|Year : 2015 | Volume
| Issue : 4 | Page : 613-616
Comparative evaluation of hyperbaric ropivacaine with hyperbaric bupivacaine for spinal anesthesia in elective gynecological surgeries
Chandra K Naren MD 1, Khanna Rajesh2, Ganapathy Usha3
1 Department of Anaesthesiology, R.I.M.S, Ranchi; Department of Anaesthesiology, VMMC and Safdarjung Hospital, New Delhi, India
2 Department of Anaesthesiology, R.I.M.S, Ranchi, India
3 Department of Anaesthesiology, VMMC and Safdarjung Hospital, New Delhi, India
|Date of Submission||11-Sep-2013|
|Date of Acceptance||05-Jul-2015|
|Date of Web Publication||29-Dec-2015|
Chandra K Naren
J-14, Type II, Safdarjung Staff Quarter, West Kidwai, Nagar, New Delhi - 110 023
Source of Support: None, Conflict of Interest: None
Hyperbaric ropivacaine provides adequate sensory and motor block for short duration surgical procedures, safe hemodynamic profile, rapid recovery, early ambulation, and less side effects.
Aim and objective
The aim of this study was to evaluate the clinical efficacy and safety of subarachnoid block with 0.5% hyperbaric ropivacaine compared with 0.5% hyperbaric bupivacaine in elective gynecological surgeries.
Fifty female patients of ASA physical status I and II were randomly selected and divided into two groups: group R and group B. Group R was given 3 ml of 0.5% hyperbaric ropivacaine (15 mg) and group B was given 3 ml of 0.5% hyperbaric bupivacaine (15 mg) during subarachnoid block. Preoperative and intraoperative hemodynamic variables such as heart rate, blood pressure, and SpO 2 were recorded. Sensory and motor block were also assessed at regular intervals.
The mean time to achieve the highest level of sensory block was 13.1 min in group R and 12.2 min in group B (P < 0.05). Maximum sensory level was T8 and T7 in group R and group B, respectively (P < 0.05). The onset time for motor block was 6.16 min with bupivacaine versus 9.04 min with ropivacaine (P < 0.05). The duration of motor block (grade I) was longer (162.8 min) with bupivacaine than (131.7 min) with ropivacaine (P < 0.05). Despite adequate hydration, 40% of patients developed hypotension in group B compared with 16% in group R.
Hyperbaric ropivacaine has lower level of cephalad spread of sensory block, takes more time for maximum spread of analgesia, has early regression of sensory block to L5, has longer onset time for motor block, shorter duration of motor block, and causes less hypotension and other side effects compared with hyperbaric bupivacaine.
Keywords: gynecological surgeries, hyperbaric bupivacaine, hyperbaric ropivacaine, local anesthetics, spinal anesthesia
|How to cite this article:|
Naren CK, Rajesh K, Usha G. Comparative evaluation of hyperbaric ropivacaine with hyperbaric bupivacaine for spinal anesthesia in elective gynecological surgeries
. Ain-Shams J Anaesthesiol 2015;8:613-6
|How to cite this URL:|
Naren CK, Rajesh K, Usha G. Comparative evaluation of hyperbaric ropivacaine with hyperbaric bupivacaine for spinal anesthesia in elective gynecological surgeries
. Ain-Shams J Anaesthesiol [serial online] 2015 [cited 2020 Sep 21];8:613-6. Available from: http://www.asja.eg.net/text.asp?2015/8/4/613/172752
| Introduction|| |
Ropivacaine is a new long-acting amide local anesthetic with structural and pharmacodynamic similarity to bupivacaine and is 30-40% less potent compared with bupivacaine, which is well studied for spinal anesthesia. Presently, hyperbaric preparations of ropivacaine are commercially not available because of difficulty in maintaining the pharmacological stability of hyperbaric solutions for clinical use. However, ropivacaine has a lower potential to the central nervous system and lower cardiotoxicity compared with bupivacaine ,, . Both hyperbaric ropivacaine and bupivacaine produce similar effect  in gynecological procedures such as hysterectomy and ovarian cystectomy. Early regression of motor and sensory blocks and complication rate is less with hyperbaric ropivacaine  . Initial reports on the use of ropivacaine for spinal anesthesia suggested that its shorter duration compared with bupivacaine could offer anesthesiologists a good option for ambulatory patients  .
| Patients and methods|| |
After approval from the institutional ethics committee, 50 patients scheduled for various lower abdominal surgeries such as hysterectomy and ovarian cystectomy were selected from the routine operating theater of government medical college and hospital. Patients were randomized in a double-blind manner. The purpose and nature of the study were explained to all patients and written informed consent was obtained from them during preanesthetic checkup visits. A total of 50 female patients of ASA physical status I and II were randomly selected. A methodical preanesthetic checkup and assessment was performed, which included detailed history taking, general and systemic examinations, and relevant investigations. Patients were specially enquired about previous surgical and anesthetic exposures, if any. Patients with previous history of complications with anesthesia were excluded from the study.
The patients were explained about premedication, preoperative procedure, and intraoperative and postoperative management. All patients were premedicated with oral alprazolam 0.25 mg and ranitidine 150 mg the night before surgery. On arrival to the operating room, each patient was identified and an intravenous 18 G cannula was inserted into a peripheral vein in the arm. Patients were preloaded with 15 ml/kg of Ringer lactate solution. The patients were then subjected to standard monitoring (pulse rate, NIBP, SpO 2 , and ECG). The preinduction values were recorded. Using a computer-generated sequence of numbers and a sealed envelope technique, patients were randomly divided into two groups of 25 patients each. Group R was given 3 ml of 0.5% hyperbaric ropivacaine (15 mg) (prepared aseptically by adding 2.75 ml of 0.75% ropivacaine to 1.25 ml of 25% dextrose achieving a concentration of 78.125 mg/ml of dextrose to make its concentration equal to 0.5% hyperbaric bupivacaine), and group B was given 3 ml of 0.5% hyperbaric bupivacaine (15 mg) (commercially available 0.5% hyperbaric bupivacaine has 80 mg/ml of dextrose) ,,, .
Spinal anesthesia was induced in the sitting position with a 25 G quincke needle using a midline approach at the L2-L3 or L3-L4 interspace. Once a free flow of clear cerebrospinal fluid was obtained, the study drug was injected. With the spinal needle bevel facing cephalad, the anesthetic solution was injected without barbotage or aspiration. Immediately after injection the patients were made to lie supine. Pulse rate, blood pressure, and SpO 2 were measured and baseline values were recorded. The values were recorded before the induction, followed by every minute for the first 10 min, every 2 min for the next 10 min, and then every 10 min. Hypotension (defined as decrease in systolic blood pressure ≥20% of the baseline) was treated with an infusion of lactated Ringer's solution 15 ml/kg. Ephedrine 6 mg intravenously was given to patients unresponsive to fluid infusion. Bradycardia (defined as heart rate <60 bpm) was treated with atropine 0.6 mg intravenously. Nausea and vomiting were treated with ondansetron 4 mg intravenously. Oxygen was routinely administered through a face mask at the rate of 6 l/min until the end of surgery.
Sensory block was assessed with loss of sensation to pin prick with a bevelled needle. The upper level of sensory block was assessed laterally in the mid clavicular line every minute for the first 10 min, followed by every 2 min for the next 10 min, and then every 10 min until the sensory block regressed to L5. The highest level of sensory block was noted and this was considered as the height of block. Patients for whom spinal blockade proved to be a failure right from the beginning were excluded from the study.
In our study, the duration of sensory blockade was considered to last up to that point in time when the pin prick sensation returned at L5 level. The onset and degree of motor blockade were recorded according to the Bromage scale (0 - no paralysis; 1 - inability to raise the extended lower limb, can flex the knee; 2 - inability to flex the knee, can flex ankle; and 3 - inability to flex ankle). Motor power was assessed every minute for the first 10 min, followed by every 2 min for the next 10 min, and then every 10 min until complete recovery of motor power. When the patient was just able to raise her extended lower limbs, the motor block was considered to have ceased. This gave the duration of motor blockade (duration of grade I motor blockade).
All data were presented as mean ± SD or frequencies when appropriate. All patients were selected on the basis of a randomized double-blind study. Analysis was performed with the use of SPSS 12.0 for Windows statistical package (SPSS Inc., Chicago, Illinois, USA). Data were assessed for normal distribution of variance. Means were assessed using one-way analysis of variance if normally distributed; medians or not normally distributed means were assessed using the Mann-Whitney U-test. Statistical significance was defined as P less than 0.05. Sample size was calculated to evaluate the block characteristics with intrathecal hyperbaric ropivacaine and bupivacaine duration of motor and sensory block. On simple interactive statistical analysis, a sample size of minimum 25 was derived using the formula for sample size calculation for multiple comparison (two-tailed) based on the assumption of a (type 1 error) = 5%, b (type 2 error) = 0.2 and power of the study = 80% to detect a difference of 25%.
| Results|| |
In our randomised double blind study, groups were comparable with regard to age, weight, height and ASA status [Table 1]. Observation about the sensory block and motor block characteristics are mentioned in [Table 2] and [Table 3] respectively. Maximum sensory block height was T8 in Ropivacaine group and T6 in Bupivacaine group (P = 0.0001, P < 0.05). The time to maximum extent of cephalad spread was more rapid in Bupivacaine group than in Ropivacaine group (P = 0.0211, P < 0.05). The mean time to complete regressioon of blockade was 154 ± 5 min with intrathecal Ropivacaine as compared to 185 ± 8 min with hyperbaric Bupivacaine (P = 0.0001, P < 0.05). Onset time for grade 3 motor block was rapid in Bupivacaine group than in Ropivacaine group (P = 0.0001, P < 0.05). Duration of grade 1 motor block was 131 ± 5 min in Ropivacaine group as compared to 162 ± 8 min in Bupivacaine group (P = 0.0001, P < 0.05). All patients underwent surgery under spinal anesthesia successfully. [Table 4] mentions the frequency of adverse effects.
| Discussion|| |
Our study has shown that 3 ml of 0.5% hyperbaric solution of ropivacaine with 25% dextrose can produce predictable and reliable spinal anesthesia for abdominal hysterectomy and ovarian cyst comparable to hyperbaric bupivacaine. Studies comparing the sensory and motor block characteristics of bupivacaine with that of ropivacaine have revealed conflicting reports. One of the earlier studies conducted by McNamee and colleagues  comparing plain solutions of intrathecal bupivacaine (0.5%) and ropivacaine (0.5%) reported that equal doses of both agents produced a sensory block of similar onset and extent, with faster regressing block with ropivacaine. The motor block also was of shorter duration with ropivacaine.
Subsequent studies conducted by Mcdonald and colleagues  using hyperbaric preparation of bupivacaine (0.5%) and ropivacaine (0.5%) in healthy volunteers not undergoing surgery also revealed findings similar to the above-mentioned study.
The conclusion of both studies raised doubts about the suitability of intrathecal ropivacaine for surgical operations. Later, a study performed by Whiteside et al.  comparing hyperbaric ropivacaine 0.5% (glucose 5%) with bupivacaine 0.5% (glucose 8%) for spinal anesthesia for elective surgery described that the onset of sensory block was slower, the extent of the sensory block was slightly less and the regression was faster with ropivacaine in comparison with bupivacaine. Both the degree and the duration of motor block were also significantly less with ropivacaine than with bupivacaine. These findings were contrary to the observation of previous studies. The authors attributed the difference in observation to the difference in baricity of both local anesthetics used in the study.
In our study, we evaluated the motor and sensory block characteristics using intrathecal bupivacaine and ropivacaine identical in baricity and dose. We compared the efficacy of 3 ml of hyperbaric ropivacaine with 3 ml of bupivacaine that has 80 mg/ml of glucose.
Our study reported findings that were similar to those reported in the study conducted by Whiteside et al.  and Kulkarni et al.  , who reported slow onset, less extent, and slightly fast regressing block and a shorter degree and duration of motor block with ropivacaine compared with bupivacaine, thus effectively proving that baricity has less influence on the motor and sensory block characteristics in comparison with dose. In the study by Kulkarni and colleagues, the type of surgery was different from that in our study. Our study also showed a safe hemodynamic profile for ropivacaine, as less number of patients had hypotension and hemodynamic instability with ropivacaine in comparison with bupivacaine. Side effects were also few and responded to treatment.
We found that ropivacaine produces effective and reliable adequate sensory and motor block for surgical procedures. Although the motor block is of shorter duration, it is still adequate for surgery of moderate duration. Greater degree of motor-sensory separation and safe hemodynamic profile with ropivacaine ensure a favorable recovery profile. A rapidly regressing motor block, analgesia, and early ambulation render ropivacaine a worthy agent for further evaluation as a promising local anesthetic in day care surgery when used through an intrathecal route.
| Conclusion|| |
We found that ropivacaine has a lower level of cephalad spread of sensory block, takes more time for maximum spread of analgesia, has early regression of sensory block to L5, has longer onset time and shorter duration, and causes less hypotension, bradycardia, nausea, vomiting, and shivering compared with bupivacaine.
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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]