Influence of fentanyl on intra-abdominal pressure during laparoscopy in dogs

To evaluate the influence of fentanyl on intra-abdominal pressures in spontaneously breathing dogs during capnoperitoneum.

Prospective clinical study.

Eleven healthy client-owned and five healthy experimental dogs undergoing laparoscopy.

Dogs were premedicated with acepromazine (0.03 mg kg(-1) IV) and carprofen (4 mg kg(-1) IV). Anaesthesia was induced with propofol and maintained with isoflurane in oxygen. The abdomen was insufflated with CO(2) (11-16 cm H(2) O). Intra-abdominal pressures were measured with a transducer. Respiratory variables were measured with a spirometry sensor and side-stream capnography. Following preparation, fentanyl (1 μg kg(-1) ) was injected over 30 seconds IV. Data were recorded 5 minutes before, during and 5 minutes after treatment. The following time points were selected for statistical analysis (anova, p < 0.05): -160, -140, -120, -100, -80, -60, -40, -20, 0, 30, 50, 70, 90, 110, 130 and 150 seconds after the start of fentanyl injection.

Intra-abdominal pressure increased during inspiration in 15 dogs but decreased in one dog. Fentanyl treatment did not alter these patterns. Peak inspiratory and end-expiratory intra-abdominal pressures continuously decreased over time during the whole experiment and fentanyl exaggerated the decrease in inspiratory pressures but did not affect the rate of decrease in expiratory pressures. Differences between intra-abdominal pressures were stable before, but decreased after fentanyl administration from 4.1 ± 1.4 to 3.3 ± 1.2 cm H(2) O (at 0 and 150 seconds time points). End-tidal CO(2) partial pressures increased from 6.0 ± 0.8 to 6.6 ± 0.9 kPa, respiratory rate decreased from 10.8 ± 2.6 to 7.8 ± 2.2 breaths per minute and tidal volume decreased from 13.7 ± 4.4 to 12.4 ± 2.9 mL kg(-1) after fentanyl but these variables did not change before fentanyl treatment. Airway pressures did not change.

Fentanyl did not increase intra-abdominal pressures in dogs.