Spinal Anesthesia with 0.75% Isobaric Ropivacaine for Lower Extremity Operation / 대한마취과학회지

BACKGROUND: Ropivacaine closely resembles bupivacaine with propyl group substitutes for butyl group at the same position. Ropivacaine is presented as 100% S-isomer with important implication of safety and less cardiotoxic than bupivacaine. Because of this, ropivacaine is used as an epidural anesthesia. However this study was performed to evaluate clinical effects of ropivacaine for spinal anesthesia. METHODS: Thirty patients (ASA I-II) scheduled for elective lower extremity operation were randomly selected and received spinal anesthesia with 3 ml of 0.75% isobaric ropivacaine. The patients were placed in the lateral position and dura puncture was performed at the L3-4 interspace using the median or paramedian approach with a 25 G Quincke spinal needle. After spinal anesthesia, sensory block was assessed using the pin-prick test every 2 min., motor block was assessed using a four-point scale, and circulatory variables were monitored every 5 min. RESULTS: The mean sensory block level was T 8.6 and the maximum sensory block level was T4. Time needed for extremity motor block was 10.8 min. and 25 of 30 patients reached Bromage scale 3. Duration of motor and sensory block were 260.6 min. and 422.3 min. Hemodynamic changes (arterial pressure and pulse) were stable during anesthesia and complications were rare. CONCLUSIONS: We concluded that 0.75% isobaric ropivacaine was suitable for spinal anesthesia with good lower extremity sensory and motor block, and it was long-lasting without any specific complications.

Analgesic Effect and Adverse Effects of Intrathecal Neostigmine Used in Spinal Anesthesia for Orthopedic Surgery / 대한마취과학회지

BACKGROUND: Intrathecal injection of analgesic agents sush as opioids, clonidine, ketamine and nalbuphine with a local anesthetic agent during spinal anesthesia for operation is an easy and convenient way to get postoperative analgesia. Intrathecal neostigmine causes an increased ACh concentration in CSF and also has an analgesic effect. This study was designed to examine its postoperative analgesic effect and adverse effects such as nausea/vomiting and urinary retention etc. METHODS: We divided 27 patients who were supposed to receive orthopedic surgery of lower extremities into 3 groups. The control group as injected with heavy bupivacaine 13 mg and normal saline and the N50 and N75 groups were injected with the same amount of bupivacaine combined with neostigmine 50 mcg and 75 mcg respectively. We examined total amount of fluid intake and side effects during operation, and time to first rescue analgesic medication, time to first urination, total applications of rescue analgesic agent, total number of urinary catheterizations for 24 hr after intrathecal injection, and adverse effects of intrathecal neostigmine in the ward. RESULTS: The N75 group showed a significantly longer analgesic duration compared with the control and N50 groups, but the incidence of urinary retention and number of urinary catheterizations increased in the N75 group significantly. Nausea/Vomiting significantly increased in N75 compared with control. Shivering was more common in N50. 2 patients who recieved neostigmine 75 mcg complained of chest discomforts suggesting myocardial ischemia in EKG taken in those episodes. CONCLUSIONS: Neostigmine 75 mcg has better analgesic effect but more frequent adverse effects than control or neostigmine 50 mcg. Therefore, we suggest using high doses of neostigmine cautiously and being aware of its side effects.

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.

Comparison of 5% and 10% Glucose for Tetracaine Spinal Anesthesia / 대한마취과학회지

BACKGROUND: One of the most important physical properties affecting the level of analgesia after intrathecal administration of a local anesthetic is baricity. This study was done to compare the distribution of 0.5% tetracaine in 5% glucose solution and in 10% glucose solution. METHODS: Tetracaine 2.6 ml (0.5% with 5% glucose or 10% glucose) added with 0.1% epinephrine 0.2 ml was administered to each of 20 patients. All patients' heights were within 160 170 cm. The cephalad spread of analgesia, the degree of motor block in the legs and hemodynamic values were assessed at 2-min intervals for the first 10 min and then at 5-min intervals until 30 min. RESULTS: In the 5% glucose and 10% glucose solutions, the maximum sensory level was T5.4 and T4.3, the maximum sensory block time was 128.1 min and 118.2 min and the time to complete motor block was 5.4 min and 5.2 min respectively. It was not statistically significant between groups. But T 8.1 (vs T 9.6 in the 5% glucose solution) of initial sensory level measured at 4 min after injection of drug was significantly higher (P < 0.05) in the 10% glucose solution. Maximum hemodynamic changes from the baseline were not different in two groups. CONCLUSIONS: Tetracaine 0.5% with 5% glucose or 10% glucose solutions showed similar distribution in the cerebrospinal fluid.

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 Relation of Maximal Sensory Block Level and the Duration of Sensory Block in Spinal Anesthesia Using a Fixed Dose of Bupivacaine / 대한마취과학회지

BACKGROUND: The duration of spinal anesthesia depends upon two factors; concentration of local anesthetics in the CSF and vascular absorption of the local anesthetics. However, there are some arguments on the relationship between the maximum block level and the duration of the block in spinal anesthesia. METHODS: Fifty seven patients scheduled for surgery on a lower limb or perineum underwent spinal anesthesia with 11 mg of 0.5% hyperbaric bupivacaine. After confirming final block heights (T12-T3, range), we took two study groups, group I (block height > OR = T6, n = 30) and group II (block height < OR = T9, n = 27). We checked the maximal sensory block level, the time to maximal sensory block level, a two-segment regression time, the duration of sensory block to T12, and L5 during the first 30 minutes at 2.5 minute intervals and then, at 30 minutes intervals. Blood pressure and pulse rate were measured in the same time interval. RESULTS: The maximal sensory block level and the time to maximal sensory block level of group I was T5.0, 14.6 minutes and that of group II were T9.7, 11.4 minutes. The mean cephalad spread of analgesia in group I was more rapidly increased at 20 minutes and there were statistically significant differences between the two groups from 5 min to 110 minutes. The duration of sensory block to T12, L5 was similar in group I and II. No significant differences in blood pressure and pulse rate were found between the two groups. CONCLUSIONS: We found that there was no relationship between the sensory block level and duration of the block in spinal anesthesia using a fixed does of local anesthetic.

The Effect of Spinal Anesthesia for Cesarean Section on Hemodynamics in Patients with Severe Preeclampsia / 대한마취과학회지

BACKGROUND: Epidural anesthesia is thought to be relatively indicated for cesarean section in patients with severe preeclampsia. In contrast, avoidance of spinal anesthesia is recommended, postulating excessive hypotensive risks. In addition, general anesthesia is often avoided in this population because malignant hypertension following tracheal intubation is common and risks for difficult airway management are excessive. METHODS: In this study, we compared hemodynamic changes in patients with severe preeclampsia and normal pregnant women during spinal anesthesia for elective cesarean section. Spinal anesthesia was performed with 10 mg of 0.5% heavy bupivacaine mixed with 25 microgram fentanyl in 18 patients with severe preeclampsia and 17 normal pregnant women. We compared MAP, CI, and SVRI changes before and after spinal anesthesia. RESULTS: MAP responses following induction of spinal anesthesia for elective cesarean section in patients with severe preeclampsia and normal pregnant women showed a statistically significant decrease from 2 min after spinal anesthesia. CI responses following induction of spinal anesthesia in patients with severe preeclampsia showed a statistically significant increase from 8 min after and normal pregnant women also showed a statistically significant increase from 4 min after spinal anesthesia. SVRI responses from induction of spinal anesthesia in patients with severe preeclampsia and normal pregnant women showed a statistically significant decrease from 2 min after spinal anesthesia. Incidence of hypotension before delivery and used total dose of ephedrine during operation were statically insignificant between severe preeclamptic and normal pregnant women. CONCLUSIONS: We conclude that changes of MAP, CI and SVRI following spinal anesthesia for elective cesarean section in the severely preeclamptic and normal pregnant women are clinically similar. We suggest that spinal anesthesia for cesarean section is not contraindicated in the severely preeclamptic patient.

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.

Spinal Anesthesia with 0.5% Hyperbaric Bupivacaine in Elderly Patients : Influence of Aging on Spread of Analgesia and Blood Pressure / 대한마취과학회지

BACKGROUND: We have studied the influence of aging on the spread of analgesia and blood pressure with 0.5% hyperbaric bupivacaine in elderly patients compared to findings with a control group. METHODS: Forty-nine patients in two groups between 22-59 yr and 70-86 yr undergoing lower limb surgery were placed in a lateral position with the side to be operated on dependent. Five minutes after the injection of 1.4 ml of 0.5% hyperbaric bupivacaine, each patient was placed in the surgical position. Noninvasive mean arterial pressure (MAP) and levels of analgesia were measured for 30 minutes. RESULTS: The maximum sensory block level was T7.5+/-2.4 in the elderly group and T8.2+/-2.4 in the control group. There was no significant difference on the highest level of analgesia between groups. The time to reach maximum level was 17.4+/-8.6 minutes in the elderly group and 16.9+/-7.0 minutes in the control group. The maximum decrease in MAP was significantly greater in the elderly group (23.3+/-11.1% of the baseline value) than in the control group (10.7+/-0.2%). The incidence of hypotension (defined as a decrease of 25% or more MAP) was 48.0% in the elderly group and 4.2% in the control group. CONCLUSIONS: There was no significant effect on the highest level of analgesia with advancing age. Decreases in mean arterial pressure were more frequent and pronounced in the elderly group than in control group. It may be appropriate to monitor patients carefully and treat hypotension immediately if it occurs.

Minimum Effective Anesthetic Concentration of Hyperbaric Tetracaine 10 mg for Spinal Anesthesia / 대한마취과학회지

BACKGROUND: Minimum effective anesthetic concentration (MEAC) of local anesthetics for spinal anesthesia, defined as the concentration at which a spinal anesthetic agent produces surgical anesthesia within 20 minutes of administration in 50% of patients. This concept is similar to the concept of minimum alveolar concentration (MAC) for inhalation anesthetic. Furthermore, as MEAC may vary with the administered dose, it will be determined using 10 mg of hyperbaric tetracaine. METHODS: 10 mg hyperbaric tetracaine containing dextrose 10 % was administered intrathecally to 12 patients (ASA I-II, age 20~40 yr), who were undergoing lower limb or urological procedures within 90 minutes, at concentrations ranging from 0.07~0.1%. The choice of tetracaine concentration was determined by Dixon's up-and-down method. Complete anesthesia was defined as: (1) pinprick anesthesia at or higher than T10 and (2) complete leg paralysis; all occurring in both lower extremities within 20 min. General anesthesia was initiated if spinal anesthesia was incomplete. RESULTS: MEAC of 10 mg hyperbaric tetracaine was 0.083 %. Mean anesthetic duration was 75.2 minutes (range: 40~100 min). The maximum sensory block level ranged from T3~T8. CONCLUSION: The aim of this study was to establish new concept of minimum effective anesthetic concentration of hyperbaric tetracaine for spinal anesthesia. We recognized that spinal anesthesia can be accomplished with very dilute solution. As fixed dose, no correlation was found between concentration of the spinal tetracaine solution with the highest sensory level, anesthetic duration and the degree of mean arterial pressure decreased.

Minimum Effective Anesthetic Concentration of Hyperbaric Tetracaine 10 mg for Spinal Anesthesia / 대한마취과학회지

BACKGROUND: Minimum effective anesthetic concentration (MEAC) of local anesthetics for spinal anesthesia, defined as the concentration at which a spinal anesthetic agent produces surgical anesthesia within 20 minutes of administration in 50% of patients. This concept is similar to the concept of minimum alveolar concentration (MAC) for inhalation anesthetic. Furthermore, as MEAC may vary with the administered dose, it will be determined using 10 mg of hyperbaric tetracaine. METHODS: 10 mg hyperbaric tetracaine containing dextrose 10 % was administered intrathecally to 12 patients (ASA I-II, age 20~40 yr), who were undergoing lower limb or urological procedures within 90 minutes, at concentrations ranging from 0.07~0.1%. The choice of tetracaine concentration was determined by Dixon's up-and-down method. Complete anesthesia was defined as: (1) pinprick anesthesia at or higher than T10 and (2) complete leg paralysis; all occurring in both lower extremities within 20 min. General anesthesia was initiated if spinal anesthesia was incomplete. RESULTS: MEAC of 10 mg hyperbaric tetracaine was 0.083 %. Mean anesthetic duration was 75.2 minutes (range: 40~100 min). The maximum sensory block level ranged from T3~T8. CONCLUSION: The aim of this study was to establish new concept of minimum effective anesthetic concentration of hyperbaric tetracaine for spinal anesthesia. We recognized that spinal anesthesia can be accomplished with very dilute solution. As fixed dose, no correlation was found between concentration of the spinal tetracaine solution with the highest sensory level, anesthetic duration and the degree of mean arterial pressure decreased.

The Effect of Preanesthetic Administration of Crystalloid for Prevention of Spinal Anesthesia-Induced Hypotension / 대한마취과학회지

BACKGREOUND: Despite many advantages of spinal anesthesia, hypotension after spinal anesthesia is a common complication. The practice of routine preemptive infusion of crystalloid before spinal anesthesia has been widespread acceptance. But the value of this practice has recently been questioned. This study was designed to determine whether preoperative administration of crystalloid decrease the incidence of hypotension after spinal anesthesia. METHODS: Thirty ASA I and II patients for elective lower extremities operations under spinal anesthesia were randomized to receive either 500 ml Ringer's lactate solution prior to induction of spinal anesthesia (group I) or no prehydration (group II). Hypotension was defined as a 30% decrease from baseline systolic blood pressure or systolic 70% of baseline, systolic blood pressure and heart rate were not significantly different between both groups. CONCLUSIONS: We conclude that, in normovolemic adult patients undergoing elective lower extremities surgery, an intravenous infusion of 500 ml of Ringer's lactate solution is ineffective in preventing hypotension during spinal anesthesia.

Effect of Additional Epinephrine on Spinal Anesthesia with Bupivacaine / 대한마취과학회지

Background: Bupivacaine was introduced to be a long-acting spinal anesthetic agent. It has been argued about whether the addition of epinephrine prolongs the bupivacaine action or not. The aim of this present investigation was to find out the effect of additional epinephrine on spinal anesthesia with bupivacaine. Methods: 47 patients undergoing an operation on lower extremity were randomly allocated to 2 groups. All patients were anesthetized by subarachnoid block with 0.5% bupivacaine in 8% glucose, which was mixed with 0.2 ml of normal saline in group non-E (n=24) and 0.2 ml of 1:1,000 epinephrine in group E (n=23). We evaluated blood pressure and heart rate, the sensory and motor blockade and voiding time after spinal anesthesia. Results: The systolic blood pressure (SBP) at 8 and 10 min after anesthesia were lower in group non-E than in group E (p<0.05). The trend of decreasing diastolic blood pressure was similar in both groups. The heart rate(HR) at 2 min after anesthesia was lower in group non-E than in group E (p<0.05). The sensory block in T10 was produced faster in group non-E (7 min) than in group E (11 min)(p<0.05). And the maximal sensory block level and its reaching time was T7 and 14 min in group non-E, and T8 and 17 min in group E (p=0.12, p=0.11). Two segment regression time was 124 min in group non-E, and 184 min in group E (p=011). The onset time of motor block to Bromage scale 3 was 12 min in group non-E and 16 min in group E (p=0.06). The recovery time from complete motor block to Bromage scale 1 after maximal motor block was 263 min in group non-E, and 278 min in group E. The time at which patients voided after anesthesia was 469 min in group non-E, and 466 min in group E. Three patients urinated by using a urinary catheter in each group. Conclusions: The addition of epinephrine to bupivacaine for spinal anesthesia can slow the decrease in SBP and increase the HR at early stage of anesthesia, and slow the sensory block.

Spinal Anesthesia Using 0.5% Hyperbaric Bupivacine/Fentanyl Mixture for Cesarean Section / 대한마취과학회지

BACKGROUND: The last two decades have seen an increase in the incidence of cesarean section. Spinal anesthesia has been popular in cesarean delivery because of the ease and effectiveness, as well as the rapidity in estabilishing adequate levels of analgesia. The clinical effects of subarachnoid administeration of preservative-free fentanyl were assessed in 30 healthy women who underwent cesarean section with spinal anesthesia using 0.5% hyperbaric bupivacaine. METHODS: Sixty parturients were allocated to group I; bupivacaine (n=30) only and group II; bupivacaine/fentanyl mixture (n=30) in random order. The dose of bupivacaine varied from 9~10 mg depending on the patients height. Maximum level of sensory blockade, time to reach T4 level, incidence of hypotension, time to get complete motor recovery, perioperative analgesic effect and complications were evaluated. RESULTS: There were no differences in maximum level of analgesia, time to reach T4 level and to get complete motor recovery, and incidence of hypotension between two groups. However, duration of analgesia was longer in group II with the bupivacaine/fentanyl mixture (191.9 +/- 77.6 min) than in group I with the bupivacaine alone (74.2 +/- 30.8 min). Spinal anesthesia was excellent in 100% of the fentanyl mixture group but in 80% of the bupivacine only group. CONCLUSION: 0.5% hyperbaric bupivacaine mixed with 25 g fentanyl provided improved perioperative analgesia without affecting the onset of sensory blockade and duration of motor blockade.

Anesthesia for Cesarean Section in a Patient with Acute Fatty Liver of Pregnancy and Acute Laryngitis: A case report / 대한마취과학회지

A 36 year old woman, at 37 week gestation, had admitted to our Obstetric-Gynecology department. On her admission, she complained mild fever, neck pain and severe hoarsness. Laboratory test demonstrated increased level of activated partial thromboplastin time 40.2 second(control 26), aspartate aminotransferase 685 IU/L(normal range 10~50), alanine aminotransferase 404 IU/L(normal range 5~45). The diagnosis, acute fatty liver of pregnancy was made by ultrasound of the liver and clinical and laboratory findings. Also the diagnosis, acute laryngitis was made by laryngoscopic and clinical and laboratory findings. On her 3rd day of admission, she complained labor pain. An emergency cesarean section was performed under spinal anesthesia. After delivery, her postoperative prognosis was uneventful, and she discharged from the hospital on postoperative 8th days.

The Effects of Intrathecal Neostigmine on Postoperative Analgesia in Patients Undergoing Total Knee Replacement / 대한마취과학회지

BACKGROUND: Intrathecal neostigmine causes analgesia in dose-dependent pattern. This study was designed to examine postoperative analgesia with intrathecal neostigmine in a randomized, blinded trial with tetracaine as the active control in patients undergoing total knee replacement (TKR). METHODS: Eighty patients scheduled for TKR were divided into seven groups ( Control; no neostigmine, N25, 50, 75, 100, 125 and 150; subarachnoid tetracaine with neostigmine 25, 50, 75, 100, 125 and 150 g, respectively). Postoperatively, patients assessed their pain on a 10-cm visual analog scale (VAS), total analgesic requirement, time to first analgesic rescue medication and side effects were assessed. RESULTS: Increasing doses of intrathecal neostigmine showed a dose-dependent pattern of analgesia defined by the overall VAS scores, time until first administration of rescue analgesic request, and the number of rescue analgesics (p<0.05). Nausea and vomiting was also increased by increasing doses of intrathecal neostigmine (p<0.05). CONCLUSIONS: Intrathecal neostigmine with tetracaine produced definitive analgesia in patients undergoing TKR, and neostigmine 75 g resulted in a better analgesic effect with fewer side effects than other doses.

Influence of Height and Vertebral Length on Spinal Anesthesia with 0.5% Hyperbaric Bupivacaine / 대한마취과학회지

BACKGROUND: Many factors determine the distribution of local anesthestics in the subaracnoid space. Especially, patient's height is considered an important determinant of the dose of spinal anesthesia. However, the relationship between height and the level of analgesia has not been clearly documented. We studied the correlation between vertebral lengths measured from C7 to the level of the iliac crest (C7-IC), to the sacral hiatus (C7-SH) and to the coccyx (C7-CX) and the level of analgesia injected a fixed amount of local anesthetic in spinal anesthesia. METHODS: Fifty six healthy patients who consented to spinal anesthesia for elective operation were studied. All patient were administered 0.5% hyperbaric bupivacaine 11 mg in the lateral decubitus position on a horizontal operation table. Immediately after drug injection, the patients were turned to the supine horizontal position. For the first 30 minutes, we measured the level of analgesia to pinprick every two minutes. RESULTS: The average of maximum cephalad spread of analgesia was T7.0 1.6. There were weak correlations between patient's height or C7-IC and the level of analgesia. However a significant correlation existed between vertebral length measured from C7 to SH and the level of analgesia. CONCLUSIONS: It is concluded that vertebral length (C7-SH) provides a more meaningful approach to dose selection than height.

Effect of Injection Speed on the Anesthetic Level and Duration of Hypobaric Spinal Anesthesia with 0.1% Tetracaine in Jack-Knife Position at 15o Head-down Tilting / 대한마취과학회지

BACKGROUND: The speed of injection of local anesthetic solutions into the subarachnoid space may influence the spread of these agents in the cerebrospinal fluid by the amount of turbulence generated, especially with large volume. To determine the proper injection speed of anesthetics in hypobaric spinal anesthesia on jack-knife position, the anesthetic level and duration were measured with the fast or slow injection speed. METHODS: Twenty patients for perianal surgery in jack-knife position under hypobaric spinal anesthesia were randomly assigned to one of two groups. Tetracaine (0.1%) in distilled water 5 ml was administered to all the patients. Group I patients received the drug with the speed of injection as 5 ml/20 sec (15 ml/min) and the others (Group II) as 5 ml/4 min (1.25 ml/min). The mean arterial pressures and heart rates at the preanesthetic period, and 5, 10, 15 and 20 min after the end of injection were measured. The anesthetic levels at 5, 10, 15 and 20 min after the injection and anesthesia duration were measured. RESULTS: There was no significant difference in mean arterial pressures, heart rates and anesthetic duration between two groups. The anesthetic level 20 min after the injection was higher in Group I than Group II, and not different at the other time sequences. CONCLUSION: At the injection speed within 1.25-15 ml/min in hypobaric spinal anesthesia on jack-knife position at 15o head-down, we acquired appropriate anesthetic level and duration for perianal surgery without any undesirable effects.

Comparative Study of Spinal Anesthesia with Bupivcaine and Tetracaine / 대한마취과학회지

BACKGROUND: Tetracaine has been the most commonly used long-acting spinal anesthetic agent. Recently, hyperbaric bupivacaine was introduced to be useful agent, and has been reported to produce the better quality of anesthesia. The aim of the present investigation was to compare the anesthetic effects of 0.5% hyperbaric bupivacaine and 0.5% hyperbaric tetracaine spinal anesthesia. METHODS: 40 ASA Class I patients undergoing lower extremity operation were randomly distributed to two groups. Group A (n=20) received 15mg, 0.5% bupivacaine in 8% glucose, while Group B (n=20) received 15mg, 0.5% tetracaine in 10% glucose in the lateral decubitus position (L3,4 interspace). We evaluated the sensory and motor blockade, cardiovascular effects and the incidence of tourniquet pain. RESULTS: The mean maximum cephalad spread of analgesia was higher in bupivacaine group (T5) than in tetracaine group (T6) and the spread time was more rapid in bupivacaine group (13.1 +/- 3.3min.) than in tetracaine group (15.8 +/- 4.3min.), but there were no statistical significances. Tetracaine group was earlier onset of motor block and the duration of complete motor block in tetracaine group was significantly longer than in bupivacaine group. The mean decrease in systolic and diastolic blood pressure was 10% to 25% in both groups and more marked in tetracaine group. The incidence of tourniquet pain was greater in tetracaine group than in bupivacaine group. CONCLUSIONS: The quality of anesthesia obtained with bupivacaine may be superior to that produced by tetracaine. We concluded that 0.5% hyperbaric bupivacaine was suitable for short orthopedic or lower abdominal surgery because of less incidence of hypotension, shorter duration of motor block and lower incidence of tourniquet pain.

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.