Intrathecal ropivacaine and clonidine for ambulatory knee arthroscopy

ABSTRACT

The aim of this study was to compare intrathecal ropivacaine at different doses with that after the addition of clonidine. A prospective double blinded, computer randomized study was conducted on 150 patients, classified as American Society or Anesthesiology physical status 1 and scheduled for knee arthroscopy. The patients were randomly assigned to receive 4 ml of the following double blinded isobaric solution 8 mg of ropivacaine [group 1, n = 30], 12 mg of ropivacaine [group 2, n = 30], 8 mg of ropivacaine plus 15 mug clonidine [group 3, n = 30], 8 mg ropivacaine plus 45 mug clonidine [group 4, n = 30] and 8 mg ropivacaine plus 75 mug clonidine [group 5, n = 30]. The level and duration of sensory anesthesia were recorded along with the intensity and duration of motor block. The patients were interviewed to identify the transient neurologic symptoms. The study concluded that ropivacaine 12 mg alone produces an adequate quality of anesthesia, but sensory and motor blockade are prolonged. So, a small dose of intrathecal clonidine [15 mug] plus 8 mg intrathecal ropivacaine produces an adequate and short-lasting anesthesia for knee arthroscopy