Anesthetized & Surgical Animal Monitoring Applications

As a multi-parameter pulse-oximeter that can monitor the cardio-pulmonary health of mice, rats and other small laboratory animals (heart rats 90 to 900 bpm), the MouseOxPlus®  is perfect for collecting data of anesthetized animals during research and monitoring vital signs during surgery. 

Parameters for Anesthetized Animal Monitoring:

  • Arterial Oxygen Saturation (SpO2) 
  • Heart Rate 
  • Breath Rate 
  • Pulse Distention (indicator of local blood flow and signal quality) 
  • Breath Distention (surrogate for intraplueral pressure)  
  • Core Temperature 

Animals that the MouseOx Plus® Can Monitor:

  • Mice  
  • Rats
  • Rodents 
  • Any animal with heart rate between 90-900 bpm (non-specific calibration)
    • Has been used successfully on Guinea Pigs, Marmosets, Rhesus Monkeys, Rabbits, Chinchillas, Ferrets, Tree Shrews, Hampsters, Pigeons, Voles, Opossum

Types of Anesthetized Monitoring: 

  • Surgery (multiple sensor options to accommodate different locations and accessibility) 
  • Surgical recovery 
  • Imaging   
  • Neonatal monitoring 
  • Lung injury and mechanical ventilation 
  • Shock models 
  • Stroke and brain injury 
  • Hypoxia and inhalation studies 

Why Use the MouseOx Plus® for Anesthetized and Surgical Monitoring?

There are many benefits of using pulse oximetry for anesthetized and surgical monitoring of mice, rats and other small animals.

  • SpO2 is a comprehensive indicator of both cardiac and pulmonary health including lung perfusion and gas exchange 
  • Continuous monitoring modality 
  • One of the most accessible and widely used human clinical parameters
    • Emergency assessment and transport 
    • Pre-op and post-op monitoring 
    • Conscious sedation monitoring 
    • Since 1998, the utilization of pulse oximetry has been mandated throughout hospital and homecare patient guidelines 
  • Completely non-invasive - no adhesives, needle sticks, catheters, IVs, surgery 
  • Measures the oxygen level in ARTERIAL blood only
    • Prior to the widespread use of pulse oximetry, studies in anesthesia journals estimated 2,000 to 10,000 deaths per year due to undetected hypoxemia (lack of oxygen in the blood).   
    • Oxygen level is clinically more important in arteries than elsewhere, but before pulse oximetry, it was difficult to measure
      • Deep location of arteries 
      • Arteries under high pressure (can cause bleeding) 
      • Difficult to seal arteries when retracting the catheter 
      • Samples are only intermittent  
  • Pulse oximetry is now recommended as a monitoring technique for anesthetized mice, rats and other laboratory animals by the NIH (just added in 8th edition):
    • “For anesthesia delivery, the use of precision vaporizers and monitoring equipment, e.g., pulse oximeter for determining arterial blood oxygen saturation levels, increases the safety and choices of anesthetic agents for use in rodents and other small species."  NIH Guide for Care and Use of Laboratory Animals, 8th ed., Pg 122 Paragraph 5, 2011.    
    • “Careful monitoring and timely attention to problems increase the likelihood of a successful surgical outcome (Kuhlman et al. 2008). Monitoring includes routine evaluation and recording 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 et al. 2008)…” NIH Guide for Care and Use of Laboratory Animals, 8th ed., Pg 119 Paragraph 1, 2011.    
    • Guide for the Care and Use of Laboratory Animals, 8th Edition, 2011 can be viewed at the following website: http://oacu.od.nih.gov/regs/guide/guide_2011.pdf.
  • Monitoring arterial oxygen saturation is very useful for identification of:
    • over-anesthetized conditions 
    • adverse reactions to anesthesia  
    • improper or inadequate ventilation 
    • general homeostasis during anesthesia 

Benefits of MouseOx® Plus over Clinical Pulse Oximeters: 

  • 4 of 5 Vital Signs from 1 monitor – clinical pulse oximeters only provide SpO2 and Heart Rate 
  • In addition to SpO2:
    • Heart Rate 
    • Breath Rate 
    • Body Temperature 
  • Unlike clinical pulse oximeters:
    • MouseOx® Plus is calibrated in situ for saturation from 100% to below 30% (clinical pulse ox devices cannot be calibrated directly at low saturation levels [< 85%])  
    • MouseOx® Plus has a fast response to physiologic changes (< 5 seconds) 
    • In addition to visual and audible parameter alarms, MouseOx® Plus has patentpending anesthesia alarms that can help monitor the depth of anesthesia 
    • MouseOx® Plus has parameter averaging functionality, rendering “eye-balling” values a thing of the past 
    • MouseOx® Plus tells the user when parameter values are not to be trusted 
  • Multiplexer™ option allows monitoring of up to 16 animals from one MouseOx® Plus device 
  • Pulse oximeter data can be recorded for archiving or further analysis 
  • Modular design – purchase only what you need
 
Ease of Use: 
  • All parameters (except temperature) from a single non-invasive clip-on sensor  
  • Multiple sensor clip locations (foot, thigh, dorsal or ventral neck) to accommodate many surgical applications 
  • Multiple sensor clip sizes – accomodates neonatal mice to large adult rats 
 

Many Others Are Using MouseOx® Plus 

Principles of Pulse Oximetry 

Several types of pulse oximeters were developed in the mid 1900’s, but the modern version used throughout hospitals today was invented in 1972.  In 1980, modern pulse oximetry was first commercialized, making it readily available - it quickly grew in popularity.  Because of its ease-of-use, low cost and non-invasive nature, pulse oximetry is mandated in nearly all hospital and home care patient care guidelines.  In the hospital, this includes first responders to post-operative and critical care monitoring.

Pulse oximetry is a technique for monitoring the level of oxygen carried to the tissues on hemoglobin molecules in red blood cells.  Since 97% of oxygen is carried on hemoglobin, pulse oximetry provides a very robust assessment of arterial oxygenation.  This is fortunate, because the alternative for monitoring arterial oxygen, an indwelling arterial catheter, is highly undesirable.  In pulse oximetry, the saturation is measured directly (not through a table or other function) with the use of 2 different wavelengths of light.  One is red, which you can see, and the other is infrared, which you cannot.  The absorption of light by hemoglobin changes based on the degree of oxygen bound to the hemoglobin.  

Most people are familiar with the fact that de-oxygenated blood appears much darker than fresh blood.  These variations can be tied back to the level of hemoglobin saturation through calibration that can be performed by the manufacturer, obviating the need for the user to do so. Moreover, the word “pulse” in pulse oximetry refers to the fact that the light absorption received by a pulse ox sensor oscillates with the cardiac pulsation.  Because blood pulsation is completely damped by the time blood enters the capillary bed, the pulsating signal can only arise from the arterial system, and therefore measurements are made only on arterial blood and not on tissues, capillary blood or venous blood.