Automation of an extracorporeal support system with adaptive fuzzy controllers.

For patients suffering from cardiogenic shock cardiopulmonary resuscitation may not be sufficient to restore normal heart function. However, their chances of survival may be increased with the use of an extracorporeal support system. With this system the patient's organs are perfused while being transported to the nearest hospital for proper treatment. In the automation of an extracorporeal support system the patient's vital signals are constantly monitored and proper adjustments are performed to improve organ perfusion. In this paper, an adaptive fuzzy controller is proposed that uses the knowledge and expertise of a perfusionist as a starting point and reference for regulation. Furthermore it is able to adapt to the patient's specific reactions by manipulating the rule base of the fuzzy controller. The performance of the adaptive fuzzy controller is tested with a simulation model of the cardiovascular system.

Design of a fuzzy controller for the automation of an extracorporeal support system with the use of a simulation environment.

The automation of a portable extracorporeal support system may greatly help people who suffer from cardiogenic shock by providing them with an optimal oxygen perfusion and avoid mult-organ failure while being transported to a hospital. This however requires the creation of tools that help in the design of the ideal controller. In this paper a simulation environment is described were a cardiovascular model from the ISR Physiome database was used together with a model of a portable extracorporeal support system. Additionally a model of an oxygenator/blender model is introduced to allow the simulation of oxygen perfusion. Fuzzy controlling was used for automation since it allows a straightforward implementation of expert knowledge. Through the simulation environment different scenarios may be created where intensive testing is possible and constant repetition for control optimization. Initial simulation results are given of the fuzzy controller adjusting the extracorporeal flow rate and oxygen administration for a case of low cardiac output.

Development of a methodology for selecting criteria and indicators of sustainable forest management: a case study on participatory assessment.

This paper describes an application of multiple criteria analysis (MCA) in assessing criteria and indicators adapted for a particular forest management unit. The methods include: ranking, rating, and pairwise comparisons. These methods were used in a participatory decision-making environment where a team representing various stakeholders and professionals used their expert opinions and judgements in assessing different criteria and indicators (C&I) on the one hand, and how suitable and applicable they are to a forest management unit on the other. A forest concession located in Kalimantan, Indonesia, was used as the site for the case study. Results from the study show that the multicriteria methods are effective tools that can be used as structured decision aids to evaluate, prioritize, and select sets of C&I for a particular forest management unit. Ranking and rating approaches can be used as a screening tool to develop an initial list of C&I. Pairwise comparison, on the other hand, can be used as a finer filter to further reduce the list. In addition to using these three MCA methods, the study also examines two commonly used group decision-making techniques, the Delphi method and the nominal group technique. Feedback received from the participants indicates that the methods are transparent, easy to implement, and provide a convenient environment for participatory decision-making.

In vitro laser welding of amniotic membranes.

OBJECTIVE: To test in vitro the feasibility of welding amniotic membranes using Nd:YAG laser energy. STUDY DESIGN: Fresh fetal membranes from term pregnancies were washed and cut into 1 cm2 pieces. Pooled cryoprecipitate (CPT), 50% albumin (Alb), or polytetrafluoroethilene (e-PTFE) were used as solder medium. The optimal settings of the laser were determined. Results were assessed quantitatively and semi-quantitatively using Pearson Chi-square analysis. RESULTS: Laser welding of amniotic membranes was successful in 82.6% of experiments with e-PTFE and in 10.7% of experiments with CPT (P < 0.001). The strength of the welding was also significantly better with e-PTFE (P < 0.001). Optimal results were obtained using 1-7 Watts and 0.1-1 seconds. Laser welding was unsuccessful in 100% of experiments with Alb. CONCLUSIONS: Laser welding of fetal membranes can be accomplished with e-PTFE and to a lesser degree with the CPT using Nd:YAG energy under low wattage-high exposure settings. Further studies are underway to test other grafting or soldering materials.