Catheter Assembly Research Articles

Enhancement of Foley Catheter Assembly Section Quality using Six Sigma (A Case Study of an Indonesian Medical Device Company)

This study aims to enhance the quality of the Foley catheter assembly section at PT XYZ, an Indonesian medical device manufacturer, using Six Sigma methodology. PT XYZ currently faces an 8% defect rate in its Foley catheter assembly section, surpassing the acceptable 3% threshold. The current Sigma level of the Shrink process within the assembly section is 2.36, while the Balloon Vulcanizing and Assembly process stands at 2.68. The Six Sigma DMAIC (Define, Measure, Analyze, Improve, Control) framework was used to identify and address root causes of defects. Data collection methods included interviews, questionnaires, and field observations, revealing key issues such as incorrect tray loading, machine calibration errors, operator skill variability, and inadequate handling techniques. Proposed improvements include updating Standard Operating Procedures (SOPs), implementing SCAMPER for calibration, comprehensive training programs, and incentive schemes. Additional measures involve template overlays for precise cutting, vendor maintenance, and control charts for consistency. The Control phase ensures sustainability through documentation, training, and monitoring using control charts and Failure Modes and Effects Analysis (FMEA). Implementing these solutions is expected to reduce the defect rate and elevate the Sigma level of both processes to 3, enhancing process efficiency and product quality. This will improve operational efficiency and customer satisfaction, providing a robust framework for PT XYZ to elevate its quality control and contribute to better healthcare device manufacturing in Indonesia.

Stress measurement of aero-engine thin-walled catheter based on ultrasonic guided wave.

A pipeline system made of catheters is used for liquid-gas transportation in aero-engines. It is important to measure the residual stresses, such as the assembly stress in this system, as they influence performance and lifetime. Compared to other testing techniques, ultrasonic measurement methods based on acoustic-elastic effects can better solve problems. For the above requirements, this paper researches an aero-engine thin-wall catheter's assembly stress measurement method based on ultrasonic guided waves's acoustic, elastic effect. The propagation and dispersion characteristics of guided ultrasonic waves in the catheter were studied. Then, the excitation frequency, guided wave mode, and single-mode excitation mode of the simulation model were determined. Next, a finite element simulation model was established for simulation experiments. In order to reduce the influence of sampling rate and working environment noise on the measurement accuracy of assembly stress, the ultrasonic guided wave signal was processed by the wavelet threshold method. A good noise reduction effect was obtained by determining the wavelet base and the number of decomposition layers. Finally, an experimental platform was built to measure the assembly stress of thin-walled catheters. The maximum measurement error of the assembly stress of a thin-walled catheter was 21.1 MPa, which verified the feasibility of the measurement method. This study provides a promising method for accurately measuring the assembly stress of thin-walled catheters in aero-engines.

Design and Validation of a Soft Robotic Simulator for Transseptal Puncture Training.

Transseptal puncture (TP) is the technique used to access the left atrium of the heart from the right atrium during cardiac catheterization procedures. Through repetition, electrophysiologists and interventional cardiologists experienced in TP develop manual skills to navigate the transseptal catheter assembly to their target on the fossa ovalis (FO). Cardiology fellows and cardiologists that are new to TP currently train on patients to develop this skill, resulting in increased risk of complications. The goal of this work was to create low-risk training opportunities for new TP operators. We developed a Soft Active Transseptal Puncture Simulator (SATPS), designed to match the dynamics, static response, and visualization of the heart during TP. The SATPS includes three subsystems: (i) A soft robotic right atrium with pneumatic actuators mimics the dynamics of a beating heart. (ii) A fossa ovalis insert simulates cardiac tissue properties. (iii) A simulated intracardiac echocardiography environment provides live visual feedback. Subsystem performance was verified with benchtop tests. Face and content validity were evaluated by experienced clinicians. Subsystems accurately represented atrial volume displacement, tenting and puncture force, and FO deformation. Passive and active actuation states were deemed suitable for simulating different cardiac conditions. Participants rated the SATPS as realistic and useful for training cardiology fellows in TP. The SATPS can help improve catheterization skills of novice TP operators. The SATPS could provide novice TP operators the opportunity to improve their TP skills before operating on a patient for the first time, reducing the likelihood of complications.

Simultaneous repair of left atrial appendage perforation and appendage closure by transatrial deployment of a septal occluder device: Preclinical and clinical validation.

Transseptal catheterization of the left atrium (LA) is an important and necessary approach for a wide range of procedures performed in interventional cardiology and electrophysiology. It is technically demanding and requires a detailed understanding of the atrial anatomy and its fluoroscopic and echocardiographic correlates. Potential complications arise if the atrial wall or structures adjacent to the septum are damaged by the catheter and needle assembly. Hemopericardium is a possible complication.

Numerical Analysis for Non-Uniformity of Balloon-Expandable Stent Deployment Driven by Dogboning and Foreshortening.

Stenting is the most common intervention for arteriosclerosis treatment; however, the success of the treatment depends on the incidence of in-stent restenosis (ISR). Stent deployment characteristics are major influencers of ISR and can be measured in terms of dogboning, asymmetry, and foreshortening. This study aimed to analyse the implications of balloon and stent-catheter assembly parameters on the stent deployment characteristics. Experimental approach to analyse the impact of the balloon and stent-catheter assembly parameters on stent deployment characteristics is a time-consuming and complex task, whereas numerical methods prove to be quick, efficient, and reliable. In this study, eleven finite element models were employed to analyse non-uniform balloon stent expansion pattern, comprised of variation in, stent axial position on balloon, balloon length, balloon folding pattern, and balloon wall thickness. Obtained results suggest that the axially noncentral position of the stent on balloon and variable balloon thickness lead to non-uniform stent deployment pattern. Also, it was proved that variation in balloon length and balloon folding pattern influence deployment process. Improved positional accuracies, uniform balloon wall thickness, and selection of the appropriate length of a balloon for selected stent configuration will help to minimize dogboning, asymmetry, and foreshortening during non-uniform stent expansion, thereby reducing the risk of restenosis. The stated numerical approach will be helpful to optimize stent catheter assembly parameters thus minimizing in-vitro tests and product development time.

Deployable ultrasound applicators for endoluminal delivery of volumetric hyperthermia

Purpose To investigate the design of an endoluminal deployable ultrasound applicator for delivering volumetric hyperthermia to deep tissue sites as a possible adjunct to radiation and chemotherapy. Method This study considers an ultrasound applicator consisting of two tubular transducers situated at the end of a catheter assembly, encased within a distensible conical shaped balloon-based reflector that redirects acoustic energy distally into the tissue. The applicator assembly can be inserted endoluminally or laparoscopically in a compact form and expanded after delivery to the target site. Comprehensive acoustic and biothermal simulations and parametric studies were employed in generalized 3D and patient-specific pancreatic head and body tumor models to characterize the acoustic performance and evaluate heating capabilities of the applicator by investigating the device at a range of operating frequencies, tissue acoustic and thermal properties, transducer configurations, power modulation, applicator positioning, and by analyzing the resultant 40, 41, and 43 °C isothermal volumes and penetration depth of the heating volume. Intensity distributions and volumetric temperature contours were calculated to define moderate hyperthermia boundaries. Results Parametric studies demonstrated the frequency selection to control volume and depth of therapeutic heating from 62 to 22 cm3 and 4 to 2.6 cm as frequency ranges from 1 MHz to 4.7 MHz, respectively. Width of the heating profile tracks closely with the aperture. Water cooling within the reflector balloon was effective in controlling temperature to 37 °C maximum within the luminal wall. Patient-specific studies indicated that applicators with extended OD in the range of 3.6–6.2 cm with 0.5–1 cm long and 1 cm OD transducers can heat volumes of 1.1–7 cm3, 3–26 cm3, and 3.3–37.4 cm3 of pancreatic body and head tumors above 43, 41, and 40 °C, respectively. Conclusion In silico studies demonstrated the feasibility of combining endoluminal ultrasound with an integrated expandable balloon reflector for delivering volumetric hyperthermia in regions adjacent to body lumens and cavities.

Small-bowel aspiration during upper esophagogastroduodenoscopy: Rao technique.

Small-bowel aspiration during upper esophagogastroduodenoscopy: Rao technique.

Patent foramen ovale prevalence in atrial fibrillation patients and its clinical significance; A single center experience

BackgroundPatent foramen ovale (PFO) has been reported in 25–30% of the general population. The most commonly used test for detecting PFO is a contrast enhanced transesophageal echocardiography (TEE). PFO presence can be confirmed during pulmonary vein isolation (PVI) procedure by passing the transseptal catheter assembly through the foramen ovale, crossing the septum from the right to the left atrium without using a trans-septal needle for puncture. MethodsWe retrospectively reviewed data from a cohort of 178 patients with AF who underwent PVI at Saint Louis University. Pre-PVI procedure, scheduled TEE reports were reviewed to assess for the presence of PFO and the PVI procedure reports were reviewed for confirmation. ResultsRecords of 178 patients (55.6% male, mean population age 60.4 ± 11.8) were reviewed. 102 of 178 patients had a PFO detected during the PVI procedure. This translates into a 57.3% prevalence of PFO in AF patients. Out of the 178 patients, 75 patients had a pre-PVI procedure TEE for whom PFO presence was reported in 18.7%. The sensitivity and specificity of TEE in detection of PFO were 36.8% and 100%, respectively. There was no statistically significant association between stroke and PFO diagnosed during PVI (RR 1.07; 95% CI, 0.53–2.19; P = 0.805). ConclusionsOur study reports a PFO prevalence of 18.7% using a pre-procedure TEE and 56.6% during the PVI procedure in AF patients. Given that TEE is the gold standard for detection of PFO, our study suggests that the prevalence of PFO may be underestimated in our AF population.

Airway challenges in bilateral temporomandibular joint ankylosis with adenoid hypertrophy: a case report

Temporomandibular joint ankylosis is one of the most challenging airway disorders associated with varying anatomical abnormalities like adenotonsillar hypertrophy, craniofacial malformations, macroglossia, etc. This case highlights the intubation difficulties confronted during the airway management of a 10-year-old girl presenting lately with bilateral temporomandibular joint ankylosis, hypoplastic mandible, and adenoid hypertrophy. This patient was intubated successfully by using a suction catheter assembly to negotiate the endotracheal tube across the adenoid, and an unmatched-size flexible intubation fiberscope through a “separate insertion” technique and external laryngeal manipulation. This case emphasises the significance of a comprehensive preoperative evaluation in preparing the anaesthetic plan of an anticipated difficult airway in a paediatric population, having diverse anatomical hurdles presenting concurrently.

Air Embolism During TEVAR: An Additional Flush Port on the Delivery System Pusher Significantly Reduces the Amount of Air Released During Deployment of a Thoracic Stent-Graft in an Experimental Setting

Purpose: To investigate the influence of (1) an additional side port for flushing the hollow pusher in Zenith thoracic stent-graft delivery systems and (2) additional carbon dioxide flushing on the amount of air released during stent-graft deployment. Methods: Twenty thoracic stent-grafts with an additional flush port to fill the hollow pusher were separated into 2 equal groups (C and D). Both groups were flushed with 20 mL of normal saline through the extra side port connected to the pusher and with 60 mL of saline through the regular flushing port. One group of grafts (group D) was additionally flushed with carbon dioxide through the regular flushing port prior to saline. All grafts were deployed into a curved plastic pipe attached to the bottom of a water-filled container. The released gas was recorded and measured using a calibrated setup. To evaluate the influence of the extra side port irrespective of the carbon dioxide flushing technique, group C was compared with a previously published reference group A without an extra side port that was flushed with the standard 60 mL of saline. Results: Volumes of gas were released in various amounts from the stent-grafts during deployment. The average amount of released gas was 0.51 mL in group C and 0.07 mL in group D (p<0.001). The mean amount of gas from group C samples (0.51 mL) was also significantly lower (p=0.002) compared with the reference group (0.79 mL). Conclusion: Thoracic endografts release air during deployment. Reducing the air-filled space inside the pusher of the catheter assembly using an additional side port can significantly reduce the amount of released air. Using the extra side port in combination with the carbon dioxide flushing technique reduces gas release further to small volumes. In a clinical setting this could be a promising approach to lower the risk of air embolism and stroke during thoracic endovascular aortic repair.

Crack in the epidural catheter filter port.

Sir, Disconnection of epidural catheter and filter is not unknown.[1] However, damage to the injection port of the epidural catheter filter is uncommon. We encountered such a problem during the use of an epidural catheter set for postoperative pain relief. A 68-year-old man posted for right total knee replacement for which lumbar epidural catheter (B. Braun Melsungen AG, Melsungen, Germany) was placed at L3–L4 space through the midline approach. The catheter assembly was used uneventfully for the initial 48 h while the patient received intermittent top-up doses of bupivacaine and morphine mixture. After 72 h, we witnessed slight leakage of the analgesic solution from injection port of the epidural catheter filter during injection of the top-up dose [Figure 1a]. On closer evaluation, we noticed that there was a crack in the catheter filter port leading to the spillage.Figure 1: (a) Epidural Filter Hub Crack. (b) Different nozzle diameters of 10-ml syringes of different makesWhile investigating the possible cause of this occurrence, we came to know that different brands of disposable 10-ml syringes are supplied to our hospital. On closer observation, we also noticed that there exists slight difference in nozzle diameter of these syringes [Figure 1b]. We suspect use of a syringe with a slightly larger diameter might have led to the damage to injection port of epidural filter. We inadvertently try to snugly fit the syringe nozzle into the injection port of the catheter filter applying excessive force. We speculate that such an attempt might have contributed to the damage and the consequent leakage of medication. If gone unnoticed, such a spillage might cause inadequate pain relief and patient dissatisfaction, apart from creating other problems. Although this event shows a lack of regulatory standardization, we suggest keeping in mind this unusual complication while administering the epidural top-up doses. Gentle application of syringe in the filter port and looking for any leakage during drug administration should be practiced. Another possible solution is use of syringes and epidural set of the same manufacturer to avoid these types of problems. Written consent for publication was obtained by the patient. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Integration of deployable fluid lenses and reflectors with endoluminal therapeutic ultrasound applicators: Preliminary investigations of enhanced penetration depth and focal gain.

Catheter-based ultrasound applicators can generate thermal ablation of tissues adjacent to body lumens, but have limited focusing and penetration capabilities due to the small profile of integrated transducers required for the applicator to traverse anatomical passages. This study investigates a design for an endoluminal or laparoscopic ultrasound applicator with deployable acoustic reflector and fluid lens components, which can be expanded after device delivery to increase the effective acoustic aperture and allow for deeper and dynamically adjustable target depths. Acoustic and biothermal theoretical studies, along with benchtop proof-of-concept measurements, were performed to investigate the proposed design. The design schema consists of an array of tubular transducer(s) situated at the end of a catheter assembly, surrounded by an expandable water-filled conical balloon with a secondary reflective compartment that redirects acoustic energy distally through a plano-convex fluid lens. By controlling the lens fluid volume, the convex surface can be altered to adjust the focal length or collapsed for device insertion or removal. Acoustic output of the expanded applicator assembly was modeled using the rectangular radiator method and secondary sources, accounting for reflection and refraction at interfaces. Parametric studies of transducer radius (1-5 mm), height (3-25 mm), frequency (1.5-3 MHz), expanded balloon diameter (10-50 mm), lens focal length (10-100 mm), lens fluid (silicone oil, perfluorocarbon), and tissue attenuation (0-10 Np/m/MHz) on beam distributions and focal gain were performed. A proof-of-concept applicator assembly was fabricated and characterized using hydrophone-based intensity profile measurements. Biothermal simulations of endoluminal ablation in liver and pancreatic tissue were performed for target depths between 2 and 10 cm. Simulations indicate that focal gain and penetration depth scale with the expanded reflector-lens balloon diameter, with greater achievable performance using perfluorocarbon lens fluid. Simulations of a 50 mm balloon OD, 10 mm transducer outer diameter (OD), 1.5 MHz assembly in water resulted in maximum intensity gain of ~170 (focal dimensions: ~12 mm length × 1.4 mm width) at ~5 cm focal depth and focal gains above 100 between 24 and 84 mm depths. A smaller (10 mm balloon OD, 4 mm transducer OD, 1.5 MHz) configuration produced a maximum gain of 6 at 9 mm depth. Compared to a conventional applicator with a fixed spherically focused transducer of 12 mm diameter, focal gain was enhanced at depths beyond 20 mm for assembly configurations with balloon diameters ≥ 20 mm. Hydrophone characterizations of the experimental assembly (31 mm reflector/lens diameter, 4.75 mm transducer radius, 1.7 MHz) illustrated focusing at variable depths between 10-70 mm with a maximum gain of ~60 and demonstrated agreement with theoretical simulations. Biothermal simulations (30 s sonication, 75 °C maximum) indicate that investigated applicator assembly configurations, at 30 mm and 50 mm balloon diameters, could create localized ellipsoidal thermal lesions increasing in size from 10 to 55 mm length × 3-6 mm width in liver tissue as target depth increased from 2 to 10 cm. Preliminary theoretical and experimental analysis demonstrates that combining endoluminal ultrasound with an expandable acoustic reflector and fluid lens assembly can significantly enhance acoustic focal gain and penetration from inherently smaller diameter catheter-based applicators.

Characterization of pharyngeal peristaltic pressure variability during volitional swallowing in healthy individuals.

Recent technological advances incorporated in high resolution manometry have justifiably heightened interest in manometric evaluation of the pharynx. Despite this interest, from both physiologic and clinical perspective there remain a number of unanswered questions regarding the magnitude of variability of pharyngeal pressure phenomena. Therefore, the aim of the present study was to characterize in healthy individuals the inter-subject and recording-site specific variability of pharyngeal peristaltic pressure phenomena. We studied 32 healthy subjects (age: 21-83years,20 under 35years) during dry,5 and 10mL water swallows ×3. Pharyngeal peristaltic pressures were recorded using a high resolution (HR) manometric system and a catheter assembly with 36 circumferential sensors spaced at 1cm intervals positioned trans-nasally to traverse the pharynx, UES and proximal esophagus. Both site-specific pressure data and the Pharyngeal contractile integral (PhCI) showed wide dispersion ranging between values under 50mm Hg to over 300mm Hg and 100-600mm Hg/cm/s,respectively. There was also wide range of dispersion of data for both the standard deviations and the coefficient of variation for all sites (P=.001). The coefficient of variation for PhCI ranged between 0.02 and 0.25 representing data dispersion of 2-25 percent of the mean among subjects (P=.001). Position, age and volume of swallowed fluid did not influence the magnitude of variability. Deglutitive Pharyngeal peristalsis generates pressures with significant degree of site-related and inter-subject variability. This variability is not influenced by age, position and volume of swallowed fluid.

Bending percutaneous drainage catheters to facilitate CT-guided insertion using curved trocar technique.

To assess the safety and efficacy of placing thoraco-abdominal drainage catheters under CT-guidance using a curved trocar technique. A retrospective study of 182 CT/CT-fluoroscopy-guided thoraco-abdominal catheter drainages was conducted; half were performed by residents or fellows under the supervision of one radiologist (Group 1) and the other half under the supervision of 10 other radiologists (Group 2). Group 1 procedures employed a curved catheter assembly placed using trocar technique (n=44) or straight catheters placed with Seldinger technique (n=47). Group 2 procedures employed a straight catheter placed using trocar technique (n=16) or straight catheters placed with Seldinger technique (n=75). Technical success, procedure time, radiation dose (CT Dose Index CTDIvol), and adverse events (Common Terminology Criteria for Adverse Events, 4.0) were compared between techniques and groups using Student's t test, Fisher's exact test or Chi-square analysis. All procedures in groups 1 and 2 were technically successful. Mean procedure time for Group 1 curved trocar technique (28±8min) was shorter than groups 1 and 2 Seldinger technique (37±11min, p=.00002). Mean CTDIvol for Group 1 curved trocar technique (107.8±54.2mGy) was lower than groups 1 and 2 Seldinger technique (136.1±99.7mGy, p=0.032). Adverse event rates for curved trocar, straight trocar, and Seldinger techniques were 2.3% (1/44), 0% (0/16), and 3.3% (4/122), respectively (p=1); all were grade 1 or 2, and no catheter malfunctions occurred. The curved catheter trocar technique is a safe and effective modification of the standard trocar technique that may facilitate CT-guided procedures impeded by CT gantry size limitations.

Preplacement check of complete central venous pressure catheter assembly: Should it be made routine?

Preplacement check of complete central venous pressure catheter assembly: Should it be made routine?

DDEL-12A SYSTEM BASED APPROACH TO CHRONIC DRUG DELIVERY - A METHOD THAT WORKS

Published retrospective analysis of failed clinical trials that have utilised Convection-Enhanced Delivery (CED) as the infusion mechanism have highlighted that a small number of system elements (targeting, device design, lack of real-time imaging etc.) can cause poor outcomes and prevent primary trial objectives being met. A limited number of systems exist for acute, stereotactically guided delivery but systems and strategies for longer term applications are lacking. The problem of achieving controlled intermittent delivery to the brain must therefore be tackled at the system level. Through a collaborative relationship between research and industry it has been possible to bring together multidisciplinary teams and implement a lab to clinic development paradigm. Engineering developments in surgical planning software, rigid tooling and surgical robotics have laid a solid foundation on which to improve surgical techniques, implant design and external re-access kits. Investigation of a guide tube catheter assembly was conducted first in the Agarose gel model and later in the porcine and canine model to help inform surgical planning strategies. Catheter design features were manipulated as a variable to induce changes in the infusion morphology and were investigated over time. Methods for ongoing distribution optimisation were also reviewed. Acquisition of anatomical targets ∼120mm deep can now be achieved sub millimetre utilising the surgical system. Greater coverage of anatomical structures is possible through device modifications which effect changes to the infusion morphology. Ongoing optimisation of infusions might be achieved through periodic imaging and implementing improved, patient specific infusion regimes. A multidisciplinary approach to the problem of chronic implantation is required to achieve successful intermittent infusions in the brain.

Percutaneous retrieval of malpositioned, kinked and unraveled guide wire under fluoroscopic guidance during central venous cannulation.

Sir, We thank the reader for their keen interest in our case report and value their useful suggestions/comments: We agree and have mentioned in the manuscript that passage of tissue dilator over malpositioned guidewire was the triggering event for its kinking. One should never advance the dilator beyond the skin and subcutaneous tissue as it may not only cause similar complications but may also cause injury to the vessels. We understand that all centers, which practice central venous cannulations cannot have interventional radiology suite. In those places when traction fails, surgical exploration remains the only option. Vigorous blind attempts at removal may cause breakage and subsequent embolization and should be avoided. We agree that manipulations like pushing the guide wire inside for a few centimeters, gently twisting or removal of guidewire and catheter assembly together are other additional maneuvers which can be of help in some cases. Deep passage of dilator at subclavian area is not good choice; however, it was used in fluoroscopic suit as a last resort and a part of retrieval of almost fully unraveled external portion of guidewire, which could not be retrieved through transfemoral route using a vascular snare.

Non-Fluoroscopic Transseptal Catheterization During Electrophysiology Procedures using a Remote Magnetic Navigation System.

Transseptal punctures are commonly performed, and left atrial (LA) access is frequently lost during lengthy, complex electrophysiology (EP) procedures. We describe a new technique for non-fluoroscopic re-crossing the fossa ovalis using a new multielectrode transseptal sheath (TS) and a new remote magnetic catheter navigation system (RMNS) (CGCI System, Magnetecs) that uses 8 rapid external electromagnets for real-time navigation of a magnet-tipped electrode catheter across the initial transseptal puncture site in 5 patients undergoing left-sided ablation procedures. The three-dimensional (3D) position of a 8.5 Fr steerable TS with 5-ring 5-15-15-5-mm spaced distal electrodes (Agilis ES©, St Jude Medical), and site of fossal ovalis crossing were "shadowed landmarks" on a 3D electroanatomic mapping (EAM) system (EnSite/NavXTM, St Jude Medical). The TS-magnetic ablation catheter assembly was pulled-back to the inferior vena cava. EAM landmarks were used with RMNS-guided "manual" and "automated" catheter navigation modalities, until septal crossing was obtained. Transseptal re-crossing was successfully performed in all patients in 6.2±8.1 sec using the "automated" RMNS-guided technique and in 30.4±28.4 sec using the "manual" RMNS-guided technique (p=0.01) without complications. This new RMNS was safely and effectively used to perform non-fluoroscopic transseptal catheterization.

SYSTEMS AND METHODS FOR MAKING AND USING A MOTOR DISTALLY-POSITIONED WITHIN A CATHETER OF AN INTRAVASCULAR ULTRASOUND IMAGING SYSTEM

A catheter assembly for an intravascular ultrasound system includes an imaging core configured and arranged for inserting into a distal end of a lumen of a catheter. The imaging core includes at least one transducer mounted to a driveshaft and configured and arranged for transforming applied electrical signals to acoustic signals and also for transforming received echo signals to electrical signals. A motor is coupled to the driveshaft between the one or more transducers and the transformer. The motor includes a rotatable magnet and at least two magnetic field windings disposed around at least a portion of the magnet.

Cocaine self-administration in the mouse: A low-cost, chronic catheter preparation

AbstractIntravenous drug self-administration is the most valid animal model of human addiction because it allows volitional titration of the drug in the blood based on an individual’s motivational state together with the pharmacokinetic properties of the drug. Here we describe a reliable low-cost mouse self-administration catheter assembly and protocol that that can be used to assess a variety of drugs of abuse with a variety of protocols. We describe a method for intravenous catheter fabrication that allows for efficient and long-lasting intravenous drug delivery. The intravenous catheters remained intact and patent for several weeks allowing us to establish stable maintenance of cocaine acquisition. This was followed by a dose response study in the same mice. For collaborators interested in premade catheters for research please make a request at www.neuro-cloud.net/nature-precedings/pomerenze.