Electrical pulse counters – pulse dividers – or shift registers: c – Applications – Counting based on number of times machine or apparatus operates
Reexamination Certificate
1999-08-03
2001-09-25
Wambach, Margaret R. (Department: 2816)
Electrical pulse counters, pulse dividers, or shift registers: c
Applications
Counting based on number of times machine or apparatus operates
C377S016000
Reexamination Certificate
active
06295330
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for repeated registration of the number of thermal cycles to which a part for medical usage has been subjected.
2. Description of the Prior Art
A large number of parts or components in medical devices require sterilization between each use. This is often accomplished by heating the part or component in an autoclave. For safety reasons, these parts or components may not be reused more than a limited number of times. Therefore, careful monitoring and reliable, tamper-proof checking of the number of times parts and components are reused are very important. The number of times a part has been autoclaved has hitherto often been determined by using a logbook, a technique which can vary as to reliability.
U.S. Pat. No. 5,383,874 describes a system for identifying and monitoring the use of ablation catheters. This system employs a usage register, whose contents are incremented by one every time the catheter is put to authorized use, to ensure that the catheter is not used too frequently.
German 05 19825 754 (corresponding to co-pending U.S. application Ser. No. 09/098,495 filed Jun. 17, 1998) describes a device for counting the number of usage cycles by a sensor for intracorporeal electrophysiological measurement and/or therapy. Here, a counter connected to the sensor contains an identification code specific to the sensor, and connection! disconnection of the sensor to/from external measurement equipment and/or therapeutic equipment is detected. The identification code is used for determining, from information stored in a main computer on previous usage, whether conditions for a new usage cycle have been met and, if so, incrementing counter contents by one usage cycle.
Another system for counting usage cycles is disclosed in U.S. Pat. No. 5,400,267.
Disinfecting indicators are also known, as described in U.S. Pat. No. 4,449,518 which discloses such an indicator using a memory alloy. The indicator is deformed when the device is used and re-assumes its shape when exposed to heat. This system does not register the number of disinfecting or heat cycles.
U.S. Pat. Nos. 5,313,935; 5,359,993; and 5,452,335 and European Application 581 400 all essentially show devices for indicating the number of thermal cycles by moving a cog wheel one step for each cycle. On the cogs, indicator numbers are placed. Through a window of the indicator numbers can be viewed, indicating a present number of thermal cycles. However, none of these devices can indicate whether the device has gone through a thermal cycle before a new use of the device. Since the indicator numbers are placed on the cogwheels, the total number of thermal cycles is limited to fairly low numbers. This because the indicator numbers must be significantly large for a user to read.
The ability to distinguished sterilized replaceable items from unsterilized items is also of the greatest importance in this field. At present, unsterilized and sterilized components are usually stored at different locations, but mix-ups may occur because the appearance of an item does not indicate whether the item has been sterilized.
SUMMARY OF THE INVENTION
An object of the present invention is to resolve the aforementioned problems associated with prior art devices and to supply the part or component for medical usage with an indicator showing the user not only the number of uses/thermal cycles but also whether the part or component has completed the prescribed thermal cycle after its most recent use.
Another object of the present invention is to provide a device for repeated usage/thermal cycle registration, where the number of cycles is almost unlimited.
The above object is achieved in accordance with the principles of the present invention in a device for repeated registration of the number of thermal cycles to which a part for medical usage is subjected, wherein a temperature-sensitive element and/or a pressure-sensitive element is arranged in conjunction with the part, the element (or elements) reversibly changing in physical shape with temperature and/or pressure (variations in pressure always occurring with changes in temperature), and wherein an indicator element is arranged to move from a first indication position to a second indication position when the aforementioned change in shape exceeds a predetermined threshold value, and wherein a registration unit identifies movement of the indicator element from the first indication position the second indication position, thereby registering the fact that the part has undergone a thermal cycle.
By using a temperature-sensitive element and/or pressure-sensitive element, whose physical shapes changes in a reversible fashion with changes in temperature and/or pressure (variations in pressure always occurring with changes in temperature), attached to the part or component, any change in shape can be utilized for moving an indicator element from a first indication position to a second indication position, thereby providing e.g. a visual indication of whether the part or component has completed the thermal cycle. The risk of non-autoclaved parts being put to use is thus eliminated. The movements of the indicator element can be registered by a registration unit. Thus, the invention is based on movements of an indicator element from a first indication position to a second indication position a large number of times.
The relevant thermal cycle is not limited to autoclaving but could also be e.g. washing in hot water.
In an embodiment of the device according to the invention, a reset arrangement automatically resets the indicator element to a first indication position upon the occurrence of a predetermined condition, such as when the part for medical usage is put to use or is attached to a mother unit. When the mother unit is a ventilator and the part for medical use is an expiration line cassette, the reset arrangement can reset the indicator element to the first indication position when an expiratory valve opens a first time. Alternatively, the indicator element can be reset with e.g. a small pulse magnet, motor or the like.
In another embodiment of the device according to the invention, the indicator element is a plate with two differently colored fields, this plate being moveable in a window to display one of the fields in the first indication position and the other field in the second indication position. In addition to direct visual observation of the plate's position, the position of the plate also can be detected e.g. with an optical detector. Alternatively, the plate can control a mechanical switch for opening and closing an electric circuit, or the plate's movement can be detected with an inductive or capacitive sensor.
In a further embodiment of the device according to the invention, a memory accumulatively stores the total number (running total) of registered shape changes made by the temperature-sensitive element and/or pressure-sensitive element. The memory can be arranged in the part for medical usage, in a separate reader unit or in a mother unit in which the part for medical usage is intended for use. In this manner, the total number of thermal cycles completed by the part for medical usage can be reliably counted.
According to another embodiment of the device of the invention, the part for medical usage is assigned a specific identification code, and the reader unit or the mother unit contains a sensor unit for sensing that code and incrementing the number of shape changes registered for the identified part by one when the part for medical usage is connected to the reader unit or mother unit after completing a thermal cycle. This makes it possible to count the total number of thermal cycles completed by the part for medical usage, even in instances in which the part is used in different mother units. This is particularly advantageous in environments using computer networks and databases for controlling, monitoring and/or supervising medical equipment.
In another embodiment of the device acc
Krahbichler Erik
Skog Goran
Slettenmark Bruno
Schiff & Hardin & Waite
Siemens-Elema AB
Wambach Margaret R.
LandOfFree
Device for repeated registration of the number of thermal... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for repeated registration of the number of thermal..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for repeated registration of the number of thermal... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2496086