel occlusion (OR 4.48, 95% CI[1.19–16.9]). The predictive value of large-vessel occlusion, on outcome was similar to an 8-point increase in NIHSS score.ConclusionIn patients presenting with acute brain ischemia, intracranial large-vessel occlusion independently predicts poor neurological outcome at hospital discharge, as does the presence of a high NIHSS score. Performing routine intracranial vascular imaging on acute stroke patients may allow for more accurate determination of prognosis and may also guide therapy.


Neurosurgery | 2001

Carbon dioxide reactivity and pressure autoregulation of brain tissue oxygen.

J. Claude Hemphill; M. Margaret Knudson; Nikita Derugin; Diane Morabito; Geoffrey T. Manley

OBJECTIVETo describe the normal relationships between brain tissue oxygen tension (PbrO2) and physiological parameters of systemic blood pressure and CO2 concentrations. METHODSLicox Clark-type oxygen probes (GMS mbH, Kiel, Germany) were inserted in the frontal white matter of 12 swine maintained under general anesthesia with a 1.0 fraction of inspired oxygen (FiO2). In seven swine, alterations in end-tidal carbon dioxide (ET-CO2) concentration (range, 13–72 mm Hg) were induced via hyperventilation or instillation of CO2 into the ventilation circuit. In nine swine, mean arterial pressure (MAP) (range, 33–200 mm Hg) was altered; phenylephrine was used to induce hypertension, and a nitroprusside-esmolol combination or systemic hemorrhage was used for hypotension. Quantitative cerebral blood flow (CBF) was measured in two animals by using a thermal diffusion probe. RESULTSMean baseline PbrO2 was 41.9 ± 11.3 mm Hg. PbrO2 varied linearly with changes in ET-CO2, ranging from 20 to 60 mm Hg (r2 = 0.70). The minimum PbrO2 with hypocarbia was 5.9 mm Hg, and the maximum PbrO2 with hypercarbia was 132.4 mm Hg. PbrO2 varied with MAP in a sigmoid fashion suggestive of pressure autoregulation between 60 and 150 mm Hg (r2 = 0.72). The minimum PbrO2 with hypotension was 1.4 mm Hg, and the maximum PbrO2 with hypertension was 97.2 mm Hg. In addition, CBF correlated linearly with PbrO2 during CO2 reactivity testing (r2 = 0.84). CONCLUSIONIn the uninjured brain, PbrO2 exhibits CO2 reactivity and pressure autoregulation. The relationship of PbrO2 with ET-CO2 and MAP appears to be similar to those historically established for CBF with ET-CO2 and MAP. This suggests that, under normal conditions, PbrO2 is strongly influenced by factors that regulate CBF.


Anesthesia & Analgesia | 2010

Multidisciplinary approach to the challenge of hemostasis.

Jerrold H. Levy; Richard P. Dutton; J. Claude Hemphill; Aryeh Shander; David L. Cooper; Michael J. Paidas; Craig M. Kessler; John B. Holcomb; Jeffrey H. Lawson

A multidisciplinary panel consisting of experts chosen by the 2 chairs of the group representing experts in anesthesiology, blood banking, hematology, critical care medicine, and various surgical disciplines (trauma, cardiac, pediatric, neurologic, obstetrics, and vascular) convened in January 2008 to discuss hemostasis and management of the bleeding patient across different clinical settings, with a focus on perioperative considerations. Although there are many ways to define hemostasis, one clinical definition would be control of bleeding without the occurrence of pathologic thrombotic events (i.e., when balance among procoagulant, anticoagulant, fibrinolytic, and antifibrinolytic activities is achieved). There are common hemostatic challenges that include lack of scientific evidence and standardized guidelines for the use of therapeutic drugs, need for reliable and rapid laboratory tools for measuring hemostasis, and individual variability. Clinically meaningful and accurate real-time laboratory data reflecting a patients hemostatic status are needed to guide treatment decisions. Current available routine laboratory tests of hemostasis (e.g., platelet count, prothrombin time/international normalized ratio, and activated partial thromboplastin time) do not reflect the complexity of in vivo hemostasis and can mislead the clinician. Although point-of-care coagulation monitoring tests including measures of thromboelastography/elastometry provide insight into overall hemostatic status, they are time-consuming to perform, complex to interpret, and require trained personnel. There is a particular need to develop laboratory tests that can measure the effects of anticoagulant and antiplatelet agents for individual patients, predict bleeding complications, and guide therapy when and if treatment with blood products or pharmacologic drugs is required. Formation of an organization comprised of specialists who treat bleeding patients will foster multidisciplinary collaborations and promote discussions of the current state of hemostasis treatment and future priorities for hemostasis research. Controlled trials with clinically meaningful end points and suitable study populations, as well as observational studies, investigator-initiated studies, and large registry and database studies are essential to answer questions in hemostasis. Because of the complexities of maintaining hemostatic balance, advances in hemostasis research and continuing communication across specialties are required to improve patient care and outcomes.


Neurocritical Care | 2004

External validation of the ICH score

Jennifer Clarke; S. Claiborne Johnston; Mary Farrant; Richard Bernstein; David Tong; J. Claude Hemphill

Introduction: The ICH score is a clinical grading scale that is composed of five components related to outcome after nontraumatic intracerebral hemorrhage (ICH): Glasgow Coma Scale score, ICH volume, presence of intraventricular hemorrhage, infratentorial origin, and age. The ICH score accurately risk-stratifies patients in the cohort from which it was developed, but it has not yet been fully externally validated. The purpose of this study was to determine whether the ICH score accurately risk-stratifies patients in an independent cohort.Methods: Records of all patients with acute ICH presenting to Stanford Medical Center and Santa Clara Valley Medical Center from 1998 through 2000 were reviewed. Outcome was assessed as mortality at 30 days.Results: A total of 175 patients formed the cohort for analysis. Thirty-day mortality for the entire cohort was 40%. ICH scores ranged from 0 to 5, and each increase in the ICH score was associated with an increase in 30-day mortality (p<0.01 for trend); 4 of 41 patients with an ICH score of 0 died, whereas all 5 patients with a score of 5 died. Receiver operating characteristic curves for the ICH score were similar for this cohort and for the initial ICH score cohort.Conclusion: The ICH score accurately stratifies outcome in an external patient cohort. Thus, the ICH score is a validated clinical grading scale that can be easily and rapidly applied at ICH presentation. A scale such as the ICH score could be used to standardize clinical treatment protocols or clinical studies.

Collaboration


Dive into the J. Claude Hemphill's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Diane Morabito

University of California

View shared research outputs
Top Co-Authors

Avatar

Jose I. Suarez

Case Western Reserve University

View shared research outputs
Top Co-Authors

Avatar

Paul Vespa

University of California

View shared research outputs
Top Co-Authors

Avatar

Wade S. Smith

University of California

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

S. Claiborne Johnston

University of Texas at Austin

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Giuseppe Citerio

University of Milano-Bicocca

View shared research outputs
Researchain Logo
Decentralizing Knowledge