Cardiopulmonary, hematological, serum chemistry and peritoneal fluid alterations associated with abdominal insufflation with carbon dioxide during standing laparoscopy in healthy horses sedated with detomidine and butorphanol

Changes in cardiopulmonary function, hematology, serum chemistry and peritoneal fluid were examined in six healthy, pharmacologically restrained, mature horses during and after abdominal insufflation with CO2 (15 mm Hg) during standing laparoscopy. Each horse underwent standing left flank exploratory laparoscopy (LFL) and a sham procedure (SLFL) (cannula placement without insufflation) in a randomized cross-over design with at least 4 weeks between procedures. Heart rate (HR), respiratory rate (RR), cardiac output (thermodilution) (CO), right atrial pressure (RAP), systemic arterial blood pressures (ABP), pulmonary arterial pressure (PAP) and arterial blood gases (ABG) were measured. Cardiac index (CI), systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) were derived from measured parameters. Baseline measurements were the average of measurements taken every 15 minutes for 60 minutes. Following baseline measurements, samples for complete blood count (CBC), serum chemistry analysis (SC) and peritoneal fluid (PF) analysis were obtained. The horses were then sedated with detomidine (0.02 mg kg−1 IV) followed in 5 minutes by butorphanol (0.02 mg kg−1 IV) and the flank was prepared for laparoscopy. Cardiopulmonary data and blood gas samples were obtained 5 minutes postdetomidine sedation, 10 minutes after butorphanol administration and at 0, 5, 15, 30, 45, and 60 minutes after abdominal insufflation with CO2 (15 mm Hg) (LFL) or instrumentation without insufflation (SLFL). CBC, SC, and PF analyses were repeated at the conclusion of insufflation and desufflation and 24 hours after the conclusion of each procedure. Significant decreases in HR, CO, and CI and significant increases in MRAP, SVR and PVR occurred immediately after detomidine administration. There were no clinically significant effects of abdominal insufflation with CO2 on any measure of cardiopulmonary function, including blood gases. There was a significant increase in peritoneal fluid total nucleated cell count 24 hours following LFL. Abdominal insufflation with CO2 (15 mm Hg) for 1 hour during the standing laparoscopy does not cause significant alterations in cardiopulmonary function, but does cause a mild inflammatory response within the peritoneal cavity.