Effects of pneumoperitoneum and position changes on blood pressure variability and heart rate variability during laparoscopy-assisted vaginal hysterectomy / 대한마취과학회지

BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: We conclude that the pneumoperitoneum and trendelenburg positions caused sympathetic activation in LAVH patients.

Correlation between the observer's assessment of alertness/sedation and the EEG-entropy during propofol infusion for sedation under spinal anesthesia / 대한마취과학회지

BACKGROUND: For the patients undergoing propofol sedation under regional anesthesia, continuous monitoring of the hypnotic level is required for adequate sedation and rapid recovery. We evaluated the correlation between the observer's assessment of alertness/sedation (OAA/S) and the EEG-entropy. METHODS: We studied 40 patients who were scheduled for spinal anesthesia. Premedication with intramuscular midazolam 0.04 mg/kg was carried out 30 minutes before spinal anesthesia. When the anesthesia level was adequate for surgery but lower than T6, an infusion of propofol 10 mg/kg/h was started and this was decreased to 5 mg/kg/h after 1 minute. We measured the response entropy (RE), the state entropy (SE) and the OAA/S score. When the OAA/S score fell to 1, the infusion dose was decreased to half. After this, the infusion dose was decreased or increased to half or twice, respectively, to keep the OAA/S score at 2 or 3. RESULTS: The OAA/S was well correlated with the RE (Spearman's rho = 0.913) and also the SE (Spearman's rho = 0.915). With the increasing depth of sedation, there was a progressive decrease in the RE and SE (the OAA/S score/the mean of the RE/the mean of the SE = 5/98/89, 4/92/85, 3/85/78, 2/78/70, 1/66/59). CONCLUSIONS: EEG-entropy provided good information for monitoring the hypnotic level for the patients undergoing propofol sedation under spinal anesthesia.