Comparative structural analysis of polyurethane and silicone catheters of totally implantable venous access devices by micro-computed tomography

Objectives: To investigate microstructural alterations of explanted long-term central venous catheters of totally implantable venous access devices, using micro-computed tomography. Methods: A total of 16 catheters (9 made of silicone and 7 made of polyurethane), all non-fractured, have been analyzed in this study. Eight catheters were implanted for an average duration of 994 days (min-max: 98-2731 days), while the remaining eight catheters (four for each material, forming the SIref and PUref control groups) were analyzed before implant and used as a reference. X-ray micro-computed tomography was used to reconstruct the three-dimensional geometry of selected segments of each catheter (ca. 10 cm per sample). Results: Morphometric analysis of the catheters revealed increases wall thickness and section area in the polyurethane group as compared with the reference central venous catheters of the same materials (wall thickness: 403 ± 12 μm in the polyurethane (PU) group vs 382 ± 4 μm in PUref, p = 0.014; wall cross-section area: 2.04 ± 0.09 mm2 in PU vs 1.91 ± 0.03 mm2 in PUref, p = 0.04), whereas implanted silicone catheters showed a larger luminal cross section as compared with their controls (lumen cross-section area = 0.851 ± 0.020 mm2 in silicone (SI) group vs 0.811 ± 0.007 mm2 in SIref, p = 0.007). All analyzed samples in this study presented some type of alteration in the catheter walls, namely, hyperdense spots (below 0.1 mm size), air gaps/bubbles and displacements of inner and outer axes causing heterogeneous wall thickness. The incidence of air gaps showed no difference with respect to both material type and duration of implant, whereas the SI group revealed more hyperdense spots as compared to all other groups. Conclusion: Morphological change and local structural alteration can occur in both silicone and polyurethane catheters. This evidence suggests the need for further studies connecting those morphological changes with modification of mechanical robustness, which ultimately can play a role for patient safety

Ultrasound- versus landmark-guided subclavian vein catheterization: a prospective observational study from a tertiary referral hospital

This was a single-center, observational, prospective study designed to compare the effectiveness of a real-time, ultrasound- with landmark-guided technique for subclavian vein cannulation. Two groups of 74 consecutive patients each underwent subclavian vein catheterization. One group included patients from intensive care unit, studied by using an ultrasound-guided technique. The other group included patients from surgery or emergency units, studied by using a landmark technique. The primary outcome for comparison between techniques was the success rate of catheterization. Secondary outcomes were the number of attempts, cannulation failure, and mechanical complications. Although there was no difference in total success rate between ultrasound-guided and landmark groups (71 vs. 68, p\u2009=\u20090.464), the ultrasound-guided technique was more frequently successful at first attempt (64 vs. 30, p\u2009<\u20090.001) and required less attempts (1 to 2 vs. 1 to 6, p\u2009<\u20090.001) than landmark technique. Moreover, the ultrasound-guided technique was associated with less complications (2 vs. 13, p\u2009<\u20090.001), interruptions of mechanical ventilation (1 vs. 57, p\u2009<\u20090.001), and post-procedure chest X-ray (43 vs. 62, p\u2009=\u20090.001). In comparison with landmark-guided technique, the use of an ultrasound-guided technique for subclavian catheterization offers advantages in terms of reduced number of attempts and complications

Adoption and application in Italy of the principal guidelines and international recommendations on venous access

Vascular access is the commonest invasive procedure in secondary care. Vascular access is understood as being access to the bloodstream of acute and chronic patients for diagnostic and therapeutic purposes such as blood sampling, vessel pressure monitoring, fluid infusions (blood transfusions, parenteral nutrition), pharmacological treatments (e.g. antibiotic therapies, chemotherapy, analgesic therapies) or apheresis/dialysis through catheters that may remain in the vessels for weeks or months. There is a wide variety of options available for venous access. Device selection for venous access must be adapted to the patient's needs, and to the type, duration and frequency of the infusion. The scenario is rapidly evolving and hence treatments such as cancer chemotherapy, total parenteral nutrition, long-term parenteral antimicrobial therapies are increasing not only in hospitalized patients, but also in contexts other than traditional ones, such as local care, in response to needs related to healthcare expenditure or patients' needs. This paper originates from the idea of a multidisciplinary group of experts to analyze the main, most recent international guidelines and recommendations on vascular access and to evaluate its implementation in Italy. It often happens that documents acquired in different contexts, however extraordinarily effective and exhaustive, are difficult to apply in contexts where the healthcare organization, professional resources, communication dynamics and regulations are different. The consequence is a progressive departure from international standards and evidence-based medicine, which is particularly burdensome in sectors (such as vascular access and devices used for access) where technological innovation requires constant updating, alignment and method sharing. The work motivation of this group of authors, which sees its final finding in the welfare standards and criteria of appropriateness contained in this document, lies in the particular ongoing and future Italian epidemiological scenario and in the assessments of health economics that demand conscious and appropriate decisions in the interest of the citizen and the healthcare system. The vascular access field is undergoing a veritable revolution; once upon a time the leading lights were those who possessed the best technical skills, the best manual skills, whereas nowadays vascular access decisions are strategic decisions involving specially trained health professionals, able to assess complex interactions and work in teams. There is a strong cultural need, not only with regard to technical aspects, but also for the execution of procedures in daily clinical practice that comply with the recommendations set out in the guidelines published and elaborated by public and private bodies and institutions, as well as by scientific societies and recognized technical and scientific associations. This document is not a manual on vascular access for consultation by all those who intend to go deeper into operating aspects (selection of the device, implantation and management), but a reflection on the most recent pointers in the field of vascular access within Italy's complex healthcare situation

Efficacy of high frequency spinal cord stimulation for the treatment of Buerger’s disease: a case report - Efficacia della stimolazione midollare ad alta frequenza per il trattamento del morbo di Buerger: caso clinico

SCS are used extensively in refractory peripheral artherosclerotic disease. The patient was a 50 year-old woman smoker affected by advanced Buerger’s disease with pain localized mostly in the distal extremities of lower limbs. Following the failure of different treatments we suggested performing SCS to obtain better pain control and better microcirculation. In 2009 the patient underwent SCS implantation and in May 2012, was found to have a decubitus ulcer in the area of the subcutaneous pocket. In October 2012 we implanted a high frequency SCS. We used a 10 cm VAS and ESAS Edmonton Symptoms Assessment Scale) to evaluate difference in quality of life, sleep, disability, pain relief and Patient Global Impression Scale (PGIS) to compare the patient’s satisfaction between treatments. The patient reported a significant improvement in pain reduction with both types of stimulators (tonic and high frequency). The quality of life improved more with the high frequency stimulation and the patient considers high frequency stimulation more effective than tonic stimulation. Our case report suggests that high frequency SCS can be a useful therapy for ischemic pain control

Neurophysiological Comparison Among Tonic, High Frequency, and Burst Spinal Cord Stimulation: Novel Insights Into Spinal and Brain Mechanisms of Action

Spinal cord stimulation (SCS) is an effective option for neuropathic pain treatment. New technological developments, as high-frequency (HF) and theta burst stimulation (TBS), have shown promising results, although putative mechanisms of action still remain debated

Comparison of methods for the microbiological diagnosis of totally implantable venous access port-related infections

Introduction. Totally implanted venous access ports (TIVAPs) are widely used in patients receiving long-term chemotherapy but may lead to serious complications such as catheter-related bloodstream infections (CRBSIs). Diagnosis of CRBSI requires catheter culture, but there is no consensus on microbiological culture methods to be adopted.Aim. To compare three different procedures to recover bacterial cells from colonized catheters and to determine which section of the TIVAP (i.e. tip, septum, reservoir) is the probable source of infection. To investigate the correlation between blood culture results and TIVAP culture in order to get further evidence about the utility of differential time to positivity (DTP) as a diagnostic tool before TIVAP removal.Hypothesis/Gap statement. Comparisons of different diagnostic procedures for catheter culture have been rarely reported for TIVAPs. We hypothesized that the optimization of methods to recover micro-organisms from different parts of TIVAPs may help to decrease the number of false-negative results in the diagnosis of TIVAP-related bloodstream infections.Methodology. A total of 53 TIVAPs removed because of suspected infection (n=36) or end of use (n=17) were evaluated. The reservoir, the septum and the catheter tip were separated and subjected to different treatments for the recovery of adherent micro-organisms: (a) flushing of the catheter lumen, (b) sonication and flushing, (c) treatment with dithiothreitol and flushing. The three methods were also evaluated in an in vitro catheter infection model with Staphylococcus epidermidis. Culture results were compared to those obtained from paired blood cultures drawn from TIVAP and peripheral vein and to the relative DTP.Results. The results obtained demonstrated that vigorous flushing/vortexing of the catheter lumen/septum, allows the recovery of a number of micro-organisms comparable to that of more complex procedures such as sonication or chemical treatment. Among 24 positive TIVAP-cultures, nine were tip-culture negative, whereas the corresponding reservoirs and septa were culture positive. A good correlation was observed between DTP and TIVAP cultures (P<0.001).Conclusions. The results support the evidence that sending the port reservoir in addition to the catheter tip to the microbiology laboratory may increase the sensitivity and the accuracy of CRBSI diagnosis. Moreover, when a TIVAP-related infection is suspected, DTP is a useful diagnostic tool to decide between device removal or a more conservative approach

Paresthesia-Independence: An Assessment of Technical Factors Related to 10 kHz Paresthesia-Free Spinal Cord Stimulation.

BACKGROUND: Spinal cord stimulation (SCS) has been successfully used to treat chronic intractable pain for over 40 years. Successful clinical application of SCS is presumed to be generally dependent on maximizing paresthesia-pain overlap; critical to achieving this is positioning of the stimulation field at the physiologic midline. Recently, the necessity of paresthesia for achieving effective relief in SCS has been challenged by the introduction of 10 kHz paresthesia-free stimulation. In a large, prospective, randomized controlled pivotal trial, HF10 therapy was demonstrated to be statistically and clinically superior to paresthesia-based SCS in the treatment of severe chronic low back and leg pain. HF10 therapy, unlike traditional paresthesia-based SCS, requires no paresthesia to be experienced by the patient, nor does it require paresthesia mapping at any point during lead implant or post-operative programming. OBJECTIVES: To determine if pain relief was related to technical factors of paresthesia, we measured and analyzed the paresthesia responses of patients successfully using HF10 therapy. STUDY DESIGN: Prospective, multicenter, non-randomized, non-controlled interventional study. SETTING: Outpatient pain clinic at 10 centers across the US and Italy. METHODS: Patients with both back and leg pain already implanted with an HF10 therapy device for up to 24 months were included in this multicenter study. Patients provided pain scores prior to and after using HF10 therapy. Each patient\u27s most efficacious HF10 therapy stimulation program was temporarily modified to a low frequency (LF; 60 Hz), wide pulse width (~470 mus), paresthesia-generating program. On a human body diagram, patients drew the locations of their chronic intractable pain and, with the modified program activated, all regions where they experienced LF paresthesia. Paresthesia and pain drawings were then analyzed to estimate the correlation of pain relief outcomes to overlap of pain by paresthesia, and the mediolateral distribution of paresthesia (as a surrogate of physiologic midline lead positioning). RESULTS: A total of 61 patients participated across 11 centers. Twenty-eight men and 33 women with a mean age of 56 ± 12 years of age participated in the study. The average duration of implantable pulse generator (IPG) implant was 19 ± 9 months. The average predominant pain score, as measured on a 0 - 10 visual analog scale (VAS), prior to HF10 therapy was 7.8 ± 1.3 and at time of testing was 2.5 ± 2.1, yielding an average pain relief of 70 ± 24%. For all patients, the mean paresthesia coverage of pain was 21 ± 28%, with 43% of patients having zero paresthesia coverage of pain. Analysis revealed no correlation between percentage of LF paresthesia overlap of predominant pain and HF10 therapy efficacy (P = 0.56). Exact mediolateral positioning of the stimulation electrodes was not found to be a statistically significant predictor of pain relief outcomes. LIMITATIONS: Non-randomized/non-controlled study design; short-term evaluation; certain technical factors not investigated. CONCLUSION: Both paresthesia concordance with pain and precise midline positioning of the stimulation contacts appear to be inconsequential technical factors for successful HF10 therapy application. These results suggest that HF10 therapy is not only paresthesia-free, but may be paresthesia-independent