Objective General anaesthesia and pneumoperitoneum are two main components of laparoscopic surgery. The aim of this study was to evaluate the effects of anaesthesia on endocrine and oxidative variables during pneumoperitoneum including: Triiodothyronine (T3), Thyroxin (T4), Cortisol, Malondialdehyde (MDA) and Total antioxidant capacity (TAC). Study Design Experimental trial Animals Twenty mixed breed adult dogs, aged between 3 to 7 years and weighing from 19 to 34 kilogram Procedures Dogs were randomly divided in 4 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 premedicated with acepromazine, morphine, and diazepam respectively. 10 minutes into the procedure, anaesthesia was induced with propofol in all subjects. After tracheal intubation, anaesthesia was maintained in groups P-M and P-S by intra venous propofol, and in groups I-M and I-S by isoflurane in oxygen while the subject’s lungs were mechanically ventilated with a rate and pressure- controlled ventilator in groups P-M and I-M. Pneumoperitoneum was induced in all subjects and IAP was maintained at 15 mmHg for 40 minutes. The concentration of T3, T4, Cortisol, MDA and TAC were measured before anaesthesia, after induction, 40 min after abdominal insufflation, and 2, 4, 6, 12, 48 h postoperatively. Results There was no significant difference between the four anesthetic groups in amounts of T3, T4, Cortisol and TAC during sampling time. Serum MDA level was significantly higher in third sampling in P-M and P-S groups. Conclusion and clinical relevance The choice of general anaesthesia during pneumoperitoneum in absence of surgical stimuli did not affect thyroid and cortisol hormones. It seems total intra venous anaesthesia (TIVA) by use of propofol in either presence or absence of mechanical ventilation can increase MDA production at the end of pneumoperitoneum.

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