Modification of the BioMedicus centrifugal pump to provide continuous irrigation for neuroendoscopy: technical note.

Continuous irrigation is an important adjunct for successful intraventricular endoscopy, particularly for complex cases. It allows better visualization by washing out blood and debris, improves navigation by expanding the ventricles, and assists with tissue dissection. A method of irrigation delivery using a centrifugal pump designed originally for cardiac surgery is presented. The BioMedicus centrifugal pump has the desirable ability to deliver a continuous laminar flow of fluid that excludes air from the system. A series of modifications to the pump tubing was performed to adapt it to neuroendoscopy. Equipment testing determined flow and pressure responses at various settings and simulated clinical conditions. The pump was then studied clinically in 11 endoscopy cases and eventually used in 310 surgical cases. Modifications of the pump tubing allowed for integration with different endoscopy systems. Constant flow rates were achieved with and without surgical instruments through the working ports. Optimal flow rates ranged between 30 and 100 ml/min depending on endoscope size. Intraoperative use was well tolerated with no permanent morbidity and showed consistent flow rates, minimal air accumulation, and seamless irrigation bag replacement during prolonged surgery. Although the pump is equipped with an internal safety mechanism to protect against pressure buildup when outflow obstructions occur, equipment testing revealed that flow cessation is not instantaneous enough to protect against sudden intracranial pressure elevation. A commonly available cardiac pump system was modified to provide continuous irrigation for intraventricular endoscopy. The system alleviates the problems of inconsistent flow rates, air in the irrigation lines, and delays in changing irrigation bags, thereby optimizing patient safety and surgical efficiency. Safe use of the pump requires good ventricular outflow and, clearly, sound surgical judgment.

Understanding adolescent response to a technology-based depression prevention program.

Guided by the Behavioral Vaccine Theory of prevention, this study uses a no-control group design to examine intervention variables that predict favorable changes in depressive symptoms at 6- to 8-week follow-up in at-risk adolescents who participated in a primary care, Internet-based prevention program. Participants included 83 adolescents from primary care settings ages 14 to 21 (M = 17.5, SD = 2.04), 56.2% female, with 41% non-White. Participants completed self-report measures, met with a physician, and then completed a 14-module Internet intervention targeting the prevention of depression. Linear regression models indicated that several intervention factors (duration on website in days, the strength of the relationship with the physician, perceptions of ease of use, and the perceived relevance of the material presented) were significantly associated with greater reductions in depressive symptoms from baseline to follow-up. Automatic negative thoughts significantly mediated the relation between change in depressive symptoms scores and both duration of use and physician relationship. Several intervention variables predicted favorable changes in depressive symptom scores among adolescents who participated in an Internet-based prevention program, and the strength of two of these variables was mediated by automatic negative thoughts. These findings support the importance of cognitive factors in preventing adolescent depression and suggest that modifiable aspects of technology-based intervention experience and relationships should be considered in optimizing intervention design.

Effect of microaerobic fermentation in preprocessing fibrous lignocellulosic materials.

Amending soil with organic matter is common in agricultural and logging practices. Such amendments have benefits to soil fertility and crop yields. These benefits may be increased if material is preprocessed before introduction into soil. We analyzed the efficiency of microaerobic fermentation (MF), also referred to as Bokashi, in preprocessing fibrous lignocellulosic (FLC) organic materials using varying produce amendments and leachate treatments. Adding produce amendments increased leachate production and fermentation rates and decreased the biological oxygen demand of the leachate. Continuously draining leachate without returning it to the fermentors led to acidification and decreased concentrations of polysaccharides (PS) in leachates. PS fragmentation and the production of soluble metabolites and gases stabilized in fermentors in about 2-4 weeks. About 2 % of the carbon content was lost as CO(2). PS degradation rates, upon introduction of processed materials into soil, were similar to unfermented FLC. Our results indicate that MF is insufficient for adequate preprocessing of FLC material.