TITLE:
Outcome Values of Adding Sodium Bicarbonate, Dexamethasone and Fentanyl to Local Anesthetic in Peribulbar Block during Vitreoretinal Surgeries. A Randomized Prospective Study
AUTHORS:
Sherif Kamal Arafa, Amir Abouzkry El-Sayed
KEYWORDS:
Fentanyl, Dexamethasone, Sodium Bicarbonate, Local Anesthesia, Peribulbar Block, Vitreoretinal Surgeries
JOURNAL NAME:
Open Journal of Anesthesiology,
Vol.8 No.1,
January
29,
2018
ABSTRACT:
Background and aims: we aimed to detect the outcome values of adding fentanyl,
dexamethasone and sodium bicarbonate to mixture of local anesthetic
in peribulbar block for vitreoretinal surgery. Methods: 120 adult ASA I & II
patients, admitted for vitreoretinal surgery under peribulbar block were included
in this comparative study. This study included 4 groups: Group I: (30)
patients using a mixture of 1 ml normal saline, 4 ml lidocaine 2% plus 4 ml
from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU. Group
II: (30) patients using a mixture of 1 ml of sodium bicarbonate (from 1 ml sodium
bicarbonate 8.4% diluted in 10 ml normal saline), 4 ml lidocaine 2%
plus 4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU.
Group III: (30) patients using a mixture of 1 ml fentanyl 20 μg (from a mixture
of fentanyl 100 μg diluted in 5 ml normal saline), 4 ml lidocaine 2% plus
4 ml from bupivacaine 0.5% 20 ml vial containing hyaluronidase 1500 IU.
Group IV: (30) patients using a mixture of 1 ml of 4 mg dexamethasone (1
ampoule = 8 mg/2 ml), 4 ml lidocaine 2% plus 4 ml from bupivacaine 0.5% 20
ml vial containing hyaluronidase 1500 IU. We measured the onset and duration
of anesthesia, IOP, eyelid and global akinesia, postoperative pain by numerical
pain rating scale, first analgesic requirement and postoperative side
effects. Results: No significant differences were detected among the four
groups as respect to age, sex and the intraocular pressure (IOP) before the
anesthesia block. While the intraocular pressure (IOP) after the anesthesia
block there was a significant difference, as IOP was markedly decreased postoperatively
in group II compared with other groups. As regard to the onset & duration of anesthesia there was significant difference among all groups,
there was rapid onset and prolonged duration of anesthesia in group III compared
with other groups (1.77 ± 0.63 & 5.03 ± 0.89) respectively. As regard the
onset of lid akinesia there was significant difference among the four groups
with better outcome in group III, as in group III represented the most rapid
onset of lid akinesia. As respecting to the onset of global akinesia there was
significant difference among the four groups. There was better outcome in
group III as it represented more rapid onset of global akinesia compared with
other groups. There were significant differences among the four groups as regard
postoperative pain all over 6 hours, better results were in group III (0.27
± 0.69) compared with group I (2.23 ± 1.17), group II (2.00 ± 1.70), group IV
(0.67 ± 0.71). As regarding to the first time for analgesic requirement there
were significant differences among groups, there was no request for analgesia
with better outcome in group III with increasing need to the analgesic medication
in group I compared to group II and group IV. As regard side effects
postoperatively there were few side effects in all groups with few numbers of
cases in groups III only one patient. Although these differences in number of
patients are not significant among the four groups. Conclusion: Addition of
sodium bicarbonate to local anesthetic mixture was the best way in lowering
the IOP other than other groups and addition of fentanyl to local anesthesia
provided more rapid onset and duration of anesthesia, more rapid onset and
duration for lid and global akinesia, less pain, less analgesic requirement and
minimal side effects than the other groups.