Specific gravity of bupivacaine with fentanyl influences bispectral index value during spinal anesthesia combined with fentanyl in patients undergoing cesarean section
Nakamoto, M.; Murao, K.; Kimoto, M.; Nakao, S.; Shingu, K.
Masui. Japanese Journal of Anesthesiology 58(4): 460-462
2009
ISSN/ISBN: 0021-4892 PMID: 19364010 Document Number: 633490
Spinal anesthesia combined with fentanyl sometimes induces sedation. We previously reported that the bispectral index (BIS) value during spinal anesthesia with isobaric bupivacaine is reduced with intrathecal fentanyl but not with intravenous or epidural fentanyl. The current study investigated whether the specific gravity of bupivacaine combined with intrathecal fentanyl in spinal anesthesia for cesarean section effected the BIS values. Thirty-one partrients scheduled for cesarean section were allocated into two groups: 0.5% isobaric bupivacaine 2 ml plus fentanyl 20 microg (I group, n = 14) or 0.5% hyperbaric bupivacaine 2 ml plus fentanyl 20 microg (H group, n = 17). BIS values were recorded throughout the anesthesia. The lowest BIS values in the I group and in the H group were 77 +/- 13 and 87 +/- 6, respectively. The cumulative time for BIS values of or below 80 in the I group was longer than that in the H group. The number of BIS decreased cases, defined as the cases in which the BIS values continuously fell down to or below 80 for more than 10 minutes, in the I group was higher than in the H group. The BIS values in patients who received intrathecal isobaric bupivacaine with fentanyl were lower than those with intrathecal hyperbaric bupivacaine and fentanyl.