Cardiovascular effects of insufflation of the abdomen with carbon dioxide in standing horses sedated with detomidine.

The research was aimed at examining the cardiovascular effects of a 60-minute carbon dioxide insufflation of the abdomen, at a pressure of 15 mm Hg, in horses standing upright and sedated with detomidine.

Methods

• The study was set up as a crossover experiment with five horses, which were randomly assigned to either the treatment or the control group. There was a washout period of at least 7 days between the two experimental periods.
• Catheters were positioned into the right atrium, the pulmonary artery, the jugular vein, and the right transverse facial artery in each horse after lidocaine infiltration.
• Every horse was sedated with detomidine at a constant rate of 8.54 microg/kg/h, intravenously.
• In the treatment group, horses were subjected to abdominal insufflation with CO2 using a laparoscopic cannula. This was done to reach and maintain an intra-abdominal pressure of 15 mm Hg for an hour.
• Various parameters, including systemic arterial pressure, right atrial pressure, heart rate, cardiac output, core body temperature, and the pH and gas tensions of arterial and mixed venous blood, were measured. The cardiac index and systemic vascular resistance were also calculated based on these measurements.
• The data collection was done in three stages: before insufflation (at -10 and -5 minutes), during insufflation (at 0, 15, 30, 45, and 60 minutes), and after insufflation (at 70 and 80 minutes).
• The efficacy of the sedation and the degree of analgesia achieved were also recorded.

Results

• The research showed that the partial pressure of oxygen in the blood (PaO2) in the treatment group was significantly higher after 60 minutes of pneumoperitoneum compared to the control group.
• Core body temperature dropped significantly from its baseline value in both the groups.
• Notably, no significant cardiovascular abnormalities were induced by a 60-minute period of abdominal insufflation to an intra-abdominal pressure of 15 mm Hg in healthy horses.

Therefore, the study established that detomidine-sedated, standing horses tolerate carbon dioxide insufflation of the abdomen well, without showing significant negative effects on their cardiovascular system.