Effects of using carbon dioxide on heart rate and arterial blood pressure during laparoscopic ovariohysterectomy in dogs

Abstract

Cardiovascular changes caused by CO2 pneumoperitoneum during laparoscopic ovariohysterectomy (LOVH) were measured in nine healthy mixed breed dogs (16.7 ± 4.6 kg). The dogs were premedicated with the combination of atropine, acepromazine, and butorphanol. General anesthesia was induced with propofol and maintained with isoflurane in oxygen. Controlled ventilation maintained partial pressure of end-tidal CO2 between 35-45 mmHg. The CO2 pneumoperitoneum was maintained at a constant pressure of 12 mmHg and the dog was placed in the 15o Trendelenburg position as LOVH was performed. Dorsal pedal artery was catheterized for measurements of heart rate (HR) and invasive arterial blood pressure (IBP). Prior to the intraperitoneal insufflation, baseline measurements of HR and IBP were made every minute for a total of 10 min. Then, measurements of HR and IBP were made every 5 min following intraperitoneal insufflation and were also made every 5 min following desufflation for a total of 10 min. The CO2 pneumoperitoneum during LOVH resulted in a significant (P < 0.05) increase in systolic arterial blood pressure at the time of the onset of insufflation. In addition, diastolic and mean arterial blood pressure increased significantly (P < 0.05) at the time of the onset of insufflation and 5 min following insufflation. The mean heart rate did not change significantly during LOVH. Although IBP showed sharp initial rise following the CO2 pneumoperitoneum, the changes were within physiological acceptable limits in these healthy, ventilated dogs.