James T. Lee

Guidelines for the prevention of intravascular catheter-related infections.

BACKGROUND Although many catheter-related bloodstream infections (CRBSIs) are preventable, measures to reduce these infections are not uniformly implemented. OBJECTIVE To update an existing evidenced-based guideline that promotes strategies to prevent CRBSIs. DATA SOURCES The MEDLINE database, conference proceedings, and bibliographies of review articles and book chapters were searched for relevant articles. STUDIES INCLUDED Laboratory-based studies, controlled clinical trials, prospective interventional trials, and epidemiologic investigations. OUTCOME MEASURES Reduction in CRBSI, catheter colonization, or catheter-related infection. SYNTHESIS The recommended preventive strategies with the strongest supportive evidence are education and training of healthcare providers who insert and maintain catheters; maximal sterile barrier precautions during central venous catheter insertion; use of a 2% chlorhexidine preparation for skin antisepsis; no routine replacement of central venous catheters for prevention of infection; and use of antiseptic/antibiotic-impregnated short-term central venous catheters if the rate of infection is high despite adherence to other strategies (ie, education and training, maximal sterile barrier precautions, and 2% chlorhexidine for skin antisepsis). CONCLUSION Successful implementation of these evidence-based interventions can reduce the risk for serious catheter-related infection.

Ten years of prospective Clostridium difficile-associated disease surveillance and treatment at the Minneapolis VA Medical Center, 1982-1991.

OBJECTIVES To understand the epidemiology, risks, and management of Clostridium difficile-associated disease (CDAD) and to establish and evaluate reliable methods of surveillance. DESIGN Case finding was done by daily ward and laboratory rounds. The criteria for CDAD diagnosis were: at least four unformed stools per day for 2 days and a positive culture or cytotoxin for C difficile, or positive endoscopy or autopsy for pseudomembranes. SETTING The surveillance covered all patients from 1982 through 1991 in the 820-bed Minneapolis Veterans Affairs Medical Center. PARTICIPANTS The criteria were met by 908 patients. Medical service patients numbered 488; surgical patients, 420. Frequencies ranged from a high of 149 cases in 1982 to a low of 50 cases in 1989. RESULTS Stool specimens were obtained on 898 (99%) of the 908 CDAD patients. Stools were culture-positive in 864 (96%) of 898, cytotoxin-positive in 569 (63%) of 898. Endoscopy was performed on 196 (22%) of the 908 patients, and 80 (41%) of 196 patients had pseudomembranes. Ten (1%) of the 908 patients were diagnosed by endoscopy without a stool specimen, or at autopsy. No treatment was needed for 135 (15%) of the 908 CDAD patients, and 19 (2%) of the 908 died before treatment was started. Oral metronidazole was the treatment for 632 (70%) of 908 patients (1% intolerance, 2% failure, 7% relapse) and oral vancomycin was given to 122 (13%) of 908 patients (1% intolerance, 1% failure, 10% relapse). Twelve patients had pseudomembranous colitis at autopsy, and it was the primary cause of death in 5 (0.6%) of 908. CONCLUSIONS CDAD usually responds to oral metronidazole or vancomycin but is nonetheless responsible for a high morbidity and occasional mortality in patients even when the diagnosis and treatment are pursued aggressively.

A fifteen-year wound surveillance study after coronary artery bypass☆

Wound infections after coronary artery bypass operations have been continuously monitored at the Minneapolis Veterans Affairs Hospital for 15 years. All patients were followed up for 30 days. From 1977 to 1991, 2,402 coronary artery bypass operations were performed, and wound infections developed in 125 (5%) patients. There were 71 (3%) chest infections of which 33 (1.4%) were major and 38 (1.6%) superficial. Greater than 94% of these grew only a single organism, of which 74% were Staphylococcus species. There were 63 (2.6%) leg wound infections. More than 50% of these grew multiple organisms, of which 68% were enteric in origin. Nine (0.4%) patients had simultaneous chest and leg infections. Wound infections were diagnosed an average of 15.3 +/- 6.7 (range, 4 to 30) days postoperatively, with 50% occurring after discharge from the hospital. Of 14 variables evaluated by multivariate logistic regression analysis, only steroids (p = 0.005) and diabetes (p = 0.003) were identified as independent risk factors for wound infections. Patients taking steroids or with diabetes tended to have chest infections, whereas obese patients tended to have more leg infections (p = 0.08). During an interval in the surveillance program, a trend toward increasing infections was identified and successfully reversed.

Volume regression of abdominal aortic aneurysms and its relation to successful endoluminal exclusion

OBJECTIVES Evaluating the success of endoluminal repair of abdominal aortic aneurysms (AAAs) is frequently based on diameter measurements and determining the presence of endoleaks. The use of three-dimensional volumetric data and observation of morphologic changes in the aneurysm and device have been proposed to be more appropriate for postdeployment surveillance. The purpose of this study was to analyze the long-term volumetric and morphologic data of 161 patients who underwent endovascular AAA exclusion and to assess the utility of volume measurements for determining successful AAA repair. METHODS Patients with spiral computed tomography scans obtained preoperatively, within the first postoperative month, at 6 months, and annually thereafter, were included in this analysis. Computerized interactive three-dimensional reconstruction of each AAA scan was performed. Total aneurysm sac volume was measured at each time interval (mean preoperative volume 169.0 +/- 78.5 mL), and the significance of volume changes was determined by mixed linear modeling, a form of repeated measures analysis, to account for longitudinal data clustered at the individual level. Sixty-two patients (38%) developed endoleaks at some time during follow-up-15 type I leaks, 45 type II leaks, and 2 type III leaks. The patients with type I and type III leaks were treated with cuffs, and the type II leaks were treated either with observation, side-branch embolization, or required open conversion. RESULTS Aneurysm sac volume increased slightly at 1-month follow-up (+3.3%), and then decreased steadily to -12.9% at 5 years (P <.0001). This effect remained unchanged after controlling for the three device types used in our study population. Patients who did not exhibit an endoleak (n = 99) showed a significant decrease in aneurysm volume across the entire follow-up duration when compared with those who did exhibit an endoleak (n = 62) (P <.0001). The presence of a 10% or greater decrease in volume at 6 months demonstrated a sensitivity of 64%, a specificity of 95%, a positive predictive value of 95%, a negative predictive value of 62%, and an accuracy of 75% for predicting primary clinical success defined by successful deployment of the device; freedom from aneurysm- or procedure-related death; freedom from endoleak, rupture, migration, or device malfunction; or conversion to open repair. CONCLUSIONS Volumetric analysis may be used to predict successful endoluminal exclusion of AAAs. Volume regression appears to be device-independent and should be expected in most clinically successful cases. The presence of volume increases in the first 6 months is suspicious for an endoleak that is pressurizing the aneurysm sac and heralds the need for closer evaluation and possible intervention. A volume decrease of 10% or greater at 6 months and continuing regression over time is associated with successful endovascular repair.

Stent-graft migration following endovascular repair of aneurysms with large proximal necks: anatomical risk factors and long-term sequelae.

Purpose: To evaluate the outcome of aortic endografts deployed in large infrarenal necks and to identify any association of preoperative aneurysm characteristics and postoperative morphological changes with the incidence of neck dilatation and device migration in this patient subset. Methods: The records of 47 patients (41 men; mean age 74, range 55–84) with large aortic neck diameters treated with Talent stent-grafts from 1998 to 2001 were reviewed. Patients with anatomical criteria that precluded aneurysm exclusion with currently available devices were preferentially selected. Mean baseline aneurysm morphology included 27.6-mm (range 18–33.4) suprarenal and 28.1-mm (range 24–34) infrarenal neck diameters; the infrarenal neck length was 26 ± 16 mm with angulation of 37° ± 18°. Computed tomographic (CT) angiograms up to 3 years were analyzed using specialized interactive software; migration was defined as >1-cm change in the distance from the lower renal artery to the top of the device. Pre- and postoperative morphological characteristics of the aneurysm were compared between patients with and without migration. Results: Of the 45 patients successfully treated, 40 had complete CT data for analysis. During a mean 17-month follow-up, 7 (17.5%) of the 40 devices exhibited distal migration. Six patients required secondary procedures; 5 were in the migration cohort. No preoperative anatomical characteristic or degree of neck dilatation over time was predictive of stent-graft migration. Aneurysm sac regression was significant at 1 (–0.09 ± 4.90 mm) and 2 (–1.48 ± 2.56 mm) years in endografts without migration (p<0.001). Distal endograft migration >1 cm predicted the need for secondary interventions (p<0.001), with 83% sensitivity and 94% specificity. Conclusions: Endovascular repair is successful in patients with large infrarenal necks and complex neck morphology. Changes in aneurysm remodeling over time were similar to reported observations in patients with more favorable neck criteria. Although no anatomical factor associated with migration could be identified from this analysis, distal displacement >1 cm correlated with the need for a secondary intervention.

Recommended Practices for Surveillance

Demonstration of quality health care includes documentation of outcomes of care. Surveillance is a comprehensive method of measuring outcomes and related processes of care, analyzing the data, and providing information to members of the health care team to assist in improving those outcomes. Surveillance is an essential component of effective clinical programs designed to reduce the frequency of adverse events such as infection or injury. Although there is no single or “right” method of surveillance design or implementation, sound epidemiologic principles must form the foundation of effective systems and must be understood by key participants in the surveillance program and supported by senior management. Teamwork and collaboration across the health care spectrum are important for the development of surveillance plants. Each health care organization must tailor its surveillance systems to maximize resources by focusing on population characteristics, outcome priorities, and organizational objectives. To ensure quality of surveillance, the following elements must be incorporated: u • A written plan should serve as the foundation of any surveillance program. The plan should outline important objectives and elements of the surveillance process so that resources can be targeted appropriately. • Thoroughness or intensity of surveillance for an area of interest must be maintained at the same level over time. Fluctuations of a surveillance rate have no meaning unless the same level of data collection is maintained. External rate comparisons are meaningless unless the systems used have comparable intensity. • All the elements of surveillance should be used with consistency over time. This includes application of surveillance definitions and rate calculation methods. • Personnel resources need to be appropriate for the type of surveillance being performed. This includes trained professionals who understand epidemiology and surveillance and who have access to continuing professional education opportunities. • Other resources essential to surveillance include computer support, information and technology services, clerical services, and administrative understanding and support to maintain a quality program. • As a means of quality control and to ensure accuracy, the data and process of surveillance should undergo periodic evaluation and validation. This document is intended to assist professionals who plan and conduct surveillance programs as well as those who assure that there is appropriate organizational support to accomplish appropriate surveillance. While design of surveillance systems must be unique for each organization, incorporation of these seven core Recommended Practices for Surveillance provides a scientific framework to approach surveillance programs.

Wound infection after infrainguinal bypass operations: multivariate analysis of putative risk factors.

Reported wound infection rates for infrainguinal bypass operations range from 17% to 44%, but there is limited appreciation of which characteristics of patients or operations are reliable markers of increased wound infection risk. The purpose of the present study was to analyze all wound infections observed after infrainguinal bypass operations during 20 years of practice in a large teaching institution. Independent risk factors for wound infection development were identified. During the 20-year period ending 31 December, 1997, 978 male patients underwent infrainguinal bypass operations at the Minneapolis Department of Veterans Affairs Medical Center. Wound infections complicated the recovery of 129 of these patients during a 30-day postoperative surveillance interval. Multivariate logistic regression analysis was used to test the association between wound infection occurrence and putative risk factors that were either features of patients or characteristics of the operations. The following variables were examined: obesity, prosthetic graft placement, diabetes mellitus, steroid use, anticoagulation use, length of preoperative hospital stay, development of incisional hematoma, duration of operation, and the preoperative presence of a non-healing wound in the extremity being revascularized. The overall wound infection rate was 13.2% (129/978). In a final logistic regression model, obesity was a significant and independent predictor of wound infection (Relative Risk 2.6, 95% confidence interval, 1.35-4.90), as was development of a post-operative incisional hematoma (Relative Risk 6.44, 95% confidence interval, 2.95-14.08). No other explanatory variable was significantly associated with wound infection development.

SIRT1 Regulator of p53 Deacetylation

The cellular NAD(+)/NADH level controls Sir2 (silent information regulator 2) deacetylase activity in regulating aging in lower species. Much work has been put forth to identify ways to activate SIRT1, the mammalian ortholog of Sir2. The identification of p53 as a bona fide substrate of SIRT1 deacetylation has linked SIRT1 to a role in tumorigenesis. Here, we review the various SIRT1 endogenous and small molecular activators and inhibitors that regulate p53 acetylation and subsequent activation of p53 tumor suppression activity.

Iliac vessel injuries

Trauma to the iliac vasculature continues to pose a significant challenge to management. In several large series, mortality for penetrating injuries is reported as approaching 40%. Uncontrollable hemorrhage originating from an anatomically inaccessible source and multiple associated injuries often contribute to this high mortality rate. This article discusses the current existing management strategies and the controversial role of PTFE in vascular reconstruction within a contaminated field. Concomitant injuries to the enteric viscera and genitourinary system are also addressed. Postoperative management including anticoagulation and the complications of liberal fasciotomy are mentioned. The evolving role of endovascular therapy as an adjunctive modality in the armamentarium of the trauma surgeon is also presented briefly.

The liver is populated by a broad spectrum of markers for macrophages. In alcoholic hepatitis the macrophages are M1 and M2

Background Liver cell injury in alcoholic hepatitis (AH) is in part, due to macrophage generated proinflammatory cytokines i.e., M1, M2a, M2b, and M2c might be involved in ALD. The T cell response to chemokines and cytokines differs not only when M1 and M2 macrophages are compared but even when individual M2 subtypes are profiled. Purpose In AH, M1 monocytes in the blood show increased sensitivity in the TNF-α response to LPS. Immunohistochemistry (IHC) studies showed that the liver sinusoids in ALD are abundantly populated by CD163 expressing type 2 macrophages. In this report, we profile many of the molecules associated with M1 and M2 macrophages in livers with AH using IHC. Methods Using immunofluorescent antibody-labeling, we profiled the receptors, cytokines and chemokines observed in M1, M2a, M2b, and M2c macrophages in liver biopsies from patients with AH. Results The increased CD 163 expression found in previous studies was confirmed as well an additional macrophage phenotypic marker CD206, suggesting that AH pathogenesis at least partially involves M2a and M2c macrophages. TGF-β was found to be robustly over expressed by liver sinusoidal macrophages. Macrophage expression of the phenotypic markers TLR-2, TLR-4 and TLR-8 – found in both M1 and M2 macrophages – as well as the chemokines CCL-1 and CCL-18 was found. However, IRF-4, which is related to IL-4 production and M2a polarization as well as the cytokines CCL-1 and Il-1β and the chemokine CXCL-1 were also observed, suggesting that M2a and M2b also play a role in AH pathogenesis. Conclusion Livers with AH show robust macrophage over expression of TGF-β, a growth factor more commonly associated with M2 type macrophages and mostly known for its fibrogenetic properties. However, our immunoprofiling of macrophage over expression also shows that AH is driven by receptors, interferons, and cytokines that are commonly associated not just with M2 macrophages, but with M1 as well. Thus, a complex interplay between different types of macrophages expressing a diverse array of molecules and receptors is involved in AH.