Approach to prophylactic measures for central venous catheter-related infections in hemodialysis: A critical review

Vascular access is the major risk factor for bacteremia, hospitalization, and mortality among hemodialysis (HD) patients. The type of vascular access most associated with bloodstream infection is central venous catheter (CVC). The incidence of catheter-related bacteremia ranges between 0.6 and 6.5 episodes per 1000 catheter days and increases linearly with the duration of catheter use. Given the high prevalence of CVC use and its direct association with catheter-related bacteremia, which adversely impacts morbidity and mortality rates and costs among HD patients, several prevention measures aimed at reducing the rates of CVC-related infections have been proposed and implemented. As a result, a large number of clinical trials, systematic reviews, and meta-analyses have been conducted in order to assess the effectiveness, clinical applicability, and long-term adverse effects of such measures. In the following article, prophylactic measures against CVC-related infections in HD patients and their possible advantages and limitations will be discussed, and the more recent literature on clinical experience with prophylactic antimicrobial lock therapy in HD CVCs will be reviewed.

Factors that influence healing of chronic venous leg ulcers: a retrospective cohort

BACKGROUND: Venous ulcers have a significant impact on patient quality of life, and constitute a worldwide public health problem. Treatment is complex, with high failure rates.OBJECTIVES: To identify clinical and therapeutic factors that influence healing of venous ulcers.METHODS: Retrospective cohort study of patients with venous ulcers. Ulcer area was measured at the first visit (T0) and after 6 months (T6) and 1 year (T12). A reduction in ulcer area of 50% or more at T6 and T12 was the outcome of interest, weighted by clinical, demographic and treatment aspects.RESULTS: Ninety-four patients were included (137 ulcers). A reduction in ulcer area of 50% or more was seen in 40.1% of patients (95% CI 31.9 to 48.4%) at T6 and 49.6% (95% CI 41.2 to 58.1%) at T12. Complete healing occurred in 16.8% (95% CI 10.5 to 23.1%) at T6 and 27% (95% CI 19.5 to 39.5%) at T12. The lowest ulcer area reductions at T6 were associated with longstanding ulcer (RR=0.95; 95% CI 0.91 to 0.98), poor adherence to compression therapy (RR=4.04; 95% CI 1.31 to 12.41), and infection episodes (RR=0.42; 95% CI 0.23 to 0.76). At T12, lower reductions were associated with longstanding ulcer (RR=0.95; 95% CI 0.92 to 0.98), longer topical antibiotic use (RR=0.93; 95% CI 0.87 to 0.99), and systemic antibiotic use (RR=0.63; 95% CI 0.40 to 0.99).CONCLUSIONS: Longstanding ulcer, infection, poor adherence to compression therapy, and longer topical and systemic antibiotic use were independently correlated with worse healing rates.

The Kallikrein Inhibitor from Bauhinia bauhinioides (BbKI) shows antithrombotic properties in venous and arterial thrombosis models

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Reproducible Venous Thrombosis Model in Horses Induced by the Combination of an Endothelial Lesion and Blood Flow Stasis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Factor V Arg306 → Thr (factor V Cambridge) and factor V Arg306 → Gly mutations in venous thrombotic disease

We investigated the prevalence of two reported mutations of the factor V gene (factor V Arg306 → Thr, or factor V Cambridge, and factor V Arg306 → Gly) in 104 relatively young patients with verified venous thrombosis and in 208 age-, sex- and race-matched controls, in order to establish whether the two mutations are associated with increased predisposition for venous thrombosis. PCR amplification followed by BstNI and MspI digestion was employed to determine the genotypes, and each mutation was confirmed by DNA sequencing. Among the controls, one individual was found to be heterozygous for the factor V Arg306 → Thr mutation and one heterozygous for the factor V Arg306 → Gly mutation; none of the patients carried either mutation. Our findings do not support factor V Cambridge and factor V Arg306 → Gly as risk factors for venous thrombosis.

Occluded Tunneled Venous Catheter in Hemodialysis Patients: Risk Factors and Efficacy of Alteplase

Thrombosis of tunneled central venous catheters (CVC) in hemodialysis (HD) patients is common and it can lead to the elimination of vascular sites. This study aimed to evaluate the incidence of thrombotic obstruction of tunneled CVC in HD patients and the efficacy of occlusion treatment with alteplase use, and identify factors associated with thrombotic occlusion. It was a prospective cohort study performed in two centers which evaluated the diagnosis and treatment of thrombotic occlusion of CVC in HD patients for 24 consecutive months. The catheter occlusion was defined as the difficulty infusing or withdrawing fluid from their paths. Alteplase dose was infused to fill the lumen of the occluded catheter and remained for 50 min. As there was no obstruction of the catheter, the procedure was repeated. Three hundred and thirty-nine CVC in 247 patients were evaluated and followed, totalling 67 244 CVC-days. One hundred fifty-seven patients had only one CVC, 88 patients had two CVC during the study, and two patients had three CVC. The median age was 58 (47–66) years, patients were predominantly men (54%), with diabetic nephropathy as the main cause of chronic kidney disease (44%), the internal jugular vein as the main site of implantation (82%), and duration of dialysis before CVC implantation of 119 (41.5 to 585.5) days. Eight hundred and fifteen occlusion episodes were diagnosed (12 episodes/1000 CVC-days), with primary success with alteplase in 596 episodes (77%) and secondary in 81 cases (10%). In 99 episodes (13%), success was not achieved after the second dose of alteplase. Two hundred and thirty CVC were removed during the study and the removal causes were arteriovenous fistula use in 88 patients (38.3%), infectious and mechanical complications in 89 (38.7%) and 21 (9.1%), respectively, and others (transplantation, transfer, or death) in 32 patients (13.9%). Adverse effects were also not observed. In the multivariate analysis, we identified the greatest number of days with CVC (OR = 1.02, CI = 1.01–1.04, P = 0.004), the presence of diabetes (OR = 1.560, CI = 1.351–1.894, P = 0.015), and exit site infection (ESI) (OR = 1.567 CI = 1347–1926, P = 0.023) as factors associated with obstruction. Thrombotic occlusion showed frequent mechanical complication in CVC of HD patients. We observed 12 episodes of obstruction per 1000 CVC-days, with a high success rate after alteplase use (87%). In the multivariate analysis, the time with CVC, the presence of diabetes, and ESI were identified as variables associated with thrombotic obstruction.

Effects of arterial oxygen tension and cardiac output on venous saturation: a mathematical modeling approach

OBJECTIVES: Hemodynamic support is aimed at providing adequate O-2 delivery to the tissues; most interventions target O-2 delivery increase. Mixed venous O-2 saturation is a frequently used parameter to evaluate the adequacy of O-2 delivery. METHODS: We describe a mathematical model to compare the effects of increasing O-2 delivery on venous oxygen saturation through increases in the inspired O-2 fraction versus increases in cardiac output. The model was created based on the lungs, which were divided into shunted and non-shunted areas, and on seven peripheral compartments, each with normal values of perfusion, optimal oxygen consumption, and critical O-2 extraction rate. O-2 delivery was increased by changing the inspired fraction of oxygen from 0.21 to 1.0 in steps of 0.1 under conditions of low (2.0 L.min(-1)) or normal (6.5 L.min(-1)) cardiac output. The same O-2 delivery values were also obtained by maintaining a fixed O-2 inspired fraction value of 0.21 while changing cardiac output. RESULTS: Venous oxygen saturation was higher when produced through increases in inspired O-2 fraction versus increases in cardiac output, even at the same O-2 delivery and consumption values. Specifically, at high inspired O-2 fractions, the measured O-2 saturation values failed to detect conditions of low oxygen supply. CONCLUSIONS: The mode of O-2 delivery optimization, specifically increases in the fraction of inspired oxygen versus increases in cardiac output, can compromise the capability of the "venous O-2 saturation" parameter to measure the adequacy of oxygen supply. Consequently, venous saturation at high inspired O-2 fractions should be interpreted with caution.

Centrilobular necrosis as a manifestation of venous outflow block in pediatric malnourished liver transplant recipients - case reports

CLN is a frequent histological finding in biopsies after pediatric: LT, and its pathogenesis has not yet been fully clarified and has different causes. Among the vascular causes, VOB is sometimes difficult to diagnose, especially when technical variants such as split-liver, reduced-liver, or living-related LT are utilized. Three liver-transplanted malnourished children (ages 12, 20, and 28 months) developed altered LFTs and post-operative ascites with right pleural effusion (two cases) and jaundice (one case). Doppler ultrasound examinations were normal and liver biopsies showed CLN interpreted as severe ACR. There were no responses to the medical treatment. Additional investigation with CT angiography suggested obstructed hepatic vein drainage, which was confirmed by interventional radiology and angioplasty of the anastomosis between the hepatic vein and the inferior vena cava, with clinical and histological resolution. It is concluded that in malnourished children undergoing LT with technical variations, in which the occurrence of severe ACR is usually less common because of the severity of the patient condition, the finding of CLN should raise the possibility of VOB, so that excessive immunosuppression and its consequences can be avoided.

Fetal venous Doppler in pregnancies with placental dysfunction and correlation with pH at birth

Objectives: To determine the correlation between ph at birth and venous Doppler parameters in pregnancies with placental dysfunction. Methods: This was a prospective cohort study of 58 pregnancies with the diagnosis of placental dysfunction between 26 and 34 weeks of gestation. Inclusion criteria were singleton pregnancies, abnormal umbilical artery (UA) Doppler, fetal growth restriction diagnosed by estimated fetal weight <10th centile for gestational age, intact membranes, and absence of fetal congenital abnormalities. The Doppler measurements were the following: UA pulsatility index (PI), ductus venosus (DV) pulsatility index for veins (PIV), intra-abdominal umbilical vein (UV) time-averaged maximum velocity (TAMxV) and blood flow and left portal vein (LPV) time-averaged maximum velocity (TAMxV) and blood flow. All Doppler parameters were transformed into z-scores (SD values from the mean) according to normative references. Results: The UA pH at birth showed a negative significant correlation with the DV-PIV (p = 0.004) and the DV-PIV z-score (p = 0.004), while LPV TAMxV (p = 0.004), LPV TAMxV z-score (p = 0.002), LPV blood flow (p = 0.01), LPV blood flow normalized (p = 0.04) and UV blood flow (p = 0.04) positively correlated with pH at birth. Multiple regression analysis was performed and the DV-PIV z-score was the variable that independently correlated with pH at birth (p = 0.002). Conclusions: the present results suggest that changes in fetal venous blood flow, mainly DV and LPV are useful in the management of cases with early onset placental insufficiency and that venous Doppler parameters correlate with pH at birth.

Genome-Wide Analysis in Brazilian Xavante Indians Reveals Low Degree of Admixture

Characterization of population genetic variation and structure can be used as tools for research in human genetics and population isolates are of great interest. The aim of the present study was to characterize the genetic structure of Xavante Indians and compare it with other populations. The Xavante, an indigenous population living in Brazilian Central Plateau, is one of the largest native groups in Brazil. A subset of 53 unrelated subjects was selected from the initial sample of 300 Xavante Indians. Using 86,197 markers, Xavante were compared with all populations of HapMap Phase III and HGDP-CEPH projects and with a Southeast Brazilian population sample to establish its population structure. Principal Components Analysis showed that the Xavante Indians are concentrated in the Amerindian axis near other populations of known Amerindian ancestry such as Karitiana, Pima, Surui and Maya and a low degree of genetic admixture was observed. This is consistent with the historical records of bottlenecks experience and cultural isolation. By calculating pair-wise F-st statistics we characterized the genetic differentiation between Xavante Indians and representative populations of the HapMap and from HGDP-CEPH project. We found that the genetic differentiation between Xavante Indians and populations of Ameridian, Asian, European, and African ancestry increased progressively. Our results indicate that the Xavante is a population that remained genetically isolated over the past decades and can offer advantages for genome-wide mapping studies of inherited disorders.

Lupus anticoagulant: a marker for stroke and venous thrombosis in primary Sjogren's syndrome

Antiphospholipid antibodies (aPL) and antiphospholipid syndrome (APS) have been described in primary Sjogren's syndrome (pSS) with controversial findings regarding aPL prevalence and their association with thrombotic events. We evaluated 100 consecutive pSS patients (American-European criteria) and 89 age-gender-ethnicity-matched healthy controls for IgG/IgM anticardiolipin (aCL), IgG/IgM anti-beta2-glycoprotein-I (a beta 2GPI), and lupus anticoagulant (LA) (positivity according to APS Sydney's criteria). Clinical analysis followed standardized interview and physical examination assessing thrombotic and nonthrombotic APS manifestations and thrombosis risk factors. aPLs were detected in 16 % patients and 5.6 % controls (p = 0.035). LA was the most common aPL in patients (9 %), followed by a beta 2GPI (5 %) and aCL (4 %). Thrombotic events occurred in five patients [stroke in two, myocardial infarction in one and deep-vein thrombosis (DVT) in four], but in none of controls (p = 0.061). Mean age at time of stroke was 35 years. Three patients with thrombotic events (including the two with stroke) had APS (Sydney's criteria) and were positive exclusively for LA. Comparison of patients with (n = 16) and without (n = 84) aPL revealed similar mean age, female predominance, and ethnicity (p > =0.387). Frequencies of livedo reticularis (25 vs. 4.8 %, p = 0.021), stroke (12.5 vs. 0 %, p = 0.024), and DVT (18.8 vs. 1.2 %, p = 0.013) were significantly higher in APL + patients. Conversely, frequencies of hypertension, dyslipidemia, diabetes, obesity, smoking, sedentarism, and hormonal contraception were similar in patients with or without aPL (p a parts per thousand yenaEuro parts per thousand 0.253). Our study identified LA as an important marker for APS in pSS, particularly for stroke in young patients, warranting routine evaluation of these antibodies and rigorous intervention in modifiable risk factors.

Effect of a video on developing skills in undergraduate nursing students for the management of totally implantable central venous access ports

Background: Handling Totally Implantable Access Ports (TIAP) is a nursing procedure that requires skill and knowledge to avoid adverse events. No studies addressing this procedure with undergraduate students were identified prior to this study. Communication technologies, such as videos, have been increasingly adopted in the teaching of nursing and have contributed to the acquisition of competencies for clinical performance. Objective: To evaluate the effect of a video on the puncture and heparinization of TIAP in the development of cognitive and technical competencies of undergraduate nursing students. Method: Quasi-experimental study with a pretest-posttest design. Results: 24 individuals participated in the study. Anxiety scores were kept at levels 1 and 2 in the pretest and posttest. In relation to cognitive knowledge concerning the procedure, the proportion of correct answers in the pretest was 0.14 (SD=0.12) and 0.90 in the posttest (SD=0.05). After watching the video, the average score obtained by the participants in the mock session was 27.20. Conclusion: The use of an educational video with a simulation of puncture and heparinization of TIAP proved to be a strategy that increased both cognitive and technical knowledge. This strategy is viable in the teaching-learning process and is useful as a support tool for professors and for the development of undergraduate nursing students. (C) 2011 Elsevier Ltd. All rights reserved.

Totally implantable venous catheters: insertion via internal jugular vein with pocket implantation in the arm is an alternative for diseased thoracic walls

Purpose: Insertion of totally implantable catheters via deep vessels that drain into the superior vena cava results in a lower incidence of venous thrombosis and infection as compared to catheters inserted into femoral and arm veins. Superior vena cava obstruction and inadequacy of the thoracic wall are conditions that prevent reservoir implantation in the chest wall. In this article, we describe a technical innovation that enables the pocket to be fixed in the arm while still allowing access to be achieved via the internal jugular vein. Method: The procedure reported maintains the use of the internal jugular vein for access even when the patient's chest is not suited for reservoir implantation, which is localized in the arm. Results: The procedure was successful and no complications occurred. The position of the catheter tip did not alter with arm movement. Conclusion: The implantation of a port reservoir in the arm following venous access via the internal jugular vein is both safe and convenient.

Brazilian urban population genetic structure reveals a high degree of admixture

Advances in genotyping technologies have contributed to a better understanding of human population genetic structure and improved the analysis of association studies. To analyze patterns of human genetic variation in Brazil, we used SNP data from 1129 individuals - 138 from the urban population of Sao Paulo, Brazil, and 991 from 11 populations of the HapMap Project. Principal components analysis was performed on the SNPs common to these populations, to identify the composition and the number of SNPs needed to capture the genetic variation of them. Both admixture and local ancestry inference were performed in individuals of the Brazilian sample. Individuals from the Brazilian sample fell between Europeans, Mexicans, and Africans. Brazilians are suggested to have the highest internal genetic variation of sampled populations. Our results indicate, as expected, that the Brazilian sample analyzed descend from Amerindians, African, and/or European ancestors, but intermarriage between individuals of different ethnic origin had an important role in generating the broad genetic variation observed in the present-day population. The data support the notion that the Brazilian population, due to its high degree of admixture, can provide a valuable resource for strategies aiming at using admixture as a tool for mapping complex traits in humans. European Journal of Human Genetics (2012) 20, 111-116; doi:10.1038/ejhg.2011.144; published online 24 August 2011