Use of Automatic Flow Regulators for Flow Modulation During Blood Collection

Abstract

A flow regulator for a blood collection assembly includes a housing having an inlet and an outlet, which defines an interior space between the inlet and the outlet. A membrane having a first surface and a second surface is disposed at least partially within the interior space. The membrane has a first position where a flow path between the inlet and the outlet is substantially open, and a second position where the flow path between the inlet and the outlet is at least partially restricted. The membrane is configured to move between the first and second positions in response to a pressure differential acting on the membrane.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The present application is a continuation application of U.S. patent application Ser. No. 13 / 737,160 filed Jan. 9, 2013 entitled “Use of Automatic Flow Regulators for Flow Modulation During Blood Collection”, which claims priority to U.S. Provisional Patent Application No. 61 / 584,451 filed Jan. 9, 2012, entitled “Use of Automatic Flow Regulators for Flow Modulation During Blood Collection”, the entire disclosures of each of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]Field of the Invention[0003]The present invention relates to flow regulators and, more particularly, automatic flow regulators for use during blood collection.[0004]Description of Related Art[0005]Needle assemblies are used for collecting specimens of fluid, such as blood, from a patient. Some such needle assemblies are intended for use with an evacuated tube and include a housing with a proximal end, a distal end, and a passage extending betwee...

AI Technical Summary

Benefits of technology

The flow regulator has a spherical projection that engages the membrane and the housing when the membrane is in the first or second position. The housing has a membrane seat that engages the membrane in the second position, which has a channel that connects to the outlet of the housing. This channel partially restricts flow between the inlet and outlet when the membrane is in the second position. The technical effect is to provide a mechanism to control the flow of a fluid through a membrane and housing.

Problems solved by technology

During certain blood collection procedures, vein collapse of the patient occurs as a result of blood being removed too quickly from the patient's vein.

This strong vacuum pressure results in an initially high flow rate of blood out of the patient's vein.

This abrupt outflow of blood coupled with the high elasticity of a patient's vein can lead to the vein wall being pulled down onto the cannula bevel and result in flow stoppage.

Blood supply can also be a contributing factor of vein collapse.

In-flow of new blood to this area is limited as a result of the capillary blood vessels.

In situations where there is limited resident blood, such as a hand collection site, the vacuum from the collection tube leads to a high flow rate out of the vein, which can lead to an outflow rate higher than the inflow rate of blood and a rapid depletion of the resident blood thereby leading to vein collapse.

For instance, there can be a lot of variability in the amount of force the user exerts on the syringe plunger and the associated flow rates.

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