Cavotricuspid Isthmus Anatomy Determines The Success Of Remote Controlled Magnetic Bidirectional Block: A Comparsion Between Magnetic 8-mm Solid Tip And 3.5-mm Magnetic Irrigated Tip Catheter

Background

Cavotricuspid isthmus (CTI) anatomy is associated with a great inter-individual variability. The aim of this study was to compare the magnetic 8-mm tip catheter versus the novel 3.5-mm magnetic irrigated tip catheter in achieving bidirectional right atrial isthmus block and to evaluate the impact of the underlying CTI anatomy on success rate.

Methods

A detailed remote controlled 3-dimensional electroanatomic (3D EA) right atrial reconstruction was performed using the magnetic navigation system with special emphasis to the CTI. CTI anatomy was evaluated utilizing the 3D EA map and classified into (A) simple (flat), (B) complex (pouch-like recess or concave shape) or (C) highly complex (pouch-like recess and concave shape). Patients were treated either with the magnetic 8-mm tip catheter (group I) or the open irrigated magnetic 3.5-mm tip catheter (group II). Primary endpoint was defined as acute bidirectional CTI block utilizing exclusively the remote controlled magnetic navigation system. Secondary endpoint was any procedure related complication and procedure time.

Results

In group I (n=10, 10 males, mean age: 65 ± 9 years) the primary endpoint was achieved in 80% (8/10 pts) requiring a median (Q1; Q3) RF application time of 37.1 min (22.8; 71.5) and a median (Q1;Q3) cumulative energy (CE) of 70.68 kJ (kilo Joule). (10.76;40.59). In group II (n=13, 10 males, mean age: 60 ± 7 years) the primary endpoint was achieved in 92 % (12/13) with a median (Q1; Q3) RF application time of 21.9 min (13.0; 27.0; p value=0.036) and a CE of 33.54 KJ (26.59; 49.22; p value=0.015). Variable CTI anatomy was identified for group I (type A: n=5 pts, type B: n=5 pts, type C: n=0 pts) and group for II (type A: n=4 pts, type B: n=7 pts, type C: n=2 pts). In group I magnetic ablation failure was associated with type B CTI anatomy (n=2 pts) and in group II with type C CTI (n=1). No procedure related complications were observed.

Conclusion

Remote controlled catheter ablation of typical atrial flutter using the magnetic navigation system appears to be safe and feasible. CTI anatomy determines remote controlled magnetic ablation success. Use of the magnetic 3.5 mm irrigated tip catheter should be considered in patients with complex CTI anatomy.     

对PICC导管使用不同封管液封管的效果研究

目的：比较使用预充式导管冲洗器（Flush）、生理盐水、肝素钠生理盐水（简称肝素盐水）三种封管液对PICC导管封管的效果。方法：将120例使用PICC导管的患者随机分成3组,分别使用预充式导管冲洗器封、生理盐水、10 U/m L的肝素盐水封管,比较三组的配药时间、最大流速、导管有无回血、有无静脉炎、穿刺点有无局部感染。结果：配药时间上,Flush组为4.3±5.8 s,生理盐水组为38.7±17.4 s,肝素盐水组为94.2±27.1 s,差异有统计学意义,P〈0.001;最大流速上,三组差异无统计学意义,P=0.412;在导管回血比较中,Flush组比生理盐水组发生导管回血的情况少,差异有统计学意义（P=0.0494）,Flush组是生理盐水组发生导管回血情况的EXP（-2.1038）=0.1220倍,肝素盐水组和生理盐水组发生导管回血情况没有差异,P〉0.05;使用三种封管液均无静脉炎和局部感染情况发生。结论：使用预充式导管冲洗器（Flush）对PICC导管进行封管,可以有效节省配药时间,有效减少PICC导管的回血;三种封管液间对PICC导管相关性静脉炎和局部感染差异无统计学意义,可能与本研究的局限性有关。     

The Supraclavicular Fossa Ultrasound View for Central Venous Catheter Placement and Catheter Change Over Guidewire

The supraclavicular fossa ultrasound view can be useful for central venous catheter (CVC) placement. Venipuncture of the internal jugular veins (IJV) or subclavian veins is performed with a micro-convex ultrasound probe, using a neonatal abdominal preset with a probe frequency of 10 Mhz at a depth of 10-12 cm. Following insertion of the guidewire into the vein, the probe is shifted to the right supraclavicular fossa to obtain a view of the superior vena cava (SVC), right pulmonary artery and ascending aorta. Under real-time ultrasound view, the guidewire and its J-tip is visualized and pushed forward to the lower SVC. Insertion depth is read from guidewire marks using central venous catheter. CVC is then inserted following skin and venous dilation. The supraclavicular fossa view is most suitable for right IJV CVC insertion. If other insertion sites are chosen the right supraclavicular fossa should be within the sterile field. Scanning of the IJVs, brachiocephalic veins and SVC can reveal significant thrombosis before venipuncture. Misplaced CVCs can be corrected with a change over guidewire technique under real-time ultrasound guidance. In conjunction with a diagnostic lung ultrasound scan, this technique has a potential to replace chest radiograph for confirmation of CVC tip position and exclusion of pneumothorax. Moreover, this view is of advantage in patients with a non-p-wave cardiac rhythm were an intra-cardiac electrocardiography (ECG) is not feasible for CVC tip position confirmation. Limitations of the method are lack of availability of a micro-convex probe and the need for training.     

Development of a novel intravascular oxygenator catheter: Oxygen mass transfer properties across nonporous hollow fiber membranes

Despite hypoxic respiratory failure representing a large portion of total hospitalizations and healthcare spending worldwide, therapeutic options beyond mechanical ventilation are limited. We demonstrate the technical feasibility of providing oxygen to a bulk medium, such as blood, via diffusion across nonporous hollow fiber membranes (HFMs) using hyperbaric oxygen. The oxygen transfer across Teflon® membranes was characterized at oxygen pressures up to 2 bars in both a stirred tank vessel (CSTR) and a tubular device mimicking intravenous application. Fluxes over 550 ml min^?1 m^?2 were observed in well‐mixed systems, and just over 350 ml min^?1 m^?2 in flow through tubular systems. Oxygen flux was proportional to the oxygen partial pressure inside the HFM over the tested range and increased with mixing of the bulk liquid. Some bubbles were observed at the higher pressures (1.9 bar) and when bulk liquid dissolved oxygen concentrations were high. High‐frequency ultrasound was applied to detect and count individual bubbles, but no increase from background levels was detected during lower pressure operation. A conceptual model of the oxygen transport was developed and validated. Model parametric sensitivity studies demonstrated that diffusion through the thin fiber walls was a significant resistance to mass transfer, and that promoting convection around the fibers should enable physiologically relevant oxygen supply. This study indicates that a device is within reach that is capable of delivering greater than 10% of a patient's basal oxygen needs in a configuration that readily fits intravascularly.     

The Influence of Drag on Nonlinear Oscillatory Flow through Concentric Annulus

A mathematical model has been developed to study the effect of particle drag parameter and frequency parameter on velocity and pressure gradient in nonlinear oscillatory two phase flow. The main purpose is to apply the model to study the combined effect of introduction of the catheter and elastic properties of the arterial wall on the pulsatile nature of the blood flow. We model the artery as an isotropic thin walled elastic tube and the catheter as a coaxial flexible tube. Blood is modeled as an incompressible particulate viscous Newtonian fluid. Perturbation technique has been applied to find the approximations for velocity and pressure gradient up to second order. Numerical solutions are investigated with graphical presentations to understand the effects of drag parameter, frequency parameter and phase angle on velocity along radial direction and pressure gradient along axial directions. As the drag parameter increases, mean pressure gradient and mean velocity will be decreased. As frequency parameter increases mean velocity profile bends near the outer wall. Due to elastic nature of artery wall, a thin catheter experience small oscillations and a thick catheter remains stationary inside the artery. Finally, the effect of catheterization on various physiologically important flow rate characteristics—mean velocity, mean pressure gradient are studied for a range of different catheter sizes, particle drag parameter and frequency parameters.     

血管与导管选择对PICC置管引发并发症的影响

目的:通过比较PICC置管的血管与导管选择,探讨其对并发症发生率的影响。方法:2005年10月至2006年7月共336例恶性肿瘤病人应用B/BRAUN单腔导管,"可分裂"穿刺针355型173例,257型163例分别选择头静脉、贵要静脉、颈外静脉进行观察。结果:头静脉病人>50%出现并发症,其中30%出现中途拔管;贵要静脉<10%出现并发症,90%完成治疗计划;颈外静脉2例因固定不妥导致导管脱出。结论:在非高速度滴注的情况下,尽量选用小管径的导管;对血管的选择应当首选责要静脉,优选右侧,穿刺点最好过肘关节,其次选择颈外静脉优选右侧;选择PICC置管操作应慎重,操作之前做好详细的评估。     

PDCA护理辅助PICC置管治疗肿瘤患者的临床效果分析

为了探讨肿瘤患者实施经外周静脉置入中心静脉导管(PICC)治疗的过程实施PDCA循环管理的价值,本研究选取博习诊疗中心实施PICC置管治疗的120例患者,采用随机数字表法将患者分为研究组和对照组,每组60例,研究组给予PDCA循环管理护理,对照组仅采取常规护理措施;对比两组干预前后的自我管理能力、PICC置管期间并发症的发生率和护理满意度的差别。研究显示,干预前,两组患者的自我管理能力无差别;干预后,研究组带管日常生活、带管运动、日常导管观察等自我管理能力得分均高于对照组(p<0.05);研究组PICC导管留置期间并发症发生率8.33%,显著低于对照组的21.67%(p<0.05)。本研究表明,肿瘤患者实施PICC留置导管治疗的过程实施PDCA循环管理有利于提高患者的自我管理能力,降低PICC留置导管并发症的发生率。     

Establishment and Characterization of UTI and CAUTI in a Mouse Model

Urinary tract infections (UTI) are highly prevalent, a significant cause of morbidity and are increasingly resistant to treatment with antibiotics. Females are disproportionately afflicted by UTI: 50% of all women will have a UTI in their lifetime. Additionally, 20-40% of these women who have an initial UTI will suffer a recurrence with some suffering frequent recurrences with serious deterioration in the quality of life, pain and discomfort, disruption of daily activities, increased healthcare costs, and few treatment options other than long-term antibiotic prophylaxis. Uropathogenic Escherichia coli (UPEC) is the primary causative agent of community acquired UTI. Catheter-associated UTI (CAUTI) is the most common hospital acquired infection accounting for a million occurrences in the US annually and dramatic healthcare costs. While UPEC is also the primary cause of CAUTI, other causative agents are of increased significance including Enterococcus faecalis. Here we utilize two well-established mouse models that recapitulate many of the clinical characteristics of these human diseases. For UTI, a C3H/HeN model recapitulates many of the features of UPEC virulence observed in humans including host responses, IBC formation and filamentation. For CAUTI, a model using C57BL/6 mice, which retain catheter bladder implants, has been shown to be susceptible to E. faecalis bladder infection. These representative models are being used to gain striking new insights into the pathogenesis of UTI disease, which is leading to the development of novel therapeutics and management or prevention strategies.     

A novel alternative placement site and technique for totally implantable vascular access ports in non‐human primates

Background Two novel approaches to implanting a central venous catheter port in non‐human primates (NHPs) using peripheral insertion are presented and compared. Methods Sixty vascular access port (VAP) implants were attempted in 52 NHPs by saphenous vein puncture (n = 20) or saphenous vein cutdown (n = 40). Results Fifty eight procedures were successful. Eighteen of 20 VAPs were successfully placed using saphenous vein puncture, and 40 of 40 using saphenous vein cutdown. There were no significant differences between procedures. Mean implantation times were similar between groups. At explant or study endpoint, all 58 VAPs were patent. Conclusions Vascular access port implantation by saphenous vein puncture or saphenous vein cutdown is safe and effective in NHPs. It is less invasive than conventional procedures, has fewer complications, provides outstanding patency, and reduces surgery time. Furthermore, it allows for cooperative in‐homecage VAP use, minimizing handling stress. We recommend these refined methods for long‐term vascular access in NHPs.     

Evaluation Of Atrial Fibrillation Burden Before Catheter Ablation Predicts Outcome After Pulmonary Vein Isolation

Background

Paroxysmal atrial fibrillation (PAF) is defined as recurrent AF terminating spontaneously within 7 days. This definition allows the consideration of any AF occurrence lasting < 7 days as paroxysmal, irrespective of the frequency and duration of episodes. The aim of this study was to investigate symptomatic AF burden (AFB) defined as total duration of symptomatic AF episodes within 3 months prior to abalation, for prediction of outcome after pulmonary vein isolation (PVI).

Methods

A total of 320 consecutive patients with symptomatic AF (PAF=244, men=214, age=58 y) were enrolled. AFB in patients with PAF was defined as time spent in AF within 3 months prior to PVI. After the AFB cut-off point was optimized at 500 h, patients with PAF were categorized into 2 groups: Group 1 - patients with AFB< 500 h (n=192), Group 2 - patients with AFB≥ 500 h (n=52). Patients with persistent AF (PersAF, n = 76) comprised control group (Group 3). PVI was performed either with irrigated tip catheter (n=215) or using cryoballoon (n=105). The endpoint of study was first documented recurrence of AF >30 sec.

Results

Symptomatic AFB was found to be appropriate for prediction of outcome after PVI. The freedom from AF within 2 years was observed in 69%, 31%, and 43% patients in Group 1, 2 and 3, respectively (Group 1 vs. Group 2, p < .001; Group 1 vs. Group 3, p< .001; Group 2 vs. Group 3, p = 0.46).

Conclusions

Low AFB < 500 h /3 months was associated with better outcome after PVI. Patients with PAF and high AFB should be treated as patients with PersAF.