Hub of arterial puncture needle

Details Hub of arterial puncture needle Hub of arterial puncture needle

1999-08-30

2001-07-17

Mendez, Manuel (Department: 3734)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

C604S264000

Reexamination Certificate

active

06261263

ABSTRACT:

FIELD OF THE INVENTION
The invention concerns the hub of an arterial puncture needle.
BACKGROUND OF THE INVENTION
Arterial puncture needles are used in particular to permit introduction of a catheter into an artery. The catheter is advanced into the artery by sliding on the needle which guides it (called the short catheter method) or by sliding on a metal guide introduced beforehand into the artery via the puncture needle (called the Seldinger method).
The practitioner using the arterial puncture needle knows that the needle is in fact in place in the artery by observing the blood exiting from the needle. In particular, the blood will have pulsatile flow if the needle is in an artery.
For visualizing the pulsatile flow of blood without risk of the practitioner coming in contact with the blood, it is known, in the case of a short catheter, to provide the needle hub with a tubular and transparent viewing chamber. This chamber is accessible, via an inlet end, to the reflux of blood in the needle and closed at an opposite outlet end by a plug which is leaktight to the blood but permeable to the air.
The arterial pressure, which is greater than the atmospheric pressure, causes the reflux of blood to completely fill the viewing chamber once the needle penetrates into the artery.
If the puncture is to be repeated, the practitioner can remove the plug in order to empty the chamber and thereafter can put the plug back in place. In such a case, the practitioner is unable to monitor the new introduction of the needle into the artery because the walls of the viewing chamber are already red with the blood from the previous puncture. On the other hand, the practitioner can leave the proximal end of the needle open allowing the blood to escape freely from the hub.
SUMMARY OF THE INVENTION
The object of the present invention is to make it possible to visualize the flow of blood even in this case and, more generally, throughout the duration of the operation of introducing the catheter into the artery, without manipulation and without contact with the patient's blood.
It has been proposed to provide the hub with means for creating a counter-pressure sufficient to maintain an air pressure at the outlet end of the viewing chamber with the amount of this air pressure varying under the effect of the variations in the pressure of the blood in the needle. These means comprises an air reserve chamber which is leaktight to the ambient air, situated outside the viewing chamber and in air communication with the outlet end of the viewing chamber (see, for example, U.S. Pat. No. 5,439,449). In this known solution, the air reserve chamber is formed by an elastomeric reservoir connected to the hub by a flexible connection and protected by a casing.
The present invention aims to provide a simple solution such that the device as a whole is easy to handle, without a flexible attachment which can be awkward when performing the puncture, and functions reliably.
According to the invention, this is achieved by using a viewing chamber which forms a rigid unit with the hub and with the air reserve chamber. The volumes of the chambers are predetermined such that the blood is visible in the viewing chamber when the diastolic pressure is minimal and such that the blood does not reach the air reserve chamber when the systolic pressure is maximal.
When the needle penetrates into the artery, the blood flows back into the needle and only partially fills the viewing chamber. The air contained initially is compressed inside the air reserve chamber and the variation in arterial pressure causes the blood to move inside the viewing chamber.
To make the device more compact, it is advantageous, according to one particular feature of the invention, to place the air reserve around the viewing chamber.


REFERENCES:
patent: 3859998 (1975-01-01), Thomas et al.
patent: 4193399 (1980-03-01), Robinson
patent: 4269186 (1981-05-01), Loveless et al.
patent: 4682980 (1987-07-01), Suzuki
patent: 5439449 (1995-08-01), Mapes et al.

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