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Dive into the research topics where Nathaniel H. Greene is active.

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Featured researches published by Nathaniel H. Greene.


Anesthesiology | 2009

Measures of Executive Function and Depression Identify Patients at Risk for Postoperative Delirium

Nathaniel H. Greene; Deborah K. Attix; B. Craig Weldon; Patrick J. Smith; David L. McDonagh; Terri G. Monk

Background:Postoperative delirium is associated with increased morbidity and mortality. Preexisting cognitive impairment and depression have been frequently cited as important risk factors for this complication. This prospective cohort study was designed to determine whether individuals who perform poorly on preoperative cognitive tests and/or exhibited depressive symptoms would be at high risk for the development of postoperative delirium. Methods:One hundred nondemented patients, aged 50 yr and older, scheduled to undergo major, elective noncardiac surgery completed a preoperative test battery that included measures of global cognition, executive function, and symptoms of depression. Known preoperative risk factors for delirium were collected and examined with the results of the preoperative test battery to determine the independent predictors of delirium. Results:The overall incidence of delirium was 16% and was associated with increased hospital duration of stay (P < 0.05) and an increased incidence of postoperative complications (P < 0.01). Delirious subjects did not differ from their nondelirious cohorts with regard to their preoperative global cognitive function, preexisting medical comorbidities, age, anesthetic management, or history of alcohol use. Preoperative executive scores (P < 0.001) and depression (P < 0.001), as measured by the Trail Making B test and Geriatric Depression Scale–Short Form, respectively, were found to be independent predictors of postoperative delirium. Conclusions:Low preoperative executive scores and depressive symptoms independently predict postoperative delirium in older individuals. A rapid, simple test combination including tests of executive function and depression could improve physicians’ ability to recognize patients who might benefit from a perioperative intervention strategy to prevent postoperative delirium.


Anesthesiology | 2009

Executive function and depression as independent risk factors for postoperative delirium.

Patrick J. Smith; Deborah K. Attix; B. Craig Weldon; Nathaniel H. Greene; Terri G. Monk

Background:Postoperative delirium has been associated with greater complications, medical cost, and increased mortality during hospitalization. Recent evidence suggests that preoperative executive dysfunction and depression may predict postoperative delirium; however, the combined effect of these risk factors remains unknown. This study examined the association among preoperative executive function, depressive symptoms, and established clinical predictors of postoperative delirium among 998 consecutive patients undergoing major noncardiac surgery. Methods:A total of 998 patients were screened for postoperative delirium (n = 998) using the Confusion Assessment Method as well as through retrospective chart review. Patients underwent cognitive, psychosocial, and medical assessments preoperatively. Executive function was assessed using the Concept Shifting Task, Letter-Digit Coding, and a modified Stroop Color Word Interference Test. Depression was assessed by the Beck Depression Inventory. Results:Preoperative executive dysfunction (P = 0.007) and greater levels of depressive symptoms (P = 0.049) were associated with a greater incidence of postoperative delirium, independent of other risk factors. Secondary analyses of cognitive performance demonstrated that the Stroop Color Word Interference Test, the executive task with the greatest complexity in this battery, was more strongly associated with postoperative delirium than simpler tests of executive function. Furthermore, patients exhibiting both executive dysfunction and clinically significant levels of depression were at greatest risk for developing delirium postoperatively. Conclusions:Preoperative executive dysfunction and depressive symptoms are predictive of postoperative delirium among noncardiac surgical patients. Executive tasks with greater complexity are more strongly associated with postoperative delirium relative to tests of basic sequencing.


Injury Prevention | 2015

Validation of ICDPIC software injury severity scores using a large regional trauma registry

Nathaniel H. Greene; Mary A. Kernic; Monica S. Vavilala; Frederick P. Rivara

Background Administrative or quality improvement registries may or may not contain the elements needed for investigations by trauma researchers. International Classification of Diseases Program for Injury Categorisation (ICDPIC), a statistical program available through Stata, is a powerful tool that can extract injury severity scores from ICD-9-CM codes. We conducted a validation study for use of the ICDPIC in trauma research. Methods We conducted a retrospective cohort validation study of 40 418 patients with injury using a large regional trauma registry. ICDPIC-generated AIS scores for each body region were compared with trauma registry AIS scores (gold standard) in adult and paediatric populations. A separate analysis was conducted among patients with traumatic brain injury (TBI) comparing the ICDPIC tool with ICD-9-CM embedded severity codes. Performance in characterising overall injury severity, by the ISS, was also assessed. Results The ICDPIC tool generated substantial correlations in thoracic and abdominal trauma (weighted κ 0.87–0.92), and in head and neck trauma (weighted κ 0.76–0.83). The ICDPIC tool captured TBI severity better than ICD-9-CM code embedded severity and offered the advantage of generating a severity value for every patient (rather than having missing data). Its ability to produce an accurate severity score was consistent within each body region as well as overall. Conclusions The ICDPIC tool performs well in classifying injury severity and is superior to ICD-9-CM embedded severity for TBI. Use of ICDPIC demonstrates substantial efficiency and may be a preferred tool in determining injury severity for large trauma datasets, provided researchers understand its limitations and take caution when examining smaller trauma datasets.


Archives of Physical Medicine and Rehabilitation | 2014

Variation in pediatric traumatic brain injury outcomes in the United States

Nathaniel H. Greene; Mary A. Kernic; Monica S. Vavilala; Frederick P. Rivara

OBJECTIVE To ascertain the degree of variation, by state of hospitalization, in outcomes associated with traumatic brain injury (TBI) in a pediatric population. DESIGN A retrospective cohort study of pediatric patients admitted to a hospital with a TBI. SETTING Hospitals from states in the United States that voluntarily participate in the Agency for Healthcare Research and Qualitys Healthcare Cost and Utilization Project. PARTICIPANTS Pediatric (age ≤ 19 y) patients hospitalized for TBI (N=71,476) in the United States during 2001, 2004, 2007, and 2010. INTERVENTIONS None. MAIN OUTCOME MEASURES Primary outcome was proportion of patients discharged to rehabilitation after an acute care hospitalization among alive discharges. The secondary outcome was inpatient mortality. RESULTS The relative risk of discharge to inpatient rehabilitation varied by as much as 3-fold among the states, and the relative risk of inpatient mortality varied by as much as nearly 2-fold. In the United States, approximately 1981 patients could be discharged to inpatient rehabilitation care if the observed variation in outcomes was eliminated. CONCLUSIONS There was significant variation between states in both rehabilitation discharge and inpatient mortality after adjusting for variables known to affect each outcome. Future efforts should be focused on identifying the cause of this state-to-state variation, its relationship to patient outcome, and standardizing treatment across the United States.


International journal of critical illness and injury science | 2012

Vascular access, fluid resuscitation, and blood transfusion in pediatric trauma.

Nathaniel H. Greene; Sanjay M. Bhananker; Ramesh Ramaiah

Trauma care in the general population has largely become protocol-driven, with an emphasis on fast and efficient treatment, good team communication at all levels of care including prehospital care, initial resuscitation, intensive care, and rehabilitation. Most available literature on trauma care has focused on adults, allowing the potential to apply concepts from adult care to pediatric care. But there remain issues that will always be specific to pediatric patients that may not translate from adults. Several new devices such as intraosseous (IO) needle systems and techniques such as ultrasonography to cannulate central and peripheral veins have become available for integration into our pre-existing trauma care system for children. This review will focus specifically on the latest techniques and evidence available for establishing intravenous access, rational approaches to fluid resuscitation, and blood product transfusion in the pediatric trauma patient.


Advances in Anesthesia | 2012

Modern and Evolving Understanding of Cerebral Perfusion and Autoregulation.

Nathaniel H. Greene; Lorri A. Lee

occurred over the past 5 to 10 years. Perhaps the most important of these changes has been a reinterpretation of older autoregulation studies that have resulted in raising the lower limit of autoregulation to approximately 70 mm Hg to 80 mm Hg, and not the previously used 60 mm Hg. � Tremendous variability in the lower limits of autoregulation exists among individuals. Using a percentage reduction below baseline blood pressure as a lower limit may result in better optimization of cerebral perfusion than using absolute blood pressure values. � Other changes in practice for the general anesthesiologist include correcting blood pressure for height differences between the site of blood pressure measurement and the brain, particularly in the sitting position, to account for the hydrostatic gradient. Rare cases of severe brain damage have been reported that may be related to hypoperfusion in the beach chair position. � Multiple physiologic and drug interactions that affect cerebral perfusion occur during every general anesthestic, and understanding the best way to optimize cerebral blood flow may potentially improve outcomes. Newer research on flow-metabolism coupling points to regional control of cerebral blood flow by the neurovascular unit, with glial cells playing a central role.


Frontiers in Immunology | 2017

The Effect of Propofol vs. Isoflurane Anesthesia on Postoperative Changes in Cerebrospinal Fluid Cytokine Levels: Results from a Randomized Trial

Miles Berger; Vikram Ponnusamy; Nathaniel H. Greene; Mary Cooter; Jacob W. Nadler; Allan H. Friedman; David L. McDonagh; Daniel T. Laskowitz; Mark F. Newman; Leslie M. Shaw; David S. Warner; Joseph P. Mathew; Michael L. James

Introduction Aside from direct effects on neurotransmission, inhaled and intravenous anesthetics have immunomodulatory properties. In vitro and mouse model studies suggest that propofol inhibits, while isoflurane increases, neuroinflammation. If these findings translate to humans, they could be clinically important since neuroinflammation has detrimental effects on neurocognitive function in numerous disease states. Materials and methods To examine whether propofol and isoflurane differentially modulate neuroinflammation in humans, cytokines were measured in a secondary analysis of cerebrospinal fluid (CSF) samples from patients prospectively randomized to receive anesthetic maintenance with propofol vs. isoflurane (registered with http://www.clinicaltrials.gov, identifier NCT01640275). We measured CSF levels of EGF, eotaxin, G-CSF, GM-CSF, IFN-α2, IL-1RA, IL-6, IL-7, IL-8, IL-10, IP-10, MCP-1, MIP-1α, MIP-1β, and TNF-α before and 24 h after intracranial surgery in these study patients. Results After Bonferroni correction for multiple comparisons, we found significant increases from before to 24 h after surgery in G-CSF, IL-10, IL-1RA, IL-6, IL-8, IP-10, MCP-1, MIP-1α, MIP-1β, and TNF-α. However, we found no difference in cytokine levels at baseline or 24 h after surgery between propofol- (n = 19) and isoflurane-treated (n = 21) patients (p > 0.05 for all comparisons). Increases in CSF IL-6, IL-8, IP-10, and MCP-1 levels directly correlated with each other and with postoperative CSF elevations in tau, a neural injury biomarker. We observed CSF cytokine increases up to 10-fold higher after intracranial surgery than previously reported after other types of surgery. Discussion These data clarify the magnitude of neuroinflammation after intracranial surgery, and raise the possibility that a coordinated neuroinflammatory response may play a role in neural injury after surgery.


Pediatric Anesthesia | 2017

Natural history of nonimmune‐mediated thrombocytopenia and acute kidney injury in pediatric open‐heart surgery

Shannon Tew; Manuel L. Fontes; Nathaniel H. Greene; Miklos D. Kertai; George Ofori-Amanfo; Robert D.B. Jaquiss; Andrew J. Lodge; Warwick A. Ames; Hercilia Mayumi Homi; Kelly A. Machovec; Edmund H. Jooste

Thrombocytopenia and acute kidney injury (AKI) are common following pediatric cardiac surgery with cardiopulmonary bypass (CPB). However, the relationship between postoperative nadir platelet counts and AKI has not been investigated in the pediatric population. Our objective was to investigate this relationship and examine independent predictors of AKI.


Case reports in pediatrics | 2016

Airway Management in a Patient with Wolf-Hirschhorn Syndrome.

John F. Gamble; Dinesh Kurian; Andrea Udani; Nathaniel H. Greene

We present a case of a 3-month-old female with Wolf-Hirschhorn syndrome (WHS) undergoing general anesthesia for laparoscopic gastrostomy tube placement with a focus on airway management. WHS is a rare 4p microdeletion syndrome resulting in multiple congenital abnormalities, including craniofacial deformities. Microcephaly, micrognathia, and glossoptosis are common features in WHS patients and risk factors for a pediatric airway that is potentially difficult to intubate. We discuss anesthesia strategies for airway preparation and management in a WHS patient requiring general anesthesia with endotracheal intubation.


Anesthesia & Analgesia | 2016

Midazolam for Anxiolysis and Postoperative Nausea and Vomiting Prophylaxis: Can We Kill Two Birds with One Stone?

Nathaniel H. Greene; Ashraf S. Habib

590 www.anesthesia-analgesia.org March 2016 • Volume 122 • Number 3 Copyright

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Mary A. Kernic

University of Washington

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