Christopher T. Clark
University of Tennessee
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Featured researches published by Christopher T. Clark.
Journal of Dermatological Case Reports | 2013
Debjeet Sarkar; Hussein A. Kammona; Leonard N. Lamsen; Bradley A. McAbee; Christopher T. Clark; Solomon S. Lee; Shane Kelley
Diffuse purpura is an uncommon skin manifestation found in platelet and coagulation disorders, meningococcemia, vasculitides and cocaine use. Reports of cocaine-related purpura predominantly involve adulteration with the anti-helminthic, levamisole. Levamisole enhances the effects of cocaine and is known to cause vasculitis. Recently, the CDC also released an advisory of oxymorphone being used intravenously causing thrombogenic thrombocytopenic purpura (TTP). We report the case of a patient with diffuse purpura ultimately diagnosed with cocaine-related thrombogenic vasculopathy. In the current environment of adulterated cocaine usage and increased prescription narcotic abuse, it is crucial to investigate substance abuse as a cause of diffuse purpura.
Journal of Infusion Nursing | 2011
Christopher T. Clark
Over the past few decades, many efforts to improve the safety of blood products have concentrated on the reduction of transfusion-associated infectious diseases, particularly human immunodeficiency virus and hepatitis C. As health care enters a time of significant economic changes and governmental agencies develop guidances to improve patient safety, new efforts are being implemented and new technologies are being developed to ensure safe delivery of blood products. This article outlines the structure of agencies responsible for blood safety in the United States, reviews the fairly recent implementation of a blood product bar-code labeling system (ISBT 128) in the United States, describes safety efforts at the level of the hospital transfusion service, and reviews some of the emerging technologies for safety in blood delivery at the bedside.
Pharmacotherapy | 2016
Anthony Shaun Rowe; Pinky S. Mahbubani; Mason H. Bucklin; Christopher T. Clark; Leslie A. Hamilton
To evaluate the efficacy and safety of an activated four‐factor prothrombin complex concentrate (aPCC) versus plasma for the reversal of warfarin‐associated hemorrhage.
The Journal of Nuclear Medicine | 2016
Alexander S. Pasciak; Laurentia Nodit; Austin C. Bourgeois; Ben E. Paxton; Patricia N. Coan; Christopher T. Clark; M Katherine Tolbert; Joleen K. Adams; Aravind Arepally; Yong C. Bradley
In 90Y radioembolization, nontarget embolization to the stomach or small bowel can result in gastrointestinal injury, a rare but difficult to manage clinical complication. However, dosimetric thresholds for toxicity to these tissues from radioembolization have never been evaluated in a controlled setting. We performed an analysis of the effect of 90Y radioembolization in a porcine model at different absorbed-dose endpoints. Methods: Six female pigs underwent transfemoral angiography and infusion of 90Y-resin microspheres into arteries supplying part of the gastric wall. Esophagogastroduodenoscopy was performed after 4 wk to assess interim gastrointestinal health. Animals were monitored for side effects for 9 wk after 90Y infusion, after which they were euthanized and their upper gastrointestinal tracts were excised for analysis. Histologic sections were used to map microsphere location, and a microdosimetric evaluation was performed to determine the absorbed-dose profile within the gastrointestinal wall. Results: 90Y radioembolization dosages from 46.3 to 105.1 MBq were infused, resulting in average absorbed doses of between 35.5 and 91.9 Gy to the gastric wall. No animal exhibited any signs of pain or gastrointestinal distress through the duration of the study. Excised tissue showed 1–2 small (<3.0 cm2) healed or healing superficial gastric lesions in 5 of 6 animals. Histologic analysis demonstrated that lesion location was superficial to areas of abnormally high microsphere deposition. An analysis of microsphere deposition patterns within the gastrointestinal wall indicated a high preference for submucosal deposition. Dosimetric evaluation at the luminal mucosa performed on the basis of microscopic microsphere distribution confirmed that 90Y dosimetry techniques conventionally used in hepatic dosimetry provide a first-order estimate of absorbed dose. Conclusion: The upper gastrointestinal tract may be less sensitive to 90Y radioembolization than previously thought. Lack of charged-particle equilibrium at the luminal mucosa may contribute to decreased toxicity of 90Y radioembolization compared with external-beam radiation therapy in gastrointestinal tissue. Clinical examples of injury from 90Y nontarget embolization have likely resulted from relatively large 90Y activities being deposited in small tissue volumes, resulting in absorbed doses in excess of 100 Gy.
Journal of Blood Transfusion | 2016
Vijay Patel; Anna W. Rains; Christopher T. Clark
To reduce the rate of inappropriate red blood cell transfusion, a provider education program, followed by alerts in the computerized provider order entry system (CPOE), was established to encourage AABB transfusion guidelines. Metrics were established for nonemergent inpatient transfusions. Service lines with high order volume were targeted with formal education regarding AABB 2012 transfusion guidelines. Transfusion orders were reviewed in real time with email communications sent to ordering providers falling outside of AABB recommendations. After 12 months of provider education, alerts were activated in CPOE. With provider education alone, the incidence of pretransfusion hemoglobin levels greater than 8 g/dL decreased from 16.64% to 6.36%, posttransfusion hemoglobin levels greater than 10 g/dL from 14.03% to 3.78%, and number of nonemergent two-unit red blood cell orders from 45.26% to 22.66%. Red blood cell utilization decreased by 13%. No additional significant reduction in nonemergent two-unit orders was observed with CPOE alerts. Provider education, an effective and low-cost method, should be considered as a first-line method for reducing inappropriate red blood cell transfusion rates in stable adult inpatients. Alerts in the computerized order entry system did not significantly lower the percentage of two-unit red blood cells orders but may help to maintain educational efforts.
Case Reports in Surgery | 2018
Eric Vick; Christopher T. Clark; James M. Lewis
Radiation exposure for the average coronary stent placement varies based on a number of factors but typically amounts to 6–11 mSv per patient (compared to 3 mSv background). As with all procedures which utilize radiation, there is an inherent risk of genetic mutation and the possible development of malignancy. Here, we present the case of a 75-year-old male who presented with an exophytic mass on his back following prolonged coronary catheterization with a radiation burn seven years prior. Biopsy of the lesion revealed the mass was consistent with an undifferentiated pleomorphic sarcoma emanating from the site of the radiation burn. After staging studies demonstrated no evidence of metastatic disease, radical excision with negative margins was performed. This case demonstrates that despite the rarity of radiation injury, each incidence necessitates strict monitoring of radiation exposure and continual follow-up due to the risk of malignancy.
Case Reports in Medicine | 2018
Tracy R. Shachner; Christopher T. Clark
Acute hemolytic transfusion reaction is a known but rare potential adverse event related to platelet transfusion. Most reported cases of platelet-related hemolytic transfusion reaction have resulted from transfusion of platelets from group O donor to group A recipient. We identified only one prior case report in the literature of hemolytic transfusion reactions resulting from transfusion of apheresis platelets from group A donor to group B recipient. In that case report, two platelet units were obtained from a single donation and transfused into two separate patients. Both patients exhibited acute hemolytic reactions. The donor is reported to have high anti-B titers, as well as report of probiotic use. We report a case of acute hemolytic reaction in group B recipient following transfusion of apheresis platelets from group A donor with high-titer anti-B but unknown status of probiotic use. This case demonstrates that while low, there still exists potential risk for hemolysis from out-of-group A plasma transfusion.
American Journal of Obstetrics and Gynecology | 2017
C. Reeder; Craig V. Towers; Christopher T. Clark; L. Chernicky; Nikki B. Zite; Kimberly Fortner
to better understand care and referral of pregnant women with suspected and confirmed ZIKV infection. CONCLUSIONS: Tools are currently in use in five countries and results will inform recommended referral pathways for pregnant women with suspected and confirmed cases of ZIKV infection. Surveys will continue to be updated based on user experience as part of ongoing QI programs. Ultimately, these tools will be available in a variety of settings for use by Ministries of Health and/or Social Welfare for adaptation as a supervision checklist and use outside of this program.
Journal of Case Reports and Studies | 2014
Marcus Winkler; Thomas C. Watkins; Christopher T. Clark
In response to the rapidly rising intravenous opioid abuse epidemic, the United States Food and Drug Administration is currently promoting the development of prescription opioid tablets that are specifically formulated to deter abuse. Opana ER (Endo Pharmaceuticals) recently underwent reformulation to include a crush-resistant coating. Only recently described, illicit intravenous injection of reformulated Opana ER is associated with a distinctive clinical syndrome of thrombotic microangiopathy. Ten patients with the appropriate history and presenting symptoms were identified within an 8 month interval (July 2012 through February 2013) at the University of Tennessee Medical Center (UTMC) Knoxville with ICD-9 code of 446.6 (thrombotic microangiopathy) by electronic search. Review of laboratory data, electronic medical records, blood product usage, and total hospital admission charges were compiled for these individual patients. We report the clinicopathologic findings and correlating laboratory data for a group of patients presenting with thrombotic microangiopathy and documented recent history of intravenous Opana ER injection. We also report the economic impact and effect on blood product utilization by this study group.
Journal of Infusion Nursing | 2013
Thomas C. Watkins; Christopher T. Clark
Sepsis is a major cause of patient morbidity and mortality. Many critically ill patients are septic, and red blood cell transfusion is often part of their treatment plan. Studies have shown that red blood cell transfusion is associated with a dose-dependent increase in patient morbidity and mortality. Although red blood cells are transfused to increase the recipients oxygen-carrying capacity, there are new and emerging data to support that red blood cell transfusion may potentially decrease perfusion and oxygen delivery to the microcirculation, particularly when older red blood cells are transfused. In addition, there are similar effects in the pathophysiology of sepsis that may overlap with the changes that occur with storage of red blood cells. This article will discuss recent literature addressing red cell transfusion in critically ill and septic patients and discuss general guidelines for red cell transfusion in this patient population. This article will also discuss the epidemiology and pathophysiology of sepsis and relate how storage and transfusion of red cells may potentially contribute to changes observed in a septic patient.