This study was designed to assess the effects of pneumoperitoneum and positional changes on the autonomic nervous system (ANS) in laparoscopy-assisted vaginal hysterectomy (LAVH) patients.

Systolic blood pressures and R-R interval were recorded for 5 minutes in 22 patients, and then power spectral analyses were conducted to evaluate the ANS. The following variables were measured at various positions: preinduction (BASE), prepneumoperitoneum (PREPP), pneumoperitoneum at head-down (PP), normoperitoneum at supine (POSTPP).

High frequency of heart rate variability (HRVHF), Low frequency of heart rate variability (HRVLF), Low frequency of blood pressure variability (BPVLF), LF/HF ratios of HRV (LFHFr) were significantly lower than that of BASE at PREPP. HRVHF, HRVLF, BPVLF were significantly lower than that of BASE at PP. At PP, normalized HF of HRV (nuHF) is significantly lower than that of BASE and normalized LF of HRV (nuLF) is significantly higher than that of BASE and PREPP (P < 0.05). LFHFr was significantly lower than that of BASE and significantly higher than that of PREPP at PP. At POSTPP, HRVHF, HRVLF, BPVLF were significantly lower than that of BASE. But, BPVLF at POSTPP was higher than that of PP.

We conclude that the pneumoperitoneum and trendelenburg positions caused sympathetic activation in LAVH patients.