Abstract: Novel devices which can be used to both collect blood samples from and administer medical fluids to a patient on a repeated and continual basis using one rather than multiple needle insertions. The device typically includes a main tubing segment confluently connected to a cannula for insertion in the patient's vein. A syringe port and a volumeter for collecting blood branch separately from the main tubing segment. The device is used to collect blood by attaching an empty blood collection syringe to the syringe port, inserting the cannula in the patient's vein, allowing passive flow of blood from the main tubing segment into the volumeter under intrinsic venous blood pressure and capillary action, and then facilitating active flow of blood from the volumeter into the blood collection syringe by extending the syringe plunger. The device may be used to administer medical fluids to the patient through the main tubing segment from a medical fluid syringe or catheter attached to the syringe port.

Abstract: Blood collecting devices for collecting blood from a patient using a single needle insertion are disclosed. Each blood collecting device typically includes a housing which is removably attached to a test tube or blood reservoir. A blood flow tube is disposed in fluid communication with the housing for distributing blood from a patient into the test tube or blood reservoir. The blood is distributed through a membrane cavity having a liquid-impervious and air-permeable membrane. At least one air opening is provided in the housing at the membrane cavity. Accordingly, air in the test tube or blood reservoir is displaced by the incoming blood through the membrane cavity and membrane and out the air opening or openings. Vacuum pressure in the test tube or blood reservoir is dispelled by the flow of air through the air opening or openings, membrane cavity and membrane and into the test tube or blood reservoir, respectively.

Abstract: Blood collecting devices for collecting blood from a patient using a single needle insertion are disclosed. Each blood collecting device typically includes a housing which is removably attached to a test tube or blood reservoir. A blood flow tube is disposed in fluid communication with the housing for distributing blood from a patient into the test tube or blood reservoir. The blood is distributed through a membrane cavity having a liquid-impervious and air-permeable membrane. At least one air opening is provided in the housing at the membrane cavity. Accordingly, air in the test tube or blood reservoir is displaced by the incoming blood through the membrane cavity and membrane and out the air opening or openings. Vacuum pressure in the test tube or blood reservoir is dispelled by the flow of air through the air opening or openings, membrane cavity and membrane and into the test tube or blood reservoir, respectively.

Abstract: Novel devices which can be used to both collect blood samples from and administer medical fluids to a patient on a repeated and continual basis using one rather than multiple needle insertions. The devices are capable of removing blood from one of the patient's veins using the intrinsic venous pressure of the blood and capillary action of the device, thereby preventing vacuum-induced collapse of the vein. The device typically includes a main tubing segment confluently connected to a cannula for insertion in the patient's vein. A syringe port and a volumeter for collecting blood branch separately from the main tubing segment.