Abstract: An improved catheter assembly featuring a hollow introducer needle, a hollow, flexible dilator containing at least one fenestration through a sidewall thereof, the dilator being slidably disposed over the needle, and a sheath slidably disposed over the dilator. A passageway is formed in the assembly to either show a rapid blood flashback along a lengthwise portion of the assembly or to conduct blood or other biological liquid from the patient to a sideport on the sheath for connection to blood pressure monitoring equipment, infusion/blood sampling equipment, or both, without the necessity of altering connections on or with the assembly after insertion of the needle into the patient.

Abstract: A catheter assembly is disclosed which includes a flexible catheter, a hub attached to the catheter which defines a lumen and an adjoining flash back chamber which communicate with the catheter, and a flexible resilient diaphragm attached to the hub through which a hypodermic needle such as a catheter introducer needle can be passed. The diaphragm prevents a liquid, such as blood, which has been introduced into the hub lumen from flowing past the diaphragm and beyond the hub when the diaphragm is unpenetrated. A hollow tubular body may also be included to which a cannulated catheter needle can be either stationarily or movably attached. The body is removably attached to the hub behind the diaphragm. If movably attached to the body, the needle has a retracted position fully recessed within the body for safe storage and an advanced operative position extending through the diaphragm, hub and catheter.