Cardiovascular effects recorded in horses during anaesthesia after treatment with trichlorfon.

The research explored the cardiovascular effects in horses after being treated with trichlorfon during anaesthesia. The study revealed that while most cardiovascular measurements were similar before and after trichlorfon treatment, certain pressures and resistance were notably different, though within normal ranges for horse anaesthesia.

Research Context and Methodology

• The researchers carried out two sets of experiments involving horses and ponies to evaluate the effects of trichlorfon, an organophosphate, during anaesthesia.
• In the first experiment, five horses were anaesthetised twice using thiopentone sodium, guaifenesin and halothane. The second anaesthesia took place 16 days after the first and two days post trichlorfon administration.
• Various cardiovascular measurements like heart rate, carotid arterial, pulmonary arterial and right atrial pressures, cardiac output, and blood temperature were recorded every 15 minutes for 120 minutes.

Initial Findings

• The study found no significant variations in heart rate, carotid arterial pressure and cardiac output on both occasions.
• However, they observed increased pulmonary arterial and right atrial pressures during anaesthesia after trichlorfon treatment, compared to values before treatment.
• Pulmonary vascular resistance was observed to decrease significantly at four measurement times post trichlorfon treatment.
• Despite these changes, all cardiovascular measurements stayed within the standard accepted range for halothane anaesthesia in horses.

Second Experiment

• In another experiment involving ponies, the anaesthetic combination used was xylazine and ketamine. The ponies were anaesthetised twice in an interval of one week. For two of them, trichlorfon was administered two days prior to the second anaesthesia.
• Cardiovascular measurements recorded during anaesthesia were not different for ponies even after trichlorfon treatment, suggesting the organophosphate does not significantly impact these measurements.
• A notable observation was that the time taken for the ponies to stand after the second anaesthesia increased significantly for all ponies, regardless of trichlorfon treatment.

Observations and Implications

• The research provides valuable insights into how trichlorfon, a common de-worming agent, affects cardiovascular parameters in horses and ponies during anaesthesia.
• While the effects aren’t drastic, they indicate that trichlorfon can cause certain changes in anaesthetised animals that may necessitate specific care during and after anaesthesia, such as monitoring and managing pulmonary pressures and vascular resistance.
• This finding can contribute to improving safety protocols and enrich the understanding of interspecies medicine dynamics.