Extraluminal Route Research Articles

The Most Common In-Hospital Causative Agent of Bladder Catheter-Associated Lower Urinary Tract Infection

Urinary tract infections are caused by an erroneous placement of catheters, This is because it is considered an invasive technique of very common hospital use, which will provide a great benefit to the patient and quite useful for the doctor. The identification in the different hospital centres of the correct technique has to be achieved to achieve an effective sterile placement and obtain a benefit rather than a harm to the patient. However, the fact of having to identify the correct techniques has shown certain deficiencies among health personnel who are in charge of these procedures. It is known that the placement of catheters by extraluminal route, has a higher incidence of infection because it is placed ascendingly and is the most common way to cause a urinary tract infection. In a large majority of infections, its causative agents are given by Gram-negative bacteria and with the appearance of resistance to antimicrobials, it has become a great concern on the part of health personnel. At the same time, it is necessary to recognize the need to indicate antimicrobial therapy when placing the catheter.

The Changing Paradigm of Bacterial Contamination of Venous Access Device: The Intra-luminal vs the Extra-luminal Route

The Changing Paradigm of Bacterial Contamination of Venous Access Device: The Intra-luminal vs the Extra-luminal Route

Skin colonisation at the catheter exit site is strongly associated with catheter colonisation and catheter-related sepsis.

The commonest mode of catheter colonisation is via the extraluminal route with skin bacteria. Catheter-related sepsis causes significant mortality and morbidity in neonates. Our aim was to study the relationships between culture-positive catheter exit site skin swabs, percutaneous central venous catheter segments and blood to determine the magnitude of associations between exit site skin colonisation, catheter colonisation and catheter-related sepsis. In a prospective study, an exit site skin swab and three formerly in vivo catheter segments (proximal, middle and tip) were taken for culture at catheter removal. In those neonates who were clinically unwell at catheter removal, a peripheral blood culture was also collected. Univariate and multivariate analyses were used to study associations. Skin swabs were culture positive in 39 (21%) of 187 catheter removals. With a culture-positive skin swab, the risk of associated catheter colonisation was nearly eight times higher (OR: 7.84, 95% CI: 3.59-17.15) and the risk of definite catheter-related sepsis with the same organism was nearly 10 times higher (OR 9.86, 95% CI: 3.13-31.00). Culture-positive skin swabs from the catheter exit site were strongly associated with catheter colonisation and with definite catheter-related sepsis with the same organism. These data provide further evidence supporting catheter colonisation via the extraluminal route and highlight the importance of optimising skin disinfection before catheter insertion.

Dressing disruption is a major risk factor for catheter-related infections*

Major catheter-related infection includes catheter-related bloodstream infections and clinical sepsis without bloodstream infection resolving after catheter removal with a positive quantitative tip culture. Insertion site dressings are a major mean to reduce catheter infections by the extraluminal route. However, the importance of dressing disruptions in the occurrence of major catheter-related infection has never been studied in a large cohort of patients. A secondary analysis of a randomized multicenter trial was performed in order to determine the importance of dressing disruption on the risk for development of catheter-related bloodstream infection. Among 1,419 patients (3,275 arterial or central-vein catheters) included, we identified 296 colonized catheters, 29 major catheter-related infections, and 23 catheter-related bloodstream infections. Of the 11,036 dressings changes, 7,347 (67%) were performed before the planned date because of soiling or undressing. Dressing disruption occurred more frequently in patients with higher Sequential Organ Failure Assessment scores and in patients receiving renal replacement therapies; it was less frequent in males and patients admitted for coma. Subclavian access protected from dressing disruption. Dressing cost (especially staff cost) was inversely related to the rate of disruption. The number of dressing disruptions was related to increased risk for colonization of the skin around the catheter at removal (p < .0001). The risk of major catheter-related infection and catheter-related bloodstream infection increased by more than three-fold after the second dressing disruption and by more than ten-fold if the final dressing was disrupted, independently of other risk factors of infection. Disruption of catheter dressings was common and was an important risk factor for catheter-related infections. These data support the preferential use of the subclavian insertion site and enhanced efforts to reduce dressing disruption in postinsertion bundles of care.

Controlling exit site infections: Does it decrease the incidence of catheter‐related bacteremia in children on chronic hemodialysis?

The aim of this retrospective study was to investigate whether the application of a chlorhexidine-impregnated dressing (Biopatch) at the exit site of tunneled-cuffed hemodialysis catheters has any effect on the incidence and etiology of catheter-related bacteremia (CRB). This study was carried out over a 5-year period in a single center, where, in the first 2(1/2) years, the exit sites were cleansed with betadine at every hemodialysis session and then covered with a transparent dressing (pre-Biopatch Era). During the next 2(1/2) years, Biopatch was applied to the exit site once a week after cleansing with betadine, and then covered with a transparent dressing (Biopatch Era). The application of Biopatch significantly decreased the incidence of exit site infections (ESI) (P<0.05). However, there was no difference in the incidence of CRBs or their microbiological distribution. The improved ESI rate had no effect on the overall catheter survival time. The antimicrobial sensitivities of the Gram-positive microorganisms were statistically different for the 2 different types of infections (P<0.05). In conclusion, even though Biopatch is effective in decreasing the incidence of ESI, it has no effect on the incidence of CRB, the etiology of CRB, or the overall catheter survival time. The distinct difference between the antimicrobial sensitivities of the ESI and CRB suggests that they are not a spectrum of the same pathogenesis. These preliminary data support the intraluminal pathogenesis of CRB, rather than the exit site as a possible entry point for the extraluminal route.

Avoiding Trouble Down the Line: The Management and Prevention of Hemodialysis Catheter-Related Infections

Over the last 2 decades, hemodialysis catheter use has increased. Annually, approximately 30% of patients using a central venous catheter (CVC) experience a septic or bacteremic episode and are subsequently at risk of its associated long-term complications and mortality. Because of the serious clinical and financial impact of hemodialysis catheter-related bacteremias (HCRIs), standardized, validated definitions based on the hemodialysis patient population are necessary in order to better diagnose, monitor, and report HCRI for patient quality assurance and research purposes. The pathophysiology of HCRI involves a complex interaction between a triad that consists of the host patient, the infecting microorganism, and the vehicle catheter. Although the microorganism contribution in the pathogenesis of HCRI is likely most important, certain patient and catheter-related characteristics may be more amenable to manipulation. The key to managing HCRI is on prophylaxis against the initial microorganism catheter adherence and subsequent biofilm development. General and specific prophylactic maneuvers directed at both an intravascular and extraluminal route of microorganism entry are discussed including antibiotic- and silver-impregnated catheters and dressings, subcutaneous access devices, and topical prophylaxis at the exit site. In addition to systemic antibiotic use, the 3 methods of HRCI treatment using catheter salvage, guidewire exchange, and concurrent antibiotic lock are compared. The outcome and complications of HCRI may be serious and highlight the importance of careful, continual infection surveillance. Although the use of a multidisciplinary hemodialysis infection control team is desirable, staffing education and physician feedback have been shown to improve adherence to infection control guidelines and reduce HCRI.

Mechanisms and risk factors for infection of pulmonary artery catheters and introducer sheaths in cancer patients admitted toan intensive care unit

Pulmonary artery catheters (PACs) are typically inserted for short periods, and the extra-luminal route is assumed to be the overriding source of contamination and/or infection. Our aim was to assess the incidence of PAC and introducer colonization in cancer patients, and to study the mechanisms and risk factors for infection.Patients with a Swan-Ganz catheter admitted to an intensive care unit were prospectively analyzed over 14 months. As soon they were no longer necessary, PACs and introducer sheaths were removed and cultured. We recorded the mean duration of placement, the number of times PACs were handled and the site of insertion.Seventy-nine catheters were inserted in 68 patients. The median (range) duration was three days (0–10) for PACs, and 3.6 days (0–18) for introducers. PAC and/or percutaneous introducer sheath colonization was diagnosed in seven patients (8.9%), but in only one case were both colonized. Colonization rates were 15.5 per 1000 days for PACs and 14.1 per 1000 days for introducers. Introducers were mainly colonized before the 5th day, while PACs were mainly colonized after the 5th day. No PAC or introducer-related local infection or bacteraemia was diagnosed. Colonization was more frequent on catheters inserted into the internal jugular vein.The colonization rate was 5% for PACs and introducers. Our findings suggest that contamination of introducers and PACs may be dissociated and could result from either extraluminal or endoluminal colonization. As three of four PAC colonizations occurred after 5 days, the duration of catheter placement should be considered important. There was little clinical impact of microbial colonization.

Postsynaptic α-adrenoceptors in the perfused canine saphenous vein in vitro

To study the relative localization of α 1- and α 2-adrenoceptors in relation to the intima and the adventitia of canine saphenous vein, a comparison was made of the potency of α 1- and α 2-adrenoceptors agonists applied by intraluminal and extraluminal route of perfused segments of that vessel. Noradrenaline was the most potent of the agonists used and was approximately as potent by intraluminal as by extraluminal route. Cocaine (12 μmol/1) caused supersensitivity to noradrenaline which was of about the same magnitude (threefold) irrespective of the route of administration of noradrenaline. The selective α 1-agonist phenylephrine was about 10 times less potent than noradrenaline and was also equieffective by both routes. The selective α 2-agonist UK-14,304, at concentrations lower than 0.3 μmol/l, caused very small responses and only in 3 out of 14 experiments. In all cases it caused responses at concentrations higher than 0.3 μmol/l. Cocaine did not change the sensitivity to either phenylephrine or UK-14,304. Thus, it is concluded that the results obtained with cocaine agreed with expectations for a homogeneously innervated tissue. Furthermore, α 1-adrenoceptors seem to predominate and to be evenly distributed throughout the media. The lack of responses to the low concentrations of UK-14,304—those selectively acting on α 2-adrenoceptors—was ascribed to the very low efficacy of this agonist on the distal part of the canine saphenous vein and to the tone created by the perfusion pressure which might be high enough to mask this small response.

Catheter-associated bacterium: An experimental study

A bacteriologically-stressed catheterized animal model was developed to evaluate the comparative importance of the intraluminal versus the extraluminal route of catheter-acquired urinary tract infections. This study indicated that in short-term catheterization (less than 7 days), contamination of the drainage spout or accidental disconnection of the drainage tube resulted in bacteriuria within a short time (32–48 hours). If a strict sterile closed drainage system was maintained, the extraluminal route assumed more importance in the development of bacteriuria, however this pathway was considerably slower (72–168 hours). It appeared that catheter-associated bacteriuria results from ascending bacterial colonization within glycocalyx-enclosed biofilm on the inside and/or outside surfaces of the catheter and drainage systems. Development of a biomaterial that inhibits bacterial adherence and does not allow upstream colonization of bacteria on the catheter drainage system would significantly influence the rate of catheter-acquired urinary tract infection.

Effects of uptake and surface of entry on the responses of the rat caudal artery to noradrenaline, adrenaline and methoxamine.

The action of adrenaline on the rat tail artery was similar to that of noradrenaline in that (i) adrenaline was more potent by the intraluminal than the extraluminal route of application, and (ii) cocaine eliminated the difference in potency by selectively enhancing the response to extraluminal adrenaline. In the absence of cocaine, extraluminal adrenaline was more potent than extraluminal noradrenaline; in the presence of cocaine, the two amines were equipotent, irrespective of the route of application. The intraluminal and extraluminal potencies of methoxamine did not differ, either in the absence or presence of cocaine. It is concluded that neuronal uptake is responsible for differences between the potencies of noradrenaline and adrenaline and for the effect of the route of applications on these potencies. Potentiation of responses to both noradrenaline and adrenaline by 27 microM deoxycorticosterone acetate was minor compared with that by cocaine. The results provide further evidence that in the rat tail artery the extraneuronal uptake system is poorly developed compared with the neuronal uptake system.

Total and static pressure measurements of the male lower urinary tract

AbstractSimultaneous total and static urethral pressure measurements were attempted in 22 male subjects who could void around a 10‐French bilumen urethral catheter. The catheter had an end‐hole at its tip and a side‐hole approximately 1 cm away from the end hole (short catheter‐tip segment). Thus, during a single voiding attempt, simultaneous total and static urethral pressures at two different urethral sites (1 cm distance) could be recorded. In addition, suprapubic vesical pressure monitoring was done in all these subjects. The studies also included a comparison of these recordings with those obtained with a 10‐French catheter that had its side‐hole placed 10 cm away from the tip (long catheter‐tip segment). The studies indicated that (1) the total pressure at a particular region of the urethra was usually higher than its static pressure; (2) the pressure sensing catheters produced “plugging effect” of the narrow segments of the outlet; and (3) the static pressure configurations that were obtained with a catheter having a long catheter‐tip segment were markedly different from those obtained through a catheter that had a short catheter‐tip segment.This presentation also includes observations on static pressure measurements obtained from a crude mechanical model that simulated the geometry of the urinary bladder and its outlet. True lateral pressures of the flowing fluid were obtained via cannulae inserted perpendicularly into the stream, through the wall of the outlet (extraluminal route). A comparison was attempted between the static pressure measurements obtained through the extraluminal route with those obtained through the catheters (10–14 French) that were directly inserted into the lumen of the outlet along its axis (intraluminal route). The studies indicated identical static pressures at the narrowest site (16–18 French) of the outlet recorded through both routes.

The influence of desipramine on the sensitivity and accumulation of noradrenaline in the isolated tail artery of the rat

Desipramine increases the sensitivity of the isolated tail artery of the rat to extraluminal noradrenaline much more than to intraluminal noradrenaline. Accumulation of radioactivity after infusions with dl-7- 3H-noradrenaline is inhibited when noradrenaline is given by the extraluminal route and is unaffected when noradrenaline is given into the lumen.