A new large-caliber trocar for percutaneous endoscopic gastrostomy by the introducer technique in head and neck cancer patients

Background and study aims In many patients, percutaneous endoscopic gastrostomy (PEG) can be limited by digestive tract stenosis. PEG placement using an introducer is the safest alternative for this group of patients, but the available devices are difficult to implement and require smaller-caliber tubes. The aim of this study was to evaluate the modification of an introducer technique device for PEG placement with regard to the following: procedure feasibility, possibility of using a 20-Fr balloon gastrostomy tube, tube-related function and problems, complications, procedure safety, and mortality. Patients and methods Between March 2007 and February 2008, 30 consecutive patients with head and neck malignancies underwent introducer PEG placement with the modified device and gastropexy. Each patient was evaluated for 60 days after the procedure for the success of the procedure, infection, pain, complications, mortality, and problems with the procedure. Results The procedure was successful in all cases with no perioperative complications. No signs of stomal infection were observed using the combined infection score. The majority of patients experienced mild-to-moderate pain both in the immediate postoperative period and at 72 hours. One major early complication (3.3%) and two minor complications (6.7%) were observed. No procedure-related deaths occurred during the first 60 days after the procedure. Conclusion The device modification for PEG using the introducer technique is feasible, safe, and efficient in outpatients with obstructive head and neck cancer. In this series, it allowed the use of a larger-caliber tube with low complication rates and no procedure-related mortality.

Safety Profile of Trocar and Insufflation Needle Access Systems in Laparoscopic Surgery

BACKGROUND: The most common laparoscopic complications are associated with trocar insertion. The purpose of this study was to develop an objective method of evaluating the safety profile of various access devices used in laparoscopic surgery. STUDY DESIGN: In 20 swine, 6 bladed and 2 needle access devices were evaluated. A force profile was determined by measuring the force required to drive the trocar or needle through the fascia and into the peritoneum, at 0 and 10 mmHg. The amount Of tissue deformation, the length of blade exposed, and the duration of exposure were measured using a high-speed digital imaging system. RESULTS: The needle system without the sheath required the least driving force and had the most favorable force profile. In contrast, the bladed, nonretractable trocar system required a higher driving force and a rapid loss of resistance. Insertion under a pneumoperitoneum did not significantly alter the force profile of the various access devices except for the amount of tissue deformation. With the bladed system, the blade itself was exposed for an average of 0.5 to 1.0 seconds for a distance of 4.5 to 5.0 cm. In comparison, the needle system was exposed for 0.2 seconds for a distance of 1.8 cm. CONCLUSIONS: We developed a reproducible method of measuring the forces required to place the access systems, their pattern of resistance loss, and the characteristics of the blade exposure. These parameters may provide an adjunctive and objective measurement of safety, allowing for more direct comparison between various trocar designs. (J Am Coll Surg 2009;209:222-232. (C) 2009 by the American College of Surgeons)

Cavopulmonary anastomosis improves left ventricular assist device support in acute biventricular failure

Objective: Right ventricular failure during left ventricular assist device (WAD) support can result in severe hemodynamic compromise with high mortality. This study investigated the acute effects of cavopulmonary anastomosis on right ventricular loading and WAD performance in a model of severe biventricular failure. Methods: LVAD support was performed by means of centrifugal pump implantation in 14 anesthetized dogs (20-30 kg) with severe biventricular failure obtained by ventricular fibrillation induction. Animals were randomized to be submitted to classical cavopulmonary anastomosis (Glenn shunt) or to control group and were maintained under WAD support for 2 h. Left and right atrial, right ventricular and systemic pressures were monitored, white total pulmonary flow was simultaneously recorded by transonic flowmeters located on the superior vena cava and pulmonary trunk. Blood gas and venous lactate determinations were also obtained. Results: Ventricular fibrillation maintenance resulted in acute WAD performance impairment after 90 min in the control group, while animals with Glenn circuit maintained normal WAD pump flow (55 +/- 13 ml kg(-1) min(-1) vs 21 +/- 4 ml kg(-1) min(-1), p < 0.001) and better peripheral perfusion (blood lactate of 29 +/- 10 pg/ml vs 46 +/- 9 pg/ml, p < 0.001). Left and right atrial pressures did not change significantly, while right ventricular pressure was tower in animals with Glenn circuit (13 +/- 3 mmHg vs 22 +/- 8 mmHg, p = 0.005). Right ventricular unloading with Glenn shunt also resulted in superior total pulmonary flow (59 +/- 13 ml kg(-1) min(-1) vs 17 +/- 3 ml kg(-1) min(-1), p < 0.001). Conclusion: The concomitant use of cavopulmonary anastomosis during LVAD support in a model of severe biventricular failure limited right ventricular overloading and resulted in better hemodynamic performance. (C) 2008 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Specification and Evaluation of Safety Properties in a Component-Based Software Engineering Process

Over the past years, component-based software engineering has become an established paradigm in the area of complex software intensive systems. However, many techniques for analyzing these systems for critical properties currently do not make use of the component orientation. In particular, safety analysis of component-based systems is an open field of research. In this chapter we investigate the problems arising and define a set of requirements that apply when adapting the analysis of safety properties to a component-based software engineering process. Based on these requirements some important component-oriented safety evaluation approaches are examined and compared.

Safety and Immunogenicity of Varicella Vaccine in Patients With Juvenile Rheumatic Diseases Receiving Methotrexate and Corticosteroids

Objective. To evaluate the safety and immunogenicity of varicella vaccine (VV) in susceptible patients with juvenile rheumatic diseases receiving methotrexate and corticosteroids. Methods. Twenty-five patients with juvenile rheumatic diseases (ages 2-19 years) and 18 healthy children and adolescents (ages 3-18 years) received a single dose of VV. All 25 patients were receiving methotrexate; 13 were also receiving prednisone and 5 were also receiving other disease-modifying antirheumatic drugs. None of the vaccinated patients or controls had a previous history of varicella. Anti-varicella-zoster virus IgG antibody (anti-VZV-IgG) titers were measured by enzyme-linked immunosorbent assay immediately before, 4-6 weeks after, and 1 year after vaccination. The patients were monitored prospectively for adverse reactions related to the vaccine, exposure, and occurrence of varicella. Disease activity was assessed 3 months before and 3 months after VV. Results. Twenty patients and all of the controls had negative preimmunization titers of VZV-IgG, and 5 patients had equivocal levels. Positive VZV-IgG titers were detected in 10 (50%) of 20 seronegative patients and 13 (72.2%) of 18 controls 4-6 weeks after VV (P = 0.2). One year after vaccination, 8 of 10 patients maintained positive VZV-IgG titers. No overt varicella episodes and no severe adverse reactions were observed during the followup period. No worsening of clinical parameters and no flares of juvenile rheumatic diseases or changes in doses of medications used were detected after vaccination. In fact, the number of active joints in patients with juvenile idiopathic arthritis was significantly lower after VV (P = 0.009). Conclusion. VV appears to be safe in patients with juvenile rheumatic diseases receiving methotrexate, as long as continuous prospective vigilance for side effects is performed.

Percutaneous Transatrial Access to the Pericardial Space for Epicardial Mapping and Ablation

Background-Puncture of the atrial appendage may provide access to the pericardial space. The aim of this study was to evaluate the feasibility of epicardial mapping and ablation through an endocardial transatrial access in a swine model. Methods and Results-An 8-F Mullins sheath was used to perforate the right (n=16) or left (n=1) atrial appendage in 17 pigs (median weight, 27.5 kg; first and third quartiles [Q1, Q3], 25.2, 30.0 kg). A 7-F ablation catheter was introduced into the pericardial space to perform epicardial mapping and deliver radiofrequency pulses on the atria. The pericardial space was entered in all 17 animals. In 15 (88%) animals, there was no hemodynamic instability (mean blood pressure monitoring, initial median, 80 mm Hg; Q1, Q3, 70, 86 mm Hg; final median, 88 mm Hg; Q1, Q3, 80, 96 mm Hg; P=0.426). In these 15, a mild hemorrhagic pericardial effusion was identified and aspirated (median, 20 mL; Q1, Q3, 15, 30 mL) during the procedure, and postmortem gross analysis revealed that the atrial perforation was closed in these animals. In 2 (12%) of the 17 animals, there was major pericardial bleeding with hemodynamic collapse. On gross examination, it was found that pericardial space was accessed through right ventricular perforation in 1 animal and the tricuspid annulus in the other. After the initial study, we used an occlusion device in 3 other animals to attempt to seal the puncture (2 at the right atrial appendage and 1 at the right ventricle). These 3 animals had no significant pericardial bleeding. Conclusions-Transatrial endovascular right atrial appendage puncture may provide a potential alternative route for pericardial access. Further studies are needed to evaluate its safety with longer and more-complex procedures before being applied in clinical settings. (Circ Arrhythm Electrophysiol. 2011;4:331-336.)

A Simple and Efficient Device for Demonstrating Cross-sectional Anatomy of the Head

Described in this article is a novel device that facilitates study of the cross-sectional anatomy of the human head. In designing our device, we aimed to protect sections of the head from the destructive action of handling during anatomy laboratory while also ensuring excellent visualization of the anatomic structures. We used an electric saw to create 15-mm sections of three cadaver heads in the three traditional anatomic planes and inserted each section into a thin, perforated display box made of transparent acrylic material. The thin display boxes with head sections are kept in anatomical order in a larger transparent acrylic storage box containing formaldehyde solution, which preserves the specimens but also permits direct observation of the structures and their anatomic relationships to each other. This box-within-box design allows students to easily view sections of a head in its anatomical position as well as to examine internal structures by manipulating individual display boxes without altering the integrity of the preparations. This methodology for demonstrating cross-section anatomy allows efficient use of cadaveric material and technician time while also giving learners the best possible handling and visualization of complex anatomic structures. Our approach to teaching cross-sectional anatomy of the head can be applied to any part of human body, and the value of our device design will only increase as more complicated understandings of cross-sectional anatomy are required by advances and proliferation of imaging technology. Anat Sci Educ 3: 141-143, 2010. (C) 2010 American Association of Anatomists.