|Year : 2016 | Volume
| Issue : 3 | Page : 526-531
Comparison of clonidine and fentanyl as adjuvant to ropivacaine in spinal anesthesia in lower abdominal surgeries
Radhe Sharan, Rajan Verma, Akshay Dhawan, Jugal Kumar
Department of Anaesthesia, Government Medical College, Amritsar, Punjab, India
|Date of Web Publication||27-Sep-2016|
Department of Anaesthesia, Government Medical College, Amritsar - 143 001, Punjab
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Ropivacaine, a newer local anesthetic, is gaining increased acceptance due to its improved safety profile over bupivacaine and lignocaine. Analgesic adjuvants have proved to be valuable in improving the quality of anesthesia and duration of analgesia.
Aim: To compare the efficacy of clonidine and fentanyl as adjuvants to ropivacaine in spinal anesthesia in lower abdominal surgeries.
Materials and Methods: A randomized, double-blind control study was carried out in 100 patients who were randomly divided into two groups. Ropivacaine-clonidine group (RC) received 30 μg of clonidine with 18.75 mg of 0.75% isobaric ropivacaine, Ropivacaine-fentanyl group (RF) received 25 μg of fentanyl with 18.75 mg of 0.75% isobaric ropivacaine intrathecally. The onset and duration of sensory and motor block, hemodynamic parameters, quality of surgical analgesia, total analgesia time, sedation score, and side effects were statistically analyzed using SPSS statistical package, paired and unpaired t-tests and Chi-square test.
Results: The duration of sensory block in RC (240.00 ± 20.99), RF (196.80 ± 18.34), and motor block in RC (192.20 ± 17.36), RF (139.20 ± 17.93) outlasted the duration of surgery. In clonidine group, there was significant prolongation of sensory block, motor block and the total analgesia time. Hypotension and bradycardia occurred more commonly in RC group, whereas pruritus was more in RF group.
Conclusion: Ropivacaine when combined with either clonidine or fentanyl provided an adequate subarachnoid block for lower abdominal surgeries. As an adjuvant, clonidine has advantage over fentanyl as it increased the duration of the subarachnoid block and the postoperative analgesia.
Keywords: Anesthesia spinal, anesthetics local, clonidine, fentanyl, ropivacaine
|How to cite this article:|
Sharan R, Verma R, Dhawan A, Kumar J. Comparison of clonidine and fentanyl as adjuvant to ropivacaine in spinal anesthesia in lower abdominal surgeries. Anesth Essays Res 2016;10:526-31
|How to cite this URL:|
Sharan R, Verma R, Dhawan A, Kumar J. Comparison of clonidine and fentanyl as adjuvant to ropivacaine in spinal anesthesia in lower abdominal surgeries. Anesth Essays Res [serial online] 2016 [cited 2020 Jul 11];10:526-31. Available from: http://www.aeronline.org/text.asp?2016/10/3/526/180781
| Introduction|| |
Postoperative pain can be a major source of fear and anxiety in hospitalized patients. Pain relief is not simply a humanitarian consideration but also an important means for reduction of morbidity and mortality. Spinal anesthesia is the most commonly used technique for lower abdominal surgeries because of its reliability, cost effectiveness, effective analgesia, muscle relaxation, and prolonged postoperative analgesia. The safety of well conducted spinal anesthesia is attested by reports of thousands of carefully followed up cases by recognized authorities. Different drugs were tried for spinal anesthesia from time to time to find out an ideal drug which not only should provide excellent surgical anesthesia but also be free of inadvertent side-effects. Bupivacaine, an amide group local anesthetic, is the most common drug being used intrathecally in lower abdominal surgeries. However, high doses of bupivacaine may lead to myocardial depression, heart blocks, and dysrhythmias. Cardiac arrest caused by higher doses of bupivacaine is more refractory to resuscitation.
Ropivacaine, a newer local anesthetic, is gaining increased acceptance as it has consistently demonstrated an improved safety profile over bupivacaine with a reduced neurotoxic and cardiotoxic potential, together with a wide clinical utility at different doses and for a wide range of indications. Ropivacaine was approved for the intrathecal route by the European Union in February 2004. Subarachnoid block with ropivacaine in lower abdominal surgeries provides adequate intraoperative anesthesia and effective pain relief in initial postoperative period, but when its effect wears off, patient starts experiencing pain. To prolong the postoperative analgesia, a number of adjuvants have been used. These adjuvants reduce the dose of local anesthetic required and still provide sufficient analgesia.
Administration of local anesthetics with opioids has become a widely accepted practice in the management of spinal anesthesia for surgical procedures. They produce a synergistic effect by acting directly on opioid receptors in the spinal cord. Fentanyl, a short-acting lipophilic opioid stimulates µ1 and µ2 receptors. It potentiates the afferent sensory blockade and facilitates reduction in the dose of local anesthetics without intensifying the motor block or prolonging recovery. Fentanyl provides good quality of intraoperative analgesia, hemodynamic stability, minimal side effects, and excellent quality of postoperative analgesia.
Central neuraxial opioids are known for their side effects such as pruritus, urinary retention and potentially catastrophic delayed respiratory depression. This has prompted further research to develop nonopioid analgesics which can be used as adjuvants to local anesthetics. Clonidine is a centrally acting selective partial α2 adrenergic agonist (220:1 α2 to α1) and provides dose-dependent analgesia. Clonidine is known for its synergism with local anesthetics but has side effects such as hypotension, bradycardia, and sedation.
The aim of this study was to assess whether the effect of spinal anesthesia with ropivacaine could be enhanced by adjuvants such as clonidine and fentanyl while still maintaining the hemodynamic stability and central nervous system safety profile for which ropivacaine is increasingly being employed.
| Materials and Methods|| |
After obtaining approval from the Hospital Ethics Committee and written informed consent from the patients, a prospective randomized, double-blind study was carried out on 100 patients in the age group of 20–65 years, of either sex, of American Society of Anaesthesiologists (ASA) Grades I, II, and III, scheduled for elective lower abdominal surgeries of duration <90 min under spinal anesthesia. Patients having unwillingness for the procedure, neurological and coagulation disorders, allergy to amide local anesthetic, morbid obesity, abnormalities of the spine, and pregnant or lactating women were excluded from the study. A day before surgery, a detailed pre-anesthetic check-up was carried out and visual analog score for pain was explained to the patients. It is a 10-point scale in which “0” indicates no pain and “10” indicates severe pain.
In the operation theater, an intravenous (IV) line was secured and injection midazolam 0.04 mg/kg body weight was given IV. The patients were preloaded with 10 ml/kg body weight of Ringer lactate solution over 15–20 min. Multiparameter monitor were attached and baseline heart rate, respiratory rate, non-invasive blood pressure, oxygen saturation, and electrocardiography was recorded. After ensuring sterile conditions, spinal anesthesia was performed by accessing the subarachnoid space with a 25-gauge Quincke spinal needle via the L2–L3 or L3–L4 inter-vertebral space in the lateral decubitus position. After ensuring the free flow of cerebrospinal fluid, patients received one of the two study drugs.
The patients were randomly divided into two groups of 50 each:
- Group I: Fifty patients received 2.5 ml of 0.75% isobaric ropivacaine hydrochloride containing 18.75 mg and clonidine 30 µg diluted with normal saline to make the final volume 3 ml
- Group II: Fifty patients received 2.5 ml of 0.75% isobaric ropivacaine hydrochloride containing 18.75 mg and fentanyl 25 µg to make the final volume 3 ml.
The drug combinations were prepared by the first anesthesiologist. However, various observations were made by the second anesthesiologist who was blinded of the drug administered. In all cases, the level of sensory and motor block and the sedation score were evaluated at 2, 4, 6, 8, 10, 15, 20, 25, 30, 45, 60, and 30 min intervals thereafter. The sensory block level was evaluated with the pin-prick test, the motor block level with a modified Bromage scale [Table 1], and the sedation degree with the Ramsay sedation scale [Table 2].
During the tracking of the sensory block levels in patients, the mean time to onset of sensory block to T10 dermatome, the maximum sensory block level achieved, time to achieve maximum sensory block level, and time for regression of sensory block level to L5 level were monitored. While tracking the motor block, the maximum motor block level, time to achieve maximum motor block level, and total duration of motor block were assessed. The quality of surgical anesthesia was assessed and graded. In the postoperative period, the time of first analgesic demand was noted and injection diclofenac (75 mg) was administered. Patients were observed for any discomfort, nausea, vomiting, shivering, pruritus, bradycardia, and any other side effects. All patients were observed in the postanesthesia recovery room and later in the ward. Severe pruritus and nausea/vomiting were treated with injection chlorpheniramine maleate and injection ondansetron, respectively.
SPSS statistical package (IBM SPSS Statistics for Windows, Version 21.0. Armonk, NY: IBM Corp) was used for statistical calculation. Data are presented as mean and standard deviation, P < 0.05 was considered statistically significant and P < 0.001 was considered highly significant. Paired and unpaired t-tests were used for statistical calculations. Categorical data were analyzed using Chi-square test. Power analysis was performed to calculate the power of the study by taking α error 0.05. The power achieved was well above 90%. Results were analyzed and compared with previous studies.
| Results|| |
The demographic data in both the groups were comparable with respect to age, gender, weight, ASA grade, type of surgery, and duration of surgery [Table 3].
The maximum sensory level achieved was T6 in both the groups. The mean time to onset of sensory block to T10 dermatome and the time to achieve maximum sensory block level was comparable in both the groups. The mean time for regression of sensory blockade to L5 dermatome was prolonged in the clonidine group (240.00 ± 20.99 min) as compared to fentanyl group (196.80 ± 18.34 min), which was highly significant, P < 0.001. The maximum motor block level achieved and the time to achieve maximum motor block level was comparable in both the groups. The mean total duration of motor block in the clonidine group (192.20 ± 17.36 min) was more than the fentanyl group (139.20 ± 17.93 min) and the difference was highly significant, P < 0.001. The time of request of the first analgesia in clonidine group was 408.00 ± 41.99 min, which was significantly more than the fentanyl group in which it was 295.20 ± 31.20 min, P < 0.001, indicating superior analgesia. The number of injections of rescue analgesia in clonidine group was 2.36 ± 0.48 and in fentanyl group was 2.92 ± 0.60. The difference in the two groups was highly significant (P < 0.001). The quality of surgical anesthesia was excellent in both the groups in the intraoperative period [Table 4].
|Table 4: Sensory and motor block characteristics in Group I and Group II|
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Baseline hemodynamic parameters were comparable in the two groups, P > 0.05. The mean heart rate [Figure 1], systolic and diastolic blood pressures [Figure 2] were comparable in both the groups preoperatively, intraoperatively, and postoperatively. Hypotension was observed in five (10%) patients in clonidine group and two (4%) patients in fentanyl group, which was statistically nonsignificant (P > 0.05). Bradycardia was seen in three (6%) patients in clonidine group and one (2%) patient in fentanyl group, which was statistically nonsignificant (P > 0.05).
|Figure 1: Graph showing mean heart rate (per min) in two groups at different time intervals during intraoperative period|
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|Figure 2: Graph showing mean systolic and diastolic blood pressure (mmHg) in two groups at different time intervals during intraoperative period|
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Sedation score in the intraoperative period was nonsignificant in between the two groups. There was no incidence of pruritus in clonidine group whereas six (12%) patients had pruritus in fentanyl group. The difference between two groups was statistically significant (P < 0.05). Nausea/vomiting was seen in seven (14%) patients in clonidine group and eight (16%) patients in fentanyl group and the difference was statistically nonsignificant (P > 0.05).
| Discussion|| |
Spinal anesthesia is simple to perform, uses small dose of drugs, offers rapid onset of action, reliable surgical anesthesia, and good muscle relaxation. These advantages are sometimes offset by a relatively short duration of action and complaints of postoperative pain when the effect wears off. The efficacy of local anesthetics can be enhanced using adjuvants such as opioids and α2 agonists.
Spinal anesthesia with ropivacaine hydrochloride is increasingly being used these days owing to its improved safety profile. In a study, forty patients were randomized to receive either 3 ml of 0.5% ropivacaine (15 mg) or 3 ml of 0.75% ropivacaine (22.5 mg) for spinal anesthesia. It showed that the durations of analgesia and motor block were longer in the 0.75% group, and the intensity of motor block was lower in 0.5% group. The study concluded that at concentrations of 0.5% and 0.75%, ropivacaine results in long-lasting spinal anesthesia.
The mean time to onset of sensory block to T10 dermatome, maximum sensory level achieved and the time to achieve maximum sensory block level was comparable in both the groups. Similar findings were seen in studies by Ogun et al., where 17.5 mg ropivacaine was compared with a combination of 15 mg ropivacaine and 30 µg clonidine in women undergoing cesarean deliveries; study by Chaudhary et al., where sixty male patients scheduled for elective transurethral resection were divided into two groups to receive an intrathecal injection of either ropivacaine 2 ml (0.75%) or ropivacaine 1.8 ml (0.75%) with fentanyl 10 µg. Similarly in another study, Yegin et al. evaluated the effect of adding either 0.5 ml of fentanyl (25 μg) or 0.5 ml of normal saline to 3 ml of 6 mg/ml hyperbaric ropivacaine (18 mg) intrathecally for transurethral resection of prostate and found similar times of onset of sensory block, as did Seetharam and Bhat  when they administered 18.75 mg isobaric ropivacaine with 25 μg fentanyl in patients scheduled for lower abdominal and lower limb surgeries.
The mean time for regression of sensory blockade to L5 dermatome was prolonged in the clonidine group (240.00 ± 20.99 min) as compared to fentanyl group (196.80 ± 18.34 min), which was highly significant, P < 0.001. In a study by Sagiroglu et al., when 12 mg 1% ropivacaine + clonidine (RC) 30 µg was administered to patients scheduled for elective lower extremity surgery, the time to regression of sensory block to S2 dermatome level was found to be 246.60 ± 18.69 min, which is in accordance with Group I of our study. Another study by Jagtap et al., sixty patients were randomly allocated to receive intrathecally either when 15 mg 0.5% ropivacaine with 25 µg fentanyl was administered to patients scheduled for major lower limb orthopedic surgeries, the time to regression of sensory block to L1 dermatome level was found to be 226 ± 46.98 min, which is comparable to Group II of our study.
The maximum motor block level achieved and the time to achieve maximum motor block level was comparable in both the groups. Similar characteristics of motor block were noted in studies by Sagiroglu et al., and Yegin et al.
The mean total duration of motor block in the clonidine group (192.20 ± 17.36 min) was more than the fentanyl group (139.20 ± 17.93 min) and the difference was highly significant, P < 0.001. In the study by Ogun et al., when a combination of 15 mg ropivacaine and 30 µg clonidine was administered intrathecally, the time to complete recovery of motor block was 153.2 ± 19.9 min. These results are nearly comparable to Group I of our study because a higher dose of ropivacaine was used in our study (18.75 mg vs. 15 mg). In the study by Chaudhary et al., when ropivacaine 1.8 ml (0.75%) with fentanyl 10 µg was administered to patients scheduled for elective transurethral resection, the duration of motor block was found to be 143.50 ± 37.19 min, which is comparable to Group II of our study.
The time of request of first analgesia in clonidine group was 408.00 ± 41.99 min, which was significantly more than the fentanyl group in which it was 295.20 ± 31.20 min, P < 0.001. The number of injections of rescue analgesia in clonidine group was 2.36 ± 0.48 and in fentanyl group was 2.92 ± 0.60. The difference in the two groups was highly significant (P < 0.001). In a study by Ogun et al., when a combination of 15 mg ropivacaine and 30 µg clonidine was administered in women undergoing cesarean deliveries, the time to first request of rescue analgesia was seen to be 6.8 ± 2.2 h, which is comparable to Group I of our study. In the study by Yegin et al. when a combination of 0.5 ml of fentanyl (25 µg) and 3 ml of 6 mg/ml hyperbaric ropivacaine (18 mg) was given intrathecally for transurethral resection of prostate, the time to first request of analgesics was found to be 210 ± 30 min, which is comparable to Group II of our study.
| Conclusion|| |
It is concluded from our study that ropivacaine when combined with clonidine or fentanyl provided adequate subarachnoid block for lower abdominal surgeries. Both the groups were effective in providing adequate surgical anesthesia and hemodynamic stability, but ropivacaine plus clonidine group is better than ropivacaine plus fentanyl group with regard to:
- Prolonged duration of the sensory block
- Longer duration of postoperative analgesia
- Lesser number of doses of rescue analgesia required.
However, prolonged motor block with clonidine was unwanted as it delays early ambulation. Side effects such as hypotension and bradycardia were more common with RC as compared to ropivacaine-fentanyl (RF), whereas pruritus was significantly more common with RF.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]