# Abstract

 

## Background and Aims: Ropivacaine is a new amide, long acting, pure S-enantiomer, local anesthetic, with differential blocking effect. The addition of clonidine to local anesthetic improves the quality of peripheral nerve blocks. This study was conducted to evaluate the effect of clonidine on characteristics of ropivacaine-induced supraclavicular brachial plexus block. 

## Material and Methods: A total of 60 adult patients were randomly recruited to two groups of 30 each: Group I: 30 ml 0.75% ropivacaine + 1 ml normal saline. Group II: 30 ml 0.75% ropivacaine + 1 mcg/kg clonidine diluted to 1 ml with normal saline. 

## Results: The onset of sensorimotor block was earlier in Group II (4.36 ± 0.81 min for sensory block and 9.83 ± 1.12 min for motor block) than in Group I (4.84 ± 0.65 min for sensory block and 10.85 ± 0.79 min for motor block). The duration of both sensory and motor block were significantly prolonged by clonidine ( *P* < 0.001). The duration of analgesia was also prolonged in patients receiving clonidine (613.10 ± 51.797 min vs. 878.33 ± 89.955 min). Although incidence of hypotension and bradycardia was higher in Group II when compared to Group I, it was not clinically significant. 

## Conclusions: Ropivacaine 0.75% is well-tolerated and provides effective surgical anesthesia as well as relief of postoperative pain. Clonidine as an adjuvant to ropivacaine significantly enhances the quality of supraclavicular brachial plexus block by faster onset, prolonged duration of sensory and motor block and improved postoperative analgesia, without associated adverse effects at the dose used. # Results There was no statistically significant difference in the demographic profile and the baseline values of hemodynamic variables between the two groups \[ [Table 1](#) \]. One patient in the control group had block failure and was given general anesthesia. He was excluded from further statistical analysis involving block characteristics and hemodynamic changes after the block. ::::table-wrap

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Demographic profile and vital signs
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![](<>):::: Significantly lower pulse rate was observed from 60 min to 180 min in the clonidine group, but was not clinically significant and did not need any intervention \[ [Figure 1](#) \]. <figure> <p><img src="" /></p> <figcaption>Comparison of mean heart rate</figcaption> </figure> Mean arterial pressure dropped at 30-min and remained so until 150-min in the clonidine group \[ [Figure 2](#) \]. No treatment was required for this fall in blood pressure. The hemodynamic parameters were comparable by 180-min. <figure> <p><img src="" /></p> <figcaption>Comparison of mean arterial pressure</figcaption> </figure> The onset of sensory block and motor block was significantly faster in clonidine group than control group \[ [Figure 3](#) \]. <figure> <p><img src="" /></p> <figcaption>Mean onset of sensory and motor block</figcaption> </figure> The duration of sensory block was 703.83 ± 42.90 min in clonidine group when compared to 556.38 ± 37.96 min in control group. The duration of motor block was 621.67 ± 46.76 min in clonidine group and 500.86 ± 44.58 min in control group \[ [Figure 4](#) \]. Both were significantly prolonged in clonidine group ( *P* < 0.001). <figure> <p><img src="" /></p> <figcaption>Mean duration of sensory and motor block</figcaption> </figure> The mean time for rescue analgesia in control group was 613.10 ± 51.797 min and in clonidine group was 878.33 ± 89.955 min. Significantly prolonged duration for rescue analgesia was observed in clonidine group ( *P* < 0.001).


Extracted trial result:
Outcome: onset of motor block (continuous)
Intervention: ropivacaine + diluted clonidine with saline
Comparator: ropivacaine + saline
Intervention group size: 30
Intervention mean: 9.83
Intervention standard deviation: 1.12
Comparator group size: 30
Comparator mean: 10.85
Comparator standard deviation: 0.79
Notes: found in abstract