Blood Pressure Monitoring

Non-invasive tail-cuff blood pressure measurement provides repeated, longitudinal hemodynamic monitoring in conscious mice without surgical instrumentation. The animal is placed in a clear acrylic restraint tube mounted on a warming platform maintained at 32-34 degrees C to ensure adequate tail blood flow and vasodilation. A pneumatic occlusion cuff encircles the proximal tail, and a distal volume-pressure recording (VPR) sensor or photoelectric plethysmograph detects the pulsatile blood flow signal. ConductMaze controls the entire measurement cycle: the cuff inflates to a supra-systolic pressure (typically 200 mmHg), then deflates at a controlled linear rate (3-6 mmHg/second) while the plethysmographic sensor detects the return of pulsatile flow. The point of pulse reappearance corresponds to systolic blood pressure, while diastolic pressure is computed from the point of maximum pulse amplitude or from the disappearance of the characteristic waveform distortion during continued deflation.

ConductMaze performs 15-25 inflation-deflation cycles per session, with the first 5-10 cycles designated as acclimation (data discarded) to allow the animal to habituate to the restraint and cuff inflation. The remaining cycles are used for measurement, and the software applies automatic outlier rejection based on signal quality metrics — rejecting cycles with excessive motion artifact, insufficient pulse amplitude, or aberrant waveform morphology. This approach yields highly reproducible systolic, diastolic, and mean arterial pressure (MAP) values that correlate well with telemetry gold-standard measurements when proper technique is observed. The method is widely used in hypertension research (Ang II infusion, DOCA-salt, L-NAME, SHR), renal disease models, metabolic syndrome (high-fat diet), and cardiovascular drug screening.

ConductMaze logs each inflation-deflation cycle with raw cuff pressure trace, plethysmographic waveform, computed systolic/diastolic/MAP values, heart rate derived from inter-pulse intervals, and signal quality score. The software computes session means and standard deviations after outlier rejection, generates trend plots across multi-day measurement campaigns, and supports automated scheduling for circadian blood pressure profiling. All raw waveforms are archived, enabling retrospective re-analysis with adjusted detection algorithms. The system supports up to 8 simultaneous restraint platforms for parallel measurement, dramatically increasing throughput for large cohort studies.