Nonivasive monitoring of equine muscle hemodynamics by time domain near infrared spectroscopy.

Non-invasive and real-time hemodynamic monitoring of equine muscle is crucial to avoid the occurrence of myopathies related to prolonged muscle compression, as it often occurs during long surgical or diagnostic procedures. In this pilot study, we explored the possibility of detecting equine muscle optical proprieties by means of Time Domain Near-Infrared Spectroscopy. A custom-made portable TD-NIRS tissue oximeter, based on pulsed diode lasers, single photon detection and timing electronics. The device was used to retrieve tissue hemodynamics on muscles of living horses, during static measurements before and after induction of anesthesia for surgical and diagnostic procedures. The potential advantage in usage of this technique lies in the fact that it allows to monitor the absolute hemodynamic parameters in real time, during prolonged measurements on hardly accessible investigation sites. A custom optical probe was developed, to avoid motion artifacts and to be robust enough to withstand the weight of the horse. The use of TD-NIRS oximetry technology seems a clinically feasible means to assess tissue oxygenation in most of adult horses, despite the presence of hair and dark skin.