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| ORIGINAL ARTICLE |
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| Year : 2021 | Volume
: 26
| Issue : 1 | Page : 11-17 |
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Intrathecal isobaric 1% 2-chloroprocaine versus hyperbaric 0.5% bupivacaine in parturients undergoing lower segment cesarean section: A randomized controlled trial
Neena Jain, Kavita Jain, Harshita Prajapat, Surendra Kumar Sethi, Veena Patodi, Arvind Khare
Department of Anaesthesiology, Jawahar Lal Nehru Medical College and Associated Group of Hospitals, Ajmer, Rajasthan, India
| Date of Submission | 06-Jul-2020 |
| Date of Acceptance | 19-Feb-2021 |
| Date of Web Publication | 29-Jun-2021 |
Correspondence Address:
Dr. Surendra Kumar Sethi
Flat No. 202, Shiv Enclave, Civil Lines, Ajmer, Rajasthan
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jmgims.jmgims_94_20
Background: Cesarean sections are usually done under spinal anesthesia (SA) using local anesthetics. This study is aimed to compare the efficacy of intrathecal isobaric 1% 2-chloroprocaine (CP) and hyperbaric 0.5% bupivacaine in parturients undergoing lower segment cesarean section (LSCS). Materials and Methods: One hundred parturients aged 18–35 years with the American Society of Anesthesiologists physical status I or II undergoing LSCS were randomly allocated into two groups. Group A (n = 50) received intrathecal isobaric 1% 2-CP 5 ml (50 mg), while Group B (n = 50) received intrathecal hyperbaric 0.5% bupivacaine 2 ml (10 mg) in SA. Onset and duration of both sensory and motor block, highest dermatomal level achieved, time to achieve highest dermatomal level, two-segment regression, duration of analgesia, hemodynamic changes, and side effects were noted. Results: The onset of sensory blockade was significantly faster in Group A (1.66 ± 0.49 min) compared to Group B (3.00 ± 0.58 min) (P < 0.05). Duration of sensory block was significantly shorter in Group A (P < 0.05). The time of two-segment regression was also significantly faster in Group A (41.44 ± 5.41 min) compared to Group B (70.24 ± 10.38 min) (P < 0.05). The onset time of the motor block was significantly faster in Group A (P < 0.05). Duration of motor blockade was significantly shorter in Group A (95.7 ± 9.8 min) as compared to Group B (186.26 ± 13.5 min) (P < 0.05). Duration of analgesia was significantly shorter in Group A (97.22 ± 11.82 min) when compared to Group B (191.58 ± 37.06 min) (P < 0.05). No significant hemodynamic changes and side effects were noted (P > 0.05). Conclusion: Intrathecal 1% 2-CP (50 mg) appears to be a safe and effective alternative, preferably in elective and uncomplicated LSCS, as it has faster onset and predictable sensory block height with shorter but adequate duration of motor block and analgesia. Keywords: 2-chloroprocaine, bupivacaine, duration of analgesia, lower segment cesarean section, motor block, sensory block, spinal anesthesia
How to cite this article:
Jain N, Jain K, Prajapat H, Sethi SK, Patodi V, Khare A. Intrathecal isobaric 1% 2-chloroprocaine versus hyperbaric 0.5% bupivacaine in parturients undergoing lower segment cesarean section: A randomized controlled trial. J Mahatma Gandhi Inst Med Sci 2021;26:11-7 |
How to cite this URL:
Jain N, Jain K, Prajapat H, Sethi SK, Patodi V, Khare A. Intrathecal isobaric 1% 2-chloroprocaine versus hyperbaric 0.5% bupivacaine in parturients undergoing lower segment cesarean section: A randomized controlled trial. J Mahatma Gandhi Inst Med Sci [serial online] 2021 [cited 2023 Mar 30];26:11-7. Available from: https://www.jmgims.co.in/text.asp?2021/26/1/11/319825 |
| Introduction | |  |
Spinal anesthesia (SA) is a reliable and safe technique for lower abdominal surgeries. However, long-acting local anesthetics (LAs) in SA may limit its use, particularly in ambulatory or daycare surgeries which include delayed ambulation, risk of urinary retention, and early pain after block regression. Cesarean section is generally done under SA using 0.5% hyperbaric bupivacaine as the LA agent of choice.[1],[2]
The availability of short-acting LAs has resurged the technique of SA particularly for the procedures of short or ultra-short duration and ambulatory surgeries. Chloroprocaine (2-Chloroprocaine, 2-CP) is an aminoester LA with a very short half-life which was introduced and has been successfully used for SA since 1952.[3],[4] This drug was abandoned thereafter because of several reports of neurological deficits in patients, who received accidental high intrathecal doses during epidural labor analgesia, which was thought to be due to sodium bisulfite as an added preservative.[5],[6] The preservative-free formulation of 2-CP, which is available nowadays, is reported to be safe in various animal studies with a favorable profile in terms of both safety and efficacy.[7],[8],[9],[10]
In comparison with bupivacaine, 2-CP showed favorable characteristics in terms of faster resolution of the motor block with early ambulation and discharge from hospital and may be a suitable alternative to low doses of long-acting LAs in ambulatory surgery. 2-CP could also be a better alternative for intrathecal short or intermediate-acting LAs, such as lidocaine and bupivacaine, as lidocaine may cause transient neurological symptoms (TNS) while bupivacaine may lead to prolongation of the motor block with delayed ambulation.[11],[12]
Very few studies have compared the efficacy of preservative-free 2-CP with bupivacaine as intrathecal LA in SA for LSCS. We hypothesized that as most of lower segment cesarean sections (LSCS) are of short duration, 1% 2-CP (50 mg) would be a suitable alternative to 0.5% bupivacaine (10 mg) for LSCS, in terms of faster onset of the sensory block along with shorter but adequate duration of motor blockade and analgesia. Hence, this randomized controlled trial was conducted to compare intrathecal isobaric 1% 2-CP (50 mg) and hyperbaric 0.5% bupivacaine (10 mg) in terms of duration of analgesia as the primary outcome measure, while the onset of sensory and motor block, duration of sensory and motor block, two-segment regression, hemodynamic changes, and side effects were the secondary outcome measures.
| Materials and Methods | | |
This prospective randomized double-blind trial (registered in Clinical Trials Registry-India; CTRI/2019/03/018342) was conducted on 100 female parturients, aged 18–35 years belonging to the American Society of Anesthesiologists (ASA) physical status I or II undergoing LSCS under SA. This study was conducted after obtaining approval from the local institutional ethics committee, and written informed consent was obtained from all participants enrolled in the trial. Parturients with contraindications to SA, with known allergy to any of the study drugs, with any spinal deformity, and those having cardiovascular, respiratory, renal, or neurological diseases were excluded from this study.
Parturients were randomly allocated into two groups of 50 each, using computer-generated table of random numbers and a sealed envelope technique. Group A (n = 50) received 5 ml (50 mg) intrathecal isobaric 1% 2-CP, and Group B (n = 50) received 2 ml (10 mg) intrathecal hyperbaric 0.5% bupivacaine in SA.
A thorough preanesthetic evaluation of the parturients was done which included taking a detailed history, performing the complete systemic examination, and all routine blood investigations. All parturients were kept nil per oral for a minimum period of 8 h before LSCS. After arrival in the operation theater, an intravenous (IV) cannula (20G) was inserted and ringer lactate infusion at the rate of 10–20 ml/kg was started. An ASA standard monitor (including noninvasive blood pressure, pulse oximetry [SpO2], and electrocardiogram) was connected and baseline hemodynamic parameters were recorded. Under all aseptic precautions, SA was performed in a sitting position at L3–L4 subarachnoid space using 25G spinal needle. After clear and free cerebrospinal fluid flow, parturients received either of the study drugs according to group allocation. After performing SA, the patients were placed in the supine position immediately. To maintain double-blinding, the resident anesthesiologist (observer) other than the anesthesiologist performing spinal block, who was blinded to the study drugs given, evaluated the sensory and motor block (a) every 1 min for the initial 5 min, (b) every 5 min up to 30 min, followed by (c) every 15 min up to 1 h, and thereafter, (d) every 30 min until the sensory block had regressed to the S1 dermatome. After achieving the T8 level of sensory block, surgery was started.
Sensory block was assessed in dermatomal areas of T4 to S1, with a blunt 23G hypodermic needle and graded as: 0 = normal sensation; 1 = loss of prick sensation (analgesia); and 2 = loss of touch sensation (anesthesia). Onset of sensory block was the time from intrathecal injection to the time taken to achieve T10 dermatomal level. The highest level of sensory block achieved with the time taken to achieve the highest level of sensory block was noted. Two-segment regression and duration of sensory block (time taken to regress sensory block up to S1 dermatome in the heel) were also noted.
Motor block was assessed using Bromage scale and graded as: Bromage score 0 = no motor block; 1 = inability to raise extended leg, able to move knees and feet; 2 = inability to raise extended leg and move knee, able to move feet; and 3 = complete motor block. The onset of motor block (time from intrathecal injection to the time taken to achieve maximum Bromage score) and duration of motor block (time taken to regress from maximum score of motor block to score 0) were recorded. Duration of analgesia was defined as the time from intrathecal injection to the time when visual analog scale (VAS) was more than 3 or when the patient demanded rescue analgesic. Postoperative pain was assessed using the VAS numeric pain distress scale (0–10).
During surgery, various hemodynamic parameters including pulse rate (PR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and SpO2 were recorded at 0, 5, 10, 15, and 20 min, then every 5 min up to 60 min. Side effects such as bradycardia (heart rate <50 beats/min), hypotension [decrease in SBP >30% from the baseline], and nausea or vomiting were observed. Bradycardia was managed with atropine 0.6 mg IV bolus, while hypotension was treated with mephentermine 6 mg or ephedrine 5 mg IV bolus. Ondansetron 0.1 mg/kg was given to treat postoperative nausea and vomiting (PONV). All the patients were also observed for LA systemic toxicity as well as delayed complications such as postdural puncture headache (PDPH), urinary retention, and TNS.
Statistical analysis
Based on a previous study[13] along with a pilot study, the sample size was calculated to be 50 patients in each group to demonstrate a power of 0.8 and type-1 error of 0.05 with the duration of analgesia as a primary outcome. Data were compared using standard qualitative and quantitative tests (unpaired Student's t-test, Chi-square test, ANOVA, etc.). Categorical data were presented as numbers (percentage), while continuous variables were presented as mean (standard deviation). Statistical analysis was performed using SPSS 13.0 for Windows (SPSS Inc., Chicago, IL, USA). P < 0.05 was considered statistically significant.
| Results | | |
A total of 110 parturients were enrolled of which 100 parturients were randomly allocated into two groups [Figure 1]. Ten parturients were excluded from the study based on exclusion criteria. The demographic profile including mean age, weight, and duration of surgery was comparable in both groups [Table 1].
The mean time for onset of sensory block in Group A and Group B was 1.66 ± 0.49 min and 3.00 ± 0.58 min, respectively, i.e., the mean time was significantly shorter in Group A than in Group B (P < 0.001). In Groups A and B, the median (range) for the highest dermatomal level of sensory block was T4 (T3–T6) and T6 (T4–T6), respectively. The mean time to achieve the highest level of sensory block was 2.96 ± 0.63 min and 5.08 ± 0.75 min in Group A and Group B, respectively. The mean time to achieve the highest sensory level was significantly shorter in Group A as compared to Group B (P < 0.001). In Group A, the mean time of two-segment regression was 41.44 ± 5.41 min, while in Group B, it was 70.24 ± 10.38 min, i.e., the mean time was significantly shorter in Group A than in Group B (P < 0.001). The mean duration of sensory block in Groups A and B was 76.74 ± 11.94 min and 168.60 ± 12.41 min, respectively, i. e., it was significantly shorter in Group A than in Group B (P < 0.05) [Table 2].
The mean time for onset of motor block was 3.27 ± 0.62 min in Group A and 4.34 ± 0.71 min in Group B. Thus, the mean time for onset of motor block was found to be significantly shorter in Group A than in Group B (P < 0.001). The mean duration of motor block in Groups A and B was 95.78 ± 9.85 min and 186.26 ± 13.56 min, respectively. The mean duration of motor block was significantly shorter in Group A than Group B (P < 0.001) [Table 3]. Similarly, the mean duration of analgesia in Group A and Group B was 97.22 ± 11.82 min and 191.58 ± 37.06 min, respectively. The mean duration of analgesia was also significantly shorter in Group A than Group B (P < 0.001) [Table 2].
There was no significant change in mean PR over time in both Groups A and B (P > 0.05) [Figure 2]. There was no significant change in mean SBP, DBP, and MAP intraoperatively (P > 0.05) [Figure 3],[Figure 4],[Figure 5]. | Figure 2: Comparison of mean pulse rate in two groups. Group A: Chloroprocaine; Group B: Bupivacaine
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 | Figure 3: Comparison of mean systolic blood pressure in two groups. Group A: Chloroprocaine; Group B: Bupivacaine
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 | Figure 4: Comparison of mean diastolic blood pressure in two groups. Group A: Chloroprocaine; Group B: Bupivacaine
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 | Figure 5: Comparison of mean arterial pressure in two groups. Group A: Chloroprocaine; Group B: Bupivacaine
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In Group A, one (2%) parturient experienced nausea, two (4%) parturients experienced vomiting, three (6%) parturients had hypotension, and one (2%) parturient had bradycardia; while in Group B, two (4%) parturients experienced nausea, two (4%) parturients experienced vomiting, eight (16%) parturients had hypotension, and two (4%) parturients had bradycardia. Hypotension and bradycardia were noted more in Group B than Group A. No parturient had PDPH, urinary retention, or TNS in the two groups [Table 4].
| Discussion | | |
The results of our study suggest that a dose of 50 mg isobaric 1% 2-CP provides a faster onset of sensory block, predictable block height, and early resolution of both sensory and motor blockade than 10 mg hyperbaric 0.5% bupivacaine.[14],[15],[16] The faster recovery from motor blockade is preferred, especially in parturients after a cesarean delivery for reducing the time for exclusive breastfeeding.[17]
In our study, the onset of sensory block was significantly faster in the 2-CP group. Our results were comparable to those of Khare et al.[18] who compared intrathecal 1% 2-CP 30 mg (Group A) with 0.5% hyperbaric bupivacaine 15 mg (Group B) in infraumbilical surgeries. They found that onset of sensory block was significantly earlier in Group A (1.8 ± 0.3 min) than in Group B (3.2 ± 0.4 min) (P < 0.001). The onset of action is usually determined by pKa of drug, which is the unprotonated form that crosses the nerve plasma membrane. However, CP has faster onset even with relatively high pKa, due to the high concentrations (1%) used.[18] In addition, the onset is also dose dependent, which could be the possible reason of significantly faster onset of sensory block in our study. Similarly, the time of onset of motor block was found to be significantly faster in Group A, i.e., 2-CP group (P < 0.001). Bojaraaj and Lalitha[16] compared 1% 2-CP 40 mg (Group A) with 0.5% bupivacaine 10 mg (Group B) given for SA in perineal surgeries. They reported a significantly faster onset of motor block in Group A than Group B (5.85 ± 1.46 min versus 7.35 ± 1.27 min, P = 0.04). Our results are in concordance with this study. This could be attributed due to higher concentration of 2-CP (1%) as compared to hyperbaric bupivacaine (0.5%). The faster onset of the motor block would provide excellent operating conditions particularly in parturients who required a faster induction of anesthesia undergoing LSCS.
The desired level of sensory blockade for LSCS is T4–T6. In our study, the peak block height of sensory block was T4 (T3–T6) in Group A, whereas it was T6 (T4–T6) in Group B. This showed that parturients in both groups achieved the desired level of sensory blockade for optimal operating conditions. Although peak block height was significantly higher in Group A when compared to Group B, none of the patients developed high spinal during the intraoperative period as has also been reported by previous studies.[19] The mean time to achieve the highest level of sensory block was significantly shorter in the CP group. Camponovo et al.[13] reported that the time to achieve the highest dermatomal level of sensory block was 8.5 min and 14 min in Group A and Group B, respectively. Thus, it was significantly shorter with CP (Group A) (P < 0.05).
The time to two-segment regression was significantly faster in the CP group. Our results concur with those of Yoos and Kopacz[19] who compared 1% 2-CP (40 mg) with hyperbaric 0.5% bupivacaine (7.5 mg). They found that the time for two-segment regression was significantly shorter in the 2-CP group (45 ± 20 min) than in the bupivacaine group (74 ± 20 min) (P = 0.01). Similarly, Lacasse et al.[14] found that the time for two-segment regression was significantly shorter in the CP group (50 min) than the bupivacaine group (75 min) (P = 0.001). However, they had used higher concentration of CP (2%) in their study. Tandan et al.[20] also reported a significantly shorter time for two-segment regression in Group A (45 min) than in Group B (70 min) (P = 0.001), which is also in concordance with the results of our study. This might be due to the rapid hydrolysis of 2-CP by plasma pseudocholinesterase.
Similarly, the duration of sensory block was significantly shorter in the CP group. Ashwini and Kumara[21] compared 25 mg 2-CP with 10 mg bupivacaine in LSCS. The duration of the sensory blockade with 2-CP (61.83 min) was significantly shorter than bupivacaine (174.67 min). The results of this study are in concordance with the results of our study in terms of duration of sensory blockade, although they had used lower dosage of 2-CP in their study. Bojaraaj and Lalitha[16] found that the duration of sensory block was shorter in Group A (74.64 ± 10.42 min) than in Group B (198.92 ± 11.95 min) (P = 0.001). The shorter duration of 2-CP may be attributed to rapid hydrolysis of 2-CP by plasma pseudocholinesterase. Although in our study, both two-segment regression and duration of sensory block were found to be of shorter duration, none of the patients required supplemental analgesics during the intraoperative period. The mean duration of surgery (45–50 min) was almost of same duration, and hence, this favors the use of 2-CP in surgical procedures of shorter duration.[16]
The duration of motor block was found to be significantly shorter in the CP group (95.78 ± 9.8 min) when compared to the bupivacaine group (186.26 ± 13.5 min). Our results coincide with those of Lacasse et al.[14] They found that the duration of motor block was significantly shorter in Group A (76 min) than in Group B (119 min) (P < 0.05). Similarly, Camponovo et al. found that the duration of motor block was significantly shorter in Group A (100 min) than in Group B (210 min) (P < 0.005).[13] Bojaraaj and Lalitha also found that the duration of motor block was shorter in Group A (59.86 ± 7.17 min) than in Group B (168.33 ± 13.62 min) (P < 0.05). Only Yoos and Kopacz found that the duration of motor block was comparable in both groups.[14],[19] The most favorable effect of 2-CP was the shorter duration of the motor block which provides earlier ambulation, thereby reducing the adverse effects associated with immobilization due to prolonged motor blockade.[13]
The mean duration of analgesia was significantly shorter in Group A (97.22 ± 11.82 min) when compared to Group B (191.58 ± 13.56 min). Our results are comparable with those of Camponovo et al., who found that the duration of analgesia was significantly shorter in Group A (120 min) than in Group B (293.5 min) (P < 0.005).[13] Our study findings were also similar to those of Ashwini and Kumara, who compared duration of analgesia in patients undergoing LSCS. They reported the duration of analgesia to be 60 min in the CP group and 174 min in the bupivacaine group (P < 0.05). Although they had used 25 mg 2-CP which seems to be a low dose for LSCS, their mean duration of surgery was about 25 min. Hence, for this duration of surgery, the sensory and motor blockade was sufficient in their study.[21] Similarly, in our study, 50 mg 2-CP was used, which provided adequate sensory and motor blockade for about 40 min, and no analgesic supplementation was required intraoperatively. Thus, early recovery might prevent complications such as urinary retention associated with long-acting LAs such as bupivacaine. The mean duration of surgery in our study was about 38 min, with the maximum duration being 42 min. CP (50 mg) is well suited with faster recovery. This has also been reported by Casati et al. in a study on 45 patients undergoing elective lower limb surgeries under SA.[15] They compared three different doses (30 mg, 40 mg, and 50 mg) of 1% 2-CP and concluded that dosage of 40 and 50 mg provided adequate SA for lower limb procedures of a duration 45–60 min without any significant side effects. The quality of analgesia was found to be good in both the groups as none of the patients required supplemental analgesics during the intraoperative period.
No significant hemodynamic changes were observed in any of the groups. These parameters were observed by previous studies which stated that there were no significant hemodynamic changes between these groups (P > 0.05).[14],[15] In our study, the complications or side effects associated with LAs were observed (nausea or vomiting, hypotension, and bradycardia) which were treated accordingly. None of our parturients had complaints of less common complications such as PDPH, urinary retention, TNS, or other neurological deficit, as the newer preparation of CP is preservative free. The incidence of TNS was common with short-acting intrathecal Las, especially lignocaine, mepivacaine, and older preparations of CP.[11],[12]
Ashwini and Kumara[21] observed hypotension in the CP and bupivacaine groups in 9 and 16 patients, respectively, bradycardia in 1 patient in the CP group and none in the bupivacaine group, and nausea in 2 patients in the CP group and none in the other group. Tandan et al.[20] found that vomiting was observed in 1 (4%) patient in each group, while none of the patients developed TNS or other neurologic symptoms. In our study, hypotension and bradycardia were noted more in Group B than Group A, but these side effects were in the acceptable range and not clinically significant.
The limitations of our study are that the assessment of pain using VAS was subjective and varied with the level of understanding between the patient and anesthesiologist. Although it is a common practice to use adjuvants with intrathecal LAs, we have not used any adjuvant, especially with CP which has shorter duration of action. Hence, complicated LSCS requiring longer surgical times than usual could not be completed using short-acting LAs such as CP. Further, research studies need to be conducted to establish the safety profile and efficacy of 2-CP, especially in parturients undergoing LSCS.
| Conclusion | | |
Intrathecal 1% 2-CP (50 mg) provides faster onset of both sensory and motor block but with faster resolution of both sensory and motor block as compared to 0.5% hyperbaric bupivacaine (10 mg). Although the two-segment regression and duration of sensory block were shorter, 2-CP (50 mg) still provides the adequate duration of analgesia without supplemental analgesics along with adequate muscle relaxation during the intraoperative period in parturients undergoing LSCS without any significant hemodynamic changes and complications or side effects. Hence, it appears to be a safe and effective alternative to hyperbaric 0.5% bupivacaine preferably for elective and uncomplicated LSCS, which is expected to be completed in a short duration of 30–40 min.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4]
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