The Comparison of Postoperative Analgesic Effect of Morphine-Bupivacaine and Morphine-Bupivacaine-Clonidine Injected Intraarticularly after Knee Arthroscopy / 대한마취과학회지

BACKGROUND: Intraarticular opioids and local anesthetics may provide effective analgesia following knee arthroscopic surgery. However, there are conflicting results about the analgesic effects of a combination of morphine, bupivacaine and clonidine injected intraarticularly following knee arthroscopic surgery. The goal of this study was to determine whether clonidine added to an intraarticular morphine- bupivacaine combination provide an analgesic benefit. METHODS: Thirty patients scheduled for knee arthroscopic surgery under epidural anesthesia were selected and divided to two groups randomly. The patients in Group 1 received a combination of morphine 3 mg 0.25% bupivacaine 30 ml and patients in Group 2 received a combination of clonidine 3microgram/kg and morphine 3 mg in 30 ml of 0.25% bupivacaine intraarticularly following knee arthroscopic surgery. Postoperative pain was assessed using the visual analogue scale (VAS) and changes of arterial blood pressure, heart rate, requirement of additional analgesics, adverse effects and sedation scale were observed at 1, 2, 4, 8 and 24 hours after intraarticular injection. RESULTS: The VAS observed at 4, 8 and 24 hours after intraarticular injection were significantly lower in group 2 than group 1. Blood pressure and heart rate were not significantly changed between group 1 and group 2. The incidence of side effects, injection of additional analgesics and sedation were similar between the groups. There were no significant differences in hemodynamic changes, analgesic requirements, sedation scale or the increase of side effects between group 1 and group 2. CONCLUSIONS: The results suggest that the combination of intraarticular morphine 3 mg in 30 ml 0.25% bupivacaine plus clonidine provides significantly better analgesia than morphine 3 mg in 30 ml 0.25% bupivacaine alone following knee arthroscopy.

The Combined Effect of Epidural Tramadol and Clonidine for Postoperative Analgesia / 대한마취과학회지

BACKGROUND: The efficacy of epidurally administered tramadol hydrochloride, a weak centrally acting analgesic, was studied for the relief of postoperative pain. Clonidine, an alpha2 adrenergic agonist, has nonopiate antinociceptive properties which might be an alternative for postoperative analgesia free of undesirable effects from opioids. The aim of this study was to evaluate the postoperative analgesic effects of an epidural administration with a combination of tramadol and clonidine. METHODS: Sixty patients undergoing lower abdominal surgery were randomly allocated to three treatment groups to be given the following agents by the epidural route: group 1, 10 ml of bupivacaine 0.125%; group 2, 10 ml of bupivacaine 0.125% with tramadol 50 mg; group 3, 10 ml bupivacaine 0.125% with tramadol 50 mg and clonidine 100 microgram. In the recovery room, postoperative analgesia was assessed by the visual analogue scale (VAS) at 30 min, 1, 2, 3, 4, 5 and 6 hour. Vital signs, sedation score and side effects were also checked. RESULTS: VAS scores were significantly lower in group 3 than group 1. In addition, VAS scores were significantly lower in group 3 than group 2 at 4 and 5 hours. Blood pressure, heart rate and sedation scores were not significantly different among the three groups. CONCLUSIONS: The combination of epidural 0.125 % bupivacaine, tramadol 50 mg and clonidine 100 microgram produces more profound and longer postoperative analgesic effects than 0.125% bupivacaine and tramadol 50 mg or only 0.125% bupivacaine for the lower abdominal surgery.

Effects of Clonidine on Postanesthetic Shivering When Administered Late Intraoperatively / 대한마취과학회지

BACKGROUND: Postoperative administration of clonidine is an effective treatment for shivering. However, the ability of this drug to stop postanesthetic shivering when administered intraoperatively remains controversial. Furthermore, the efficacy of clonidine during isoflurane and propofol/fentanyl anesthesia remains unknown. We therefore evaluated the incidence of postanesthetic shivering in patients given clonidine during isoflurane/N2O or propofol/fentanyl/N2O anesthesia. METHODS: Sixty patients scheduled for hysterectomy were divided into 4 groups (each group n = 15):(Group 1:isoflurane/clonidine; group 2:isoflurane/saline; group 3:propofol,fentanyl/clonidine; group 4:propofol,fentanyl/saline). The patients of groups 1 and 2 were anesthetized with N2O/O2/isoflurane and in group 3 and 4 with a continuous infusion of propofol (5 10 mg/kg), fentanyl (0.5 microgram/kg) and N2O. Five minutes before tracheal extubation, patients in each group were randomly assigned to receive saline or 2.5 microgram/kg clonidine intravenously. Postanesthetic shivering was evaluated by a blind investigator. We checked mean arterial pressure, pulse, rectal temperature at baseline, immediately after extubation, and subsequently at 5 min intervals for 60 min. RESULTS: Postoperative shivering was observed in 33% of the patients given isoflurane without clonidine and in 13% of the patients given propofol without clonidine (p < 0.05). No patient given clonidine shivered. The incidence of postanesthetic shivering was less after propofol anesthesia than after isofurane/ N2O anesthesia. Clonidine administration 5 minutes before tracheal extubation improved hemodynamic changes without respiratory depression. CONCLUSIONS: A late intraoperative bolus adminstration of 2.5 microgram/kg clonidine prevents postoperative shivering in patients given either type of anesthesia.

The Effect of Clonidine Added to Bupivacaine on Intercostal Nerve Block for Postoperative Pain Control / 대한마취과학회지

BACKGROUND: The addition of clonidine to local anesthetics for regional block has been shown to increase the duration of anesthesia and analgesia. This study was designed to determine whether the addition of clonidine to bupivacaine would produce an extension of the analgesic effect after intercostal nerve block (ICNB). METHODS: After informed consent, 30 ASA 1 or 2 patients undergoing appendectomy under general anesthesia were randomly divided into two groups. Before induction of anesthesia, ICNB using a posterior approach was performed with 15 ml of 0.25% bupivacaine plus epinephrine 1:200,000 with (Group BEC; n = 15) or without (Group BE; n = 15) clonidine 75 microgram. Analgesia was assessed by cold testing at 1/min intervals until cold sensation decreased. The duration of analgesia (time between injection and onset of pain) was recorded. We also recorded the visual analogue scale (VAS) of pain, the number of supplemental analgesics, heart rate and blood pressure, and side effects over 24 hours postoperatively. RESULTS: The onset time, duration of analgesia, number of analgesics, and heart rate and blood pressure were comparable in both groups. VAS scores were significantly lower in Group BEC than in Group BE at 12, 16, and 20 hours postoperatively. CONCLUSIONS: The addition of clonidine to bupivacaine with epinephrine may be a useful adjunct and can prolong the duration of analgesia after ICNB without significant side effects.

Effects of Oral Clonidine and Intravenous Esmolol on Blood Pressure and Heart Rate during Tracheal Intubation / 대한마취과학회지

BACKGROUND: This study was designed to determine the efficacy of a combined use of oral clonidine and intravenous esmolol for blunting the sympathetic response during tracheal intubation. METHODS: Forty-eight patients for hysterectomy were randomly divided into four groups: placebo A and B in Group I (n = 12), placebo A and esmolol (1.0 mg/kg) in Group II (n = 12), clonidine (4 microgram/kg) and placebo B in Group III (n = 12), and clonidine (2 microgram/kg) and esmolol (0.5 mg/kg) in Group IV (n = 12) were administered respectively. Premedication with oral clonidine or placebo A at 90 minutes before induction and intravenous esmolol or placebo B just prior to induction were given. Patients were induced with thiopental and ventilated with N2O-O2-enflurane (1.5 vol%). Vecuronium was given immediately after administration of thiopental for tracheal intubation. BP and HR were recorded at the resting state before premedication (control), at 1 min before induction (T - 1), immediately after intubation (T + 0), 3 min and 5 min after intubation (T + 3 and T + 5), and were converted into a percentage (%) of the control value (Vcontrol). RESULTS: SBP increased in Group I (T + 0 and T + 3) and decreased in Group III (T + 5) compared with Vcontrol (P < 0.05). HR increased in Group I (T + 0 and T + 3) and Group III (T + 0) compared with Vcontrol (P < 0.05). SBP% of Vcontrol in Groups II, III and IV (T + 0 and T + 3) were lower than that of Group I (P < 0.05). HR% of Vcontrol in Group II and IV (T + 0, T + 3 and T + 5) were lower than those of Groups I and III (P < 0.05). There were one episode of hypotension in Group II at 5 min after intubation and two cases of intraoperative hypotension in Group III. CONCLUSIONS: Combined administration of oral clonidine and intravenous esmolol was effective in attenuating the increase of BP and HR during tracheal intubation without any side effects. This combined method would be an effective method when dose-related side effects of each drug limit their use.

The Influence of Anesthetic Technique on the Responses of White Blood Cells and Interleukin-6 in Patients Undergoing Low Abdominal Surgery / 대한마취과학회지

BACKGROUND: Surgical trauma and anesthesia are associated with postoperative immune suppression. Alterations in immune response have been suggested in the same surgery, according to anesthetic techniques. Therefore, this study was conducted to investigate whether regional anesthesia or premedication with clonidine change postoperative circulating neutrophils, lymphocytes and monocytes, and interleukin 6 (IL-6) responses. METHODS: Thirty patients undergoing elective low abdominal surgery were randomly divided into 3 groups: the control group and spinal group received no premedication and the clonidine group received general anesthesia with clonidine premedication. Blood samples were obtained to measure subpopulations of white blood cells (WBC) and IL-6 at pre-induction, immediately after the operation, and 24 h after incision. RESULTS: Increase in total WBC and percentage of neutrophils, decrease in percentage of lymphocytes and monocytes, and increase in IL-6 levels were significant after surgery, compared to the baseline values within the three groups. However, no significant differences of subsets of WBC and IL-6 level were seen among the groups throughout the study periods. CONCLUSIONS: Anesthetic technique did not influence the levels of circulating WBC and IL-6.

The Effect of Clonidine Pretreatment on Cardiovascular Response and Seizure Duration according to Electroconvulsive Therapy / 대한마취과학회지

BACKGROUND: Elecroconvulsive therapy (ECT) is frequently associated with cardiovascular complications such as hypertension and tachycardia. The aim of this study was to evaluate whether clonidine given as an oral preanesthetic medication would influence the hemodynamic stress response, peripheral oxygen saturation and seizure duration which follows ECT. METHODS: Twenty-two ASA physical status I, II patients with major depressive disorders were included in a crossover study design and assigned randomly to either a control group who received placebo, or a clonidine group who received oral clonidine of 3 microgram/kg 90 min before preparation of ECT. All patients received glycopyrrolate 0.2 mg intramuscularly 60 min before anesthetic induction. Electrocardiography, pulse oximetry, and blood pressure monitors were applied to all patients. Patients were pre-oxygenated with 100% O2. Patients received thiopental 2.5 mg/kg and succinylcholine 0.5 mg/kg for anesthetic induction. Noninvasive mean arterial blood pressure (MAP), heart rate, and oxygen saturation were recorded just before test drug administration, immediately before ECT, and each minute for five minutes after ECT. The times from ECT stimulus to the cessation of clonic-tonic motor activity in the "isolated" arm were noted. RESULTS: There was a significant decrease in MAP (P = 0.007) through the peri-ECT period in groups with oral clonidine pretreatment (3 microgram/kg) relative to the control group. There were no significant differences in heart rate and peripheral oxygen saturation values between two groups. The duration of motor seizure activity was similar between the clonidine pretreatment and placebo groups. CONCLUSIONS: We conclude that oral clonidine 3 microgram/kg as a pretreatment medication is effective in attenuating the MAP increase in routine ECT.

The Effects of Pressor Response upon Intravenous Ephedrine Following Oral Clonidine Premedication in Anesthetized Patients / 대한마취과학회지

BACKGROUND: In some studies, 5 microgram/kg clonidine premedication was claimed to enhance the pressor effects of ephedrine in anesthetized patients. We studied hemodynamic responses to intravenous responses, themselves responses to intravenous ephedrine in patients who received clonidine 3 microgram/kg. METHODS: 40 ASA pysical status I or II patients were randomly assigned to either the clonidine group (n = 20), receiving oral clonidine 3 microgram/kg 90 min before general anesthesia, or the control group (n = 20), receiving no clonidine. Hemodynamic measurements were made at one-minute intervals for ten minutes after ephedrine 0.1 mg/kg was injected as a bolus. RESULTS: The magnitude of maximal systolic blood pressure increases in the clonidine group (13.2+/-9.3%) was no different in the control group (12.4+/-12.3%). There were no difference in the pressor effect and duration of response of ephedrine in both groups. CONCLUSIONS: The pressor effect of ephedrine is not enhanced in patients given 3 microgram/kg clonidine premedication during general anesthesia.

The Effect of Intrathecal Tramadol and Clonidine on Saddle Block with Heavy Bupivacaine / 대한마취과학회지

BACKGROUND: The saddle block with heavy bupivacaine is confinal to the lower lumbar and sacral dermatomes. We reduced the infusion dose of bupivacaine to confine the blocked area to the perineum, and evaluated intrathecal bupivacaine with intrathecal bupivacaine and tramadol or clonidine for their anesthetic and analgesic effect in patients undergoing hemorrhoidectomy. METHODS: Sixty patients (ASA I - II, aged 20 to 55) scheduled for hemorrhoidectomy were divided into three groups. We gave a 0.2 ml placebo (0.9% normal saline) in the control group (n = 20), 0.2 ml tramadol (10 mg) in the tramadol group, and 0.2 ml clonidine (50 microgram) in the clonidine group (n = 20) intrathecally 1 minute after saddle block with 0.5% heavy bupivacaine 2 mg. We compared the effects of the sensory and motor blocks by using the analgesic time and the degree of anal relaxation and the side effects. RESULTS: The analgesic time was greater in the tramadol group than is the control group (P < 0.05), and in the clonidine group if was group then in the tramadol group (P < 0.05) and the control group (P< 0.01). Anal relaxation for hemorrhoidectomy in the tramadol group and the clonidine group was better than that of the control group. The incidence of paresthesia of the foot in the clonidine group (n = 16) was higher than in tramadol group (n = 3) and the control group (n = 1) (P < 0.01). The incidence of patients with urinary retention was significantly lower in the control group than in the tramadol group (n = 3) and the clonidine group (n = 4). CONCLUSIONS: Both bupivacaine 2 mg with tramadol and clonidine were efficient in hemorhoidectomy provided good conditions for hemorhoidectomy.

The Effect of Intrathecal Tramadol and Clonidine on Saddle Block with Heavy Bupivacaine / 대한마취과학회지

BACKGROUND: The saddle block with heavy bupivacaine is confinal to the lower lumbar and sacral dermatomes. We reduced the infusion dose of bupivacaine to confine the blocked area to the perineum, and evaluated intrathecal bupivacaine with intrathecal bupivacaine and tramadol or clonidine for their anesthetic and analgesic effect in patients undergoing hemorrhoidectomy. METHODS: Sixty patients (ASA I - II, aged 20 to 55) scheduled for hemorrhoidectomy were divided into three groups. We gave a 0.2 ml placebo (0.9% normal saline) in the control group (n = 20), 0.2 ml tramadol (10 mg) in the tramadol group, and 0.2 ml clonidine (50 microgram) in the clonidine group (n = 20) intrathecally 1 minute after saddle block with 0.5% heavy bupivacaine 2 mg. We compared the effects of the sensory and motor blocks by using the analgesic time and the degree of anal relaxation and the side effects. RESULTS: The analgesic time was greater in the tramadol group than is the control group (P < 0.05), and in the clonidine group if was group then in the tramadol group (P < 0.05) and the control group (P< 0.01). Anal relaxation for hemorrhoidectomy in the tramadol group and the clonidine group was better than that of the control group. The incidence of paresthesia of the foot in the clonidine group (n = 16) was higher than in tramadol group (n = 3) and the control group (n = 1) (P < 0.01). The incidence of patients with urinary retention was significantly lower in the control group than in the tramadol group (n = 3) and the clonidine group (n = 4). CONCLUSIONS: Both bupivacaine 2 mg with tramadol and clonidine were efficient in hemorhoidectomy provided good conditions for hemorhoidectomy.

The Effect of Intravenous or Epidural Clonidine on Intra- and Postoperative Analgesia / 대한마취과학회지

BACKGROUND: Intravenous and epidural clonidine both produce intraoperative hemodynamic stability and analgesia. The study was designed to investigate the analgesic effect of epidural or intravenous clonidine as the sole analgesic agent during and after operation. METHODS: Thirty nine patients undergoing total abdominal hysterectomy under general anesthesia with propofol were studied. At induction, clonidine infusion was started at the dose of 5 microgram/kg in 10 ml during 15 min, followed by 1 microgram/kg/hr (5 ml/hr) either by the epidural (n=19) or the intravenous route (n=20). During the operation, increase in blood pressure and heart rate that did not response to propofol (0.5 mg/kg) was treated with fentanyl (1 microgram/kg). Clonidine and propofol were discontinued at the beginning of peritoneal closure. Postoperative analgesia was assessed by patient-controlled analgesia (PCA) requirements and the visual analogue scale at rest and cough 0, 1.5, 3, 6, 12, 18, 24, 36 and 48 after surgery. Sedation score and side effects were also recorded. The concentrations of plasma epinephrine, norepinephrine and glucose were measured before and after clonidine infusion. RESULTS: The total doses of propofol and fentanyl used intraoperatively were not different between the two groups. Epidural and intravenous clonidine maintained the intraoperative hemodynamic stability at the same extent. The concentrations of plasma epinephrine and norepinephrine in the two groups were not increased after the clonidine infusion. Compared with intravenous clonidine, epidural clonidine significantly prolonged the time to first PCA use and reduced the postoperative PCA requirements during the first 12 hours. CONCLUSIONS: Epidural or intravenous clonidine used as the sole analgesic agent provided the hemodynamic stability associated with surgical stimulation without major side effect. Epidural clonidine produces better postoperative analgesia than intravenous clonidine.

The Effect of Epidural Clonidine on Plasma Catecholamine Response during General Anesthesia / 대한마취과학회지

BACKGROUND: Tracheal intubation and skin incision are potent stimuli that can induce increased sympathetic activity, tachycardia and hypertension. The purpose of this study is to evaluate whether the epidural clonidine pretreatment reduce the sympathetic activity and cardiovascular response. We compared the hemodynamic changes and catecholamine concentration before, during and after general anesthesia with epidural clonidine pretreatment. METHODS: Forty patients undergoing lower abdominal surgery were randomly allocated into the two groups. In Group 1, 10 ml of 0.9% normal saline was administered epidurally 15 minutes before induction of anesthesia as control. In Group 2, 3 microgram/kg clonidine diluted in 10 ml normal saline was administered epidurally 15 minutes before induction of anesthesia. We measured the blood pressure, heart rate and plasma catecholamine concentration at preinduction, 1 minute after intubation (T1), 1 (T2) and 30 minutes after skin incision (T3), 1 (T4) and 2 (T5) hours after arrival at recovery room and the results were compared between group 1 and group 2. RESULTS: There was statistically significant difference in systolic pressure at T1 and T2 between the two groups. Heart rate was statistically significant difference at T1 and T4 between the two groups. There was statistically significant difference in epinephrine and norepinephrine concentration at T1 and T2 between the two groups. CONCLUSION: The elevation of blood pressure, heart rate and plasma catecholamine concentration accompanying tracheal intubation and skin incision may be reduced by administration of epidural clonidine.

Postoperative Analgesia for Arthroscopic Knee Surgery with Intraarticular Bupivacaine and Clonidine / 대한마취과학회지

BACKGROUND: A randomized, double-blind, controlled study was conducted in patients undergoing elective knee arthroscopy to assess the analgesic effect of intraarticular bupivacaine alone and the combination of bupivacaine and clonidine. METHODS: Patients in bupivacaine group (n=15) received 0.125% bupivacaine 20 ml, patients in the bupivacaine and clonidine group (n=15) received a combination of 0.125% bupivacaine 20 ml and 150 microgram clonidine. These drugs were injected each other intraarticularly. We assessed postoperative pain by visual analogue scale (VAS) score at 1, 2, 3, 6, 12 and 24h after intraarticular injection. The need for supplemental analgesia was recorded. And the side effects of two groups were evaluated. RESULTS: VAS scores were significantly increased at 6hr after surgery than other times in bupivacaine group (p<0.05), but there was no significant difference of VAS score in bupivacaine and clonidine group. And in bupivacaine and clonidine group, VAS scores were significantly lower than that in bupivacaine group at 6 hr and 12 hr after surgery (p<0.05). Analgesic requirment was not used in bupivacaine and clonidine group, but 9 patients in bupivacaine group requires analgesics. Side effect in both groups, like hypotension and bradycardia, did not occur. CONCLUSIONS: Intraarticular 150 microgram clonidine with 0.125% bupivacaine 20 ml was significantly reduced postoperative pain following knee arthroscopy without side effect.

Clinical Effects of Addition of Clonidine to Ldegrees Cal Anesthetics in Hypertensive Patients Undergoing Senile Cataract Surgery / 대한마취과학회지

BACKGROUND: Although the effect of clonidine, an alpha2 adrenoreceptor agonist, is well established, there is no study to evaluate the effects of addition of clonidine to ldegrees Cal anesthetics in elderly hypertensive patients. The aim of this study is to evaluate the effects of addition of clonidine to ldegrees Cal anesthetics in elderly hypertensive patients undergoing senile cataract surgery. METHODS: Forty elderly hypertensive patients who scheduled for elective senile cataract surgery were divided into two groups. The control group (n=20) received oral diazepam 0.1 mg/kg 60 min before surgery and the clonidine group (n=20) did not received premedication. A mixture of 2% liddegrees Caine and 0.5% bupivacaine with normal saline 0.7 ml (control group) or clonidine 100 ug (clonidine group) was used as a ldegrees Cal anesthetics. Perioperative blood pressure, heart rate, sedation score, and intradegrees Cular pressure were measured. RESULTS: After anesthesia, there was a significant fall in blood pressure and intradegrees Cular pressure in clonidine group, and increase in sedation score in clonidine group than control group. There was no difference in the perioperative heart rate between the two groups. CONCLUSIONS: The above results show that addition of clonidine to ldegrees Cal anesthetics in elderly hypertensive patients undergoing senile cataract surgery produced reduction in blood pressure, intradegrees Cular pressure and produced intraoperative sedation.

Effects of Epidural Clonidine on Lidocaine Epidural Anesthesia / 대한마취과학회지

BACKGROUND: This study was undertaken in surgical patients to evaluate the comparative analgesic, hemodynamic, sedative effects of clonidine or epinephrine when added to lidocaine solution in patients receiving epidural anesthesia. METHODS: The effects of clonidine were assessed in 38 men scheduled for knee surgery. Patients received 20 ml of 2% lidocaine with clonidine 50 microgram (group C50, n=11), with clonidine 100 microgram (group C100, n=10), with epinephrine 100 microgram (group E, n=9), or plane (group L, n=8) via epidural catheter. Sensory anesthetic level was assessed by pinprick and the time to L1 analgesia and the maximum number of segments of analgesia were checked. Systolic blood pressure (BP) and heart rate (HR) were measured at 2, 5, 10, 15, 20, 30, 45, 60 min after epidural injection. Sedation was defined on a scale of 0 to 3. The sedation score was checked at 5-minute intervals after epidural injection. Samples of venous blood were obtained before and 5, 10, 20, 30, 45, 60, 90 min after epidural injection. RESULTS: No significant differences in the time of L1 analgesia and number of segments of analgesia found at any observation period among the four groups of patients. There was no decrease in BP and no differences among four groups. HR decreased significantly in patients given clonidine, but did not change in those given lidocaine plain or with epinephrine. Significant differences were also observed in sedation scores between clonidine group and group L or E. Maximal plasma lidocaine concentrations in group C100 were similar to the group C50 and L, but were significantly greater than those in group E (p<0.05). CONCLUSIONS: These results indicate that the addition of clonidine to lidocaine for epidural anesthesia provides a sedative effect and relatively stable hemodynamics, and that clonidine in a concentration 1:200,000 in contrast to 1:200,000 epinephrine, tends to increase rather than to suppress the plasma lidocaine concentration.

The Effect of Clonidine Added to Lidocaine on the Duration of Anesthesia and Analgesia after Brachial Plexus Block / 대한마취과학회지

BACKGROUND: When clonidine is mixed with local anesthetics, it extends the duration of both the motor and sensory elements of spinal, epidural, axillary, peripheral nerve block. This study was designed to determine whether the addition of clonidine to 1% lidocaine would produce significant extension of anesthetic and analgesic effect after axillary brachial plexus block and to assess the incidence and severity of side effect. METHOD: Sixty patients who were scheduled for hand surgery received 1% lidocaine 40 ml (Group L), 1% lidocaine 40 ml with clonidine 75 microgram (Group C75) or 150 microgram (Group C150) during axillary plexus block. Time from the performance of the block to 1) loss of pain sensation to pinprick, 2) return of pain sensation to pinprick, 3) onset of postsurgical pain and 4) time of first analgesic medication were recorded. Blood pressure, heart rate and sedation and pain score were checked every 10 min after block. RESULTS: The onset time of anesthesia in Group C75 and Group C150 were shorter than that of Group L (p<0.05). The duration of anesthesia and analgesia and the time to first analgesics medication in Group C75 and Group C150 were longer than that of Group L (p<0.05). Group C75 and Group C150 represented higher sedation score than Group L (p<0.05). CONCLUSION: The addition of clonidine (75 microgram or 150 microgram) to 1% lidocaine significantly prolongs the duration of anesthesia and analgesia after brachial plexus block and induces some degree of sedation without significant side effects.

Effects of Clonidine Pretreatment on Bupivacaine-Induced Cardiac Toxicity Resuscitation in Dogs / 대한마취과학회지

BACKGROUND: Bupivacaine is a amide type local anesthetic agent, widely used for its excellent quality of analgesia and long duration of action. But unintended intravenous injection causes severe complication such as convulsion and cardiovascular collapse, which is known for its difficulty in resuscitation. With all the study, the exact mechanism is still unclear and there are much debate on the method of resuscitation. METHOD: We studied the effect of clonidine pretreatment on bupivacaine-induced cardiac toxicity and resuscitation in anesthetized dog. Twelve dogs were divided into two groups. : saline pretreatment group (control, N=6) and clonidine pretreatment group (clonidine group, N=6). The dogs were anesthetized with N2O-O2-enflurane and vecuronium. Thoracotomy was done in 4th or 5th intercostal space for open cardiac massage. After confirming stability of vital signs, we administered clonidine (10 mcg/kg) or saline, and then administered bupivacaine with the rate of 2 mg/kg/min. When the electeocardiogram showed asystole, 20 mcg/kg of epinephrine was administered via central venous line and open cardiac massage with the rate of 120 beat/min. was performed. We observed electrocardiogram (lead II), arterial blood pressure, heart rate, dose of infused bupivacaine to be required for QRS widening and arrest, required time and administered dose of epinephrine for resuscitation. RESULTS: Clonidine group showed significant decrease of heart rate after pretreatment (p<0.05). There was no significant difference in required dose for QRS widening between two groups. The dose administered for inducing arrest was less in clonidine group than control group (p<0.05). The time required for resuscitation was shorter in clonidine group than control group (p<0.05). The total dose of epinephrine required for resuscitation was less in clonidine group than control group (p<0.05). The blood concentration of catecholamine did not showed significant difference during the whole course of experiment. CONCLUSIONS: Above results demonstrated that clonidine, a central nervous system-mediated sympatholytic agent, facilitated cardiac arrest when bupivacaine was infused intravenously and cardiac rescucitation.

Effect of Intrathecal Clonidine in Hyperbaric Bupivacaine Spinal Anesthesia / 대한마취과학회지

BACKGROUND: Vasoconstrictors have been used as an adjunct to local anesthetics to prolong the duration of spinal anesthesia. Recently, clonidine, an 2-receptor agonist has been shown to prolong the duration of spinal anesthesia following intrathecal administration. Bupivacaine has been used for spinal anesthesia and compared with tetracaine in recent studies. We have undertaken this study to further evaluate the effect of clonidine in hyperbaric 0.5% bupivacaine spinal anesthesia. METHODS: Thirty patients who were scheduled for lower limb or urologic operation were divided into 2 groups: Group A (hyperbaric bupivacaine 13 mg, 2.6 ml + N/S 1 ml), Group B (hyperbaric bupivacaine 13 mg, 2.6 ml + clonidine 150 g, 1 ml). We used standardized techniques and injected above drugs to group A and B intrathecally for spinal anesthesia. We investigated the onset and the duration of spinal anesthesia along with hemodynamic changes (blood pressure and heart rate) in patients. RESULTS: There were no significant differences in the onset of spinal anesthesia and hemodynamic changes between two groups. The time taken to recover from the nerve block was more prolonged in the group B (touch 225, pain 262, foot dorsiflexion 271, knee flexion 290 minutes) than group A (touch 154, pain 188, foot dorsiflexion 198, knee flexion 216 minutes). There were no significant differences in sedation, and in experiencing dry mouth and other side effects between two groups. CONCLUSION: Intrathecal clonidine 150 g has been proved to prolong the duration of hyperbaric 0.5% bupivacaine spinal anesthesia without neurotoxicity or dangerous hemodynamic depression. Therefore, clonidine can be used as an effective adjunct in hyperbaric bupivacaine spinal anesthesia.

Effect of Clonidine on the Blood Pressure, Heart Rate and Plasma Catecholamine Concentration during General Anesthesia / 대한마취과학회지

BACKGROUND: Induction of general anesthesia with tracheal intubation and skin incision are potent stimuli that can induce increased sympathetic activity, heart rate and blood pressure. We compared the hemodynamic response and catecholamine concentration during general anesthesia with intravenous clonidine pretreatment, a centrally acting -2 adrenoceptor agonist, and without pretreatment. METHODS: Forty ASA I or II patients aged from 20 to 60 years undergoing elective surgery were randomly allocated to two groups. In group I, 5 ml of 0.9% normal saline as control administered intravenously 10 minutes before induction of anesthesia, and anesthesia was induced with thiopental sodium, succinylcholine and maintained with N2O (2.5L/min)-O2 (2.5L/min)-enflurane (1.3~1.8 vol%). In group II, 4 g/kg clonidine diluted in 5ml of normal saline administered intravenously 10 minutes before induction of anesthesia, and anesthesia was induced with thiopental sodium, succinylcholine and maintained with N2O-O2-enflurane (0.5~1.0vol%) and 2 g/kg/hr clonidine was continuously infused. We measured blood pressure, heart rate and plasma catecholamine at preinduction, 1 minute after intubation (T1), 1 (T2) and 30 minutes after skin incision (T3) and compared with group I. RESULTS: There was statistical significance in systolic and diastolic pressure at T1 between two groups. There was statistical significance in heart rate, epinephrine and norepinephrine at T1, T2 and T3 between two groups. CONCLUSION: The elevation of blood pressure, heart rate and plasma catecholamine accompanying tracheal intubation and skin incision may be prevented by administration of intravenous clonidine.

Continuous Epidural Clonidine for Analgesia after Cesarean Section / 대한마취과학회지

BACKGROUND: Clonidine, an 2-adrenergic agonist, shows the analgesic effect and potentiates the analgesic effect of opioid. However, when it is injected with bolus technique, it reveals the short duration of inadequate analgesia and induces hypotension, bradycardia or sedation. We examined the analgesic and side effects of clonidine administered by continuous epidural infusion over 24 hrs, following epidural morphine injection. METHODS: Sixty parturients, scheduled for elective cesarean section under epidural anesthesia were randomly allocated into three groups. They received an infusion of saline alone (group 1, n= 20), clonidine 20 g/hr (group 2, n= 20), or 40 g/hr (group 3, n= 20) respectively, following epidural morphine 3 mg injection at the end of operation. The total doses and number of request for supplemental analgesic, blood pressure, heart rate, and degree of sedation were measured during 24 hrs. RESULTS: There were significant differences in pain relief between clonidine groups and group 1. The total doses and number of patient's request for supplemental analgesic in clonidine groups, compared to group 1 were significantly decreased (p<0.05), but no significant differences between the two clonidine groups. The diastolic pressure of group 3 was significantly lower than that of group 1 over 24 hrs, and that of group 2 at 18 hr, 24 hr (p<0.05). However, there was no severe hypotension, bradycardia or sedation in the three groups. CONCLUSION: Clonidine administered by continuous epidural infusion over 24 hrs enhances the analgesic effect of epidural morphine, and the infusion of clonidine with 20 g/hr rather than 40 g/hr shows minimal changes of blood pressure. Therefore, administration of epidural clonidine (20 g/hr) following epidural morphine may be considered as a regimen for pain management after cesarean section.