Objective To compare the cardiopulmonary effects of the head-down position, with or without capnoperitoneum, in halothane-anesthetized horses. Study design Prospective randomized study.
Animals Five ponies (four mares, one stallion; bodyweight 302 ± 38.4 kg [mean ± SD]) were used. Methods The ponies were anesthetized with xylazine, guiafenesin, ketamine, and maintained with halothane/oxygen and lungs were ventilated to 40 ± 2 mm Hg (5.3 ± 0.3 kPa) end-tidal CO2 tension.
After baseline cardiopulmonary measurements, ponies were kept in horizontal position for 30 minutes, then tilted head-down 30° to the horizontal position for 60 minutes, and then returned to a horizontal position for final measurements.
Capnoperitoneum (intra-abdominal pressure: 12 mm Hg [1.6 kPa]) was introduced after baseline cardiopulmonary measurements, until 5 minutes before the final measurements (treatment INS). Ponies in the control treatment (CON) did not receive capnoperitoneum.
