General anesthesia and pneumoperitoneum are two main components of laparoscopic surgery. The aim of this study was to evaluate the effects of anesthesia on endocrine and oxidative variables during pneumoperitoneum including as follows: triiodothyronine (T3), thyroxin (T4), cortisol, malondialdehyde (MDA), and total antioxidant capacity (TAC). Twenty mixed-breed adult dogs were randomly divided into four groups: propofol and mechanical ventilation (group P-M), propofol and spontaneous ventilation (group P-S), isoflurane and mechanical ventilation (group I-M), isoflurane and spontaneous ventilation (group I-S). The dogs were pre-medicated with acepromazine, morphine, and diazepam respectively. Anesthesia was induced by propofol in all the subjects. After tracheal intubation, anesthesia was maintained in P-M and P-S groups by intravenous propofol and in I-M and I-S groups by isoflurane in oxygen, while the subjects’ lungs were mechanically ventilated in P-M and I-M groups. Pneumoperitoneum was induced in all subjects and intra-abdominal pressure (IAP) was maintained at 15 mmHg for 40 min. The concentrations of T3, T4, cortisol, MDA, and TAC were measured before and after the induction of anesthesia, 40 min after abdominal insufflation and 2, 4, 6, 12, 24, and 48 h postoperatively. There was no significant difference among four anesthetic groups in the concentrations of T3, T4, cortisol, and TAC during the sampling. Serum MDA level was significantly higher in the third sampling in P-M and P-S groups. The type of general anesthesia, during pneumoperitoneum in the absence of surgical stimuli, did not affect thyroid and cortisol hormones. It appears that the total intravenous anesthesia using propofol can increase MDA production at the end of pneumoperitoneum.

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