Benefits of Pulse Oximetry over Blood Gas Measurements in Small Animal Research

Blood gas and pulse oximetry are two types of measurements that provide insight into blood gas exchange.  There are significant differences in how each is measured.

Blood gases are measured by removal of a small sample of blood, which is then delivered into a device that measures parameters directly from the blood.  Blood gas machines conduct basic measurements on 3 parameters:

  1. Dissolved oxygen
  2. Dissolved carbon dioxide
  3. pH

Pulse oximetry on the other hand, measures the amount of oxygen attached to hemoglobin.  Because 97% of oxygen carried to tissues is attached to hemoglobin, this measurement effectively records the total content of oxygen in the blood.  It does not provide insight into the level of arterial carbon dioxide or pH, so if knowledge of these is required, a blood gas becomes necessary.   

The real advantage to pulse oximetry however is that it is completely non-invasive.  It can be measured with a simple clip that attaches to an appendage on the animal’s body.  The advantages of using the MouseOx® Plus over blood gas measurements are as follows:   

Completely non-invasive

  1. no adhesives, needle sticks, catheters, IVs, surgery
  2. can be repeated as often as desired enabling serial measurements over life span of mouse(longitudinal study)
  3. no need for blood draws enables use on tiny animals
  4. no disturbance of physiology from occlusions or changes in blood volume or hematocrit
  5. no special care for catheters
  6. lower mortality reduces number of animals required to complete a study

Pulse-ox is a continuous monitoring modality

  1. Pulse oximetry allows you to monitor vitals signs continously during research study or surgical procedures.


  1. Low-cost hardware
  2. No maintenance or upkeep on primary measuring device
  3. No service contracts
  4. No consumable items
    • pipettes
    • cal fluids/gases
    • syringes
    • anesthesia
    • surgical supplies
    • catheter care materials
  5. Sensor is only semi-consumable item – 100 hours use per sensor

No calibration necessary

  1. No expensive calibration fluids or gas tanks
  2. No daily, weekly or monthly cal procedures