European Journal of Cardiovascular Medicine

Spinal anaesthesia has garnered recognition as a safe and effective method for delivering local anaesthetic agents for surgeries involving the lower limbs and the area below the umbilicus. A procedure that induces deep, consistent sensory analgesia and motor blockade with a small amount of drug that has minimal systemic effects is widely regarded as both safe and efficient.[1]

Numerous studies have utilized adjuvants, such as fentanyl, clonidine, ketamine, morphine, and buprenorphine, to prolong the effect of intrathecal bupivacaine, thereby extending the duration of analgesia into the postoperative period. Alpha-2 agonists, substances that enhance the effects of anaesthesia and pain relief, represent a notable group of adjuvants in this context.[2]

Clonidine Hydrochloride is an imidazoline derivative that displays alpha-2 adrenergic agonistic activity, boasting a selectivity ratio of 200:1 in favour of alpha-2 receptors. Intrathecal clonidine has been demonstrated to potentiate the effect of subarachnoid block while also reducing the local anaesthetic agent requirement. Moreover, intrathecal clonidine offers prolonged postoperative analgesia, reduced shivering associated with subarachnoid block, and lacks the side effects commonly observed with intrathecal opioids.[3]

This study set out to evaluate the efficacy of clonidine as an adjuvant to bupivacaine hyperbaric 0.5% in patients undergoing infra-umbilical surgeries.

A prospective observational study was conducted with 60 individuals, aged 18 to 65 years, of both genders, categorized as ASA Grade I or II, and scheduled for infra-umbilical surgery at C.U. Shah Medical College and Hospital in Surendranagar, Gujarat, after receiving study authorization from the Institutional Review Board.

Their participation was based on clear selection criteria, given that participants underwent thorough preoperative evaluations and were categorized, into two groups:

• GROUP A: Participants were administered 3 ml (15 mg) of hyperbaric bupivacaine 0.5% plus 0.2 ml of normal saline intrathecally.
• GROUP B: Consisted of individuals who received 3 ml (15 mg) of hyperbaric bupivacaine 0.5% plus 0.2 ml (30 µg) of clonidine, administered similarly in an intrathecal manner.

Inclusion Criteria:

1. Age Group: 18–65 years
2. ASA Class I and II
3. Candidates requiring infra-umbilical surgical procedures utilizing spinal anaesthesia

Exclusion Criteria

1. Not willing to participate in study
2. Any Contraindication of spinal Anaesthesia like:-
3. Coagulopathies
4. Local Infection
5. Neurological deficits
6. History of drug allergy

All patients were evaluated for their preoperative state one day prior to the scheduled surgery. Demographic information, such as age, gender, weight, and vital signs like heart rate, systolic blood pressure (sbp), diastolic blood pressure (dbp), and oxygen saturation (spo2), were documented. A detailed account of the patient's medical history and examination findings related to the airway, cardiovascular, respiratory, and other bodily systems were recorded. As part of the standard protocol, routine investigations such as complete blood count (cbc), coagulation profile, renal and liver profile, random blood sugar (rbs), chest x-ray, and electrocardiogram (ecg) were conducted on all patients. Patients were instructed to refrain from eating or drinking for a period of 6 hours prior to the surgical procedure.

Preoperative Preparation

Inside the operating theatre, an 18G intravenous (IV) catheter was inserted, and Ringer's lactate IV fluid was initiated. Each subject was connected to a multiparameter monitor for continuous monitoring of vital signs. All patients received 0.2 mg of Glycopyrrolate, 4 mg of Ondansetron, and 1 mg of Midazolam iIntrathecally as premedication.

Technique:

Under strict aseptic precautions, with the patient positioned either sitting or in the left lateral position (depending on the surgery and patient comfort), a 25-gauge quincke spinal needle was used by the anesthetist to perform lumbar puncture at the L3-L4 intervertebral space using a midline approach. The medication was given slowly, ensuring a smooth and uninterrupted flow of cerebrospinal fluid (csf). Patients were then turned to a supine position. Pulse, blood pressure, respiratory rate, and spo2 were recorded every 5 minutes for the first half hour, then every 15 minutes until the surgery was completed. The following observations were made: onset of sensory and motor block, highest dermatomal level, time for two-segment regression, duration of sensory and motor blockade (using the modified Bromage scale), and time until the first request for rescue analgesia.

Sensory block 

A 24-gauge blunt needle was used to assess the degree of sensory block, noted as a loss of sensation to pinprick. The time taken to reach sensory level at the T8 dermatome following subarachnoid injection was documented as the onset of sensory block. The duration of the sensory block was measured by the time taken from the onset of sensory loss to the return of sensation at the T8 level.

Time for two segment regression was noted.

Motor block 

The motor block was assessed by a Modified Bromage scale as follows:

1. No motor block
2. Inability to raise extended leg; but is able to move knees and feet
3. Inability to raise extended leg and move knees; able to move feet
4. Complete block of motor limb

Time of onset : Time from intrathecal injection to grade 3 motor block.

 Duration of motor block : Time from intrathecal injection to grade 0 motor block.

Post operative analgesia:

The level of postoperative pain was evaluated using the Visual Analog Scale (VAS), which ranges from no pain (0) to the worst pain (10). The time taken for the need for rescue analgesia was recorded. The first dose of rescue analgesic was administered when the VAS score was ≥ 4, consisting of 75 mg of intravenous Diclofenac. The duration of analgesia and the time until the first dose of rescue medication were documented.

Statistical analysis:

The recorded data was compiled and entered into a spreadsheet program (Microsoft Excel 2007) on the computer and then exported to data editor page of SPSS Version 26.0 of the Statistical Package for Social Sciences.A P-value of less than 0.05 is considered significant.

Observation and Results:

There was no notable distinction between the two groups in terms of demographic characteristics, as indicated in table 1, with p value>0.05.

Table 1. Demographic characteristics

Table 2. Hemodynamic parameters

Table 2 indicates that all groups were comparable with respect to their hemodynamic parameters, including pulse rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and SpO2. No significant differences were found between the two groups.

Table 3. Onset of Blockage and Two segment regression

Table 3 displays the onset of sensory and motor block, which was similar in both groups. Group B exhibited an earlier onset of sensory blockade at the T8 level, with a mean time of 3.20 ± 0.72 minutes compared to Group A's mean time of 3.57 ± 0.88 minutes; however, this difference was statistically insignificant (p > 0.05). The mean onset of motor blockade (grade 3 Bromage) was also earlier in Group B (mean 3.46 ± 0.84 minutes) than in Group A (mean 3.82 ± 0.90 minutes), but this difference was likewise statistically insignificant (p > 0.05). Notably, the mean time for two-segment regression was significantly faster in Group A (112.86 ± 12.29 minutes) than in Group B (155.18 ± 17 minutes), which was statistically highly significant (p < 0.0001).

Table 4. Duration of Blockage and Analgesia

As shown in Table 4, the mean duration of motor block was significantly longer in Group B (study group) at 225.20 ± 13.2 minutes, compared to Group A (control group) at 172.80 ± 14.4 minutes. Furthurmore, there was a statistically noticeable difference in the length of sensory block between Group B (264.61 ± 19.2 minutes) and Group A (220.39 ± 18.1 minutes). The duration of postoperative analgesia was also significantly longer in Group B (378.06 ± 10.2 minutes) compared to Group A (302.80 ± 17.1 minutes), which was statistically highly significant (p < 0.0001).

Table 5. Side Effects

The above table no.5 shows the side effects experienced in both groups. Two patient in Group B experienced bradycardia, while One patients in Group A had bradycardia; the difference was not statistically significant (p > 0.05). In Group B Five patients experienced hypotension, while only three patients in Group A did so.However, this difference also being non-significant (p > 0.05). Notably, none of the patients in either group experienced nausea or vomiting.

Subarachnoid block is commonly administered for lower abdominal and lower extremity surgeries due to its simplicity and reliability, along with several potential advantages. In recent years, the use of intrathecaladjuvants with local anesthetics has gained popularity to enhance postoperative analgesia and improve the quality of spinal block, facilitating patient’s functional recovery^[4]. Singh RB et al. (2014)^[5]observed that adding a small dose of clonidine to the solution significantly extended the duration of sensory block, motor block, and analgesia in patients undergoing spinal anesthesia (SAB). Therefore, this study aimed to determine the effects of adding intrathecalclonidine to hyperbaric bupivacaine in spinal anesthesia for patients undergoing infra-umbilical surgeries.

Demographic parameters such as age and weight were comparable in both groups.

In our study, we noted that Group B (mean onset time 3.46 ± 0.84 minutes) experienced a quicker onset of motor block (grade 3 Bromage) compared to Group A (mean onset time 3.82 ± 0.90 minutes); however, this difference was statistically insignificant (p > 0.05). Similarly, Arora P et al. (2020)^[6] found that the mean onset time of motor block was faster in Group III (12.5 mg bupivacaine with 30 mcg clonidine) and Group II (bupivacaine 12.5 mg with 15 mcg clonidine) compared to Group I (bupivacaine 12.5 mg alone intrathecally), although the differences were not statistically significant. According to Saxena H et al. (2010)^[7], the onset of motor block in clonidine groups with different doses was faster, but again statistically insignificant.

We also observed that Group B (mean onset time 3.20 ± 0.72 minutes) experienced an earlier onset of sensory block than Group A (mean onset time 3.57 ± 0.88 minutes); this difference was statistically insignificant (p > 0.05). Arora P et al. (2020)^[6] concluded in their study that the mean onset time of sensory block was shorter in Group III (12.5 mg bupivacaine with 30 mcg clonidine) compared to Group II (bupivacaine 12.5 mg with 15 mcg clonidine) and Group I (bupivacaine 12.5 mg alone intrathecally), but this was also statistically insignificant.

In our study, the mean time for two-segment regression was significantly faster in Group A (112.86 ± 12.29 minutes) compared to Group B (155.18 ± 17 minutes), with a statistically significant difference (P < 0.0001). Manish Patil et al. (2018)^[8] found that the time for two-segment regression in the clonidine group (bupivacaine 13.5 mg with 75 mcg clonidineintrathecally) was 204 minutes, in comparison to 126 minutes for the control group (13.5 mg bupivacaine with 0.5 ml normal saline), which was statistically significant (P < 0.01).

We found that the mean duration of motor block was significantly longer in Group B (225.20 ± 13.2 minutes) compared to Group A (172.80 ± 14.4 minutes) (p < 0.0001). Manish Patil et al. (2018)^[8] concluded that the duration of motor block was longer in Group B (bupivacaine 13.5 mg with 75 mcg clonidineintrathecally), lasting 205 minutes, compared to Group A (13.5 mg bupivacaine with 0.5 ml normal saline), which lasted 154 minutes, with a statistically significant difference (P < 0.05). Singh RB et al. (2014)^[5] also found that the mean duration of motor block in Group B (bupivacaine 0.5 percent, 3 ml with 50 mcg clonidine) was significantly longer (280.80 ± 66.88 minutes) than in Group A (bupivacaine 0.5 percent, 3 ml with normal saline) (183.60 ± 77.06 minutes).

On comparing the duration of sensory block between the two groups, a significant prolongation was observed in Group B (264.61 ± 19.2 minutes) compared to Group A (220.39 ± 18.1 minutes), which was statistically highly significant (p < 0.0001). Deshmukh P et al. (2020)^[3] also found that the mean duration of sensory block in Group C (bupivacaine 0.5 percent, 3 ml with clonidine 60 mcg) was substantially longer (340 ± 28.69 minutes) than in Group B (bupivacaine 0.5 percent, 0.4 ml with normal saline) (250.62 ± 30.98 minutes), with this difference being extremely statistically significant.

The mean duration of analgesia was significantly prolonged in Group B (378.06 ± 10.2 minutes) compared to Group A (302.80 ± 17.3 minutes), which was also statistically highly significant (p < 0.0001). This led to decreased need for postoperative analgesics. This finding aligns with the study by Manishpatil et al. (2018)^[8], which reported that the duration of postoperative analgesia in Group B (bupivacaine 13.5 mg with clonidine 75 mcg intrathecally) was 512 minutes, compared to 220 minutes in Group A (13.5 mg bupivacaine with 0.5 ml normal saline) (p < 0.01).

In terms of vital parameters, no statistically significant difference was found, which coincides with the study conducted by De Negri P et al. (1997)^[9], who noted that the addition of 105 mcg clonidine to hyperbaric bupivacaine resulted in minimal changes in vital parameters.

In our study, we observed that side effects such as bradycardia and hypotension were more prevalent in Group B (clonidine group) than in Group A (plain bupivacaine group); however, this difference was not statistically significant. This finding is similar to that of Shah ZA et al. (2012)^[10], who reported no significant differences in heart rate and blood pressure between Group A (bupivacaine heavy 12.5 mg (0.5%) with clonidine 1 mcg/kg intrathecally) and Group B (bupivacaine heavy 12.5 mg (0.5%) with an identical volume of saline).

The present study demonstrated that the addition of clonidine to 0.5% hyperbaric bupivacaine at a dose of 30 µg significantly prolongs the duration of sensory and motor blockade, improves the quality of the block, and increases the duration of analgesia compared to bupivacaine alone. However, the onset time of sensory and motor block was not significantly affected. These outcomes not only decrease the required dose of bupivacaine but also reduce the need for sedatives and other analgesics, all while maintaining minimal acceptable side effects.

Limitation of the study: Further research is needed with a larger sample size. The side effects like  bradycardia and hypotension require more evaluation.

Ethical Clearance: It was taken from the institutional ethics committee.

Source of Funding: Self.

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