Voltage changes in the lithium dilution cardiac output sensor after exposure to blood from horses given xylazine.

This article discusses a study investigating whether xylazine, a drug commonly used in veterinary medicine, interferes with the accuracy of lithium dilution cardiac output (LiDCO) sensors in horses. The study found that exposure of LiDCO sensors to horse blood containing xylazine significantly changed the sensors’ voltage readings for up to 15 minutes.

Introduction and Methodology

• The article presents a follow-up to a previous in vitro study made by the same authors, which showed that certain drugs could alter the voltages of lithium dilution cardiac output (LiDCO) sensors and hence influence their accuracy in measuring lithium concentrations.
• For this study, five healthy adult warm-blood horses were administered with xylazine intravenously. They then collected physiological saline solution and venous blood samples to run through the same LiDCO sensor at various intervals both before and after the xylazine injection.
• Sensor voltages were recorded, and the differences between the voltages generated by the saline and the blood samples were compared at each time point.

Results of the Study

• It was observed that the sensor voltages for both saline-exposed and blood-exposed samples increased in a non-linear pattern throughout the experiment.
• However, an abrupt increase in voltage was noted in the blood-exposed sensor readings after xylazine was injected. This suggests an interaction between the xylazine drug and the LiDCO sensor leading to altered voltage readings.
• Before the administration of xylazine, the voltage difference between the saline- and blood-exposed sensors was around 7 (6.1-8) millivolts, but this significantly dropped to 5 and 15 minutes after the drug treatment.
• The highest observed drug-induced voltage change was between 1.6 and 7 millivolts.

Conclusion

• This study demonstrated that a LiDCO sensor exposed to horse blood containing a clinically relevant dose of xylazine exhibits a change in sensor voltages for approximately 15 minutes after drug administration.
• The authors therefore suggest the potential utility of comparing saline- and blood-exposed sensor voltages as a method to detect interactions between a given drug and the LiDCO sensor–a finding that could be pivotal in ensuring accurate readings in LiDCO sensors (a critical aspect in managing cardiovascular diseases especially in veterinary medicine).