Prolongation of lidocaine spinal anesthesia with phenylephrine

The effect of added phenylephrine on the duration of sensory analgesia during lidocaine spinal anesthesia was determined in 65 ASA class I-III patients randomly divided into three groups. Group 1 (n = 25) received 62.5 mg lidocaine in 7.5% glucose; group 2 (n = 21) received lidocaine with 2 mg phenylephrine; and group 3 (n = 19) received lidocaine with 5 mg phenylephrine. The level of analgesia to pin prick was assessed by an anesthesiologist unaware of the drug combination used. The mean +/- SD cephalad level of analgesia did not differ among the groups. In group 1, the times for two- and for four-segment regression of the level of analgesia, and the time for regression of analgesia to the T-12 dermatome, were 77 +/- 19 (1 SD), 99 +/- 24, and 109 +/- 26 min, respectively. The corresponding values were 98 +/- 25, 118 +/- 27, and 130 +/- 36 min in group 2 and 124 +/- 32, 142 +/- 31, and 162 +/- 35 min in group 3. All the regression times in group 2 were significantly longer than those in group 1 (P less than 0.05). All the regression times in group 3 were significantly longer than those in group 2 (P less than 0.02). It is concluded that clinically useful prolongation of sensory analgesia may be obtained by addition of phenylephrine to lidocaine during spinal anesthesia.     

Fentanyl improves analgesia but prolongs the onset of axillary brachial plexus block by peripheral mechanism

We evaluated the effects of fentanyl added to lidocaine for axillary brachial plexus block in 66 adult patients scheduled for elective hand and forearm surgery. In this double-blinded study, all patients received 40 mL of 1.5% lidocaine with 1:200,000 epinephrine, injected into the brachial plexus sheath using the axillary perivascular technique, and they were randomized into three groups. Group 1 was given lidocaine containing 2 mL of normal saline plus 2 mL of normal saline IV. Patients in Group 2 received lidocaine containing 100 microg fentanyl plus 2 mL of normal saline IV. Group 3 patients received lidocaine containing 2 mL of normal saline plus 100 microg fentanyl IV. Sensory and motor blockade were evaluated by using a pinprick technique and by measuring the gripping force, respectively. The success rate of sensory blockade for radial and musculocutaneous nerves and the duration of the sensory blockade significantly increased in Group 2 (323 +/- 96 min) as compared with Group 1 (250 +/- 79 min). However, onset time of analgesia was prolonged in every nerve distribution by adding fentanyl to brachial plexus block. IV fentanyl had no effect on the success rate, onset, or duration of blockade. We conclude that the addition of fentanyl to lidocaine causes an improved success rate of sensory blockade but a delayed onset of analgesia, although this may be accounted for by the decreased pH caused by the fentanyl. Implications: It is still unclear whether the addition of a peripheral opioid is useful for nerve blockade in humans. Peripheral application of fentanyl to lidocaine for axillary brachial plexus blockade in this study provided an improved success rate of sensory blockade and prolonged duration.     

Reversal of lidocaine with epinephrine epidural anesthesia using epidural saline washout

BACKGROUND AND OBJECTIVES: Prolonged motor and sensory block following epidural anesthesia can be associated with extended postoperative care unit stays and patient dissatisfaction. Previous studies have demonstrated a more rapid motor recovery following the administration of epidural crystalloids in patients who had received plain bupivacaine and lidocaine epidural anesthesia. However, epinephrine is commonly added to local anesthetics to improve the quality and prolong the duration of the epidural block. The objective of this study was to determine the relationship of 0.9% NaCl epidural catheter flush volume (i.e., washout) to the recovery of motor and sensory block in patients undergoing 2% lidocaine with epinephrine epidural anesthesia. METHODS: A prospective, randomized, double-blind study design was utilized. Thirty-three subjects scheduled for elective gynecologic or obstetrical surgical procedures underwent epidural anesthesia using 2% lidocaine with epinephrine (1:200,000). A T4 dermatome level of analgesia, determined by toothpick prick, was maintained intraoperatively. Following surgery, subjects were randomized to 1 of 3 treatment groups. Group 1 (control, n = 11) received no epidural 0.9% NaCl (normal saline [NS]) postoperatively. Group 2 (15 mL NS x 1, n = 10) received an epidural bolus of 15 mL NS. Group 3 (15 mL NS x 2, n = 12) received an epidural bolus of 15 mL NS postoperatively and a second 15-mL NS bolus 15 minutes later. Assessment of motor and sensory block was performed at 15-minute intervals until complete motor and sensory recovery. RESULTS: Times to partial and full motor and sensory recovery were significantly faster in the epidural NS groups than in the control group. Full motor recovery was more rapid in subjects receiving two 15-mL NS epidural NS boluses (30 mL total) compared with those receiving a single 15-mL NS bolus (108 +/- 9 min v 136 +/- 13 min) and significantly faster than control group subjects (153 +/- 14 min). Both NS x 1 and NS x 2 epidural bolus groups experienced significantly reduced times to complete sensory recovery when compared with the control group (NS x 1 = 154 +/- 13 min, NS x 2 = 153 +/- 9 min, control 195 +/- 14 min). CONCLUSIONS: A more rapid recovery of motor and sensory block in patients undergoing 2% lidocaine with epinephrine epidural anesthesia can be achieved with the use of 30 mL NS epidural washout. Reg Anesth Pain Med 2001;26:246-251.     

Spinal anesthesia with tetracaine--effect of added vasoconstrictors

The effect of adding 0.2 ml of 1:1000 epinephrine or 0.5 ml of 1% phenylephrine to 1.5 ml of 1% tetracaine for spinal anesthesia was assessed in 30 patients in a double-blind study. Phenylephrine but not epinephrine produced a significant prolongation of sensory loss in the T12 dermatome. Both vasoconstrictors produced a significant prolongation of the total duration of sensory and motor blockade. These findings differ from those in previous studies in which lidocaine and bupivacaine were used.     

The anesthetic and recovery profile of two doses (60 and 80 mg) of plain mepivacaine for ambulatory spinal anesthesia

Reports of transient neurological symptoms with the use of subarachnoid lidocaine has generated interest in alternate local anesthetics of intermediate duration, such as mepivacaine. This prospective randomized, double-blinded, dose-response study examined the anesthetic and recovery profiles of 60- and 80-mg doses of preservative-free plain mepivacaine for ambulatory spinal anesthesia. Sixty patients undergoing ambulatory anterior cruciate ligament repair of the knee under spinal anesthesia were randomized into two groups; Group 1 (29 patients) received 4 mL of 1.5% (60-mg dose) and Group 2 (31 patients) received 4 mL of 2% (80-mg dose) of plain mepivacaine. All patients received a combined spinal-epidural anesthetic technique. The epidural catheter was used only in the event the surgery outlasted the duration of surgical anesthesia with subarachnoid mepivacaine. Epidural supplementation was administered in three patients (12%) in Group 1 and one patient (3%) in Group 2 when the sensory block regressed to L-1 with surgery expected to last longer than 15 min. The cephalad dermatome level of the block and degree of motor block was comparable in the two groups. Times to two-segment and T-10 regression were comparable in the two groups (112 +/- 26 min in Group 1 versus 122 +/- 28 min in Group 2). Time to L-1 regression was significantly longer in Group 2 (146 +/- 28 min in Group 1 versus 159 +/- 19 min in Group 2). All of the ambulatory milestones were significantly faster in Group 1. Side effects, such as hypotension and emesis were negligible, severe bradycardia and urinary retention did not occur, and none of the patients in the two groups reported transient neurological symptoms over 24 h. In conclusion, plain mepivacaine in a 60- or 80-mg dose is a suitable local anesthetic choice for ambulatory spinal anesthesia with respect to anesthetic, as well as recovery profiles. IMPLICATIONS: We evaluated the anesthetic and recovery profiles of 60- and 80-mg doses of plain mepivacaine for ambulatory spinal anesthesia. Both doses produced comparable sensory and motor block. Sensory and motor regression and ambulatory milestones were 20-30 min longer with the 80-mg dose. Side effects were negligible and transient neurological symptoms were not reported during a 24-h follow-up.     

Brachial plexus anesthesia with verapamil and/or morphine

Calcium channel blockers potentiate the analgesic properties of both local anesthetics and opioids. We examined the analgesic effects of administering morphine, verapamil, or its combination into the brachial plexus sheath with lidocaine in 75 patients undergoing upper extremity orthopedic surgery. All patients received brachial plexus anesthesia with 40 mL of 1.5% lidocaine and epinephrine 5 microg/mL. In addition, patients were randomized to 1 of 5 groups: Group 1 received IV saline; Group 2 received IV verapamil 2.5 mg and morphine 5 mg; Group 3 received IV verapamil 2.5 mg and morphine 5 mg was added to the lidocaine solution; Group 4 received IV morphine 5 mg and verapamil 2.5 mg was added to the lidocaine solution; and Group 5 received verapamil 2.5 mg and morphine 5 mg were added to the lidocaine solution. Postoperatively, patients rated their pain (0-10) at 1, 6, 12, and 24 h. Patients were instructed to take 1 acetaminophen 325 mg/oxycodone 5 mg tablet every 3 h whenever the pain score exceeded 3. Analgesic duration was significantly increased in those patients receiving brachial plexus blocks with morphine (Groups 3 and 5) (P < 0.005). The total 24 h acetaminophen/oxycodone use was also less in Groups 3 and 5 (P < 0. 03). Duration of anesthesia (time of abolition of pinprick response) was significantly increased in those patients receiving brachial plexus blocks with verapamil (Groups 4 and 5) (P = 0.002). We conclude that the addition of verapamil to brachial plexus block with lidocaine can prolong the duration of sensory anesthesia, but it had no effect on analgesic duration of 24 h analgesic use. Implications: The addition of verapamil to brachial plexus block with lidocaine and morphine prolongs the duration of sensory anesthesia, but has no effect on analgesic duration or 24 h analgesic use.     

Comparison of pH-adjusted lidocaine solutions for epidural anesthesia

One hundred forty-eight adult patients having epidural anesthesia for cesarean section, postpartum tubal ligation, lower extremity orthopedic procedures, or lithotriptic therapy were assigned to five groups. Group 1 patients were given a commercially prepared 1.5% lidocaine solution with 1:200,000 epinephrine plus 1 ml of normal saline per 10 ml of lidocaine; the solution pH was 4.6. Group 2 patients were given commercially prepared 1.5% lidocaine solution plus 1:200,000 epinephrine, with 1 mEq (1 ml) NaHCO3 per 10 ml of lidocaine; the solution pH was 7.15. Group 3 patients received the commercial solution of 1.5% lidocaine with 1:200,000 epinephrine; the solution pH was 4.55. Group 4 patients were given a mixture of 18 ml of 2% lidocaine with 30 ml of 1.5% lidocaine, both commercially packaged with 1:200,000 epinephrine, plus 1 mEq (1 ml) of NaHCO3 added per 10 ml of solution; the solution pH was 7.2. Group 5 patients received 1.5% plain lidocaine to which epinephrine was added to a final concentration of 1:200,000; the solution pH was 6.35. Times of onset of analgesia (time between the completion of the anesthetic injection and loss of scratch sensation at the right hip (L-2 dermatome] and of surgical anesthesia (time between completion of injection and loss of discomfort following tetanic stimulation produced by a nerve stimulator applied to skin on the right hip) were significantly more rapid in the groups that received the pH-adjusted solutions (groups 4 and 2). Group 4 had the fastest mean onset time, 1.92 +/- 0.17 min, followed by group 2, 3.31 +/- 0.23 min.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prolongation of isobaric bupivacaine spinal anesthesia with epinephrine and clonidine for hip surgery in the elderly

The effects of vasoconstrictors on the duration of isobaric bupivacaine spinal anesthesia are unknown. A prospective controlled study was conducted on 60 ASA class II or III patients aged 75 yr or more who were scheduled for spinal anesthesia for orthopedic hip surgery. The subjects were randomly allocated into three groups. All patients received 15 mg bupivacaine plain solution in 4 ml in the horizontal position. Group I patients received bupivacaine plus 1 ml normal saline; group II patients received bupivacaine plus 0.2 mg epinephrine; group III patients received bupivacaine plus 0.15 mg clonidine. The segmental level of sensory loss was tested using forceps. In one case in group III, anesthesia was unsatisfactory. The time course required for maximal spread of the sensory blockade did not differ in the three groups. No difference was observed between mean highest levels of sensory anesthesia. The mean time to two-segment regression from the highest level was significantly longer in group III than in groups I and II. Mean time for regression to the L2 segment was also significantly longer in groups II and III than in group I. This time tended to increase more with the bupivacaine plus clonidine solution than with the bupivacaine plus epinephrine solution. Significant prolongation of motor block was also associated with the addition of clonidine.     

Effects of adding epinephrine plus fentanyl to low-dose lidocaine for spinal anesthesia in outpatient knee arthroscopy

BACKGROUND: This study investigated whether addition of 15 microg epinephrine plus 25 microg fentanyl to lidocaine spinal anesthesia for outpatient knee arthroscopy makes it possible to use a subanesthetic lidocaine dose. The aim was to assess the quality of anesthesia and the suitability of this protocol for outpatient knee arthroscopy. METHODS: Seventy-five outpatients scheduled for knee arthroscopy were randomly assigned to one of three spinal anesthetic protocols: Group L10F25 received 10 mg of lidocaine plus 25 micro g fentanyl; Group L10F25E15 received 10 mg of lidocaine plus 25 microg fentanyl plus 15 microg epinephrine; and Group L20F25 received 20 microg lidocaine plus 25 microg fentanyl. Tourniquet pain and surgical pain were assessed using a visual analog scale. If spinal anesthesia was inadequate despite supplementary intravenous analgesia and sedation, the patient was converted to general anesthesia. Recovery times and side-effects in the early postoperative period were recorded. RESULTS: The highest level of sensory block was above the T12 dermatome in all patients. Compared with the other groups, significantly more patients in Group L10F25 converted to general anesthesia. Group L10F25 had a significantly higher mean surgical pain score than the other groups. The mean tourniquet pain score was significantly higher in Group L20F25 than Group L10F25E15. Group L10F25E15 had a significantly shorter time to discharge than the other groups. Post-operative nausea and vomiting and drowsiness were more frequent in Group L10F25 than in the other groups. CONCLUSION: The combination of 10 mg lidocaine and 25 microg fentanyl plus 15 microg epinephrine provides adequate spinal anesthesia and has favorable recovery characteristics for outpatient knee arthroscopy.     

Effect of epinephrine on intrathecal fentanyl analgesia in patients undergoing postpartum tubal ligation

Eighty women receiving spinal anesthesia for postpartum tubal ligation were entered into a double-blind, randomized protocol studying the effects of epinephrine on intrathecal fentanyl-induced postoperative analgesia. All patients received 70 mg hyperbaric lidocaine with either 0.2 mg epinephrine (LE), 10 micrograms fentanyl (LF), epinephrine and fentanyl (LFE), or 0.4 ml saline (L). Onset and regression of anesthesia, degree of intraoperative comfort, incidence of pruritus, and extent of postoperative analgesia were evaluated. The simultaneous administration of epinephrine and fentanyl prolonged the duration of complete analgesia (137 +/- 47 min (LFE); 76 +/- 32 min (LE); 85 +/- 44 min (LF); 65 +/- 36 min (L)) and the duration of effective analgesia (562 +/- 504 min (LFE); 227 +/- 201 min (LE); 203 +/- 178 min (LF); 198 +/- 342 min (L)). Administration of epinephrine decreased the incidence of pruritus associated with intrathecal fentanyl (1/18 (LFE); 1/21 (LE); 8/19 (LF); 2/19 (L)).     

复合应用利多卡因对鞘内注射布比卡因时效的影响

背景由于阻滞持续时间较长，布比卡因蛛网膜下腔阻滞技术在门诊手术中使用受限。近期动物研究结果证实复合利多卡因后能缩短布比卡因蛛网膜下腔阻滞的持续时间。我们的研究旨在证实人类蛛网膜下腔阻滞时布比卡因复合利多卡因是否如同动物实验结果一样能够缩短其阻滞时间。方法采用随机双盲的方法将90例纳入本项研究的经尿道行膀胱肿瘤切除或前列腺切除的患者分为3组。每组均鞘内注射0．5％布比卡因重比重液1．5ml及下述溶液0．6ml：组Ⅰ（30例，对照组）生理盐水，组Ⅱ（30例）1％利多卡因，组Ⅲ（30侧）2％利多卡因。记录感觉阻滞最高平面、达到感觉阻滞最高平面的时间、从感觉阻滞最高平面到消退两个节段以及消退至L1和S2平面的时间、在感觉阻滞最高平面时和平面消退至L1和S2时的运动阻滞评分及在麻醉恢复室（PACU）的留观时间。结果3组患者达到感觉阻滞最高平面的时间相似。组Ⅱ患者的感觉阻滞最高平面消退两个节段和消退至L1和S2水平的时间，以及PACU内留观时间均较组Ⅰ患者显著缩短。组Ⅲ患者的感觉阻滞最高平面消退至L1和S2水平的时间，以及PACU内留观时间均显著延长。结论复合使用利多卡因（6mg）能够缩短布比卡因（7．5mg）的蛛网膜下腔阻滞时间，阻滞后患者恢复程度较单独使用相同剂量布比卡因（7．5mg）的脊髓麻醉更加迅速。     

Spinal 2-chloroprocaine: a dose-ranging study and the effect of added epinephrine

With the availability of preservative- and antioxidant-free 2-chloroprocaine (2-CP), there may be an acceptable short-acting alternative to lidocaine for spinal anesthesia. We examined the safety, dose-response characteristics, and effects of epinephrine with spinal 2-CP. Six volunteers per group were randomized to receive 30, 45, or 60 mg of spinal 2-CP with and without epinephrine. Intensity and duration of sensory and motor blockade were assessed. When 11 of the 18 volunteers complained of vague, nonspecific flu-like symptoms, breaking of the blind revealed that all spinal anesthetics associated with the flu-like symptoms contained epinephrine. There were no complaints of flu-like symptoms in the volunteers who received 2-CP without epinephrine. No further spinal anesthetics containing epinephrine were administered, resulting in 29 anesthetics (11 with epinephrine, 18 without epinephrine.) Plain 2-CP demonstrated a dose-dependent increase in peak block height and duration of effect at all variables except time to 2-segment regression and time to regression to T10. Time to complete sensory regression with plain 2-CP was 98 +/- 20, 116 +/- 15, and 132 +/- 23 min, respectively. 2-CP with epinephrine produced times to complete sensory regression of 153 +/- 25, 162 +/- 33, and 148 +/- 29 min, respectively. Preservative and antioxidant free 2-CP can be used effectively for spinal anesthesia in doses of 30-60 mg. Epinephrine is not recommended as an adjunct because of the frequent incidence of side effects. IMPLICATIONS: Hyperbaric spinal 2-chloroprocaine is effective and has an anesthetic profile appropriate for use in the surgical outpatient over the dose range of 30-60 mg without signs of transient neurologic symptoms. The addition of epinephrine is not recommended because of the frequent incidence of side effects.     

Prolongation of tetracaine spinal anesthesia by oral clonidine.

The effects of oral clonidine on the duration of isobaric tetracaine spinal anesthesia were studied in 30 patients undergoing urologic procedures. All patients received 15 mg of tetracaine intrathecally in isobaric saline solution. Group 1 (n = 10) received 0.25 mg of oral triazolam; group 2 (n = 10) received 0.15 mg of oral clonidine; and group 3 (n = 10) received 0.25 mg of oral triazolam and 0.75 mg of intrathecal phenylephrine. In group 1, the times for two- and four-segment regression of the level of analgesia to pin-prick were 80 +/- 17 and 123 +/- 22 min, respectively (mean +/- SD). The corresponding values of those measurements were 170 +/- 27 and 273 +/- 48 min in group 2 and 175 +/- 34 and 273 +/- 68 min in group 3. All the regression times in groups 2 and 3 were significantly longer than those in group 1. Regression times were not different between groups 2 and 3. The authors conclude that prolongation of tetracaine sensory analgesia may be produced by premedication with 0.15 mg of oral clonidine. The prolongation is similar to that produced by intrathecal phenylephrine.     

The clinical use of small-dose tetracaine spinal anesthesia for transurethral prostatectomy

In a double-blinded study, we compared conventional dose tetracaine (8 mg), small-dose tetracaine (4 mg) with added fentanyl and epinephrine, and small-dose tetracaine (4 mg) with added fentanyl subarachnoid anesthesia. Forty-five patients scheduled for transurethral resection of prostate (TURP) under subarachnoid anesthesia were randomly assigned to Group 1 (8 mg hyperbaric tetracaine), Group 2 (4 mg hyperbaric tetracaine, 10 microg fen-tanyl, and 0.2 mg epinephrine), and Group 3 (4 mg hyperbaric tetracaine, 10 microg fentanyl, and 0.2 mL saline). Evaluations were performed after spinal anesthesia. Subarachnoid block was successful in all patients except one in Group 1, who required general anesthesia by mask. The median peak sensory levels 10 min after the induction of spinal anesthesia in Group 1 was T8, which was significantly higher than Group 2 and Group 3 (P < 0.05). The time of sensory and motor recovery in Group 3 was less than in Groups 1 and 2 (P < 0.05). Hypotension was observed in four patients in Group 1 and none in Groups 2 and 3. We conclude that small-dose 4-mg hyperbaric tetracaine plus 10 microg fentanyl might provide adequate anesthesia and fewer side effects for TURP when compared with the conventional (8 mg) dose. IMPLICATIONS: Small-dose hyperbaric tetracaine (4 mg with 10 microg fentanyl added) may provide adequate anesthesia and fewer side effects for transurethral resection of the prostate.     

Effect of increasing amounts of epinephrine during isobaric bupivacaine spinal anesthesia in elderly patients

The effects of adding epinephrine to isobaric bupivacaine spinal anesthesia were investigated in 96 ASA class II-III patients aged 75 yr or more scheduled for lower extremity surgery. The subjects were randomly allocated into six groups. All patients received 15 mg bupivacaine plain solution in 4 ml, in the horizontal position. Patients in group 1 received bupivacaine plus 1 ml normal saline; patients in other groups received bupivacaine plus increasing dosages of epinephrine: 0.1 mg (group 2), 0.2 mg (group 3), 0.3 mg (group 4), 0.4 mg (group 5), 0.5 mg (group 6). The segmental level of sensory loss was tested using forceps. The time required for maximal spread of the sensory blockade was significantly 50% greater in group 5 than in group 1. No difference was observed, however, between mean highest levels. Addition of 0.2 mg epinephrine prolonged by a significant 25% regression time to L-2 level. Addition of 0.3 and 0.4 mg epinephrine significantly prolonged two-segment regression time by 36 and 53%, respectively, and regression to L-2 level by 29 and 44%, respectively. Addition of 0.5 mg epinephrine did not result in further prolongation of anesthesia. Motor blockade was also increased by addition of epinephrine. It is concluded that addition of 0.3 mg epinephrine may be useful to increase duration of isobaric bupivacaine spinal anesthesia.     

Epinephrine does not prolong lidocaine spinal anesthesia in term parturients

The effect of adding epinephrine to spinal anesthesia performed with lidocaine in young, healthy patients was determined in a prospective, controlled, randomized double-blind study. Patients were randomly assigned to one of two groups. One group received lidocaine in dextrose, and the other, lidocaine in dextrose plus epinephrine. Maximum segmental level, time to maximum level, and duration as determined by time to two-segment regression were determined for each of the two groups. There were no significant differences between the two groups in any of the observed parameters, most notably, duration. The present results substantiate those from a previous study in an older population that showed that epinephrine did not significantly prolong lidocaine spinal anesthesia. The present results do not, however, support the hypothesis based upon these earlier data that failure of epinephrine to prolong lidocaine spinal anesthesia is restricted to elderly patients.     

Dose response relationships for isobaric spinal mepivacaine using the combined spinal epidural technique.

Mepivacaine, a local anesthetic with similar physiochemical properties to those of lidocaine, is an adequate alternative for patients undergoing ambulatory procedures, and is associated with a lower incidence of transient neurologic symptoms (TNS) than lidocaine. We studied the dose-response characteristics of isobaric intrathecal mepivacaine using the combined spinal epidural technique for patients undergoing ambulatory arthroscopic surgery of the knee. Seventy-five patients were randomized prospectively to receive one of three doses of isobaric mepivacaine for spinal anesthesia: 30 mg (2 mL 1.5%), 45 mg (3 mL 1.5%), or 60 mg (4 mL 1.5%). An observer, blinded to the dose, recorded sensory level to pinprick and motor response until resolution of the block. In addition, the incidence of TNS was determined. An initial intrathecal dose of 30 mg of isobaric mepivacaine 1.5% produced satisfactory anesthesia in 72% of ambulatory surgical patients undergoing unilateral knee arthroscopy with a significantly shorter duration of sensory (158 +/- 32 min) and motor blockade (116 +/- 38 min) than doses of 45 and 60 mg. An intrathecal dose of 45 mg produced satisfactory anesthesia in all patients with a shorter duration of sensory (182 +/-38 min) and motor blockade (142 +/- 37 min) than 60 mg of mepivacaine 1.5% (203 +/- 36 min and 168 +/- 36 min, respectively). The incidence of TNS was 7.4% overall (1.2%-13.6% confidence intervals), less than the rates previously reported after spinal anesthesia with lidocaine in ambulatory surgical patients undergoing knee arthroscopy. We conclude that mepivacaine can be used as an adequate alternative to lidocaine for ambulatory procedures. IMPLICATIONS: This study evaluated the postoperative duration of spinal anesthesia after varying doses of isobaric mepivacaine and the incidence of transient radiating back and leg pain. We found that 45 mg of mepivacaine provided adequate anesthesia, a timely discharge, and a lower incidence of back pain than that previously reported after lidocaine spinals.     

Blood levels of lidocaine during continuous epidural anesthesia as indicated by leg skin temperature

Arterial blood concentrations of lidocaine were measured in 7 patients undergoing pancreas operation during continuous epidural anesthesia and repeated doses of lidocaine were given according to the skin temperature of the toe. After the epidural catheter placement at the middle level of thoracic spine, 3 ml (test dose) plus 9 ml of 2% lidocaine with epinephrine (1:200,000) were injected. Additional doses of lidocaine, 6 ml, were injected when the skin temperature of the toe decreased for 0.3 degrees C. Two cases were excluded from this study because the skin temperature did not increase following additional doses of lidocaine. Lidocaine was added for 3.4 times on an average during anesthesia (duration 345 +/- 35 min, mean +/- SE). The first, second, third and fourth intervals of repeated injections from the initiation of epidural anesthesia were 119 +/- 10 min, 184 +/- 16 min, 251 +/- 20 min and 323 +/- 27 min, respectively. Arterial blood concentrations of lidocaine before each injection were 2.4 to 2.8 micrograms.ml-1 and these values showed no significant changes. These results demonstrate that the estimation of the necessity of additional injections by monitoring the skin temperature during prolonged epidural anesthesia prevents the lidocaine intoxication.     

Epidural phenylephrine attenuates hypotension induced by alkalinized lidocaine epidural anesthesia.

In this double-blinded, randomized study, we examined the hemodynamic effects of lumbar epidural injection of alkalinized lidocaine with phenylephrine in 81 patients undergoing inguinal herniorrhaphy. Patients assigned to four equal groups received 20 mL of alkalinized lidocaine (17 mL of 2% lidocaine + 3 mL of 7% sodium bicarbonate) with one of four doses of phenylephrine: 0 (Group 1), 50 (Group 2), 100 (Group 3), or 200 microg (Group 4) injected via a lumbar epidural catheter. Blood pressure, heart rate, and skin temperature on the foot were recorded every 5 min for 1 h after injection and were compared among groups. Hypotension was defined as mean arterial pressure < 80% of baseline. The incidence of hypotension was 45%, 55%, 35%, and 15% in Groups 1-4, respectively. Patients in Group 4 showed the smallest reduction in blood pressure compared with Groups 1 and 2 (one-sided Fisher's exact test, P < 0.05). We conclude that the 200-microg dose of epidural phenylephrine (1:100,000 concentration) reduced the incidence of hypotension after epidural anesthesia with alkalinized lidocaine. IMPLICATIONS: Hypotension after epidural anesthesia is common in general clinical practice. Phenylephrine administered epidurally in combination with alkalinized lidocaine may reduce the incidence of hypotension.     

Small-dose intrathecal clonidine and isobaric bupivacaine for orthopedic surgery: a dose-response study

We examined the dose-response relationship of intrathecal clonidine at small doses (相似文献