¹Assistant Professor, ²Associate Professor, Department of Anaesthesia, ICU and Pain, Shri Guru Ram Rai Institute of Medical and Health Science, Dehradun. Uttrakhand, INDIA.

Email: dranoopnegi@gmail.com

RESULTS

Table 1: Age Distribution

Table 1 shows the age distribution of the study participants. The most common age group in both arms was 31-40 years involving 42% (21) of Group I and 46% (23) of Group II. The mean age for group I and II was 36.12 and 37.6 years respectively and regarding age group the two groups were comparable (p value= 0.502).

Table 2: Sex Distribution

The sex distribution of the study subjects according to their respective group. We observed a male predominance in both groups as 62% (31) of group I and 66% (33) of group II were male. Difference between both groups for sex wise distribution was statistically not significant(p value =0.67).

Table 3: Duration of Surgery

The comparison of mean duration of surgery between two groups. The mean duration of surgery in group I and group II was 75.54±6.50 minutes and 90.02±12.42 minutes respectively. Difference between both groups for duration of surgery was statistically significant (p value =0.001).

Table 4: Onset of Sensory Blockade

The distribution of study subjects in both groups according to the onset of sensory blockade. Onset of sensory blockade was in the range of 121-180 seconds in majority of patients (n=34, 68%) in group I and (n=33, 66%) in group II. The difference in onset of analgesia among both the groups was statistically not significant (p value= 0.699), indicating that addition of clonidine had not shortened the onset of sensory blockade.

Table 5: Onset of Motor Blockade

The distribution of study subjects in both groups according to the onset of motor blockade. Onset of motor blockade was in the range of 241-300 seconds in majority of patients in both groups (n=22, 44%) in group I and (n=23, 46%) in group II. The difference in onset of motor blockade among both the groups was not significant statistically (p value= 0.113) indicating that addition of clonidine had not shortened the onset of motor blockade

Table 6: Grade of motor blockade (Bromage scale 1962)

The distribution of study subjects in both groups according to the grade of motor blockade. All patients had a grade 3 motor blockade in both groups.

Table 7: Level of Sensory Block

The distribution of study subjects in both groups according to the level of sensory block. Majority of patients in both group had level of sensory block up to T7 level. Level of sensory block obtained in both group were statistically not significant (p value= 0.835).

Table 8: Level of Motor Block

The distribution of study subjects in both groups according to the level of motor block. Majority of patients in both group had level of motor block up to T8 level. Level of motor block obtained in both group were statistically insignificant (p value= 0.205).

Table 9: Sedation Score

Comparison of sedation score between two groups is mentioned. In group I (n=28, 56%) of patients were having score of 1 which is significant. In group II (n=48, 96%) of the patients were having sedation score of 0. So, better sedation was achieved by addition of clonidine.

Table 10: Comparison of Mean VAS Score

The comparison of mean VAS score between two groups at different time intervals. Mean VAS score was significantly lower in group I as compared to group II. The difference between the mean VAS score at different time, among both the groups, was statistically significant (p < 0.001).

DISCUSSION

The present study was carried out to evaluate the efficacy of clonidine administered in subarachnoid space with 0.5% bupivacaine (heavy) and its influence on the extent of postoperative analgesia.100 patients of either sex belonging to ASA I and II in age group of 20-60 years and body weight between 45-80 kg were included. All the patients underwent elective lower limb surgical procedures. The patients were divided into two groups of 50 each according to drug administered. The group I received 3ml of 0.5% bupivacaine (heavy) with 0.5ml (75µg) of clonidine. The group II received 3 ml of 0.5% bupivacaine (heavy) alone. Our findings were in consonance with the studies by B.S. Sethi et al.8 and L Niemi.¹⁰ In the study of L Niemi μg.kg-1 of clonidine was added to 15mg of 0.5% bupivacaine administered intrathecally in patients undergoing knee arthroscopy.¹¹ This is consistent with the studies done by Strebel S, et al^[12 Sethi BS, et al.¹³ and Saxena H et al., who observed the complete motor blockade of the lower extremity in all patients.¹⁴ Our study almost concurs with the study conducted by Kaabachi O. et al.¹⁵ who observed the mean duration of motor blockade to be 252±79mins when using clonidine of 1µg/kg. Subarachnoid clonidine alone even in doses up to 450 µg, does not induce motor block or weakness. In contrast subarachnoid clonidine combined with local anaesthetics significantly potentiates the intensity and duration of motor blockade. The explanation could be that alpha₂ adrenergic agonists induce cellular modification in the ventral horn of the spinal cord (motor neuron hyperpolarisation) and facilitates local anaesthetic action. In the present study 15 patients in group I were wide awake (SS-0) compared to48 patients in group II during the intraoperative period. There were 28 patients who had Sedation score 1 and 7 patients had Sedation score 2 in group I. It is quite clear that addition of clonidine has improved sedation in group I which is often a desirable effect during the intra and post operative period. In a study conducted by Saxena H et al.,¹⁴ higher incidence of sedation was seen in the clonidine group (37.5 µg). The authors found 90% of the patients were asleep but arousable in the clonidine group (37.5µg). Jain P N et al. 2003 reported that 60% patients were sedated after 75µg subarachnoid clonidine. Clonidine produces dose-dependent sedation over the dose range 50-900 µg of rapid onset (<20 min) regardless of route of administration.¹⁶ Sedation commonly accompanies the use of clonidine for regional anesthesia, consistent with the known sedative/anesthetic sparing properties of alpha₂ adrenergic agonists by action in the locus cereleus. This brain stem nucleus is associated with a wide variety of physiologic regulatory process, including regulation of sleep and wakefulness and is inhibited by alpha₂ adrenergic agonists via a G-protein mediated mechanism that involves inhibition of adenylatecyclase. In this study patients were closely monitored intraoperatively and postoperatively for complications if occurred. In group I there were 5 patients had hypotension and 5 patients had bradycardia while in group II, 4 patients had hypotension and 5 patients had bradycardia. Incidence of hypotension was not statistically significant and was well control by ephedrine. Two patients in each group had nausea and vomiting. Equal number of patients had shivering in both the groups. No incidence of backache, headache, pruritus, respiratory depression and urinary retention occurred throughout the study. Hence, overall we observed that addition of clonidine (75µg) in subarachnoid block produces excellent intraoperative and postoperative prolonged analgesia with minimal side effects in lower abdominal surgery.

CONCLUSION

Addition of clonidine to 0.5% hyperbaric bupivacaine in the dose of 75 μg significantly improves the quality of block, prolongs the onset as well as duration of motor blockade and increases the duration of analgesia as compared to bupivacaine alone. These outcomes not only decreased the dose of bupivacaine required but also the need of sedatives and other analgesics with minimum acceptable side effects.

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