The effects of adding various doses of clonidine to ropivacaine in spinal anesthesia

In this study, we compared the clinical effects of combined doses of ropivacaine and clonidine.

Seventy-five patients between ages 18 and 75, in ASA I-III groups who were to undergo elective lower extremity surgery, were included in the study with informed consent. Subjects were randomly assigned to 3 groups. Group I: % 1 ropivacaine 12 mg, group II: % 1 ropivacaine 12 mg + clonidine 15 µg, group III: % 1 ropivacaine 12 mg + clonidine 30 µg. Mean arterial pressure, breathing, heart rate and peripheral oxygen saturation, total amount of ephedrine and atropine used, sensory and motor block levels, level of sedation, pain level and complications were monitored.

The mean arterial pressure recorded in group III decreased significantly at 75, 105 and 120 min compared to groups I and II. In group I, time to two segment regression and time to sensory block to S2 was shorter when compared to the other groups (P<0.0001). The time to voiding and the duration of motor blockade was significantly longer in group I in comparison to the other groups. The need for atropine in group III was significantly higher (P<0.001). The incidence of hypotension and the requirement for ephedrine were significantly higher in groups II and III as compared to group I (P<0.01). Similarly, sedation in group III was significantly higher compared to the other groups (P<0.05).

In summary, our study revealed that clonidine can be added to ropivacaine for spinal anesthesia in surgical interventions to obtain deeper and longer sensory and motor block. However, hypotension, bradycardia and sedation should be monitored closely.