Bloodstream infections related to totally implantable venous access port: What is the situation in our hospital?

Port-a-Cath© (PAC) are totally implantable devices that offer an easy and long term access to venous circulation. They have been extensively used for intravenous therapy administration and are particularly well suited for chemotherapy in oncologic patients. Previous comparative studies have shown that these devices have the lowest catheter-related bloodstream infection rates among all intravascular access systems. However, bloodstream infection (BSI) still remains a major issue of port use and epidemiology data for PAC-associated BSI (PABSI) rates differ strongly depending on studies. Also, current literature about PABSI risk factors is scarce and sometimes controversial. Such heterogeneity may depend on type of studied population and local factors. Therefore, the aim of this study was to describe local epidemiology and risk factors for PABSI in adult patients in our tertiary- care university hospital. We conducted a retrospective cohort study in order to describe local epidemiology. We also performed a nested case-control study to identify local risk factors of PABSI. We analyzed medical files of adult patients who had a PAC implanted between January 1st, 2008 and December 31st, 2009 and looked for PABSI occurrence before May 1st, 2011 to define cases. Thirty nine PABSI occurred in this population with an attack rate of 5.8%. We estimated an incidence rate of 0.08/1000 PAC-days using the case-control study. PABSI causative agents were mainly Gram positive cocci (62%). We identified three predictive factors of PABSI by multivariate statistical analysis: neutropenia on outcome date (Odds Ratio [OR]: 4.05; 95% confidence interval [CI]:1.05- 15.66; p=0.042), diabetes (OR: 11.53; 95% CI: 1.07-124.70; p=0.044) and having another infection than PABSI on outcome date (OR: 6.35; 95% CI: 1.50-26.86; p=0.012). Patients suffering from acute or renal failure (OR: 4.26; 95% CI: 0.94-19.21; p=0.059) or wearing another invasive device (OR: 2.99; 95%CI:0.96-9.31; p=0.059) did not have a statistically increased risk for developing a PABSI according to classical threshold (p<0.05) but nevertheless remained close to significance. Our study demonstrated that local epidemiology and microbiology of PABSI in our institution was similar to previous reports. A larger prospective study is required to confirm our results or to test preventive measures.

Hypertonie oculaire dans l'orbitopathie dysthyroidienne: considerations physiopathologiques, diagnostiques et therapeutiques. A propos de trois cas significatifs. [Intraocular high pressure in thyroid-associated orbitopathy: physiopathological mechanisms, diagnosis, and management. Three case reports]

PURPOSE: To determine the mechanisms and treatment of ocular hypertension in patients with thyroid-associated orbitopathy and to differenciate it from glaucomatous damage. DESIGN: Three case reports. METHODS: Retrospective review of clinical findings, course, and treatment of the three patients. RESULTS: Elevated intraocular pressure in thyroid-associated orbitopathy observed in the three cases may involve different physiopathological abnormalities such as disturbances of venous circulation, compression by infiltrative muscles, and long corticosteroid use. In the first two cases, defects demonstrated in the perimetry are in consistent with glaucomatous damage. In the third case, visual field abnormalities may be compatible with a glaucomatous disease, but all defects resolved after therapy. Treatement was of the greatest difficulty for the three cases, associating antiglaucomatous medication, steroids, orbital radiotherapy, orbital decompression and extraocular muscle surgery. Intraocular pressure was controlled in all cases. CONCLUSIONS: Elevated intraocular pressure in thyroid-associated orbitopathy is distinguished from glaucomatous disease by its physiopathological mechanisms, clinical course, visual field defects, and treatment. The management of this hypertension is closely related to the treatment of dysthyroid orbitopathy.

Ocular and systemic bio-distribution of rhodamine-conjugated liposomes loaded with VIP injected into the vitreous of Lewis rats.

PURPOSE: Local delivery of therapeutic molecules encapsulated within liposomes is a promising method to treat ocular inflammation. The purpose of the present study was to define the biodistribution of rhodamine-conjugated liposomes loaded with vasoactive intestinal peptide (VIP), an immunosuppressive neuropeptide, following their intravitreal (IVT) injection in normal rats. METHODS: Healthy seven- to eight-week-old Lewis male rats were injected into the vitreous with empty rhodamine-conjugated liposomes (Rh-Lip) or with VIP-loaded Rh-Lip (VIP-Rh-Lip; 50 mM of lipids with an encapsulation efficiency of 3.0+/-0.4 mmol VIP/mol lipids). Twenty-four h after IVT injection, the eyes, the cervical, mesenteric, and inguinal lymph nodes (LN), and spleen were collected. The phenotype and distribution of cells internalizing Rh-Lip and VIP-Rh-Lip were studied. Determination of VIP expression in ocular tissues and lymphoid organs and interactions with T cells in cervical LN was performed on whole mounted tissues and frozen tissue sections by immunofluorescence and confocal microscopy. RESULTS: In the eye, 24 h following IVT injection, fluorescent liposomes (Rh-Lip and VIP-Rh-Lip) were detected mainly in the posterior segment of the eye (vitreous, inner layer of the retina) and to a lesser extent at the level of the iris root and ciliary body. Liposomes were internalized by activated retinal Müller glial cells, ocular tissue resident macrophages, and rare infiltrating activated macrophages. In addition, fluorescent liposomes were found in the episclera and conjunctiva where free VIP expression was also detected. In lymphoid organs, Rh-Lip and VIP-Rh-Lip were distributed almost exclusively in the cervical lymph nodes (LN) with only a few Rh-Lip-positive cells detected in the spleen and mesenteric LN and none in the inguinal LN. In the cervical LN, Rh-Lip were internalized by resident ED3-positive macrophages adjacent to CD4 and CD8-positive T lymphocytes. Some of these T lymphocytes in close contact with macrophages containing VIP-Rh-Lip expressed VIP. CONCLUSIONS: Liposomes are specifically internalized by retinal Müller glial cells and resident macrophages in the eye. A limited passage of fluorescent liposomes from the vitreous to the spleen via the conventional outflow pathway and the venous circulation was detected. The majority of fluorescent liposomes deposited in the conjunctiva following IVT injection reached the subcapsular sinus of the cervical LN via conjuntival lymphatics. In the cervical LN, Rh-Lip were internalized by resident subcapsular sinus macrophages adjacent to T lymphocytes. Detection of VIP in both macrophages and T cells in cervical LN suggests that IVT injection of VIP-Rh-Lip may increase ocular immune privilege by modulating the loco-regional immune environment. In conclusion, our observations suggest that IVT injection of VIP-loaded liposomes is a promising therapeutic strategy to dampen ocular inflammation by modulating macrophage and T cell activation mainly in the loco-regional immune system.

The "Abdominal Circulatory Pump": An Auxiliary Heart during Exercise?

Apart from its role as a flow generator for ventilation the diaphragm has a circulatory role. The cyclical abdominal pressure variations from its contractions cause swings in venous return from the splanchnic venous circulation. During exercise the action of the abdominal muscles may enhance this circulatory function of the diaphragm. Eleven healthy subjects (25 ± 7 year, 70 ± 11 kg, 1.78 ± 0.1 m, 3 F) performed plantar flexion exercise at ~4 METs. Changes in body volume (ΔVb) and trunk volume (ΔVtr) were measured simultaneously by double body plethysmography. Volume of blood shifts between trunk and extremities (Vbs) was determined non-invasively as ΔVtr-ΔVb. Three types of breathing were studied: spontaneous (SE), rib cage (RCE, voluntary emphasized inspiratory rib cage breathing), and abdominal (ABE, voluntary active abdominal expiration breathing). During SE and RCE blood was displaced from the extremities into the trunk (on average 0.16 ± 0.33 L and 0.48 ± 0.55 L, p < 0.05 SE vs. RCE), while during ABE it was displaced from the trunk to the extremities (0.22 ± 0.20 L p < 0.001, p < 0.05 RCE and SE vs. ABE respectively). At baseline, Vbs swings (maximum to minimum amplitude) were bimodal and averaged 0.13 ± 0.08 L. During exercise, Vbs swings consistently increased (0.42 ± 0.34 L, 0.40 ± 0.26 L, 0.46 ± 0.21 L, for SE, RCE and ABE respectively, all p < 0.01 vs. baseline). It follows that during leg exercise significant bi-directional blood shifting occurs between the trunk and the extremities. The dynamics and partitioning of these blood shifts strongly depend on the relative predominance of the action of the diaphragm, the rib cage and the abdominal muscles. Depending on the partitioning between respiratory muscles for the act of breathing, the distribution of blood between trunk and extremities can vary by up to 1 L. We conclude that during exercise the abdominal muscles and the diaphragm might play a role of an "auxiliary heart."

How to prevent venous cannula orifice obstruction during extracorporeal circulation.

Venous cannula orifice obstruction is an underestimated problem during augmented cardiopulmonary bypass (CPB), which can potentially be reduced with redesigned, virtually wall-less cannula designs versus traditional percutaneous control venous cannulas. A bench model, allowing for simulation of the vena cava with various affluent orifices, venous collapse and a worst case scenario with regard to cannula position, was developed. Flow (Q) was measured sequentially for right atrial + hepatic + renal + iliac drainage scenarios, using a centrifugal pump and an experimental bench set-up (afterload 60 mmHg). At 1500, 2000 and 2500 RPM and atrial position, the Q values were 3.4, 6.03 and 8.01 versus 0.77*, 0.43* and 0.58* l/min: p<0.05* for wall-less and the Biomedicus(®) cannula, respectively. The corresponding pressure values were -15.18, -31.62 and -74.53 versus -46.0*, -119.94* and -228.13* mmHg. At the hepatic position, the Q values were 3.34, 6.67 and 9.26 versus 2.3*, 0.42* and 0.18* l/min; and the pressure values were -10.32, -20.25 and -42.83 versus -23.35*, -119.09* and -239.38* mmHg. At the renal position, the Q values were 3.43, 6.56 and 8.64 versus 2.48*, 0.41* and 0.22* l/min and the pressure values were -9.64, -20.98 and -63.41 versus -20.87 -127.68* and -239* mmHg, respectively. At the iliac position, the Q values were 3.43, 6.01 and 9.25 versus 1.62*, 0.55* and 0.58* l/min; the pressure values were -9.36, -33.57 and -44.18 versus -30.6*, -120.27* and -228* mmHg, respectivly. Our experimental evaluation demonstrates that the redesigned, virtually wall-less cannulas, allowing for direct venous drainage at practically all intra-venous orifices, outperform the commercially available control cannula, with superior flow at reduced suction levels for all scenarios tested.

Whole-heart coronary vein imaging: a comparison between non-contrast-agent- and contrast-agent-enhanced visualization of the coronary venous system.

The feasibility of three-dimensional (3D) whole-heart imaging of the coronary venous (CV) system was investigated. The hypothesis that coronary magnetic resonance venography (CMRV) can be improved by using an intravascular contrast agent (CA) was tested. A simplified model of the contrast in T(2)-prepared steady-state free precession (SSFP) imaging was applied to calculate optimal T(2)-preparation durations for the various deoxygenation levels expected in venous blood. Non-contrast-agent (nCA)- and CA-enhanced images were compared for the delineation of the coronary sinus (CS) and its main tributaries. A quantitative analysis of the resulting contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) in both approaches was performed. Precontrast visualization of the CV system was limited by the poor CNR between large portions of the venous blood and the surrounding tissue. Postcontrast, a significant increase in CNR between the venous blood and the myocardium (Myo) resulted in a clear delineation of the target vessels. The CNR improvement was 347% (P < 0.05) for the CS, 260% (P < 0.01) for the mid cardiac vein (MCV), and 430% (P < 0.05) for the great cardiac vein (GCV). The improvement in SNR was on average 155%, but was not statistically significant for the CS and the MCV. The signal of the Myo could be significantly reduced to about 25% (P < 0.001).

Jambes lourdes, insuffisance veineuse des membres inférieurs et hormonothérapie substitutive [Heavy legs, venous insufficiency of the legs and hormone substitution therapy]

The effects of estrogens and gestagens on veins and circulation have been studied since prescription of these hormones as oral contraception and description of related thromboembolic events. The identification of different receptors and the description of these receptors in venous walls have helped to understand some hormonal effects. However, the actual knowledge remains insufficient to explain the complexity of the actions of hormones on venous function. The distribution, the density and the receptor types vary with age, gender, hormonal status and vascular bed. Gestagens mainly reduce the tone of venous walls, whereas estrogens have various effects. Between 25% and 50% of European adults and even 80% or more in some risk groups complain about heavy legs, with or without chronic venous insufficiency. The number of women to whom hormonal substitution is or could be prescribed increases along with aging of populations and the better understanding of potential benefits. The need for a better understanding of vascular effects of sexual hormones is growing, since the incidence of chronic venous insufficiency of the legs increases with age. The life prognosis will not be affected by a deterioration of a chronic venous insufficiency. In contrast, the quality of life, morbidity and the cost of treatment will be expected to change. In addition, thromboembolic events have to be considered, as has been shown in recent studies. These findings outline the need for further studies on the relation between hormones and venous function and for some caution when prescribing hormonal substitution.

Vacuum assisted venous drainage does not increase trauma to blood cells.

Although gravity drainage has been the standard technique for cardiopulmonary bypass (CPB), the development of min imally invasive techniques for cardiac surgery has renewed interest in using vacuum assisted venous drainage (VAVD) Dideco (Mirandola, Italy) has modified the D903 Avant oxygenator to apply a vacuum to its venous reservoir. The impact of VAVD on blood damage with this device is analyzed. Six calves (mean body weight, 71.3 +/- 4.1 kg) were con nected to CPB by jugular venous and carotid arterial cannu lation, with a flow rate of 4-4.51 L/min for 6 h. They were assigned to gravity drainage (standard D903 Avant oxygen ator, n = 3) or VAVD (modified D903 Avant oxygenator, n = 3). The animals were allowed to survive for 7 days. A standard battery of blood samples was taken before bypass, throughout bypass, and 24 h, 48 h, and 7 days after bypass. Analysis of variance was used for repeated measurements. Thrombocyte and white blood cell counts, corrected by hematocrit and normalized by prebypass values, were not significantly different between groups throughout all study periods. The same holds true for hemolytic parameters (lactate dehydrogenase [LDH] and plasma hemoglobin). Both peaked at 24 hr in the standard and VAVD groups: LDH, 2,845 +/- 974 IU/L vs. 2,537 +/- 476 IU/L (p = 0.65), respectively; and plasma hemoglobin, 115 +/- 31 mg/L vs. 89 +/- 455 mg/L (p = 0.45), respectively. In this experimental setup with prolonged perfusion time, VAVD does not increase trauma to blood cells in comparison with standard gravity drainage.

Superior venous drainage in the "LifeBox": a portable extracorporeal oxygenator with a self-expanding venous cannula.

BACKGROUND: In an experimental setting, the performance of the LifeBox, a new portable extracorporeal membrane oxygenator (ECMO) system suitable for patient transport, is presented. Standard rectilinear percutaneous cannulae are normally employed for this purpose, but have limited flow and pressure delivery due to their rigid structure. Therefore, we aimed to determine the potential for flow increase by using self-expanding venous cannulae. METHODS: Veno-arterial bypass was established in three pigs (40.6+/-5.1 kg). The venous line of the cardiopulmonary bypass was established by cannulation of the external jugular vein. The arterial side of the circulation was secured by cannulation of the common carotid artery. Two different venous cannulae (SmartCanula 18/36F 430mm and Biomedicus 19F) were examined for their functional integrity when used in conjunction with the centrifugal pump (500-3000 RPM) of the LifeBox system. RESULTS: At 1500, 2000, 2500, and 3000 RPM, the blood flow increased steadily for each cannula, but remained higher in the self-expanding cannula. That is, the 19F rectilinear cannula achieved a blood flow of 0.93+/-0.14, 1.47+/-0.37, 1.9+/-0.68, and 1.5+/-0.9 l/min, respectively, and the 18/36F self-expanding cannula achieved 1.1+/-0.1, 1.9+/-0.33, 2.8+/-0.39 and 3.66+/-0.52 l/min. However, when tested for venous line pressure, the standard venous cannula achieved -29+/-10.7mmHg while the self-expanding cannula achieved -13.6 +/-4.3mmHg at 1500 RMP. As the RPM increased from 2500 to 3000, the venous line pressure accounted for -141.9+/-20 and -98+/-7.3mmHg for the 19F rectilinear cannula and -30.6+/-6.4 and -45+/-11.6mmHg for the self-expanding cannula. CONCLUSION: The self-expanding cannula exhibited superior venous drainage ability when compared to the performance of the standard rectilinear cannula with the use of the LifeBox. The flow rate achieved was approximately 40% greater than the standard drainage device, with a maximal pump flow recorded at 4.3l/min.

The year in cardiology 2014: peripheral circulation.

In 2014, the debate on the indication of revascularization in case of asymptomatic carotid disease continued, while another one regarding the use of surgery vs. stenting addressed some new issues regarding the long-term cardiac risk of these patients. Renal arteries interventions trials were disappointing, as neither renal denervation nor renal artery stenting was found associated with better blood pressure management or outcome. In contrast, in lower-extremities artery disease, the endovascular techniques represent in 2014 major alternatives to surgery, even in distal arteries, with new insights regarding the interest of drug-eluting balloons. Regarding the aorta, the ESC published its first guidelines document on the entire vessel, emphasizing on the role of every cardiologist for screening abdominal aorta aneurysm during echocardiography. Among vascular wall biomarkers, the aorta stiffness is of increasing interest with new data and meta-analysis confirming its ability to stratify risk, whereas carotid intima-media thickness showed poor performances in terms of reclassifying patients into risk categories beyond risk scores. Regarding the veins, new data suggest the interest of D-dimers and residual venous thrombosis to help the decision of anti-coagulation prolongation or discontinuation after the initial period of treatment for deep vein thrombosis.

Diagnosing pulmonary embolism in outpatients with clinical assessment, D-dimer measurement, venous ultrasound, and helical computed tomography: a multicenter management study.

PURPOSE: To evaluate a diagnostic strategy for pulmonary embolism that combined clinical assessment, plasma D-dimer measurement, lower limb venous ultrasonography, and helical computed tomography (CT). METHODS: A cohort of 965 consecutive patients presenting to the emergency departments of three general and teaching hospitals with clinically suspected pulmonary embolism underwent sequential noninvasive testing. Clinical probability was assessed by a prediction rule combined with implicit judgment. All patients were followed for 3 months. RESULTS: A normal D-dimer level (&lt;500 microg/L by a rapid enzyme-linked immunosorbent assay) ruled out venous thromboembolism in 280 patients (29%), and finding a deep vein thrombosis by ultrasonography established the diagnosis in 92 patients (9.5%). Helical CT was required in only 593 patients (61%) and showed pulmonary embolism in 124 patients (12.8%). Pulmonary embolism was considered ruled out in the 450 patients (46.6%) with a negative ultrasound and CT scan and a low-to-intermediate clinical probability. The 8 patients with a negative ultrasound and CT scan despite a high clinical probability proceeded to pulmonary angiography (positive: 2; negative: 6). Helical CT was inconclusive in 11 patients (pulmonary embolism: 4; no pulmonary embolism: 7). The overall prevalence of pulmonary embolism was 23%. Patients classified as not having pulmonary embolism were not anticoagulated during follow-up and had a 3-month thromboembolic risk of 1.0% (95% confidence interval: 0.5% to 2.1%). CONCLUSION: A noninvasive diagnostic strategy combining clinical assessment, D-dimer measurement, ultrasonography, and helical CT yielded a diagnosis in 99% of outpatients suspected of pulmonary embolism, and appeared to be safe, provided that CT was combined with ultrasonography to rule out the disease.

Prevalence and clinical importance of mesenteric venous thrombosis in the swiss inflammatory bowel disease cohort.

OBJECTIVE. The purpose of this study was to evaluate the prevalence of mesenteric venous thrombosis (MVT) in the Swiss Inflammatory Bowel Disease Cohort Study and to correlate MVT with clinical outcome. MATERIALS AND METHODS. Abdominal portal phase CT was used to examine patients with inflammatory bowel disease (IBD). Two experienced abdominal radiologists retrospectively analyzed the images, focusing on the superior and inferior mesenteric vein branches and looking for signs of acute or chronic thrombosis. The location of abnormalities was registered. The presence of MVT was correlated with IBD-related radiologic signs and complications. RESULTS. The cases of 160 patients with IBD (89 women, 71 men; Crohn disease [CD], 121 patients; ulcerative colitis [UC], 39 patients; median age at diagnosis, 27 years for patients with CD, 32 years for patients with UC) were analyzed. MVT was detected in 43 patients with IBD (26.8%). One of these patients had acute MVT; 38, chronic MVT; and four, both. The prevalence of MVT did not differ between CD (35/121 [28.9%]) and UC (8/39 [20.5%]) (p = 0.303). The location of thrombosis was different between CD and UC (CD, jejunal or ileal veins only [p = 0.005]; UC, rectocolic veins only [p = 0.001]). Almost all (41/43) cases of thrombosis were peripheral. MVT in CD patients was more frequently associated with bowel wall thickening (p = 0.013), mesenteric fat hypertrophy (p = 0.005), ascites (p = 0.002), and mesenteric lymph node enlargement (p = 0.036) and was associated with higher rate of bowel stenosis (p < 0.001) and more intestinal IBD-related surgery (p = 0.016) in the outcome. Statistical analyses for patients with UC were not relevant because of the limited population (n = 8). CONCLUSION. MVT is frequently found in patients with IBD. Among patients with CD, MVT is associated with bowel stenosis and CD-related intestinal surgery.

Extracorporeal membrane oxygenation support after heart explantation: a proposal on how to deal with hyperacute rejection of heart transplant

Purpose: In extreme situations, such as hyperacute rejection of heart transplant or major bleeding per-operating complications, an urgent heart explantation might be the only means of survival. The aim of this experimental study was to improve the surgical technique and the hemodynamics of an Extracorporeal Membrane Oxygenation (ECMO) support through a peripheral vascular access in an acardia model. Methods: An ECMO support was established in 7 bovine experiments (59±6.1 kg) by the transjugular insertion to the caval axis of a self-expanded cannula, with return through a carotid artery. After baseline measurements of pump flow and arterial and central venous pressure, ventricular fibrillation was induced (B), the great arteries were clamped, the heart was excised and right and left atria remnants, containing the pulmonary veins, were sutured together leaving an atrial septal defect (ASD) over the cannula in the caval axis. Measurements were taken with the pulmonary artery (PA) clamped (C) and anastomosed with the caval axis (D). Regular arterial and central venous blood gases tests were performed. The ANOVA test for repeated measures was used to test the null hypothesis and a Bonferroni t method for assessing the significance in the between groups pairwise comparison of mean pump flow. Results: Initial pump flow (A) was 4.3±0.6 L/min dropping to 2.8±0.7 L/min (P B-A= 0.003) 10 minutes after induction of ventricular fibrillation (B). After cardiectomy, with the pulmonary artery clamped (C) it augmented not significantly to 3.5±0.8 L/min (P C-B= 0.33, P C-A= 0.029). Finally, PA anastomosis to the caval axis was followed by an almost to baseline pump flow augmentation (4.1±0.7 L/min, P D-B= 0.009, P D-C= 0.006, P D-A= 0.597), permitting a full ECMO support in acardia by a peripheral vascular access. Conclusions: ECMO support in acardia is feasible, providing new opportunities in situations where heart must urgently be explanted, as in hyperacute rejection of heart transplant. Adequate drainage of pulmonary circulation is pivotal in order to avoid pulmonary congestion and loss of volume from the normal right to left shunt of bronchial vessels. Furthermore, the PA anastomosis to the caval axis not only improves pump flow but it also permits an ECMO support by a peripheral vascular access and the closure of the chest.