ABSTRACT
Mechanical ventilation is often used to treat patients with acute respiratory distress syndrome (ARDS). However, the optimal setting is still controversial, and physicians often rely on experience and intuition. The purpose of this research is to develop a model of the essential lung mechanics to help determining the optimal ventilator setting in clinical situations. The model is a compilation of physiologically based mechanics parameters, which are adjustable to represent patient specific conditions. Further investigation improvements are required, however it shows good initial for eventual clinical use.
ABSTRACT
A durable and thromboresistant ceramic heart valve comprised of a single crystal alumina disk and titanium nitride (TiN) valve ring has been developed. Blood compatibility was examined by scanning electron microscopy (SEM) examinations of the valves implanted in sheep for 35 (#1), 26 (#2), 20 (#3), 23 (#4), and 26 (#5) days. The single crystal alumina and TiN surfaces were free of platelet aggregation or fibrin networks, except for some depositions of fibrin and platelets on the outflow TiN ring in #3, and isolated red cells on the outflow TiN ring in #5. Durability testing under high pressure (1750 mmHg = 233 KPa) pulsatile conditions showed that the safety factor of the ceramic valve was more than seven times greater than anticipated. The ceramic valve is promising as an artificial heart valve.
