Abstract
Background and Aims:
The purpose of this study was to compare the clinical efficacy and safety of 3 mL (15 mg) of 0.5% hyperbaric bupivacaine and 3 mL (22.5 mg) of 0.75% hyperbaric ropivacaine for infraumbilical surgeries under spinal anaesthesia in terms of sensory and motor blockade onset and duration, as well as haemodynamic stability.
Methods:
This is a prospective randomised comparison study of 60 patients undergoing elective infraumbilical operations under SA at Apollo Main Hospital in Chennai. Based on inclusion and exclusion criteria, they were randomised into Group R, who received 3 mL of 0.75% hyperbaric ropivacaine (21 mg), and Group B, who received 3 mL of hyperbaric bupivacaine (15 mg).
Results:
Our study result shows that patients receiving 0.75% hyperbaric ropivacaine had sensory and motor block for a shorter amount of time than those receiving 0.5% hyperbaric bupivacaine. Patients who received 0.75% ropivacaine as opposed to 0.5% bupivacaine also experienced a delayed onset of motor as well as sensory block. The group receiving ropivacaine had a lower incidence of complications such as hypotension and fewer haemodynamic alterations than bupivacaine.
Conclusion:
This study concludes that ropivacaine is a suitable drug for spinal anaesthesia for procedures of intermediate duration since it has a quicker recovery profile than the widely used hyperbaric 0.5% bupivacaine. It is also equivalent in terms of block quality.
Introduction
The development of spinal anaesthesia can be attributed to James Leonard Corning, a neurologist from New York who accidentally gave cocaine spinal anaesthesia in 1885.
In 1898, German surgeon August Karl Gustav Bier performed the first successful application of operative spinal anaesthesia in lower limb surgery.[1]
Regional anaesthesia is simpler to administer to awake patients without the need for airway manipulation, has a lower risk of aspiration, begins sensory and motor blockade more quickly, avoids polypharmacy, provides site-specific pain relief and postoperative analgesia and allows for early mobility and discharge. Therefore, regional anaesthesia techniques are preferable to general anaesthesia.[2]
Aside from the benefits of regional anaesthesia, spinal anaesthesia has additional benefits, including fewer postoperative complications such as deep vein thrombosis and pulmonary emboli, less blood loss and fewer blood transfusions.[2] Among anaesthesiologists in practice, subarachnoid block remains the most used anaesthesia method, particularly for day care procedures, due to its generally favourable safety profile and high success rate.[3]
Spinal anaesthesia is the most commonly used type of regional anaesthesia in infraumbilical procedures because it provides extensive and reliable motor blockage.[2]
Bupivacaine, an amino-amide molecule, was produced and first used in clinical practice in 1963, where it proved to be a highly efficient long-acting local anaesthetic agent.[4] Historically, bupivacaine has been the preferred medication for spinal anaesthesia, despite concerns about its unwanted side effects such as bradycardia, hypotension, cardiotoxicity and toxicity to the central nervous system. When used in large concentrations or unintentionally injected into the bloodstream, bupivacaine has been linked to cardiotoxicity.[3]
Being a pure S enantiomer, ropivacaine, a relatively newer local anaesthetic medication, has a greater margin of safety than bupivacaine, including less cardiotoxicity and quicker recovery from motor blockage. When compared to bupivacaine, it creates a shorter-lasting motor blockade, reducing the psychological stress caused by the patient’s prolonged immobility after surgery.[2]
In this study, we compare the intrathecal efficacy and haemodynamic stability of 0.5% bupivacaine against 0.75% ropivacaine in infraumbilical surgeries. The primary objective was to compare the drugs based on the onset and duration of sensory and motor blockage. The second objective was to compare the drugs in terms of haemodynamic stability.
Materials and Methods
After getting institutional ethics committee approval (Register no: NEW EC Reg no-EC/NEW/INST/2022/TN/0195), patients undergoing infraumbilical surgeries will be randomly divided into two groups. A randomisation technique will be adopted to select the cases. Fifteen blocks with a size of four sequence combinations will be selected. The block randomisation sequence will be computer-generated using Microsoft Excel. These generated block sequences will be put into a sealed envelope, and the selection of patients into treatment Group B or Group R will be based on the randomised sequence. Using this randomisation technique, all 60 cases are put into two groups.
Patients who were scheduled for infraumbilical surgeries and had provided written informed consent between January 2023 and January 2024 were recruited for this study. Patients who were undergoing elective robotic radical prostatectomy between the ages of 18 and 80 and who came under the American Society of Anesthesiologists (ASA) 1 to 2 were included in this study.
Patients with local anaesthetic allergy, neurological disorders, end-stage illness, ASA 3 to 4, infection or significant coagulation disorders were excluded.
Methodology
All patients underwent preoperative evaluation, which included a thorough history, a general physical and a systemic examination. Prior to surgery, all investigations required for the administration of anaesthesia were completed and optimised. Patients were kept on nil per oral eight hours before the surgery. Baseline data were recorded with an electrocardiogram (ECG) monitor, a non-invasive blood pressure monitor and a pulse oximeter attached to the operation room. An intravenous (IV) cannula was used to secure IV access. Depending on the group selected, the following drugs will be assigned—Group B: 3 mL of 0.5% heavy bupivacaine; Group R: 3 mL of 0.75% heavy ropivacaine. Under strict aseptic precautions, the patient in a sitting position, the lumbar region is painted and draped. The L3-L4 intervertebral space is identified by using Tuffier’s line. The skin is then infiltrated with 2 mL of 2% lignocaine. The midline technique involves inserting a 26G/27G Quincke’s needle into the subarachnoid region. After confirming free flow of clear cerebrospinal fluid (CSF), 3 mL of 0.5% hyperbaric bupivacaine/3 mL of 0.75% ropivacaine is administered. Patient’s pulse rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP) and saturation are observed at 1, 5, 10, 15, 30, 45, 60, 75, 90 and 120 minutes after subarachnoid blockade. We also observed the onset and duration of sensory and motor block. Sensory block was assessed by loss of sensation to pinprick. Time to commencement of sensory block was the time required to reach T10 dermatome level, and duration was the time of regression to the S1 dermatomal level. (time of regression up to S1 dermatomal level). Degree of motor blockade was assessed by modified Bromage scale. The degree of motor blockage was determined using the modified Bromage scale. The time it takes for motor block to occur was the time required to attain a Bromage score of 3, and the duration of the motor block was the time of regression to the Bromage score 0.
Common adverse effects of a subarachnoid block include hypotension and bradycardia. A 20 % reduction in blood pressure from baseline was considered hypotension, and it was treated with either fluids or a single 6-milligram IV bolus of ephedrine. An IV atropine dose of 0.6 mg was used to treat bradycardia, which is defined as a pulse rate of less than 60 bpm. When there is respiratory distress, defined as respiratory rate (RR) <10/min and saturation (SpO2) <90 %, oxygen supplementation using a mask 4-6 L/min is used to treat the condition.[2]
Statistical Analysis
Descriptive statistics for categorical and continuous components were provided as frequency (%) and mean (standard deviation [SD]), respectively. Median (interquartile range [IQR]) was presented for the skewed data. The normality of the data was checked by using Shapiro-Wilk test. Student’s t-test/Mann-Whitney U test was used to determine the significant difference between bupivacaine and ropivacaine. Chi-squared/Fisher’s exact test was used to determine the association between two independent categorical factors. Paired sample t-test/Wilcoxon Sign rank test were used to determine the significant changes between preoperative and 120 minutes postoperative visits. P value < .05 was considered as statistically significant. The entire analysis was performed using SPSS (IBM, 28.0).
Results
Observation and Results
In our prospective randomised comparative study, 60 patients who met the inclusion criteria for infraumbilical surgeries under subarachnoid block were examined. Patients were equally divided into two groups: Group B and Group R. The two groups were comparable in terms of age, gender, height, weight and ASA classification. In Group B, the average age was 51 ± 12.1 years, while in Group R, it was 56.9 ± 13.8 years. The mean age of both groups was similar (P > .05) [Tables 1 and 2].
Demographic factors
The median time for the onset of sensory block was five minutes in the ropivacaine group and three minutes in the bupivacaine group. Thus, bupivacaine has a faster onset than ropivacaine, with a P value < .001, which is statistically significant [Table 2, Figure 1].
Clinical parameters
Time of onset of sensory blockade in minutes
Group B had a significantly longer mean duration of sensory blockade than Group R (163.6 ± 3.3 minutes) [Table 2, Figure 2].
Duration of sensory blockade in minutes
The median period of time of onset of motor blockade was 11 in the bupivacaine group and 15 in the ropivacaine group, with a statistically significant P value of less than .001 [Table 2, Figure 3].
Time of onset of motor blockade
Comparing Group B (184.3 ± 4.3 minutes) to Group R (124.8 ± 2.8 minutes), the mean duration of motor blockage was substantially longer in Group B, and it is statistically significant [Table 2, Figure 4].
Duration of motor blockade in minutes
The heart rate was observed to be lower in Group R patients at all study intervals except at 120 minutes, which was statistically significant when compared to Group B. However, there was no significant difference in heart rate from baseline (P > .05) [Table 3, Figure 5].
Pulse rate
Change in pulse rate(bpm) from baseline
There was a significant difference in systolic blood pressure between the two groups at all study intervals up to 30 minutes (P value < .05), and variations from baseline values were statistically significant from 1 minute post-spinal to 30 minutes (P value < .05) [Table 4].
Systolic blood pressure
Except for the 5- and 10-minute intervals, no significant difference in diastolic blood pressure was found between the two groups. However, the difference in diastolic blood pressure from baseline was statistically significant (P > .05) at all study periods [Table 5]. There was a statistically significant difference in MAPs between the two groups following spinal anaesthetic administration, with Group B recording a lower MAP at 3, 5, 10 and 15 minutes. However, at all study intervals, Group B experienced a statistically significant decrease in MAP from baseline (P < .05) [Table 6].
Diastolic blood pressure
**Paired sample t-test/Wilcoxon Sign rank test.
Mean arterial pressure
Spo2 changes between two groups were comparable between the two groups except at 3, 5, 15, 30 and 90 minutes, whereas the SpO2 change between the two groups from baseline was found to be statistically not significant at all study intervals except at 3-minute and 30-minute intervals [Table 7].
Saturation
Study results show that two patients in Group B and three patients in Group R both experienced bradycardia. Eleven patients in Group B and five patients in Group R both experienced hypotension. Both hypotension and bradycardia occur in two patients in Group B and none of the patients in Group B. All the differences were not statistically significant [Table 8, Figure 6].
Side effects
Bar graph for side effects
Discussion
The first pure S(–) enantiomer local anaesthetic, ropivacaine, is less toxic than racemic bupivacaine and shares structural and pharmacological similarities with it.[5]
Ropivacaine is less likely to cause cardiotoxicity and neurotoxicity than bupivacaine, the racemic preparation. In comparison to bupivacaine, ropivacaine is less soluble in lipids, which results in a reduced penetration of myelinated motor neurons, lower motor blockade and an increase in sensorimotor differentiation.[6]
This study compares the efficacy and safety of hyperbaric bupivacaine versus hyperbaric ropivacaine.
The primary objective of our study was to compare the time of onset and duration of sensory block and the time of onset and duration of motor blockade.
In our study, we observed that the median time for the onset of sensory block was three minutes in the bupivacaine group and five minutes in the ropivacaine group; thus, bupivacaine has a faster onset than ropivacaine with a P value < .001, which is statistically significant.
As a result, our study’s findings concur with those of Khara and Deopujari.[7] When they used equal dosages of hyperbaric ropivacaine (4 mL of 0.5%) and hyperbaric bupivacaine (4 mL of 0.5%) to examine the start of sensory blockade, they discovered that the onset of bupivacaine was more rapid (P < .05) than in the ropivacaine group. According to our study, in the bupivacaine group, the mean duration of sensory blocking was 206.5 ± 6.9, while in the ropivacaine group, it was 163.6 ± 3.3, with a statistically significant P value of less than .001.
Dar et al.[8] carried out research on 200 patients aged between 40 and 75 years who were undergoing hip and lower limb surgeries. They were split into two groups randomly: Group B (bupivacaine) and Group R (ropivacaine). Each group was given an intrathecal injection of 3 mL of hyperbaric bupivacaine 0.5% or 3 mL of hyperbaric ropivacaine 0.5%. It was discovered that the group treated with ropivacaine had a substantially shorter total duration of sensory block (160 ± 12.9 min) than the group treated with bupivacaine (260 ± 16.1 min; P < .05). Their result is similar to our study.
Our study found that the median period of time until motor blockade start was 11 in the bupivacaine group and 15 in the ropivacaine group, with a statistically significant P value of less than .001. Consequently, bupivacaine produces motor blockage more quickly than ropivacaine. Our study is in concordance with those of Dar et al.,[8] who likewise found a rapid onset of motor blockade with hyperbaric bupivacaine. Duration of motor block was the time of regression to Bromage score 0. Our study indicates that the mean duration of motor blockade was 184.3 ± 4.3 in the bupivacaine group and 124.8 ± 2.8 in the ropivacaine group, with a statistically significant P value of less than .001.
According to the Bhagya et al.[9] study, the mean regression time to modified Bromage grade 0 motor blockage for 40 patients undergoing infraumbilical surgeries was around 243.15 minutes for the hyperbaric bupivacaine group and 155.40 minutes for the hyperbaric ropivacaine group. Similar to the findings of our investigation, bupivacaine caused a significant extended motor block (P = .00) in their study.
The heart rate changes from baseline in our investigation were not statistically significant (P > .05) at various study intervals between two groups. But the changes were less in ropivacaine than in bupivacaine. Our findings, which showed that there was no significant difference in heart rate from the baseline (P > .05), are consistent with the research conducted by Kharat and Deopujari.[7]
Our study shows no significant difference in the incidence of bradycardia between the two groups, and they responded easily to injection with atropine. These results were similar to Mahajan et al.[2] and Kulkarni et al.[10]
In our investigation, MAP showed considerable variations. The intraoperative drop in MAP was less in ropivacaine than in bupivacaine; these results were exactly the same as those of a study carried out by Gupta et al.[11]
Eleven patients (36.7%) in Group B had hypotension, compared to five patients (16.7%) in Group R. This difference is statistically insignificant in our analysis, but it is clinically important. With its quicker recovery time, improved haemodynamic profile and earlier mobilisation, ropivacaine is therefore a good choice for quick procedures carried out in daycare centres.[6] None of the patients in both groups required oxygen supplementation.
Our study has some limitations, such as the sample size being small. We focused solely on ASA I and II; therefore, we were unable to evaluate the efficacy and side effects of the two medicines in high-risk individuals. Furthermore, we conducted this research solely on elective operations. Regardless of these drawbacks, the study’s strength resides in its randomised, double-blind comparison methodology.
Future Directions
Future studies can focus on the elderly and high-risk populations with larger sample sizes. Similar studies can be conducted using optimal dosing approaches, as well as comparing the effectiveness of various intrathecal long-acting spinal drugs with adjuvants.
Conclusion
This study concluded that 0.75% intrathecal hyperbaric ropivacaine has a later onset and shorter duration of effect than 0.5% intrathecal hyperbaric bupivacaine, with superior haemodynamic stability. It is also equivalent in terms of block quality.
Footnotes
Acknowledgements
To the Research Department, Apollo Hospitals, Chennai.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.
Funding
The authors received no financial support for the research, authorship and/or publication of this article.
Institutional ethical committee approval number
Institutional Ethical Committee approval has been obtained (New EC Reg. No. EC/NEW/INST/2022/TN/0195).
Informed consent
Informed consent has been obtained from the patient.
Credit author statement
Vinitha and Sumathi contributed to conceptualisation and design of the study report, data collection and analysis, multiple draft versions including rewriting the revised submission, and concept and identification of unmet need in available literature, manuscript writing, referencing and administrative support.
All the authors have reviewed and approved the manuscript.