|Year : 2020 | Volume
| Issue : 1 | Page : 29-33
Effect of fentanyl addition to local anesthetic mixture in peribulbar block for cataract surgery
Aya Fouad, Manal Foad Abd-Elmoniem, Sameh Ghoneim
Department of Anesthesiology and Intensive Care, Faculty of Medicine, Al-Azhar University, Cairo, Egypt
|Date of Submission||23-Dec-2019|
|Date of Decision||06-Jan-2020|
|Date of Acceptance||08-Jan-2020|
|Date of Web Publication||20-Apr-2020|
MD Manal Foad Abd-Elmoniem
Lecturer in Anesthesiology and Intensive Care, Faculty of Medicine, Al-Azhar University, 11535
Source of Support: None, Conflict of Interest: None
Background In peribulbar regional anesthetic blocks, injection of local anesthetic mixtures alone provide unsatisfactory surgical conditions as regards block intensity and duration especially for relatively lengthy operations. So, additives may improve the quality of the block and provide good postoperative analgesia.
Aim To examine the effect of adding fentanyl to local anesthetics in peribulbar block on the onset and duration of lid and globe akinesia (primary outcome) and postoperative analgesia (secondary outcome).
Patients and methods Patients were classified randomly allocated in a blind manner into two groups; each group contained 30 patients. The control group received a measure of 7 ml [3 ml lidocaine 2%+0.5 ml hyaluronidase (150 U)+2.5 ml bupivacaine 0.5%+1 ml saline] which was used locally and the fentanyl group received a measure of 7 ml [3 ml lidocine2%+0.5 ml hyaluronidase (150 U)+2.5 ml bupivacaine 0.5%+1 ml saline containing 20 μg fentanyl] which was used locally.
Results Statistically significant decreased mean time of complete akinesia decreases the mean time to sensory block in the fentanyl group compared with the control group.
Conclusion Fentanyl is an effective drug as an additive to local anesthetic mixture in peribulbar anesthesia, as it shortens the onset time of corneal anesthesia and globe akinesia, prolongs block duration, and good postoperative analgesia.
Keywords: cataract, fentanyl, local anesthetic, peribulbar block
|How to cite this article:|
Fouad A, Abd-Elmoniem MF, Ghoneim S. Effect of fentanyl addition to local anesthetic mixture in peribulbar block for cataract surgery. Sci J Al-Azhar Med Fac Girls 2020;4:29-33
|How to cite this URL:|
Fouad A, Abd-Elmoniem MF, Ghoneim S. Effect of fentanyl addition to local anesthetic mixture in peribulbar block for cataract surgery. Sci J Al-Azhar Med Fac Girls [serial online] 2020 [cited 2020 Aug 5];4:29-33. Available from: http://www.sjamf.eg.net/text.asp?2020/4/1/29/282858
| Introduction|| |
Local anesthesia of the eye has achieved greater popularity over general anesthesia in ophthalmic surgeries  due to lesser incidence of respiratory depression and hemodynamic changes, and good postoperative analgesia . Peribulbar block gained a wider use due to its ability to provide the anesthetic effect with lower rate of complications than retrobulbar block. The use of short needles proved to be an easy, simple, and less painful technique providing good akinesia and analgesia . Addition of opiates improves the quality of the block and provides more postoperative analgesia . Fentanyl mediates its analgesic effect through central and peripheral opioid receptors .
| Aim|| |
To evaluate the effect of adding fentanyl to local anesthetics in peribulbar block on the onset and duration of lid, globe akinesia (primary outcome), and postoperative analgesia (secondary outcome).
| Patients and methods|| |
This randomized, prospective double-blinded control study was carried out at Al-Zahraa University Hospital, Cairo, Egypt, from January to September (2019). After obtaining approval from hospital ethics committee, written informed consents were obtained from 60 patients who were scheduled for cataract operation under local anesthesia. Patients were aged between 40 and 60 years, of both sexes, with ASA I or II. Exclusion criteria were as follows: patients with impaired orbital/periorbital sensation, patients having a history of abnormal bleeding or allergy to local anesthetics, patients receiving anticoagulants, patients with complicated vitreous hemorrhage such as retinal detachment, extensive epiretinal membranes, drooped nucleus, or surgery takes a long time or when the surgeon expected prolonged surgery (>2 h), patients with posterior staphyloma, patients with axial length of more than 28 mm, patients with disturbed conscious level, having difficulty in communication, for example, mental retardation or deafness.
All patients were examined ophthalmologically to exclude complicated vitreous hemorrhage, diagnosis of any associated disorders, and diagnosis of posterior staphyloma if it was present.
After complete ophthalmological examination by the ophthalmologist and after ophthalmic ultrasound and biometry performed on all cases, the axial length was measured.
Patients were classified randomly in a blind manner by the ophthalmologist into two groups (the control group and the fentanyl group) of 60 patients; each group contained 30 patients. Control group 1: received a volume of 7 ml [3 ml lidocaine 2%+0.5 ml hyaluronidase (150 U)+2.5 ml bupivacaine 0.5%+1 ml saline] which was used locally.
Fentanyl group 2: received a volume of 7 ml [3 ml lidocaine 2%+0.5 ml hyaluronidase (150 U)+2.5 ml bupivacaine 0.5%+1 ml saline containing 20 μg fentanyl] which was used locally.
A intravenous cannula (20 G) was inserted to all patients scheduled to cannulation. Standard monitoring consisting of intermittent noninvasive blood pressure, continuous ECG, heart rate, and pulse oximetry by (Draeger Vista XL; Drager Medical System, Inc., USA; Telford, Germany) which were recorded; O2 supplementation was vianasal catheter. Patients were not premedicated or sedated before or during the procedures.
Technique of local anesthesia: peribulbar block was performed using a 26 G, 13-mm short beveled needle; the needle was inserted through the conjunctiva as far laterally as possible in the inferotemporal quadrant. Once the needle is under the globe, it was directed along the orbital floor, passing the globe’s equator to a depth controlled by observing the needle/hub junction reach the plane of the iris. A measure of 3.5 ml of the ‘prepared drug’ was injected slowly by the ophthalmologist. In the same way, another portion of 3 ml of the ‘prepared drug’ was injected at 2 mm medial and inferior to the supraorbital notch. Gentle ocular massage was applied to the eye ball to promote the spread of local anesthetic and to decrease the intraocular pressure; at the same time, intraocular pressure was measured using Schiotz tonometry at 5 min before injection and 5 min after peribulbar block. Corneal sensation was evaluated using a cotton wick. Ocular movement was also evaluated at 2-min intervals using a 3-point scale.
Drugs used in peribulbar block
Lidocaine 2% vial containing 50 ml (20 mg/ml) (Alexandria Company, Alawaeed, Gameila AbuHreed Street, Alexandria, Egypt), bupivacaine 0.5% vial containing 20 ml (100 mg bupivacaine; Sunny Pharmaceutical, Badr City, Egypt), fentanyl: available as an ampule of 2 ml 50 μg/ml. It is manufactured by (Sunny Pharmaceutical under Licens Hameln pharmaceutical Germany), hyaluronidase (Shreya Life Sciences Pvt Ltd, Salem,Tamil Nadu, ABBOT, India).
Corneal anesthesia and ocular movement were evaluated using a cotton wick at 2-min intervals till the onset of anesthesia. Ocular movement was evaluated at 2-min intervals in all four directions using a three-point scale. 0 indicates complete akinesia, 1 limited akinesia, and 2 indicates normal movement. If a block is inadequate for more than 10 min after injection of the prepared drug, additional injection with 40 mg of 2% lidocaine was injected inferotemporally and time of onset to sensory block. Hemodynamic variables (mean arterial blood pressure, heart rate) were recorded every 5 min until completion of surgery and every 30 min in the first two postoperative hours. Hypotension and bradycardia were defined as a 20% decrease in blood pressure and heart rate in relation to the preblock value. Peripheral oxygen saturation continuous monitoring was done until completion of surgery. Postoperative analgesia was assessed by using the visual analog score (VAS) every hour up to 6 h postoperatively as follows: 0=no pain; 1, 2, and 3=mild pain; 4, 5, and 6=moderate pain; 7, 8, and 9=severe pain; 10=very severe pain or maximum pain imaginable. As per time of the first analgesia required (if VAS>4) 75 mg diclofenac intramuscular was given. Surgery satisfaction by the ophthalmologist, 0=complete satisfied,1=partially satisfied, 2=not satisfied.
Recorded data were analyzed using the Statistical Package for Social Sciences, version 20.0 (SPSS Inc., Chicago, Illinois, USA). Quantitative data were expressed as mean±SD. Qualitative data were expressed as frequency and percentage:
- Independent-samples t test of significance was used when comparing between two means.
- Mann–Whitney U test: for two-group comparisons in nonparametric data.
- χ2 test of significance was used in order to compare proportions between qualitative parameters.
- The confidence interval was set to 95% and the margin of error accepted was set to 5%. So, the P value was considered significant as in the following:
P value less than or equal to 0.05 was considered significant.
P value more than 0.05 was considered insignificant.
P value less than or equal to 0.001 was considered as highly significant.
| Results|| |
The results of the present study are demonstrated in the following:
As regards demographic characteristics (age, sex, weight) and duration of surgery: no statistically significant difference between two groups as shown in [Table 1].
|Table 1 Comparison of demographic characteristics between the control group and the fentanyl group (mean±SD and range)|
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As regards time of complete akinesia: highly statistically significant decreased mean time of complete akinesia of fentanyl group compared with the control group as shown in [Table 2].
|Table 2 Comparison between control group and fentanyl group according to time of complete akinesia (min)|
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As regards the onset time to sensory block (min): highly statistically significant decreased mean time to sensory block (min) of fentanyl group compared with the control group as shown in [Table 3].
|Table 3 Comparison between control group and fentanyl group according to the onset time of sensory block (min)|
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As regards hemodynamic parameters heart rate, mean arterial blood pressure, and peripheral oxygen saturation were not statistically different between two groups, P value more than 0.05.
VAS shows statistically highly significant decrease in the mean of fentanyl group compared with the control group according to VAS at 1–4 h as shown in [Table 4].
|Table 4 Comparison between control group and fentanyl group according to visual analog score (mean±SD)|
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As regards the time to the first analgesia required (h): highly statistically significant increase in the mean of fentanyl group compared with the control group according to time to the first analgesia required. The time was 2.07±0.41 h in the control group while it was 3.40±0.42 h in the fentanyl group as shown in [Table 5].
|Table 5 Comparison between control group and fentanyl group according to time of the first analgesia required (h)|
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As regards surgery satisfaction there was no statistically significant difference between the control group and the fentanyl group according to surgery satisfaction by the surgeon as complete satisfaction equally from 20 (66.7%) patients and partial satisfaction from 10 (33.3%) patients in each group as shown in [Table 6].
|Table 6 Comparison between control group and fentanyl group according to surgery satisfaction (numbers of patients and %)|
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| Discussion|| |
The results were obtained in the present study will appropriately be discussed under the following headings:
As regards corneal anesthesia, globe akinesia, sensory block, and postoperative pain analgesia:
The onset time of corneal anesthesia and globe akinesia was significantly shorter in the fentanyl group than the control group (P<0.05). This result is in agreement with the study of Abdelhamid et al.  who compared the effect of fentanyl as an additive to local anesthetics and he found that fentanyl as an additive leads to significantly shortened onset of corneal anesthesia and globe akinesia in comparison with the control group which received local anesthesia alone.
The study of Sameh et al.  found that either fentanyl (3 µg/ml) or ketamine (2.5 mg/ml) as an additive to a local anesthetic mixture containing hyaluronidase in single-injection peribulbar block in patients presented for vitreoretinal surgeries is beneficial in improving onset, duration, and quality of the block with decreased postoperative requirements of analgesics and without postoperative complications.
These results are also consistent with the study done by Abo El Enin et al. , who studied the effects of added fentanyl to local anesthesia solution [5 ml mepivacaine 3%+1 ml hyaluronidase (150 μg)+3 ml bupivacaine 0.5%] for peribulbar block in 40 patients undergoing vitrectomy due to vitreous hemorrhage not associated with retinal detachment. They found that the addition of fentanyl to local anesthetic solution accelerates the onset and prolongs the duration of lid and globe akinesia in comparison to the control group.
The result of the current study is in agreement with the previous trial done by Nehra et al. , who added fentanyl or clonidine (alpha 2 agonist) to the local anesthetic mixture during peribulbar block and reported the rapid onset time of globe akinesia in fentanyl group (F) and clonidine group (C) compared with the control group (S). They also reported that the duration of motor block and analgesia were significantly longer in group F and group C compared with group S. Abu Elyazed and Mostafa  found that (2 µg/ml) fentanyl or (50 mg) magnesium sulfate as additive to local anesthetic solution during peribulbar block in patients undergoing cataract surgery fentanyl decreases the onset time of lid and globe akinesia and provides better akinesia score.
Kamel et al.  found that addition of fentanyl more than or equal to 2–3 μg/ml to local anesthetic peribulbar anesthesia did not affect onset time or duration of globe akinesia but only improved postoperative analgesia.
As regards heart rate, mean arterial blood pressure, and O2 saturation: this study showed stable perioperative hemodynamics with the use of fentanyl as an adjuvant to local anesthetic for peribulbar block. The result of the present study coincided with the study done by Abdelhamid et al.  who demonstrated that in peribulbar anesthesia, fentanyl is a useful drug as an additive to bupivacaine and provides satisfactory level of intraoperative sedation with stable hemodynamics.
As regards VAS: VAS pain score, considered the gold standard of pain quantification, was used to evaluate postoperative pain severity on a scale of 1–10 in all the included patients in this study.
This study found that there was high significantly lower pain score in the fentanyl group at 1, 2, 3, and 4 h postoperatively (P<0.05). However, no significant difference was detected at any other time interval, which suggests that the fentanyl group is effective for relatively long-lasting analgesia.
The results of this study are consistent with the observations by Abo El Enin et al.  who reported that there were statistically significant differences between the fentanyl and control group as regards the median VAS at 1, 2, 3, 4, 5, and 6 h postoperatively as the fentanyl group had lower median pain score than the control group, VAS more than 5. Postoperative analgesia was given in both groups.
As regards the time of the first analgesia required: in our study, there was significant difference between both groups in the first request of analgesia (P>0.05). Also, the average of the time needed for first request of analgesia was significantly greater in the fentanyl group than the control group. Of the patients, 75% required rescue analgesia 3 h postoperatively while in the control group 30% required it in first hour and 55% in the second hour and 15% in the third hour.These results agreed with Maha et al.  who compared the effect of fentanyl versus clonidine as an addictive to local anesthetic anesthesia for peribulbar block in 90 patients scheduled for cataract surgery. They found that the addition of either clonidine or fentanyl to the local anesthetic mixture decreases the onset time and prolonged the duration period of the peribulbar block with a longer time of postoperative analgesia as compared with the control group. Abo El Enin et al.  who concluded that adding fentanyl 20 µg to a mixture of mepivacaine and bupivacaine significantly increases the time of postoperative analgesia. Abu Elyazed and Mostafa  found significantly prolonged time of first analgesic request in both fentanyl and magnesium sulfate groups compared with the control group (P<0.05)when they added fentanyl or magnesium sulfate to peribulbar anesthesia in cataract surgery.
This study concluded that 20 μg of fentanyl is an effective dose as an additive to local anesthetic mixture (lidocaine and bupivacaine) and hyaluronidase during peribulbar anesthesia, as it shortens the onset time of corneal anesthesia and globe akinesia, prolongs block duration time, and decreases the postoperative pain score which lead to prolonged duration of analgesia with hemodynamic parameter stability and no respiratory depression.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]