Effect of epidural clonidine on characteristics of spinal anaesthesia in patients undergoing gynaecological surgeries: A clinical study

Analgesic efficacy of Clonidine as an adjuvant in ultrasound-guided rectus sheath block for midline incisional hernia repair - A randomized double-blind controlled trial

Background and Aims

Clonidine as an adjuvant has not been evaluated in rectus sheath block (RSB) for postoperative pain management in incisional hernia repair. The study aims to evaluate clonidine as an adjuvant in single-shot RSB along with general anesthesia (GA).

Material and Methods

This randomized, double-blind controlled study was conducted following IEC-Human approval and written informed consent from 30 patients of either sex, aged 16 to 60 years, ASA physical status I or II undergoing midline incisional hernia repair under GA. All patients received ultrasound-guided bilateral RSB following administration of GA. The subjects enrolled in the study were randomly allocated to receive either normal saline 1 mL (group B) or clonidine 1 μg/kg diluted to 1 mL with normal saline (group BC) as adjuvant along with 9 mL bupivacaine hydrochloride 0.25%. Inj. tramadol 1 mg/kg was administered for rescue analgesia. The primary outcome was the time to first request for analgesia, and secondary outcomes were total consumption of rescue analgesic over 24 h, numerical rating score (NRS), patients' satisfaction, hemodynamics, and side effects. Unpaired t-test and Chi-square test were used.

Results

On intergroup analysis, the mean time to first request for analgesia (in min) was significantly higher in group BC i.e., [9.60 (± 5.23) vs 5.33 (± 3.53); (P < 0.034]; whereas, the mean rescue analgesic consumption in 24 h (in mg) was higher in group B i.e., [(88.00 ± 60.97) vs (46.00 ± 48.08)]; (P < 0.045)]. Hemodynamic parameters i.e., mean blood pressure and heart rate were comparable between the two groups, and there were no side effects.

Conclusion

Clonidine as an adjuvant in single-shot ultasonography (USG)-guided RSB along with GA is efficacious for postoperative pain management following midline incisional hernia repair.

Clonidine as a Sole Epidural Adjuvant in Combined Spinal-epidural: Clinical Study

Background and Aims:

Clonidine has been used as an epidural adjuvant along with local anesthetics; however, its use as a sole epidural adjuvant in combined spinal-epidural (CSE) anesthesia has not been explored; thus, this study aimed to assess the effects of clonidine as a sole epidural adjuvant in CSE on sensory and motor characteristics of 0.5% hyperbaric bupivacaine given by subarachnoid route.

Methodology:

A total of 60 patients belonging to the American Society of Anesthesiologists Classes I and II aged 18–60 years were randomized in two groups; group G300 and group GNS. G300 group received 300 mg clonidine and GNS received normal saline through epidural route followed by 15 mg of 0.5% hyperbaric bupivacaine as subarachnoid block. Onset of sensory block (time to T10) and motor block (time to Bromage 3), level of sedation (using Modified Ramsay Sedation Score), and hemodynamic changes were recorded. Two-segment regression, duration of analgesia (time for 1^st rescue analgesia), and motor block (time to Bromage 0) were recorded. Student's t-test (two-tailed, independent) and Chi-square/Fisher's exact probability test were used for statistical analysis.

Results:

The demographic data were comparable between the groups. The onset of sensory and motor block was significantly faster in G300 (sensory-71.63 ± 4.51 s, motor-55.63 ± 2.54 s) as compared to GNS (sensory-90.13 ± 4.88 s, motor-118.43 ± 9.50 s) (P < 0.001 and < 0.001, respectively). The two-segment regression was 199.33 ± 19.11 min and 79 ± 9.77 min in G300 and GNS, respectively, (P < 0.001). Duration of analgesia was 317.90 ± 15.32 min and 207 ± 20.66 min for G300 and GNS, respectively (P < 0.001), and duration of motor block was 409.9 ± 34.87 min and 204 ± 22.79 min for G300 and GNS, respectively (P < 0.001). The side effects such as hypotension and bradycardia were statistically and clinically not significant.

Conclusion:

Clonidine used as a sole epidural adjuvant in dose of 300 mg, for infraumbilical surgeries, has significantly faster onset of sensory and motor block with prolonged duration of analgesia and motor blockade and no significant side effects on a conventional subarachnoid block performed with 0.5% hyperbaric bupivacaine.

Alpha-2 Agonists

Alpha-2 adrenergic receptors are spread throughout the central and peripheral nervous system, specifically in the pontine locus coeruleus, medullospinal tracts, rostral ventrolateral medulla, and the dorsal horn of the spinal cord. Alpha-2 agonist agents cause neuromodulation in these centers, leading to sedation, analgesia, vasodilatation, and bradycardia with little effect on the respiratory drive, which accounts for their good safety profile. The 2 major drugs in this group are clonidine and dexmedetomidine. Their clinical applications in anesthesia practice include providing sedation in the intensive care unit or for minor procedures, adjuvant to general and regional anesthesia, analgesia, and as premedicating agents.