Combination of Small Doses of Subarachnoid Bupivacaine/Fentanyl and Epidural Bupivacaine in Combined Spinal-Epidural Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: An intrathecal injection of a small-dose local anesthetic and an opioid using combined spinal-epidural anesthesia (CSEA) technique is a new trend in regional anesthesia for cesarean section. Prophylactic epidural injection may be useful to complete the new regimen. METHODS: Spinal anesthesia via the CSEA technique was performed with 6 mg 0.5% hyperbaric bupivacaine plus 20ng fentanyl in 75 parturients undergoing cesarean section. group S (study, n = 38) received an epidural injection of 10 ml of 0.25% bupivacaine 5 min after intrathecal injection, and was compared with group C (control, n = 37) in sensory levels and Bromage scores, incidences of side effects such as hypotentsion, pain and discomfort, nausea and vomiting, dizziness, pruritus and shivering. Recovery times from sensory and motor block and the duration of postoperative analgesia were assessed between the groups. RESULTS: Sensory block levels were higher (but remained

Comparison between Epidural Analgesia and Combined Spinal-Epidural Analgesia for Labor and Delivery / 대한마취과학회지

BACKGROUND: This study was designed to compare analgesic efficacy and side effects of intrathecal morphine and fentanyl with epidural bupivacaine. METHODS: Twenty nine healthy women, ASA physical status 1 or 2 with an uncomplicated pregnancy and single fetus in vertex position were given lumbar epidural or combined spinal-epidural analgesia. In the epidural analgesia group (n = 18), 0.25% bupivacaine 8 - 10 ml and fentanyl 50 - 75ng was injected into the epidural space. In the CSE group (n = 11), analgesia performed dural puncture with a 27 gauge spinal needle and fentanyl 15ng and morphine 0.2 mg in 2 ml normal saline solution was injected. In both groups, whenever the patient requests further analgesia, we injected 0.125% bupivacaine 10 ml and fentanyl 50 - 75ng into the epidural space. RESULTS: There was no significant difference between the two groups in duration of analgesia, the second stage of labor and pushing. The CSE group offers rapid onset time. The total dose of bupivacaine and fentanyl administered during analgesia was significantly more in the epidural group than the CSE group. After intrathecal fentanyl 15ng and morphine 0.2 mg, the duration of analgesia was 162 +/- 122 min. After the first 0.25% bupivacaine 10 ml and fentanyl 50 - 75ng, it was 92.5 +/- 5 min in the epidural group and 190 +/- 101 min in the CSE group (P < 0.05). CONCLUSIONS: Compared with epidural analgesia, Intrathecal fentanyl 15ng and morphine 0.2 mg as part of CSE analgesia provide rapid onset time and prolonged analgesia, and a lower total dose of local anesthetics for labor and delivery. However women who received CSE analgesia were more likely to itch (64%) than solely epidural analgesia.

Influence of Temperature and Injection Speed of a 0.5% Bupivacaine Solution on the Distribution in a Spinal Canal Model Filledwith Human Cerebrospinal Fluid / 대한마취과학회지

BACKGROUND: The density of 0.5% bupivacaine solution at 37degreesC is known to be slightly hypobaric. However, its clinical character in spinal anesthesia appears to be nearly isobaric. We tried to find evidence on how the hypobaric 0.5% bupivacaine solution could show the pattern of isobaric distribution in the subarachnoid space. METHODS: The distribution of 0.5% bupivacaine solution containing 0.029 mg methylene blue per milliliter of bupivacaine solution (BMB) was examined in a vertically mounted spinal canal model filled with human cerebrospinal fluid (CSF) at 37degreesC. The CSF was collected from natural drainage bags of 5 brain tumor patients. Three milliliters of the BMB solution at 22degreesC or 37degreesC was injected into the middle of the spinal canal four times with a high speed of injection (0.6 ml/sec) and four times with a slow speed (0.05 ml/sec). Nine 1-ml samples were drawn simultaneously from the 9 sampling sites in the longitudinal direction, each 5 cm apart, then those samples were analyzed for the spectrophotometric absorbance of methylene blue concentration. RESULTS: The concentrations of methylene blue were decreased toward the upper and lower parts of our spinal model with the highest concentrations at the central 5th sampling site, regardless of the temperature and injection speed of the BMB solution. However, the high temperature (37degreesC) and low injection speed respectively contributed to a little more distribution of the BMB solution toward the upper part of the spinal model, and the low temperature (22degreesC) contributed to a little more distribution of the BMB solution toward the lower part of the spinal model. CONCLUSIONS: Our study shows that the distribution of plain 0.5% bupivacaine solution in the subarachnoid space is similar to that of isobaric solutions.

Interaction between Bupivacaine, Ropivacaine and Diltiazem in the Isolated Rat Heart / 대한마취과학회지

BACKGROUND: Local anesthetics are often used for a regional block in patients who are being treated with calcium channel blockers (CCB). Bupivacaine is a local anesthetic with potential for serious cardiovascular toxicity. Ropivacaine is a relatively new local anesthetic. It is clinically equipotent and chemically similar to bupivacaine. Diltiazem (CCB) is a potent coronary and systemic vasodilator with antiarrhythmic properties. Local anesthetics such as bupivacaine and ropivacaine have been suggested to show drug interactions with diltiazem. Therefore, we tried to observe the drug interactions between bupivacaine, ropivacaine and diltiazem using an animal model. METHODS: This study was performed using an isolated rat heart (N = 40) by the Langendorff method. After a stabilization period, all hearts were subjected to the application of local anesthetics of a 1 microgram/ml or 3/ml concentration, respectively. Thereafter, they were subdivided into four groups; the bupivacaine (B) group, bupivacaine with diltiazem (BD) group, ropivacaine (R) group, and ropivacaine with diltiazem (RD) group. Parameters such as, LVP, dp/dt, heart rate (HR), coronary flow (CF), DO2, and MVO2 were measured. RESULTS: All parameters decreased in all groups, respectively (P < 0.05). The BD group and R group showed a lower LVP and dp/dt than those of the B group (P < 0.05). The BD group and B group showed lower HR than that of the R group (P < 0.05). The RD group showed a higher CF than other groups (P < 0.05). CONCLUSIONS: The negative inotropic potency of bupivacaine was enhanced in the presence of diltiazem. We suggest that diltiazem has a protective effect against reduction of CF by ropivacaine. Therefore, we should consider this when selecting local anesthetics for cardiovascular patients under the treatment of diltiazem.

The Evaluation of the Efficacy of the Egg PC/HA/water Drug Delivery System / 대한마취과학회지

BACKGROUND: Local anesthetics have been widely used to control postoperative pain and chronic pain. However, their usage in controlling long-lasting pain has been limited due to a relatively short duration of action. Many attempts have been made to develop a controlled release drug delivery system to provide long-lasting anesthesia. The goal of this study was to evaluate the histocompatibility and effectiveness of a new injectable lipid gel type drug delivery system (PHW, egg phosphatidylcholine/hyaluronic acid/water) using bupivacaine. METHODS: Eighty-four male Sprague-Dawley rats were divided into 3 groups; 44 in the bupivacaine group, 20 in the PHW-bupivacaine (PHW-B) group, and 20 in the PHW group; and each drug mixture was injected in a 0.1 ml solution near the sciatic notch. Motor block was assessed by direct observation of motor skills to splay toes. Sensory block was assessed by measuring withdrawal response latencies to radiant heat using an analgesiameter. Gross and microscopic examinations on the sciatic nerve and surrounding muscle were performed for 3weeks after the injection. RESULTS: Nerve block was significantly prolonged in the PHW-B group (190.0 +/- 42.8 min) compared to the plain bupivacaine group (99.0 +/- 30.5 min). There was no sign of nerve block in the PHW group. We observed moderate perimuscular inflammation in the PHW and PHW-B groups for the first 3 days. After 3 days, we did not observe inflammation of muscles and there was no sign of perineural inflammation. CONCLUSIONS: In conclusion, the histocompatibility of a bupivacaine incorporated PHW drug delivery system was satisfactory and the controlled releasing property of this drug delivery system was evaluated as effective.

Comparison of 0.075% Bupivacaine/Fentanyl and 0.125% Ropivacaine/Fentanyl Infusion for Postoperative Epidural Analgesia / 대한마취과학회지

BACKGROUND: The new, long-acting local anesthetic ropivacaine is structurally very similar to bupivacaine, but the motor block is less profound and of shorter duration. The aim of this study was to compare analgesic effectiveness and side effects during postoperative pain control after a Caesarean section with either a bupivacaine/fentanyl or ropivacaine/fentanyl mixture. METHODS: Thirty-nine patients undergoing a Caesarean section were randomized in a double-blinded manner to receive bupivacaine or ropivacaine. Postoperative epidural analgesia was provided using a PCA pump with either bupivacaine/fentanyl 0.075%/3.4 microgram/ml after 10 ml of 0.125% bupivacaine with morphine (n = 18) or ropivacaine/fentanyl 0.125%/3.4 microgram/ml after 10 ml of 0.2% ropivacaine with morphine (n = 21). Verbal rating pain scores (rest and cough), side effects (nausea, vomiting, pruritus, sedation, motor block and hypotention) and time to ambulation were measured for 48 hr after surgery. RESULTS: There were no significant differences between the groups in verbal pain scores, sensory level, motor blockade and other side effects, but time to ambulation was earlier in the ropivacaine group. CONCLUSIONS: 0.125% ropivacaine with 3.4 microgram/ml fentanyl provided similar successful pain relief as 0.075% bupivacaine/fentanyl. However, earlier recovery of ambulation in patients receiving ropivacaine/ fentanyl will improve outcome after surgery.

Comparing the Effects between a Continuous Epidural Infusion of an Opioid or an Opioid-Local Anesthetic Mixture and a Continuous IV Infusion of an Opioid after a Spinal Laminectomy / 대한마취과학회지

BACKGROUND: Postoperative pain after a spinal laminectomy has very harmful effects on human physiology, and many people are trying to control it more easily and safely. There are controversies in methods used for controlling postoperative pain after a spinal laminectomy. The purpose of this study was to examine an effective way to control postoperative pain after a spinal laminectomy. METHODS: Ninety patients (ASA I-II, aged 40 to 70) scheduled for a spinal laminectomy were divided into three groups. In group A, we administered fentanyl 1,000 microgram and morphine 5 mg (mixed in 0.9% normal saline) using the continuous epidural infuser; in group B, we administered fentanyl 500 microgram and morphine 5 mg and 0.25% bupivacaine (mixed in 0.9% normal saline) using the continuous epidural infuser; in group C, we administered fentanyl 1,500 microgram and morphine 10 mg (mixed in 0.9% normal saline) using the continuous IV infuser. We compared effects between the continuous epidural infusion and the continuous intravenous infusion by using the visual analogue scale and side effects. RESULTS: There was no significant difference between continuous epidural infusion groups. When the continuous epidural infusion groups and the continuous IV infusion group were compared, there were significant differences in 3 hr, 6 hr, and 12 hr VAS scores (P < 0.01). The incidence of side effects was very low, and there was no significant difference in side effects between the continuous epidural infusion and the continuous IV infusion groups. CONCLUSIONS: It was found that continuous epidural infusion methods were more effective than the continuous IV infusion method, but none of them showed satisfactory postoperative pain control in the early periods.

Electrocardiographic and Hemodynamic Changes during Recovery from Bupivacaine Toxicity in Anesthetized Dogs / 대한마취과학회지

BACKGROUND: Severe cardiac arrhythmia after accidental intravascular injection of bupivacaine in the practice of regional anesthesia has been reported and is known to be difficult to treat. We evaluated the electrocardiographic and hemodynamic changes during recovery from bupivacaine-induced cardiac toxicity. METHODS: In eight male dogs receiving pentobarbital, after baseline recordings were obtained, 0.5% bupivacaine was infused at a rate of 0.5 mg/kg/min intravenously until cardiac output decreased to 50% or less(1/2 CO), which was defined as the point of cardiac depression in this study. The hemodynamic and electrocardiographic parameters were recorded at 1/2 CO, and 5, 10, 15, 20, 30 and 40 min after 1/2 CO. The following electrocardiographic parameters were measured: duration of QRS complex and T wave, PR interval and the corrected QT interval, all determined on the lead II. RESULTS: Mean arterial pressure was significantly decreased throughout the experimental period after 1/2 CO, and cardiac output and SO2 were significantly decreased until 20 min after 1/2 CO in comparison with those at baseline. All dogs had serious changes on the ECG. Heart rate and ECG changes returned to baseline within 20 min after 1/2 CO, but QRS duration remained increased until 30 min after 1/2 CO. Systemic vascular resistance, pulmonary vascular resistance and serum electrolytes were not changed with time. CONCLUSIONS: In the absence of hypoxia, acidosis, and hyperkalemia, QRS duration returned to control values more slowly than other variables on the EKG after bupivacaine cardiac toxicity. MAP and PCWP recovered the slowest of all hemodynamic variables.

Differential Analgesic and Adverse Effects of 0.125% Bupivacaine vs. Ropivacaine Coadministered Epidurally with Morphine / 대한마취과학회지

BACKGROUND: This study aimed to compare analgesic efficacy and occurance of motor block and other side effects of a 48 hr postoperative continuous epidural infusion of 0.125% bupivacaine or ropivacaine with morphine. METHODS: Forty patients undergoing a Cesarean section were allocated randomly into two groups. Both groups received an epidural injection of 2.0% lidocaine 18 20 ml and 0.5% bupivacaine 2 5 ml with fentanyl 50microgram 20 minutes before surgical incision and received 2 mg of epidural morphine by bolus 40 minutes after surgical incision. For post-operative pain control, a continuous epidural infusion was started using a two day infusor containing 6 mg of morphine in 100 ml of 0.125% bupivacaine (Group 1, n = 20) or 100 ml of 0.125% ropivacaine (Group 2, n = 20). Visual analog scale (VAS) for pain during rest and movement, sensory change and motor blockade were assessed for 48 hrs. after surgery. RESULTS: There were no significant differences in VAS for pain during rest and movement. The incidences of side effect were similar in both groups. CONCLUSIONS: Using 0.125% bupivacaine with morphine via the epidural route provided similar pain relief and side effects as 0.125% ropivacaine with morphine.

Effects of Intravenous and Epidural Patient-Controlled Analgesia on Postoperative Pain and Knee Rehabilitation after a Unilateral Total Knee Replacement / 대한마취과학회지

BACKGROUND: Postoperative pain is a major concern after a total knee replacement (TKR). It hinders early intense physical therapy, the most influential factor for good postoperative knee rehabilitation. The purpose of this study was to compare intravenous patient-controlled analgesia (IV-PCA) using morphine and continuous ketorolac IV infusion with patient-controlled epidural analgesia (PCEA) using morphine and continuous bupivacaine infusion in terms of analgesic efficacy and postoperative knee rehabilitation after a unilateral TKR. METHODS: Eighteen patients undergoing a unilateral total knee replacement were randomly allocated to one of the two groups. In group IV-PCA (n = 9), 30 min before the end of surgery, patients received ketorolac 30 mg IV bolus followed by continuous infusion with ketorolac (5 mg/h) and IV-PCA with morphine (20microgram/kg, lockout 10 min). In group PCEA (n = 9), 30 min before the end of surgery, patients received 2 mg morphine bolus followed by continuous infusion with 0.1% bupivacaine (2 ml/h) and PCEA with morphine (1 mg, lockout 15 min). RESULTS: There were significant differences in visual analogue scale scores at the first 2-hours after the unilateral TKR, cumulative morphine consumption and number of postoperative days required to obtain 90o knee flexion. CONCLUSIONS: PCEA using a morphine-bupivacaine combination provided better pain relief and faci litated the continuous passive motion more than IV-PCA using a morphine-ketorolac combination. This results in possible faster postoperative knee rehabilitation.

How Long Should a Patient Stay in Lateral Position for Unilateral Spinal Anesthesia with Hyperbaric Bupivacaine? / 대한마취과학회지

BACKGROUND: In searching for a differential spinal block between dependent and nondependent sides, we evaluated the influence of the duration of lateral decubitus on the spread of hyperbaric bupivacaine during spinal anesthesia. METHODS: Spinal anesthesia with 1.2 ml of hyperbaric 0.5% bupivacaine (6 mg) was administered with a 25-gauge Whitacre unidirectional needle to 50 ASA 1 patients undergoing unilateral knee arthroscopy. The patients were allocated randomly to three groups according to the duration of lateral decubitus after spinal injection in the lateral position operation side dependent: Group 1, 10 min in lateral decubitus then supine; Group 2, 20 min in lateral decubitus then supine; Group 3, 30 min in lateral decubitus then supine. Sensory and motor block (pinprick/modified Bromage scale) as well as skin temperature were compared between the dependent and nondependent sides. Circulatory variables were recorded for 10 min after being turned supine. RESULTS: The sensory block between dependent and nondependent sides were significantly different in Group 3. In Group 1, the level of maximum sensory block was higher than Group 3 on nondependent side. There was no difference in the number of patients having achieved Grade 3 and 0 motor block among three groups on dependent and nondependent sides. The skin temperature in lateral decubitus was significantly higher on the dependent side than nondependent side in three groups. In Groups 1 and 2, the skin temperatures of nondependent side were increased after turned supine, but that was maintained during supine position in Group 3. The circulatory variables were stable in all 50 patients. CONCLUSIONS: We conclude that when a small dose of 0.5% hyperbaric bupivacaine is injected into patients in the lateral position, complete unilateral spinal anesthesia is achieved when the patients arekeep in a lateral position for more than 30 min after spinal injection.

Comparison of Intrathecal Meperidine, Fentanyl, or Placebo Added to 0.5% Hyperbaric Bupivacaine for Cesarean Section / 대한마취과학회지

BACKGROUND: The addition of various opioids to 0.5% hyperbaric bupivacaine intrathecally seems to potentiate analgesic effects of bupivacaine and to prolong the duration of analgesia. We compared the effect of intrathecal meperidine 0.25 mg/kg and 0.5 mg/kg, fentanyl 0.15 microgram/kg, and placebo when administered together with 0.5% hyperbaric bupivacaine 9 mg for cesarean section. METHODS: Forty-four healthy term parturients were randomly allocated (n = 11 per group) to receive the test solution (1 ml) containing preservative-free normal saline (control group), fentanyl 0.15 microgram/kg, meperidine 0.25 mg/kg, or meperidine 0.5 mg/kg intrathecally, immediately followed by the injection of 0.5% hyperbaric bupivacaine 9 mg. We observed the effective postoperative analgesic duration (time to VAS > or = 4), quality of anesthesia and side effects. RESULTS: The effective postoperative analgesic duration significantly increased in the groups receiving opioid compared with the control group (P < 0.05); control group 101.4 +/- 28.6 min; fentanyl group 192.3 +/- 29.2 min; meperidine 0.25 mg/kg group 208.8 +/- 21.7 min; meperidine 0.5 mg/kg group 289.8 53.6 min (data expressed as mean +/- SD). The quality of anesthesia was excellent in 100% of the meperidine group but in 82% of the fentanyl group and 91% of the control group. The incidence of nausea and vomiting were higher in the meperidine 0.5 mg/kg group (73%) than in the remaining groups (P < 0.05). CONCLUSIONS: The addition of fentanyl 0.15 microgram/kg or meperidine 0.25 mg/kg to 0.5% hyperbaric bupivacaine 9 mg for spinal anesthesia improves intraoperative analgesia and provides analgesia into the immediate postoperative period with no adverse effects on mother or neonate.

The Effects of Epidural "Top-up" on Spinal Block during Combined Spinal Epidural Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: Epidural "top-up" has been known to enhance spinal anesthesia in combined spinal-epidural anesthesia. Saline and local anesthetics were reported to have a volume effect when infused as epidural "top-up". In cesarean deliveries where high sensory block has been achieved using a combined spinal-epidural technique, we evaluated the effects of epidural "top-up" on the underlying spinal block. METHODS: Sixty-six parturients were allocated randomly into group C (control, n = 21), S (saline, n = 21), or B (bupivacaine, n = 24). Ten minutes after they received 8 mg of 0.5% hyperbaric bupivacaine intrathecally, nothing, 10 ml saline, or 10 ml of 0.25% bupivacaine were infused, respectively. The sensory level at 10 min, the maximal level and the time to reach it, and degrees of motor block and muscle relaxation were compared. We also investigated intraoperative side effects and postoperative findings in the PACU. RESULTS: There were significant changes in sensory level after epidural top-ups in the group S and B, but no differences in maximal height of sensory block and degree of muscle relaxation among the groups. Intraoperative pain was complained in fewer patients in the group B. Times to sensory and motor recovery were longer in patients of the group B. CONCLUSIONS: Eight milligrams of hyperbaric bupivacaine using a combined spinal-epidural technique was not sufficient for cesarean section. Epidural saline top-up showed volume effect, which didn't improve the spinal block. Epidural "top-up" of 0.25% 10 ml bupivacaine enhanced the spinal block and sustained the block postoperatively.

Effects of Local Anesthetics and Opioids on Human Isolated Umbilical Arteries / 대한마취과학회지

BACKGROUND: An adequate uteroplacental and fetal blood flow during labor and cesarean delivery is of prime importance for fetal well-being and neonatal outcome. METHODS: Using the vascular smooth muscle of the human isolated umbilical arteries, this study was performed to see whether commonly used local anesthetics (bupivacaine, lidocaine and 2-chloroprocaine) and opioids (morphine,fentanyl and meperidine) could induce contracion or relaxation of these resting and precontracted vessels. Rings from human umbilical arteries were prepared by microdissection. The vessel rings were mounted in tissue baths for an isometric recording of the contractile activity. For resting muscles, the reactivity to drugs is expressed as a percentage of a maximal KCl-induced contraction, and for precontracted muscle, it is expressed as a percentage of a submaximal KCl-induced contraction. RESULTS: Bupivacaine, lidocaine and 2-chloroprocaine all induced contractions. Bupivacaine showed a maximal contraction (46.7 +/- 10.5%) at concentrations of 43 micrometer, lidocaine 19.7 +/- 4.8% at 0.11 mM. and 2-chloroprocaine showed 14.6 +/- 2.9% at 0.65 mM. Morphine, fentanyl and meperidine all induced contractions. Morphine showed a maximal contraction (19.6 +/- 7.1%) at a concentration of 10 4 M, meperidine at 17.2 +/- 8.4% at 3 x 10 5 M, and fentanyl at 1.7 +/- 2.0% at 3 x 10(-6)M. When umbilical arteries were induced to contract with a submaximal concentration of KCl, bupivacaine and lidocaine showed an ability to increase the magnitude of the sustained contraction, but 2-chloroprocaine showed a relaxation of the sustained contraction. Morphine, fentanyl and meperidine showed no change in the sustained contraction. CONCLUSIONS: This study demonstrates these local anesthetics and opioids as vasoactive on human umbilical arteries. If applicable in vivo, these drugs might have some influence on umbilical vessel tone and thus might reduce umbilical blood flow.

The Effects of Insulin in Treating Bupivacaine-Induced Cardiac Depression / 대한마취과학회지

Backgroud: Bupivacaine blocks the sodium channels enhanced by hypokalemia. Bupivacaine also inhibits the transient outward K+ current (Ito). Insulin, in contrast, enhances Ito and induces hypokalemia. The current study was performed to confirm the efficacy of insulin for the treatment of bupivacaine- induced cardiac depression in dogs. METHODS: After dogs were anesthetized with pentobarbital, 0.5% bupivacaine was administered at a rate of 0.5 mg/kg/min until S O2 decreased to 60% or less, which was defined as the point of cardiac depression in this study. The insulin group (n = 9, 16.9 +/- 3.1 kg) received 2 ml/kg of a mixed solution of regular insulin 30 units and 5% D/W 50 ml, followed by a glucose infusion (50 ml 5% dextrose in water) over 15 min. The control group (n = 9, 15.8 +/- 3.4 kg) received 2 ml/kg of 5% D/W 50 ml, followed by a normal saline infusion over 15 min. Mean arterial pressure (MAP), heart rate (HR), pulmonary artery pressure (PAP), central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), SO2, blood gas analysis, serum electrolytes, ECG and the local anesthetic concentraton of the blood were taken. RESULTS: Changes in hemodynamic variables and ECG of the insulin group normalized more rapidly than in the control group. There were no statistical differences in serum Na and Ca2 concentratons between the two groups. The serum K concentration of the insulin group was lower than that of the control group after 5 min of resuscitation. The changes in plasma bupivacaine concentration over time were not significantly different between groups. CONCLUSIONS: Insulin is effective in reversing bupivacaine-induced cardiac depression. This study suggests insulin can be considered an immediate treatment for cardiac depression by bupivacaine.

Effect of Speed of Injection on the Level of Spinal Anesthesia with 0.5% Hyperbaric Bupivacaine for a Cesarean Section / 대한마취과학회지

BACKGROUND: The purpose of this study was to determine whether the injection rate affects the spread of spinal anesthesia in cesarean sections. METHODS: Spinal anesthesia was performed on 45 parturients in a cesaren section. Dural puncture was performed in the sitting position with a 27-gauge Whitacre needle. All patients received a mixture of 10 mg hyperbaric bupivacaine and 15 microgram fentanyl. Twenty five (Group I) patients received rapid injections (about 0.2-0.3 ml/sec) and twenty (Group II) received slow injections (about 0.1 ml/sec). Anesthetic levels, time to T4 sensory block, maximal height sensory block and incidence of hypotension were measured. RESULTS: There was significantly rapid T4 sensory block in group I but no differences in maximal height of sensory block and incidence of hypotension between the two groups. CONCLSIONS: We conclude that injection rate (about 0.1-0.3 ml/sec) has a statistically insignificant influence on the maximal height sensory block and incidence of hypotension.

The Effect of Intrathecal Midazolam on Bupivacaine Induced Spinal Anesthesia after Hemorrhoidectomy / 대한마취과학회지

BACKGROUND: Benzodiazepines acting on the GABA receptor complex in the spinal cord are known to induce antinociception. In the present study we aimed to evaluate the effect of intrathecal midazolam with bupivacaine following hemorroidectomy. METHODS: Forty five patients were involved in this study. Patients were randomly allocated to one of 3 groups: the control group received 0.5% heavy bupivacaine 5 mg and 0.9% NaCl 0.2 ml intrathecally, group BM1 0.5% bupivacaine and midazolam 1 mg (0.2 ml), group BM2 0.5% bupivacaine 5 mg and midazolam 2 mg (0.4 ml), respectively. The analgesic effects and side effects were compared among the 3 groups. RESULTS: There was a significant difference among the 3 groups in time-to-first-pain medication and total consumption of analgesics during the 24 h after surgery. Furthermore, the analgesic effect of midazolam was dose-dependent: 2 mg of midazolam showed better results than 1 mg. All the patients showed no considerable side effects. CONCLUSIONS: We conclude that intrathecal midazolam caused a significant delay in time-to-first-pain medication and reduced utilization of analgesics within 24 h. Therefore, intrathecal midazolam can be used as an effective adjunct for spinal anesthesia for postoperative pain control.

Patient Controlled Analgesia Using Surgical Wound Infusion / 대한마취과학회지

BACKGROUND: This study was undertaken to evaluate the analgesic effect of a self administered surgical wound infusion of local anesthetic alone compared to combination of local anesthetic and morphine or ketorolac. METHOD: Forty eight patients undergoing minor surgery were randomly classified into four groups: Group 1 (saline, n = 10), Group 2 (bupivacaine only, n = 11), Group 3 (bupivacaine with morphine, n = 14), and Group 4 (bupivacaine with ketorolac, n = 13). A two-hole 19 G epidural catheter was tunneled subcutaneously into the surgical wound and was connected to 100 ml elastometric balloon pump filled with either 0.5% bupivacaine only, 0.5% bupivacaine and morphine 40 mg, or 0.5% bupivacaine and ketorolac 80 mg. We assessed the postoperative visual analogue scale (VAS) pain scores at postoperative 0.5, 1, 2, 6, 12, 24, 36, and 48 hours, and the side effects, sedation score and total amount of infused bupivacaine were recorded. RESULTS: VAS pain score were significantly decreased until 36 hours in groups 2, 3, and 4 compared to group 1, and significantly lower at 1, 2, 12, and 24 hrs in groups 3, 4 than in group 2 (P < 0.05). The total requirement of infused bupivacaine in groups 3, 4 is significantly decreased compared to that of group 2. Side effects like nausea, vomiting, urinary retension, pruiritis, respiratory difficulty, sedation, and dizziness did not occur in the four groups but seroma did in one case. CONCLUSION: Patient-controlled surgical wound infusion of bupivacaine reduced postoperative pain after minor surgery without any side effects. The combination of bupivacaine with morphine or ketorolac gave rise to a significant additive effect to local analgesia.

The Effects of Midazolam and Droperidol Pretreatment on the Cardiac Toxicity of Bupivacaine in Rabbits / 대한마취과학회지

BACKGROUND: Unintended intravenous injection of bupivacaine causes severe cardiovascular complication, which is known for its difficulty in resuscitation. This study was performed to evaluate the effects of pretreatment with midazolam and droperidol in the cardiac toxicity caused by intravenous infusion of bupivacaine. METHODS: Thirty rabbits were divided into three groups; saline- as a control, midazolam, and droperidol pretreated group. We observed the time intervals for the arrhythmia, 25% and 50% reduction in baseline mean arterial blood pressure, and arrest. We also checked the dose of infused bupivacaine to be required for arrest during continuous intravenous infusion of bupivacaine at the rate of 1 mg/kg/min. RESULTS: The onset of dysrhythmia and the time to 50% reduction in baseline mean arterial blood pressure and arrest were significantly more delayed in the midazolam group than the control group (P < 0.05). With respect to the time to 25%, 50% reduction in baseline mean arterial blood pressure and arrest, the data of the droperidol group was significantly shorter than that of the control group (P < 0.05). CONCLUSIONS: Droperidol pretreatment hastened bupivacaine induced cardiac arrest in rabbits. Midazolam pretreatment exerted protective effects on arrhythmia and cardiac arrest. Thus midazolam would be a preferable agent as a supplement for regional anesthesia using bupivacaine.

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.