The subarachnoidal or epidural opioid reveals excellent analgesic effect for postoperative pain and intractable cancer pain, but it side effects such as nausea, vomiting, voiding difficulty, pruritus and respiratory failure limit its use. There
were
many studies for decreasing frequency and severity of side effects and reinforcing the analgesic effect of opioid by administrating other drugs. Clonidine is one of such drugs which is able to be administered epidurally with opioids for that
purpose. We
studied the changes of cardiovascular response, analgesic and sedative effect according to the dose of epidural clonidine.
The analgesic effect of epidural clonidine was investigated in 30 patients who underwent anal surgery with epidural anesthesia using 15 ml of 1.5∼2% lidocaine. The time of maximal intensity of pain after disapperance of injected lidocaine was
checked.
Thirty patients were divided into three groups randomly. In group 1 (n=10), the dose of epidural clonidine was 50㎍; Group 2 (n=10) was 150㎍; Group 3 (n=10) was 450㎍. Changes in the arterial pressure, pulse rate, sedation state and SpO2 were
observed
before and during 60 minutes after epidural clonidine administration. And the analgesic effect was assessed by measuring VAS pain score.
Blood pressures and pulse rates decreased according to increase of dosage of clonidine. Group 1 showed the analgesic effect of 34%, group 2 showed 77% and group 3 showed 81% at 60 minutes after administration. Sedation effect was seen in group 2
and 3
but SpO2 was not decreased significantly. We thought that the respiratory depression of epidural clonidine was not so significant to limit the use for the postoperative pain control.
We conclude that it is better to administer clonidine with opioids epidurally than clonidine alone to get better analgesic effect and less sedative effect, because the analgesic effect of epidural clonidine increases according to increase of
dosage
but
the sedative effect increases also. (Korean J Anesthesiol 1995; 29: 709∼717)
|