|Year : 2022 | Volume
| Issue : 2 | Page : 68-73
Comparison of block characteristics in continuous spinal anesthesia and continuous epidural anesthesia for lower limb orthopedic surgeries: An interventional study
Pratibha Jain Shah1, Ketan Shah2, Nikita Vipul1, Pratiksha Agrawal1
1 Department of Anaesthesiology and Pain Management, Pt. J.N.M. Medical College and Dr. B. R. Ambedkar Memorial Hospital, Raipur, Chhattisgarh, India
2 Department of Orthopaedics, Raipur Institute of Medical Sciences, Raipur, Chhattisgarh, India
|Date of Submission||15-May-2022|
|Date of Decision||23-Sep-2022|
|Date of Acceptance||30-Oct-2022|
|Date of Web Publication||02-Dec-2022|
Dr. Nikita Vipul
New PG Girl's Hostel, Pt. J. N. M. Medical College Campus, Opposite Central Jail, Jail Road, Moudhapara, Raipur - 492 001, Chhattisgarh
Source of Support: None, Conflict of Interest: None
Background: Continuous epidural anesthesia (CEA) is commonly used in routine practice even though it needs a higher dose of local anesthetics (LA) and is sometimes associated with a patchy or unilateral block. Despite advantages, continuous spinal anesthesia (CSA) is underutilized because of concern related to infection and postdural puncture headache. Our aim was to compare the block characteristics and hemodynamic changes following CSA and CEA in lower limb orthopedic surgeries. Materials and Methods: After approval from the Institutional Scientific and Ethics Committee and Registration with (Clinical Trials Registry of India/2021/02/031575), a prospective, double-blind, randomized study was conducted in 144 patients, American Society of Anesthesiologists I-II, aged 18–65 years, scheduled for lower limb orthopedic surgeries. Patients were randomly divided into two groups according to anesthesia technique used (n = 72), i.e., Group CSA and Group CEA. Block characteristics, hemodynamic variables, intraoperative LA requirement, and complications were recorded. Results: Demographic and surgical data, grade of sensory and motor blockade, and incidence of complications were comparable in both the groups. Induction time was significantly shorter in CSA (8.14 ± 0.88 min vs. 15.75 ± 3.29 min, P < 0.0001). Performance time (5.31 ± 0.92 min vs. 4.92 ± 1 min; P = 0.008), duration of blockade (68.3 ± 4.23 min vs. 65.54 ± 4 min; P < 0.0001), and analgesia (230.48 ± 40.76 min vs. 222.86 ± 39.79 min; P = 0.024) were significantly longer in CSA. A significant fall in diastolic blood pressure and mean arterial pressure occurred in CEA. LA requirement was significantly lower in CSA (11.62 ± 2.5 mg vs. 65.35 ± 7.71 mg; P < 0.00001). Conclusions: Considering shorter induction time, prolonged sensory blockade, and analgesia with greater hemodynamic stability, CSA could be preferred over CEA for lower limb orthopedic surgeries.
Keywords: Block characteristics, continuous epidural anesthesia, continuous spinal anesthesia
|How to cite this article:|
Shah PJ, Shah K, Vipul N, Agrawal P. Comparison of block characteristics in continuous spinal anesthesia and continuous epidural anesthesia for lower limb orthopedic surgeries: An interventional study. J Ind Coll Anesth 2022;1:68-73
|How to cite this URL:|
Shah PJ, Shah K, Vipul N, Agrawal P. Comparison of block characteristics in continuous spinal anesthesia and continuous epidural anesthesia for lower limb orthopedic surgeries: An interventional study. J Ind Coll Anesth [serial online] 2022 [cited 2023 Oct 1];1:68-73. Available from: https://www.jicajournal.in//text.asp?2022/1/2/68/362607
| Introduction|| |
Regional anesthesia, especially central neuraxial blockade owing to several benefits, is frequently used in most orthopedic surgeries involving the extremities. Over the past few decades, continuous epidural anesthesia (CEA), i.e., intraoperative epidural anesthesia combined with postoperative epidural analgesia, has been associated with reduced incidence and severity of perioperative physiological perturbations and postoperative morbidity. However, its efficacy has been questioned due to slow progression and unpredictable effect even after larger volume of drug administration as well as technical difficulties associated with it. Continuous spinal anesthesia (CSA) is the technique, in which small doses of local anesthetics (LA) are injected intermittently into subarachnoid space through a catheter. CSA is a safe technique for high-risk patients, as it gives a higher control of LA spread with lesser cardiovascular consequences, safer preoperative confirmation of catheter position, faster onset, and more reliable block. Moreover, only 1/10-1/5 of anesthetics used for epidural are required in CSA, lowering the risk of systemic toxicity. Besides technique, drug used for neuraxial block is also of equal importance. Ideally, the drug should provide adequate anesthesia and optimum duration of action with least possible systemic interaction. Unfortunately, the misconception around its complications has kept CSA underutilized in modern anesthesia practice and reserved for use in high-risk elderly patients, as reflected by majority of studies conducted earlier.
A previous study in our institute suggested that CSA is a safe technique with minimal hemodynamic alterations even in adult for orthopedic lower limb surgeries as compared to single-shot spinal anesthesia. Till now, in the best of our knowledge, there have been very less studies comparing the two in adults. Hence, this present prospective, randomized, double-blind study was conducted to compare CSA and CEA in adult patients posted for lower limb orthopedic surgeries in terms of induction time as primary objective and block characteristics, hemodynamic changes, intraoperative LA requirement, and incidence of complications as secondary objectives.
| Materials and Methods|| |
After approval from the Institutional Scientific and Ethics Committee (No./MC/Ethics/2020/276), registration with Clinical Trials Registry of India (2021/02/031575), and written informed consent, a prospective, double-blind, randomized study was conducted in Pt. J. N. M. Medical College and Dr. B. R. Ambedkar Memorial Hospital, Raipur (C. G.), within 12 months study duration from September 2020 to October 2021.
Total 180 participants were enrolled for the study, out of which 30 did not meet the inclusion criteria which included age 18–65 years, weight 30–90 kg, height 140–170 cm, American Society of Anesthesiologists physical status (ASA) I-II posted for lower limb orthopedic surgeries. Exclusion criteria were patient refusal, duration of surgery >4 h, sensory block level below T10 or above T8, major cardiorespiratory, neurological, hepatic or renal disorders, history of allergic reaction to LA, and presence of any contraindication to neuraxial anesthesia. Thus, from an accessible population of 150, 2 participants refused intervention. The remaining 148 participants were randomly allocated into two groups according to anesthesia technique used by sequentially numbered opaque sealed envelope technique (n = 74). Group CSA (n = 74) received CSA and Group CEA (n = 74) received CEA [Figure 1]. Four participants were dropped after group allocation as they needed general anesthesia due to failure of CSA and CEA. The patient and observer both were blinded to anesthesia technique which was performed by the experienced anesthesiologist who himself/herself was not involved in intraoperative management. Finally, the data of 72 participants in each group were analyzed.
As per the institutional protocol, all patients underwent a preanesthetic evaluation and were kept nil per oral for 6 h. In operation theater, patients were positioned supine. A large bore intravenous (IV) line was secured and maintenance ringer lactate infusion at 5 ml/kg/h was started. Both CSA and CEA were performed in sitting position under aseptic precautions after local infiltration with 2% lignocaine. In the CSA group, subarachnoid space was accessed through L3-L4 interspace using 19G Tuohy's pediatric epidural needle (Vygon-5, rue Adeline, 95440 Ecouen, France). A 22G catheter was inserted through it and fixed in situ considering 2 cm into intrathecal space. After confirmation of CSF through catheter, 1 ml of 0.5% bupivacaine heavy was injected. Subsequently, 0.5 ml 0.5% bupivacaine heavy was injected at every 10 min through intrathecal catheter until T10 level was achieved. Considering 0.5 ml of dead space of catheter and filter, catheter was flushed with 0.5 ml of saline after each bolus. Under strict aseptic precautions, the catheter was removed at the end of surgery and all patients were followed up for 7 days. In the CEA group, epidural space was accessed through L4-L5 interspace using 18G Tuohy epidural needle (Smiths Medical Czech Republic a.s. Olomoucká 306, 753 01 Hiranice, Czech Republic). After identification of epidural space by loss of resistance technique, 20G catheter was inserted 3 cm cephalad and a test dose of 3 ml of 2% lignocaine with adrenaline (1:200,000) was administered. Following 3 min, 10 ml of 0.5% plain bupivacaine was injected via epidural catheter. Subsequently, 2 ml/segment of 0.5% plain bupivacaine was administered every 20 min through epidural catheter until T10 level was achieved to a maximum of 25 ml. Epidural catheter was kept in situ for postoperative pain relief.
Performance time (P1-P2) was calculated from start of skin filtration to placement of patient in supine position after putting the catheter. Induction time (P3-P4), the primary outcome, was calculated from time of LA injection to time of T10 sensory blockade. Duration of sensory blockade (P4-P5) was calculated from time of T10 sensory blockade to time at two-segment regression of block. Duration of analgesia (P4-P6) was calculated from time of induction to time of first rescue analgesic. Grade of sensory and motor blockade was assessed at time P4. Sensory blockade was assessed according to Hollmen's criteria: 0 – same sensation as compared to unanesthetized area, 1 – felt as a blunt puncture, 2 – felt as touching, 3 – pricking sensation lost, using pin prick from T10 to S1 immediately after block and every minute till peak effect was achieved. Motor blockade was assessed by moving the limb according to modified Bromage Scale. Hemodynamic variables were monitored just after induction every 5 min up to 30 min and then every 15 min till completion of surgery. Hypotension was considered systolic blood pressure (SBP) ≤20% of baseline level or mean arterial pressure (MAP) <60 mmHg and bradycardia as heart rate (HR) <50 bpm which were managed by repeated, iv., mephentermine 3 mg and iv atropine 0.5 mg, respectively. Total dose and boluses of LA used intraoperatively were also recorded. Complications such as severe hypotension/bradycardia/rigors/nausea/vomiting/postdural puncture headache (PDPH)/delayed micturition/meningitis/focal sensory block were observed and managed according to standard protocol. Postoperative pain was evaluated by visual analog score (VAS) every half an hour after surgery. If VAS ≥3, in CSA, as first rescue analgesia, iv. paracetamol 10–15 mg/kg body weight was infused, and in CEA, 10 ml of 0.25% bupivacaine was given via epidural catheter.
Sample size was estimated using previous data from Elfeky et al. taking into consideration the expected proportion of onset time as 5.24 and 18.20 min in CSA and CEA, respectively, with a significance level of α = 0.05 and power of study as 80%. The calculated sample size was 144 (n ≈ 72) [Figure 2]. The collected data were entered into an Excel sheet. Statistical analysis was carried out using IBM SPSS (Statistical Package for the Social Sciences) statistical version 21 (IBM Corp., Armonk, New York, U.S.). Numerical data such as age, weight, height, body mass index, HR, SBP, diastolic blood pressure (DBP), MAP, performance time, induction time, duration of surgery, blockade and analgesia, and intraoperative LA requirement were summarized by mean ± standard deviation (SD) and intergroup and intragroup comparison by Student's t-test. Sex ratio was compared using Z-test for population proportions. Categorical data such as ASA physical status, grade of sensory and motor block, level of block, and incidence of complications were summarized as percentage and compared by Chi-square test. P < 0.05 was considered statistically significant.
| Results|| |
Demographic and surgical profile was statistically comparable in both the groups. None of the patients in either group had block level above T8 [Table 1].
Performance time was significantly higher, while induction time was significantly shorter in CSA as compared to CEA group. Duration of sensory blockade as well as analgesia was significantly higher in CSA group [Table 2]. Maximum number of patients in both the groups reached sensory Grade 2 [Graph 1] and motor Grade 3 block at time P4, i.e., a time taken to reach T10 sensory level [Graph 2]. A significant fall from baseline values in DBP at 20 and 120 min and in MAP at 15 and 120 min intraoperative was observed in CEA. Furthermore, the groups differed significantly with respect to DBP and MAP at similar time intervals [Graph 3] and [Graph 4]. Intraoperative LA requirement was significantly lower in CSA group with respect to mean total dose and mean total volume [Table 3].
Both the groups were comparable in terms of incidence of complications [Table 4]. None of the patients in either group reported any incidence of bradycardia, rigors, delayed micturition, PDPH, meningitis, or focal sensory block. Out of the 4 participants who required general anesthesia, 2 of them encountered failure of catheter insertion under CSA, whereas 2 had inadequate sensory block under CEA. These were excluded from the study.
| Discussion|| |
In the present study, the mean (±SD) induction time in CSA was significantly shorter, while the performance time in CSA was significantly higher than CEA. Maximum number of patients in both the groups reached Grade 2 of sensory block (according to Hollmen's criteria using pinprick test) and Grade 3 of motor block at time P4. The mean (±SD) duration of sensory blockade and analgesia in CSA was significantly higher than CEA. HR, SBP, and SaO2 in CSA and CEA were statistically comparable preoperatively and also at various intraoperative times within the group and between both the groups. In CEA, there was a significant fall in DBP from the baseline intraoperatively at 20 and 120 min and in MAP at 15 and 120 min as compared to CSA. Intraoperative requirement of LA was significantly lower in CSA with respect to mean total dose and mean total volume. There was no significant difference in the incidence of severe hypotension, nausea, and vomiting between the two groups. None of the patients in either group reported any incidence of bradycardia, rigors, delayed micturition, PDPH, meningitis, or focal sensory block.
Significantly shorter induction time in CSA as compared to CEA could be related to the shorter time needed to block spinal nerve rootlets once LA is injected into subarachnoid space. Our findings were consistent with those of Elfeky et al. In contrast, longer induction time (17 ± 11 min vs. 8.14 ± 0.88 min) in CSA as observed by Ebied et al. might be attributed to 0.5% isobaric bupivacaine. Favarel-Garrigues et al. also noted longer induction time (17 ± 1.4 min vs. 8.14 ± 0.88 min) in CSA, which could be because of 30° head-up supine position immediately after first LA injection.
Longer performance time in CSA in the present study might be due to more complexity in catheter introduction and subsequent removal of introducing needle. This was consistent with findings of Elfeky et al. and Amin et al. Use of different types of needles may explain variation in performance time across studies.
In the present study, maximum number of patients in both the groups reached Grade 2 of sensory block (40 vs. 38 patients; P = 0.91) and Grade 3 (complete) of motor block (43 vs. 44 patients; P = 0.86) at induction (P4). Grade of sensory block was assessed according to Hollmen's criteria using pinprick test and the result was similar to that of Camorcia and Capogna, who, in epidural block using the same scale, had observed no differences between right and left side 10th min onward. On the other hand, de Andrés et al. found significantly higher incidence of insufficient analgesia in the CSA group than single-dose spinal anesthesia group (7.7% vs. 0%; P < 0.05), which was attributed to the use of 32G microcatheter whose small diameter and high resistance was responsible for maldistribution. The rest of the reviewed studies assessed the level of sensory block using pin-prick method, but its grading was unclear as ordinal scale was not used. Regarding motor block, the findings of the present study were consistent with previous studies as the grade of motor block was assessed only after T10 level of sensory block had been achieved. Serial assessment of grade of motor block was not done in the present study.
Duration of sensory blockade and analgesia were significantly higher in CSA. Use of different types and different initial doses of LA may explain the variation in two-segment regression time (or duration of sensory blockade) across studies. In previous studies, many authors have evaluated their patients for the need of first rescue analgesia/postoperative analgesia. However, they did not calculate the duration of analgesia, which made comparison with the present study difficult.
Our findings of significantly lower intraoperative MAP from baseline in CEA compared to CSA were similar to that of Elfeky et al. and Sutter et al. However, there was 0.75% fall in SBP from the baseline in CEA group at 20 min as compared to CSA group, which could be explained by the slower development of blockade in that group. This finding was consistent with that of Ahmed Abd El-Ali et al. Greater hemodynamic stability in CSA is attributed to lower initial dose and smaller aliquots of LA used.
As compared to the present study, Amin and Sadek noted higher total dose of hyperbaric bupivacaine used for CSA, i.e., 5.6 ± 0.7 mg, which was because of higher initial dose (2 ml) and top-up (1.2 ml). Ahmed Abd El-Ali et al. also reported higher intraoperative requirement of 0.5% bupivacaine in CSA (6.63 ± 2.88 mg vs. 11.62 ± 2.5 mg) due to higher level of block required for cesarean section. In contrast, Elfeky et al. reported a smaller dose of bupivacaine used in CSA (9.80 mg vs. 11.62 mg), which might be attributed to the addition of fentanyl with initial intrathecal LA.
Hypotension was seen in 6 patients in CEA vs. 2 in CSA and nausea in 3 patients in CSA versus 2 in CEA and these were not statistically significant. One patient each in both the groups had vomiting and this was also not statistically significant. None of the patients in either group reported any incidence of bradycardia, rigors, delayed micturition, PDPH, meningitis, or focal sensory block pointing toward the safety of macrocatheter used for CSA block. The findings of the present study were comparable with previous studies. We used only hyperbaric bupivacaine as repeated doses of lignocaine is established to have neurotoxic effects. Furthermore, the previous studies,,,, have reported no adverse neurological outcomes as well as acceptable hemodynamic effects with multiple intermittent doses of hyperbaric bupivacaine in subarachnoid space. Lower incidence of hypotension in CSA was attributed to smaller aliquots of LA injected to maintain the desired level of block.
The results of the present study cannot be extrapolated to other surgeries requiring higher level of block. Individual differences in subjective experience of pain might affect the grade of sensory block. Different definition of duration of blockade and analgesia made it difficult to compare the result among the studies. Drug administration was limited till the end of surgery and was not extended for postoperative analgesia in CSA due to resistance from the surgical colleagues. Inclusion of patients having wide range of weight might affect the height of block, although considered to be less important.
The same study can be tried in surgeries requiring higher level of block or can be extended in postoperative period to compare the analgesic efficacy. These techniques can be compared using different adjuvants with LA to prolong or improve the quality of block and analgesia.
| Conclusion|| |
Both CSA and CEA are safe centrineuraxial techniques in adults with minimal complications. Although performance time was prolonged in CSA, considering shorter induction time, prolonged sensory blockade, and analgesia with greater hemodynamic stability, CSA could be preferred over CEA for lower limb orthopedic surgeries in adults.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]