Valved ports for accessing blood vessels and other body lumens include a lock mechanism which locks the valve fully open when a needle or other access tube is placed into the port. The lock mechanism includes a latch typically comprising one or more laterally deflectable elements, such as a pair of opposed balls. The deflected elements are pushed outwardly by the needle to engage a recess in the port which locks the valve open until the needle is removed.
CROSS-REFERENCES TO RELATED APPLICATIONS
The present application is a continuation-in-part of non-provisional application Ser. No. 08/942,990, filed on Oct. 2, 1997, (now U.S. Pat. No. 6,007,516, issued Dec. 28, 1999), which claimed the benefit of provisional Application Ser. No. 60/036,124, filed on Jan. 21, 1997, the full disclosures of which are incorporated herein by reference.
A pressure measurement device usable for monitoring pressure of fluids such as blood, waste, and replacement fluid in a blood treatment system provides a reliable signal and other benefits by virtue of a number of features of the various embodiments disclosed. The pressure of fluid carried by a vessel or tube is measured by measuring a change in shape of the vessel or tube via a sensor element contacting it. Materials, shape, and mechanical support cooperatively ensure that the little inelastic strain occurs and pressure measurements are repeatable. The embodiments are compatible with the use of disposable vessels and tubes.
