MousePZT: A Simple, Reliable, Low-Cost Device for Vital Sign Monitoring and Respiratory Gating in Mice Under Anesthesia

Small animal studies in biomedical research often require anesthesia to reduce pain or stress experienced by research animals and to minimize motion artifact for imaging or other measurements. Anesthetized animals should be closely monitored to avoid complications and unintended effects of altered physiology during such procedures. Many currently available monitoring devices can be expensive, invasive, or interfere with experimental design. Here, we present a low-cost device, based on a simple piezoelectric sensor, with a custom circuit and computer software that allows for measurements of both respiratory rate and heart rate in a non-invasive, minimal contact manner. We find the accuracy of the MousePZT device in measuring respiratory and heart rate under anesthesia and with pharmacologically induced changes in heart rate match those of commercial or more invasive systems. We also demonstrate that changes in respiratory rate can precede changes in heart rate associated with alterations in anesthetic depth. Additional circuitry on the device outputs a respiration locked trigger signal for respiratory-gating of imaging or other data acquisition that has high sensitivity and specificity for detecting respiratory cycles. We provide detailed construction documents and all necessary microcontroller and computer software, enabling straightforward adoption of this device.