Christopher J Gannon

University of Maryland, Baltimore, Baltimore, MD, United States

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Publications (11)29.43 Total impact

  • Steven C Cunningham, Christopher J Gannon, Lena M Napolitano
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    ABSTRACT: Diffuse jejunoileal diverticulosis with pneumoperitoneum but without peritonitis is an uncommon but well-documented entity. Cases of jejunoileal diverticular perforation in which the perforation is evident are managed with resection of the diseased bowel and primary anastomosis. In the absence of an intraoperative finding of a perforation or an area of discrete inflammation, copious irrigation and closure of the abdomen is appropriate in cases of diffuse small-bowel diverticulosis.
    The American Journal of Surgery 08/2005; 190(1):37-8. · 2.52 Impact Factor
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    ABSTRACT: Nosocomial pneumonia in trauma patients is a significant source of resource utilization and mortality. We have previously described increased rates of pneumonia in male trauma patients in a single institution study. In that study, female trauma patients had a lower incidence of postinjury pneumonia but a higher relative risk for mortality when they did develop pneumonia. We sought to investigate the hypothesis that male trauma patients have an increased incidence of postinjury pneumonia in a separate population-based dataset. Prospective data were collected on 30,288 trauma patients (26,231 blunt injuries, 4057 penetrating injuries) admitted to all trauma centers (n = 26) in Pennsylvania over 24 months (January 1996 to December 1997). Gender differences in pneumonia were determined for the entire dataset. A second analysis examined all blunt injury patients and excluded all patients with a hospital length of stay less than 24 h, eliminating patients who expired early after admission. In trauma patients with minor injury (ISS < 15), there was no significant difference between male and female patients in the rate of postinjury pneumonia (male 1.37%, female 1.11%). In the moderate-injury group (ISS > 15), male trauma patients had a significantly increased incidence of postinjury pneumonia (ISS 15-30, male 8.85%, female 6.45%; ISS > 30, male 24.35%, female 17.30%). Logistic regression analysis of blunt trauma patients revealed that gender, ISS, injury type, admission Revised Trauma Score (RTS), admission respiratory rate, history of cardiac disease, and history of cancer were all independent predictors of pneumonia. Trauma patients with nosocomial pneumonia had a significantly higher mortality rate (P < 0.001) than patients without pneumonia. There was no gender-specific difference in mortality among pneumonia patients. Male gender is significantly associated with an increased incidence of postinjury pneumonia. In contrast to our initial study, there was no gender difference in postinjury pneumonia mortality rates identified in this population-based study.
    Shock 06/2004; 21(5):410-4. · 2.61 Impact Factor
  • Christopher J Gannon, Lena M Napolitano
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    ABSTRACT: Management of severe anemia in a critically ill Jehovah's Witness is challenging. In the past, conservative therapy was the only option available to the practitioner. Recently, new interventional treatment strategies have become available, including human and bovine hemoglobin substitutes and high-dose recombinant human erythropoietin. Case report. Intensive care unit in a quaternary care center. A patient with severe, life-threatening anemia caused by gastrointestinal hemorrhage who refused all blood products on religious grounds. Bovine hemoglobin substitute and high-dose recombinant human erythropoietin. A 50-yr-old Jehovah's Witness presented with massive upper gastrointestinal hemorrhage; initial hemoglobin was 3.5 g/dL. Endoscopy revealed a prepyloric ulcer, and hemorrhage control was achieved by epinephrine injections into the peri-ulcer mucosa. Despite control of hemorrhage, the patient became hemodynamically unstable. A total of 7 units of a bovine hemoglobin-based oxygen carrying compound (HBOC-201) was administered to enhance the patient's oxygen delivery. High-dose recombinant human erythropoietin was administered daily (500 units/kg). Hemoglobin levels were initially maintained and then slowly increased to a maximum of 7.6 g/dL on day 24 of therapy. This case demonstrates that the concurrent administration of hemoglobin-based oxygen carriers and recombinant human erythropoietin in severe, life-threatening anemia (hemoglobin, 3.5 g/dL) was associated with patient survival and a significant increase in hemoglobin to 7.6 g/dL, without the administration of allogeneic blood. Hemoglobin-based oxygen carriers can adequately serve as initial therapy to maintain tissue oxygen delivery while awaiting the maximal effect of recombinant erythropoietin on bone marrow red blood cell production. High-dose recombinant human erythropoietin offers these patients the best chance for normalization of hematocrit and survival in the long term.
    Critical Care Medicine 09/2002; 30(8):1893-5. · 6.12 Impact Factor
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    ABSTRACT: Women usually have lower mortality rates than men do at any age. This pattern is observed for most causes of death from chronic diseases. Significant controversy still exists about gender differences in outcomes in trauma. We previously reported no differences in in-hospital mortality based on gender in a large single-institution study (n= 18,892) that had a significant limitation in that it was not population based. This current study was performed to validate our earlier findings in a separate, statewide, population-based dataset of trauma victims. Prospective data were collected on 22,332 trauma patients (18,432 blunt, 3,900 penetrating) admitted to all trauma centers (n = 26) in Pennsylvania over 24 months (January 1996 to December 1997). Gender differences in in-hospital mortality were determined for the entire dataset and for the subsets of blunt and penetrating injury patients. A second analysis examined all blunt injury patients and excluded all patients with a hospital length of stay of less than 24 hours, eliminating patients who expired soon after admission. The null hypothesis was that female gender is protective in trauma outcomes. Multiple logistic regression analysis identified age (odds ratio [OR] 1.03, confidence interval [CI] 1.02 to 1.03), Injury Severity Score (OR 1.06, CI 1.05 to 1.06), non-Caucasian race (OR 1.72, CI 1.39 to 2.15), blunt injury type (OR 0.327, CI 0.26 to 0.41), and Revised Trauma Score (OR 0.44, CI 0.41 to 0.47) as independent predictors of in-hospital mortality in trauma. Preexisting diseases, including cardiac disease (OR 1.53, CI 1.12 to 2.09) and malignancy (OR 4.08, CI 1.64 to 10.17), were also identified as independent predictors of in-hospital mortality in trauma. Female gender was not associated with decreased mortality (OR 0.83, CI 0.67 to 1.03, p = 0.093). A second multiple regression analysis in blunt trauma patients admitted for longer than 24 hours (which eliminated early deaths and patients with minor injuries) determined that in-hospital mortality was not significantly different in male or female blunt trauma patients stratified by Injury Severity Score and age. The same factors that were predictive of in-hospital mortality in the total dataset were also significant in this secondary analysis. These population-based data confirm that female gender does not adversely affect in-hospital mortality in trauma when patients are appropriately stratified for other variables, including Injury Severity Score and age, that do significantly affect outcomes.
    Journal of the American College of Surgeons 08/2002; 195(1):11-8. · 4.50 Impact Factor
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    ABSTRACT: Anemia is common in cancer patients and is associated with reduced survival. Recent studies document that treatment of anemia with blood transfusion in cancer patients is associated with increased infection risk, tumor recurrence, and mortality. We therefore investigated the incidence of preoperative anemia in colorectal cancer and assessed risk factors for anemia. Prospective data were collected on 311 patients diagnosed with colorectal cancer over a 6-year period from 1994 through 1999. Patients were stratified by age, gender, presenting complaint, preoperative hematocrit, American Joint Committee on Cancer (AJCC) stage, and TNM classification. Discrete variables were compared using Pearson's Chi-square analysis. Continuous variables were compared using Student's t test. Differences were considered significant when P < 0.05. The mean age of the study cohort was 67 +/- 9.2 with 98 per cent of the study population being male. The mean AJCC stage was 2.2 +/- 1.2 and the mean preoperative hematocrit was 35 +/- 7.9 with an incidence of 46.1 per cent. The most common presenting complaints were hematochezia (n = 59), anemia (n = 51), heme-occult-positive stool (n = 33), bowel obstruction (n = 26), abdominal pain (n = 21), and palpable mass (n = 13). Preoperative anemia was most common in patients with right colon cancer with an incidence of 57.6 per cent followed by left colon cancer (42.2%) and rectal cancer (29.8%). Patients with right colon cancer had significantly lower preoperative hematocrits compared with left colon cancer (33 +/- 8.5 vs 36 +/- 7.4; P < 0.01) and rectal cancer (33 +/- 8.5 vs 38 +/- 6.0; P < 0.0001). Patients with right colon cancer also had significantly increased stage at presentation compared with left colon cancer (2.3 +/- 1.3 vs 2.1 +/- 1.2; P < 0.02). Age was not a significant risk factor for preoperative anemia in colorectal cancer. We conclude that there is a high incidence of anemia in patients with colon cancer. Patients with right colon cancer had significantly lower preoperative hematocrits and higher stage of cancer at diagnosis. Complete colon evaluation with colonoscopy is warranted in patients with anemia to improve earlier diagnosis of right colon cancer. A clinical trial of preoperative treatment of anemic colorectal cancer patients with recombinant human erythropoietin is warranted.
    The American surgeon 06/2002; 68(6):582-7. · 0.92 Impact Factor
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    ABSTRACT: Surgical site infections (SSI) are the most common nosocomial infection in surgical patients, accounting for 38% of all such infections, and are a significant source of postoperative morbidity resulting in increased hospital length of stay and increased cost. During 1986-1996 the Center for Disease Control and Prevention's National Nosocomial Infections Surveillance system reported 15,523 SSI following 593,344 operations (2.6%). Previous studies have documented patient characteristics associated with an increased risk of SSI, including diabetes, tobacco or steroid use, obesity, malnutrition, and perioperative blood transfusion. In this study we sought to reevaluate risk factors for SSI in a large cohort of noncardiac surgical patients. Prospective data (NSQIP) were collected on 5031 noncardiac surgical patients at the Veteran's Administration Maryland Healthcare System from 1995 to 2000. All preoperative risk factors were evaluated as independent predictors of surgical site infection. The mean age of the study cohort was 61 plus minus 13. SSI occurred in 162 patients, comprising 3.2% of the study cohort. Gram-positive organisms were the most common bacterial etiology. Multiple logistic regression analysis documented that diabetes (insulin- and non-insulin-dependent), low postoperative hematocrit, weight loss (within 6 months), and ascites were significantly associated with increased SSI. Tobacco use, steroid use, and chronic obstructive pulmonary disease (COPD) were not predictors for SSI. This study confirms that diabetes and malnutrition (defined as significant weight loss 6 months prior to surgery) are significant preoperative risk factors for SSI. Postoperative anemia is a significant risk factor for SSI. In contrast to prior analyses, this study has documented that tobacco use, steroid use, and COPD are not independent predictors of SSI. Future SSI studies should target early preoperative intervention and optimization of patients with diabetes and malnutrition.
    Journal of Surgical Research 04/2002; 103(1):89-95. · 2.02 Impact Factor
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    ABSTRACT: Two recent studies have documented that sigmoidoscopy as a screening tool for colorectal cancers may miss advanced proximal colonic neoplasms. The purpose of this study was to assess the prevalence of distal synchronous lesions in patients with proximal colon cancer. We sought to determine if screening sigmoidoscopy would have missed these proximal colon cancers. Data were collected on all patients (n = 305) diagnosed with colorectal cancer over a 6-year period. Patients were stratified by age, sex, tumor location, presenting complaint, AJCC stage, and TNM classification. The colonoscopy results of patients diagnosed with proximal colon cancer were analyzed to determine the incidence of synchronous distal colon lesions. Proximal colon cancer was diagnosed in 88 patients (29%). Of those studied, 45 (54%) did not have synchronous distal lesions detected by colonoscopy. The patients with proximal colon cancer were elderly (mean age 67), had advanced tumor size [59 patients (67%) T3/T4], and had advanced AJCC stages [37 patients (42%) stage III/IV]. Nearly all patients [84 (95%)] with proximal colon cancer were symptomatic. In this study, the majority of patients with proximal colon cancer did not have a synchronous lesion in the distal colon. Current screening methods for colon cancer based on sigmoidoscopy would not have identified these proximal lesions. These findings support the incorporation of screening colonoscopy in protocols designed to identify early colon cancer.
    Surgical Endoscopy 04/2002; 16(3):446-9. · 3.43 Impact Factor
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    ABSTRACT: Previous studies on patients with hip fractures and in patients with colorectal cancer have documented that perioperative transfusion is associated with a significant increase in postoperative infection rate. Therefore, we sought to investigate the incidence of preoperative and postoperative anemia in noncardiac surgical patients and to determine if transfusion is an independent risk factor for infection and adverse outcome postoperatively. Prospective data from the National Veterans Administration Surgical Quality Improvement Program (NSQIP) was collected on 6301 noncardiac surgical patients at the Veterans Affairs Maryland Healthcare System from 1995 to 2000. The mean age of the study cohort was 61 +/- 13. Descriptive data revealed 95% were male, 44% used tobacco, 19% were diabetic, 9% had COPD, 9% used alcohol, 3% used steroids, 1.7% had a diagnosis of cancer, and 1.2% had ascites. Preoperative anemia (hematocrit less than 36) was found in 33.9% and postoperative anemia was found in 84.1% of the study cohort. In the postoperative period, 32.5% of patients had a hematocrit of 26-30, and 26.5% had a hematocrit of 21-25. Mean units of blood transfused in the perioperative period ranged from 0.1 +/- 0.9 in patients without anemia to 2.7 +/- 2.9 in those with anemia. Incidence of pneumonia increased from 2.6 to 5% with increasing degree of anemia. Multiple logistic regression analysis documented that low preoperative hematocrit, low postoperative hematocrit, and increased blood transfusion rates were associated with increased mortality (P < 0.01), increased postoperative pneumonia (P < or = 0.05), and increased hospital length of stay (P < 0.05). There is a high incidence of preoperative and postoperative anemia in surgical patients, with a coincident increase in blood utilization. These factors are associated with increased risk for perioperative infection and adverse outcome (mortality) in surgical patients. Consideration should be given to preoperative diagnosis and correction of anemia with iron, vitamin B12, folate supplementation, or administration of recombinant human erythropoietin.
    Journal of Surgical Research 02/2002; 102(2):237-44. · 2.02 Impact Factor
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    ABSTRACT: BACKGROUND:Women usually have lower mortality rates than men do at any age. This pattern is observed for most causes of death from chronic diseases. Significant controversy still exists about gender differences in outcomes in trauma. We previously reported no differences in in-hospital mortality based on gender in a large single-institution study (n = 18,892) that had a significant limitation in that it was not population based. This current study was performed to validate our earlier findings in a separate, statewide, population-based dataset of trauma victims.STUDY DESIGN:Prospective data were collected on 22,332 trauma patients (18,432 blunt, 3,900 penetrating) admitted to all trauma centers (n = 26) in Pennsylvania over 24 months (January 1996 to December 1997). Gender differences in in-hospital mortality were determined for the entire dataset and for the subsets of blunt and penetrating injury patients. A second analysis examined all blunt injury patients and excluded all patients with a hospital length of stay of less than 24 hours, eliminating patients who expired soon after admission. The null hypothesis was that female gender is protective in trauma outcomes.RESULTS:Multiple logistic regression analysis identified age (odds ratio [OR] 1.03, confidence interval [CI] 1.02 to 1.03), Injury Severity Score (OR 1.06, CI 1.05 to 1.06), non-Caucasian race (OR 1.72, CI 1.39 to 2.15), blunt injury type (OR 0.327, CI 0.26 to 0.41), and Revised Trauma Score (OR 0.44, CI 0.41 to 0.47) as independent predictors of in-hospital mortality in trauma. Preexisting diseases, including cardiac disease (OR 1.53, CI 1.12 to 2.09) and malignancy (OR 4.08, CI 1.64 to 10.17), were also identified as independent predictors of in-hospital mortality in trauma. Female gender was not associated with decreased mortality (OR 0.83, CI 0.67 to 1.03, p = 0.093). A second multiple regression analysis in blunt trauma patients admitted for longer than 24 hours (which eliminated early deaths and patients with minor injuries) determined that in-hospital mortality was not significantly different in male or female blunt trauma patients stratified by Injury Severity Score and age. The same factors that were predictive of in-hospital mortality in the total dataset were also significant in this secondary analysis.CONCLUSIONS:These population-based data confirm that female gender does not adversely affect in-hospital mortality in trauma when patients are appropriately stratified for other variables, including Injury Severity Score and age, that do significantly affect outcomes.
    Journal of The American College of Surgeons - J AMER COLL SURGEONS. 01/2002; 195(1):11-18.
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    ABSTRACT: A 67-year-old male presented with complaints of chronic postprandial pain in the epigastric region. The patient had undergone a vagotomy, antrectomy, and loop gastrojejunostomy for peptic ulcer disease 25 years prior. Abdominal computed tomography (CT) revealed markedly thickened walls of the gastric remnant with infiltration of the adjacent fat planes. An esophagogastroscopy demonstrated erythematous, friable remnant mucosa. Gastric biopsies revealed invasive adenocarcinoma. At laparotomy a large tumor mass involving the gastric remnant and the antecolic loop gastrojejunostomy was identified. Further exploration revealed a firm nodule in the left lobe of the liver and several small nodules on the diaphragm and the lesser omentum. Biopsies confirmed metastatic adenocarcinoma at all sites. Curative resection was abandoned. Gastric remnant carcinoma (GRC) typically presents more than 20 years after resection for peptic ulcer disease and has a history of poor survival rates. With increased use of diagnostic endoscopy, GRC has been detected at earlier stages. Recent cohort studies demonstrate that GRC has similar survival rates after stage stratification when compared with primary proximal gastric carcinoma. The increased incidence of GRC in later decades (>20 years) after operation in conjunction with decreasing numbers of patients suggests that screening endoscopy should be considered on a 2- to 5-year basis in this population.
    Surgical Endoscopy 12/2001; 15(12):1488. · 3.43 Impact Factor
  • C J Gannon, D L Malone, L M Napolitano
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    ABSTRACT: There are several subtypes of sigma receptor, one of which is found throughout the immune system. SR31747A is a unique sigma ligand that possesses potent immune modulatory properties. Previous in vivo studies have documented that administration of SR31747A in murine models of sepsis resulted in decreased proinflammatory (IL-1, IL-6, TNF-alpha) and increased anti-inflammatory (IL-10) response (serum, splenocyte). Studies regarding the effect of this sigma ligand on purified macrophages are lacking. We therefore sought to investigate the effect of SR31747A in LPS-stimulated murine macrophages (RAW 264.7). RAW cells were incubated at 2.5 x 10(5) cells/well; controls were incubated with media alone, experimental groups contained LPS (0.01 microg) and SR31747A (1 nM, 10 nM, 100 nM, 1 microM, 10 microM). Supernatant and cells were harvested at 24 and 48 h. Concentrations of nitric oxide (Greiss reaction) and IL-10 were determined in the supernatant; cellular IL-10 mRNA was assessed. SR31747A induced a dose-dependent reduction in NO and IL-10 protein release in LPS-stimulated murine macrophages. The decrease in IL-10 protein synthesis was paralleled by a significant dose-dependent reduction in IL-10 mRNA. SR31747A is a novel immunomodulator that down regulates nitric oxide and IL-10 protein and mRNA expression. This in vitro reduction of IL-10 protein and mRNA expression is in contrast to previous in vivo murine studies. These data suggest that peripheral macrophages are not the source of the increased anti-inflammatory (IL-10) response induced by SR31747A.
    Surgical Infections 02/2001; 2(4):267-72; discussion 273. · 1.87 Impact Factor

Publication Stats

469 Citations
29.43 Total Impact Points

Institutions

  • 2001–2004
    • University of Maryland, Baltimore
      • Department of Surgery
      Baltimore, MD, United States
  • 2002
    • University of Maryland Medical Center
      • Department of Surgery
      Baltimore, MD, United States