Medical Devices and Techniques for Rodent and Small Mammalian Based Research

Abstract

A method and system of supplying rodents, such as mice, to medical researchers pre-installs and / or embeds physiologic sensors onto or within the rodents prior to selling the modified rodents to the researchers. The specialty skills, such as small animal surgical and anesthesia skills and sensor placement and testing, are centralized in one organization rather than being spread about a collection of researchers. The subjects with preinstalled, pre-tested hardware, are sold to the researcher as needed. Communication hardware and software will be supplied for the user to convert their desktop computer into a wireless monitoring station. Additionally an external pulse oximeter for small rodents, such as mice, provides measurements on a hand or foot of the rodent with a sensor configured to avoid shunting around the rodent appendage, and configured for high heart rates (200-900 beats per minutes) of the subjects.

Description

RELATED APPLICATION[0001]The present application is a continuation of U.S. patent application Ser. No. 11 / 115,072 entitled “Medical Devices and Techniques for Rodent and Small Mammalian Based Research” filed Apr. 26, 2005. U.S. patent application Ser. No. 11 / 115,072 claims the benefit of provisional patent application Ser. No. 60 / 565,708 entitled “Medical Devices and Techniques for Rodent and Small Mammalian Based Research” filed Apr. 26, 2004.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to medical devices and techniques for rodent and small mammalian based research, in particular rodents with physiologic sensors such as pre-embedded research related hardware and external rodent pulse oximeter systems.[0004]2. Background of the Invention[0005]In conducting research on small mammals, such as, most commonly mice, a researcher must spend time and money on designing and implementing the data collection methods and devices that will be req...

AI Technical Summary

Benefits of technology

[0019]Another aspect of the present invention relates to external pulse oximeter in small rodents such as mice. The present invention provides a method and apparatus in which excellent results are obtained through taking measurements on a hand or foot of the rodent with a sensor configured to avoid shunting around the rodent appendage.

[0020]One aspect of the rodent pulse oximeter according to the present invention is sizing and shaping of the emitter and detector package to align with and conform to the shape of the rodents paw (hand or foot). Another embodiment of the rodent pulse oximeter according to the present invention provides for reducing the effective area of the emitter and detector currently utilized in human photo-sensors with a simple restricting adapter. A further aspect of the rodent pulse oximeter according to the present invention relates to the collimating of the light as it leaves the emitter, or as it approaches the detector, by using the depth of the restricting adapter. Further collimating the light may be obtained by adding a reflective surface to the inner wall of the restrictive adapter. Another feature of the rodent pulse oximeter according to the present invention is increasing the light transmission to / from the appendage by filling the aperture of the restrictive adapter with gel that approximates the refractive index of the rodent's skin. Another aspect of the rodent pulse oximeter according to the present invention is collecting more light from the emitter and detector used in human photo-sensors by adding at least one lens to the restrictive adapter. Another aspect of the rodent pulse oximeter according to the present invention is collecting more light from the emitter and detector used in human photo-sensors by adding an ellipsoidal reflector to the restrictive adapter. A further aspect of the rodent pulse oximeter according to the present invention is that the present invention measures saturation and pulse rate for rates between 200 and 900 BPM. Any heart beats greater than 900 BPM or less than 200 BPM are attenuated and / or ignored. The present invention further includes a simple effective system to protect the external sensor from being removed by the subject, and this protective system can be used with any similarly placed or situated sensors. The organization that supplies the modified rodents can transport rodents, such as mice, with the external sensors pre-attached, validated and calibrated as needed, with the protective system, such as a bootie, preventing the rodent from damaging or removing the sensor. The sensor can be left in place for a relatively long time and does not need to be attached by the end user.

Problems solved by technology

Small mammals provide other unique problems for similar research.

There are several drawbacks with the existing procedures for performing research on small rodents.

First, researchers must spend considerable time developing the tools to conduct their research instead of focusing on the specified research itself.

This wasted set up time significantly delays the subsequent research, which is an impediment to the general progress of science and potentially very costly in competitive commercial areas.

Second, researchers will unduly waste materials in the development of the specialized tools.

For example, in embedding hardware in small mammals, such as mice, the researcher's unfamiliarity with the devices and with the specific effect of anesthetic on the small mammals can lead to a very high morbidity rate.

The services provided by Charles River Labs, and possibly other service providers, can reduce yield loss, but it does little to reduce lead time for research.

Certain service providers, such as Charles Rivers Labs, limit the source of the animals further restricting the researcher.

Consider the problems associated with external physiologic sensors that are useful for research, such as oximeter and pulse monitoring technology, when applied to small mammals such as mice.

These technologies are also of significant interest to researchers of small mammals as well, but the application of this technology to small mammals presents numerous difficulties.

The inventor has identified that one of the most common difficulties with designing or implementing existing sensors for small mammal research is sensor sizing and placement in order to assure quality physiologic signals.

The problem is that a mouse's appendages and other hairless areas are smaller than the light emitters and light detectors employed in the external sensors.

This causes light shunting on the appendages.

This increases the shunting problems, particularly with small rodents.

If light shunting occurs, it creates an enormous amount of noise, or extraneous signal, in a photo-plethysmograph.

As illustrated in FIG. 3, emitters 10 and detectors 18 utilized for humans will not work for mice and small rats because the fingers, toes and even the entire feet or paw 30 of these subjects are so small that significant optical shunting is unavoidable.

There is a further problem with other possible locations for the existing pulse oximeters sensors for small mammals such as mice.

In addition to where to locate an appropriate pulse oximeter on a small rodent, there are other unique problems.

If the rodent subject is not anesthetized, in a very short period of time, the rodent will destroy the sensor or sensor cable by biting it.

The existing sensors and associated software do not accommodate such rates.

The inability to effectively use existing sensors on mice and small rodents have led certain companies to exclude their oximeters for use on small (or very small) mammals.

For example, Kent Scientific sells a pulse oximeter for “use with small animals” and the device clearly states that “the available sensor will not work with mice”, which is particularly un-helpful for researchers utilizing mice.

The complex techniques for obtaining the respiratory rate from pulse oximetry sensors of the prior art simply do not translate to small mammals, such as mice.

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