Vacuum indicator

Abstract

Abstract An apparatus for withdrawing blood from a body vessel of the type including a tube with a partial vacuum pressure therein sealed at an open end by a flexible stopper, a needle having a sharp end for penetrating a vessel, an interior blood carrying cavity, an opposite sharp end, and a sleeve attachable to the needle so that the opposite end of the needle extends into the sleeve and adapted for receiving the stopper so that, when the one needle end penetrates the vessel, the stopper moves within the sleeve toward the opposite needle end which punctures the stopper and causes the blood to be drawn through the interior of the needle into the tube. In order to avoid unnecessary damage to blood vessels from attempts to withdraw blood with tubes which have lost their partial vacuum pressure, a quantity of material such as hemoglobin having a color which varies with the pressure about it is disposed within the tube before it is evacuated. The material can be dry and painted on the tube walls or liquid. Other indicators include cytochrome, myoglobin, heme and leucobases. In a further embodiment, two objects which have different air resistances, so that in full or partial pressure they fall under the influence of gravity, are disposed within the tube.

Inventors

• 👤 J Elliott

Bibliographic Details