The Basics of Physiological Monitoring of Rodents

Posted on 12/20/2021

Working with rodents in biomedical research is a privilege granted to the scientific community on the expectation that studies will provide significant new insights into human health.

Since the mid-19th Century, mice and rats have served as the preferred species for such research owing to their genetic and physiological similarities to humans. Mice have proven to be exceptional models for studying hereditary deafness, contributing to the identification of over 55 non-syndromic human deafness genes. While rats are routinely bred to study multifactorial cardiovascular conditions like diabetes and obesity. The caveat to using these incredibly valuable resources is the expectation that rodents will be treated humanely and that studies will prioritize animal welfare.

Introducing Physiological Monitoring of Rodents

When we talk about rodent physiological monitoring, we are primarily referring to the assessment of the animal’s core vital signs while under anesthesia. The 8^th Edition of the NIH Guide for Care and Use of Laboratory Animals covers the regulations, policies, and principles of appropriate sedation, analgesia, and anesthesia of laboratory animals. It states that precise physiological monitoring using specialist equipment is mandatory from an animal welfare perspective – but it can have significant cost-benefits too.

Specialized physiological monitoring of rodents can maximize the likelihood of successful surgical outcomes in both major and minor survival surgeries, while allowing researchers to extract the most accurate data and to prioritize animal safety. It is an ideal method for mitigating variables which may cause complications for protocols involving surgery and postoperative care. So, which variables must be monitored to meet regulatory requirements and to ensure a successful surgical outcome?

The 8^th Edition of the NIH Guide for Care and Use of Laboratory Animals states:

“Careful monitoring and timely attention to problems increase the likelihood of a successful surgical outcome (Kuhlman 2008). Monitoring includes routine evaluation of anesthetic depth and physiologic functions and conditions, such as body temperature, cardiac and respiratory rates and pattern (Flegal et al. 2009), and blood pressure (Kuhlman 2008), and should be appropriately documented.”

Anesthesia dramatically alters the normal responses of a rodent’s body. Thus, variations in cardiac and respiratory rates, temperature, and/or blood pressure are precise indicators of animal wellbeing while anesthetized.

How to Conduct Rodent Physiological Monitoring

Most historic physiological monitoring equipment for rodents has been based on the same basic systems built used for humans, but this offers limited insight into the actual condition of mice and rats under anesthetic. Though rodents are similar to humans from a genetic and physiological standpoint, there are various key differentiators which means they require specially designed physiological monitoring systems to more accurately track fluctuations in physiologic condition.

The 8^th Edition of the NIH Guide for Care and Use of Laboratory Animals specifically mentions the requirement to use small animal or mouse pulse oximeters to measure blood oxygen saturation under anesthetic. However, obtaining the most successful results requires a multifaceted approach to physiological monitoring. You may need to monitor several critical physiological variables in tandem, including blood pressure, heart rate, end-tidal CO₂ (ETCO₂), and so on.

At Kent Scientific, we offer a suite of physiological monitoring systems designed specifically for monitoring key physiological parameters of rodents under anesthetic. Our PhysioSuite® system is a modular concept which allows researchers to build specific functions into a single unit (i.e. pulse oximetry combined with CO₂monitoring). We also provide temperature and blood pressure monitors designed specifically for humane monitoring of rodents in surgical settings. Interested in learning more about our product range? Contact a member of the team today.

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