Combined spinal-epidural and epidural anesthesia in operations on the vessels of the lower extremities

Eighty-eight anesthesias in patients operated on the lower limb vessels are analyzed. In group 1 (77 pts) combined spinal-epidural anesthesia (CSEA) was used, in group 2 (16 pts) epidural anesthesia (EA). Segmentary blocking was induced by 2% lidocaine and 0.5% bupivacaine. CSEA was characterized by a shorter (in comparison with EA) latent period (12.9 +/- 1.3 min vs. 24.7 +/- 3.4 min, p < 0.05), a lower dose of bupivacaine (lidocaine: 735 +/- 89 mg in CSEA and 848 +/- 92 mg in EA; bupivacaine: 28.3 +/- 7.2 mg in CSEA and 92.6 +/- 8.5 mg in EA, p < 0.01), and a higher reliability. Combined anesthesia with bupivacaine is characterized by a greater contribution of the spinal component (than with lidocaine) and thus improve the quality of anesthesia, decrease the anesthetic dose, and maintain the stability of hemodynamic parameters. Four cases with inadequate blocking were due to erroneous position of the epidural catheter. Accidental perforation of the dura mater occurred in two patients, and prolonged spinal anesthesia was carried out. No headaches ensued. Hence, CSEA should be preferred to common prolonged EA in operations on the lower limb vessels.     

Inhibition of cardiac sympathetic nerve activity during intravenous administration of lidocaine.

The antiarrhythmic action of lidocaine has been attributed solely to its direct electrophysiological effects on the heart. However, lidocaine is particularly effective in treating ventricular arrhythmias associated with increased sympathetic activity, e.g., in myocardial infarction and digitalis toxicity. We tested the hypothesis that lidocaine administered intravenously depressed cardiac sympathetic nerve activity (CSNA). We measured CSNA in six dogs in control state and after lidocaine in doses of 0.625, 1.25, and 2.5 mg/kg i.v. over 2 min. These doses of lidocaine produced graded decreases of CSNA of -8 +/- 2, -18 +/- 1, and -41 +/- 5%, respectively (P less than 0.05, mean +/- SE). In six additional experiments the bolus of lidocaine was followed by an infusion for 20 min (1.25 mg/kg followed by 100 micrograms/kg per min and 2.5 mg/kg followed by 200 micrograms/kg per min). Infusion of lidocaine maintained depression of CSNA at a level that was 23 +/- 3 and 35 +/- 5% less than control (P less than 0.05), respectively, at plasma lidocaine levels of 5.2 +/- 0.6 and 7.5 +/- 1.4 micrograms/ml, respectively. CSNA returned to control during recovery periods. CSNA did not decrease with the passage of time or administration of vehicle. In five dogs with vagi intact, carotid sinuses isolated and held at a pressure of 100 mmHg, and aortic baroreceptors denervated, administration of lidocaine (2.5 mg/kg followed by 200 micrograms/kg per min) decreased renal nerve activity to 71 +/- 8% of control. Increases in left ventricular systolic pressure and maximum derivative of pressure with respect to time (dP/dtmax) resulting from electrical stimulation of preganglionic sympathetic nerves were not significantly altered by lidocaine, but were markedly attenuated by hexamethonium, a ganglionic blocker. In conclusion, lidocaine administered intravenously produces dose-dependent and sustained decreases in cardiac sympathetic nerve activity. These decreases can occur with therapeutic plasma levels. We speculate that this effect is due to central nervous system effects of the drug and that this effect may contribute to the antiarrhythmic actions of lidocaine.     

The effect of pre-incisional infiltration of tonsils with bupivacaine on the pain following tonsillectomy under general anesthesia.

The aim of the present study was to test the hypothesis that blockade of nociceptive input with bupivacaine during tonsillectomy can decrease pain beyond the immediate postoperative period. Fourteen patients between the ages of 6 and 18 years scheduled for tonsillectomy (with or without adenoidectomy) were randomly divided into two groups. The patients of both groups received 0.006 mg/kg atropine and anesthesia was induced by inhalation of halothane. Atracurium 0.5 mg/kg was used for myorelaxation. After oral intubation anesthesia was maintained with isoflurane plus nitrous oxide 67% in oxygen. In the bupivacaine group, 5 min before incision the tonsillar fossae were infiltrated with 0.25% bupivacaine with epinephrine (1 : 200,000). In the control group, the tonsillar fossae were infiltrated with normal saline with epinephrine (1 : 200,000). All patients received morphine 0.07 mg/kg (in the recovery room) and oral elixir with codeine 0.05 mg/kg plus acetaminophen 5 mg/kg every 4 h. Pain assessments were made using the visual analog (100 mm scale) self-rating method. Two types of pain were assessed: constant incisional pain and pain caused by drinking 100 ml of water. In the bupivacaine group, the constant pain score on the second day after surgery was 19 +/- 6 compared to 74 +/- 8 in the saline group (P less than 0.0002). By the 4-5th day after surgery almost no constant pain occurred in the bupivacaine group, but the pain score remained at the 40-60 level in the saline group. The difference in pain intensity on swallowing between the bupivacaine and saline groups was present even on the 10th postoperative day (1 +/- 1 vs. 14 +/- 5, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Pharmacodynamic and pharmacokinetic interactions between lidocaine and verapamil

Lidocaine (3 mg/kg i.v.) injected during steady-state verapamil infusions (3 micrograms/kg i.v.) induced slight and transient hemodynamic changes in nine conscious dogs. Systemic vascular resistance and left ventricular dP/dt decreased by 16% from 41 +/- 4 mm Hg/liter/min and by 20% from 2876 +/- 137 mm Hg/sec, respectively, whereas heart rate and cardiac output increased by 18% from 100 +/- 5 beats/min and by 17% from 2.5 +/- 0.2 liters/min, respectively. Simultaneously, lidocaine induced a transient but more pronounced decrease in verapamil plasma concentration of 48% from 60 +/- 3 ng/ml. This pharmacokinetic interaction was not the result of a lidocaine-induced decrease in the fraction of verapamil bound to plasma protein because in vitro lidocaine failed to displace verapamil from its protein binding site. Moreover, an increase in verapamil total clearance was not the only mechanism because steady-state lidocaine (6 mg/kg over 5 min followed by 60 micrograms/kg/min) in the presence of steady-state verapamil (200 micrograms/kg over 3 min followed by 3 micrograms/kg/min) also resulted in a transient decrease in verapamil plasma concentration from 59 +/- 9 to 23 +/- 2 ng/ml in six conscious dogs. Although verapamil did not affect lidocaine pharmacokinetics, in the presence of the steady-state lidocaine we recorded an increase in verapamil initial volume of distribution of 44% from 40 +/- 4 liters, and intercompartmental clearance increased by 88% from 101 +/- 20 liters/hr, combined with an increase in verapamil total clearance of 47% from 54 +/- 6 liters/hr (n = 6).     

Intraocular pressure and quality of blockade in peribulbar anesthesia using ropivacaine or lidocaine with adrenaline: a double-blind randomized study

The aim of this study was to compare the effects of ropivacaine with those of lidocaine on the intraocular pressure (IOP) and the quality of the blockade in peribulbar anesthesia for cataract surgery. Fifty patients were allocated randomly into two groups and received 7-10 ml of 0.75% ropivacaine or 2% lidocaine with adrenaline, though the peribulbar two-point injection. The quality of the blockade was assessed by ocular and eyelid akinesia, pain during the peribulbar injection, and surgical satisfaction. The duration of the motor block was also evaluated after surgery. The IOP was measured using a Tonopen before the blockade (control) and at 1, 5, and 10 min after injection of the anesthetic. Lidocaine induced significantly lower akinesia scores at 6, 8, and 10 min post-injection than did ropivacaine. The mean IOP (mmHg) was significantly lower with respect to the baseline level at 10 min after blockade in the ropivacaine group compared with the lidocaine group. Ropivacaine also caused less pain on injection. There was no difference in surgical satisfaction between the groups. The duration of the motor block obtained with ropivacaine was longer than that obtained with lidocaine. Our data indicate that ropivacaine has efficacy similar to lidocaine, with slightly longer onset and duration of the motor blockade. In addition, ropivacaine (0.75%) induces lower IOP and less pain on injection than does lidocaine (2%) when used in peribulbar anesthesia for cataract surgery.     

Endotracheal lidocaine administration via an esophageal combitube

The purpose of this study was to test the hypothesis that lidocaine is systemically absorbed after administration via a Combitube placed in the esophagus, and that therapeutically significant plasma lidocaine concentrations can be attained using this route with standard endotracheal doses (2.0 mg/kg). During general anesthesia, 27 elective surgical patients received 2.0 mg/kg lidocaine (diluted as necessary with 0.9% saline to a minimum total volume of 10 mL) via a Combitube (study group, n = 13) or an endotracheal tube (control group, n = 14). Venous blood samples were drawn for 3 h after lidocaine administration and plasma concentrations determined by gas chromatography using a nitrogen-phosphorus detector (NPD). Overall, average lidocaine concentrations were maximal after 5 min, reaching 0.8+/-0.7 and 1.7+/-0.7 microg/mL in the Combitube and endotracheal tube groups, respectively. Individual patient peak concentrations averaged 1.0+/-0.7 and 2.2+/-1.1 microg/mL in the same two groups, 19+/-16 and 10+/-15 min after lidocaine administration, respectively. No patients reported chest discomfort or dyspnea upon awakening, and no other side effects were noted. In support of the hypothesis, administration of lidocaine via an esophageal Combitube results in systemic drug uptake; however, at conventional endotracheal doses, plasma concentrations are subtherapeutic. It remains to be determined whether higher doses of lidocaine administered via an esophageal Combitube will result in therapeutic plasma concentrations.     

A dose-response study of epidural liposomal bupivacaine in rabbits.

Liposomes are drug delivery systems used to prolong local effects of bupivacaine. We studied the relationships between motor and hemodynamic changes and epidural doses of plain bupivacaine (P) and liposomal bupivacaine (L) in rabbits equipped with chronical lumbar epidural and femoral arterial catheters. Liposomal (phosphatidylcholine-cholesterol) suspensions contained 20 mg ml-1 of lipid, and different doses of bupivacaine (Lipo 7.5=7.5-; Lipo 3.7=3. 75-; Lipo 2.5=2.5-; Lipo 1.2=1.25-; and Lipo 0.7=0.65-mg of bupivacaine per ml). Forty rabbits were randomly assigned to five groups to receive epidural anesthesia (1 ml) as follows: Groups I to V received 0.65 to 7.5 mg of bupivacaine as P then as L. Release rate of bupivacaine from liposome was significantly slower using Lipo 3.7 than after Lipo 2.5 (Td was 3.9 h and 1.7 h respectively). Increasing the doses of L and P resulted in faster onset time for complete motor blockade and in a prolonged duration of motor effects. Liposomal formulation appears to be a powerful delivery system to prolong the motor effects of bupivacaine since E50 was lower and Emax higher than after the use of plain solution (E50 4.49+/-1.81 mg and Emax 152+/-40 min for P; and E50 2.61+/-0.23 mg and Emax 202+/-9 min for L). Hemodynamic changes were linearly related to doses of bupivacaine injected. The best bupivacaine-to-lipid ratio to prolong motor effects using our model was 3.75 mg and 20.0 mg respectively (Lipo 3.7).     

Low-dose lidocaine reduces secondary hyperalgesia by a central mode of action

Sodium channel blockers are approved for intravenous administration in the treatment of neuropathic pain states. Preclinical studies have suggested antihyperalgesic effects on the peripheral as well as the central nervous system. The objective of this study was to determine mechanisms of action of low-dose lidocaine in experimental induced, secondary hyperalgesia. In a first experimental trial, participants (n=12) received lidocaine systemically (a bolus injection of 2 mg/kg in 10 min followed by an intravenous infusion of 2 mg kg(-1)h(-1) for another 50 min). In a second trial, a modified intravenous regional anesthesia (IVRA) was administered to exclude possible central analgesic effects. In one arm, patients received an infusion of 40 ml lidocaine, 0.05%; in the other arm 40 ml NaCl, 0.9%, served as a control. In both trials capsaicin, 20 microgram, was injected intradermally and time course of capsaicin-induced pain, allodynia and hyperalgesia as well as axon reflex flare was determined. The capsaicin-induced pain was slightly reduced after systemic and regional application of the anesthetic. The area of pin-prick hyperalgesia was significantly reduced by systemic lidocaine, whereas the inhibition of hyperalgesia was absent during regional administration of lidocaine. In contrast, capsaicin-induced flare was significantly decreased after both treatments. We conclude that systemic lidocaine reduces pin-prick hyperalgesia by a central mode of action, which could involve blockade of terminal branches of nociceptors. A possible role for tetrodotoxin resistant sodium channels in the antihyperalgesic effect of low-dose lidocaine is discussed.     

A comparative analysis of the efficacy of trimecaine, lidocaine and bupivacaine for a prolonged brachial plexus block

Local anesthetic effects of trimecaine, lidocaine and bupivacaine have been compared in high axillary brachial plexus blockade in 110 patients operated on the lower limb. The clinical pattern of conductive anesthesia and its efficacy (90 to 95.5%) did not depend on the kind of the anesthetic used. The rate of analgesia development in this technique is determined by physicochemical properties of the drug. Trimecaine effect is of minimum duration (130.0 +/- 1.3 min), while bupivacaine effect is of maximum duration (375.7 +/- 22.7 min). Lidocaine has an intermediate position (161.4 +/- 2.6 min).     

Difference in analgesia following epidural blockade in patients with postoperative or chronic low back pain

Subjective responses of continuous epidural analgesia with bupivacaine were compared in 30 patients with acute (postoperative) or chronic (low back) pain. In the acute pain patients, sensory block was 4 dermatomes at 9 h and 6 dermatomes at 64 h. Corresponding values in the chronic pain patients were 8 and 6 dermatomes respectively. Motor blockade of the lower limbs was more profound in the acute pain group. The acute pain patients had significantly better pain relief (VAS: 85-96% vs. 55-70%) and a significantly higher proportion of these patients reported a global score of 3 (excellent; 80% vs. 7%). The mean dosage of bupivacaine decreased in the acute pain group from 21.0 +/- 5.7 (mean +/- S.D.) mg/h at 9 h to 15.1 +/- 8.5 mg/h at 64 h. Corresponding values for the chronic pain group were 20.7 +/- 5.9 and 12.0 +/- 6.0 mg/h respectively. Mean plasma concentration of bupivacaine increased from 1.2 +/- 0.8 micrograms/ml at 9 h to 2.1 +/- 1.4 micrograms/ml at 64 h in the acute pain patients and was 0.8 +/- 0.3 micrograms/ml at 9 h to 1.0 +/- 1.0 micrograms/ml at 64 h in the chronic pain patients. The incidence of side effects was approximately the same in both groups. No signs of accumulation or toxic reactions to bupivacaine were seen.     

地塞米松延长骨科手术中布比卡因硬膜外麻醉及术后镇痛的时效

观察地塞米松对布比卡因硬膜外麻醉效果的影响。方法：选择中等骨科手术患者,随机分两组,Ａ组采用０．７５％布比卡因１０ｍｌ＋１％利多因卡因２００ｍｇ硬膜外麻醉;Ｂ组采用０．７５％布比卡因１０ｍｌ＋１％利多卡因２００ｍｇ＋地塞松松１０ｍｇ硬膜外麻醉,观察麻醉起效时间和术后镇痛时间。     

Concentrations of cefmetazole in plasma and tissue resulting from peri-incisional administration before appendectomy.

The levels of cefmetazole in plasma and tissue were determined after injection of a dose of 30 mg/kg into the zone of the wound of each of 15 patients undergoing appendectomy. The mean plasma levels of cefmetazole at the start and end of surgery (8.9 +/- 2.4 and 31.7 +/- 6.4 min after dosage) were 21.1 and 59.0 micrograms/ml, respectively; concentrations of the drug were 14.6 and 4,486.9 micrograms/g in skin, 9,165.0 and 1,756.4 micrograms/g in subcutaneous tissue, and 8,669.6 and 2,022.9 micrograms/g in muscle.     

Feasibility of an infraclavicular block with a reduced volume of lidocaine with sonographic guidance.

OBJECTIVE: A successful brachial plexus block requires a large volume of a local anesthetic. Sonography allows reliable deposition of the anesthetic around the cords of the brachial plexus, potentially lowering the anesthetic requirement. METHODS: Fifteen sonographically guided infraclavicular blocks were performed in 14 patients with 2% carbonated lidocaine with epinephrine through a 17-gauge Tuohy needle. The amount of lidocaine injected at several points around each cord was based on satisfactory spread observed sonographically. A 19-gauge catheter was then placed with its tip between the posterior cord and axillary artery, and tip position was confirmed by observing the spread of 1 to 2 mL of injected air. Lidocaine was injected through the catheter if necessary to prolong the blocks. RESULTS: Surgery was performed in all patients without general anesthesia, rescue blocks, or infiltration. A heroin user was given an additional 50 microg of fentanyl before the block. One patient required 5 mL of lidocaine through the catheter for an incomplete radial nerve block 5 minutes after initial injection. Seven patients received additional midazolam (mean, 2.5 mg) for alleviation of anxiety despite excellent blocks. The mean +/- SD volume of lidocaine for the initial block was 16.1 +/- 1.9 mL (4.2 +/- 0.9 mg/kg). In 4 patients, additional lidocaine 1 hour after an initial successful block increased the total volume to 19.5 +/- 7.1 mL (5 +/- 1.9 mg/kg). The mean times to perform the block, onset of the block, and achieving surgical anesthesia and the duration of surgery were 10.8 +/- 3.3, 2 +/- 1.3, 5.9 +/- 2.6, and 92.7 +/- 54.4 minutes, respectively. CONCLUSIONS: A successful infraclavicular block in adults with 14 mL of lidocaine is feasible with the use of sonography. The reduced volume does not seem to affect the onset but shortens the duration of the block.     

蛛网膜下腔注射左旋布比卡因与布比卡因运动阻滞效应的比较

目的比较患者蛛网膜下腔注射左旋布比卡因与布比卡因的运动神经阻滞效应。方法择期腰硬联合麻醉下拟行泌尿外科腔镜手术患者60例,年龄18～64岁,ASA分级I或Ⅱ级,按随机数字表法分为0．5％左旋布比卡因组和0．5％布比卡因组（n=30）,按照序贯法进行试验,阻滞有效,则下一例患者采用低一级剂量,阻滞无效,则下一例患者采用高一级剂量,初始剂量均为4mg,剂量梯度1mg,阻滞有效的标准：蛛网膜下腔给药后5或10min任一下肢的运动神经阻滞评分〉0分。采用序贯法计算蛛网膜下腔注射左旋布比卡因或布比卡因运动神经阻滞的半数有效剂量（ED50）。结果患者蛛网膜下腔注射左旋布比卡因和布比卡因运动神经阻滞的ED50及其95％置信区间分别为6．68（6．27,7．13）mg和5．06（4．56,5．47）mg,效力比为0．76。结论患者蛛网膜下腔注射左旋布比卡因运动神经阻滞效力小于布比卡因。     

Pharmacokinetics and tissue penetration of single-dose cefotetan used for antimicrobial prophylaxis in patients undergoing colorectal surgery.

The pharmacokinetics and tissue penetration of cefotetan were studied after a single injection of 2 g given intravenously for antimicrobial prophylaxis to 16 consecutive patients undergoing colorectal surgery. Concentrations in tissue greater than or equal to the MIC for 90% of the main pathogens tested were considered adequate. The elimination half-life at beta phase was 4.6 +/- 1.4 h, the total body clearance was 0.75 +/- 0.19 ml/kg/min, and the volume of distribution was 260 +/- 71 ml/kg. At the time of incision (33 +/- 16 min after the injection), cefotetan concentrations were 14.2 +/- 7 micrograms/g in abdominal-wall fat, 16.4 +/- 1 micrograms/g in epiploic fat, and 163 +/- 62 mg/liter in serum. At the time of surgical anastomosis (151 +/- 54 min), cefotetan concentrations were 33.3 +/- 6 micrograms/g in the colonic wall and 73 +/- 34 mg/liter in serum. Upon closure of the abdomen (216 +/- 76 min), cefotetan concentrations were 6.3 +/- 3 micrograms/g in abdominal-wall fat, 6.1 +/- 4 micrograms/g in epiploic fat, and 64 +/- 38 mg/liter in serum. Cefotetan tissue penetration was 10% into abdominal and epiploic fat and 46% into the colonic wall. Levels in tissue were compared with the MIC for 90% of the most frequently encountered pathogenic germs (Staphylococcus aureus, Bacteroides fragilis, and Escherichia coli). Adequate concentrations in tissue were obtained up to anastomosis but not upon closure. The authors therefore recommend the injection of an additional dose of 1 g before closure in order to ensure optimal efficacy throughout the surgical procedure.     

Penetration of ofloxacin into heart valves, myocardium, mediastinal fat, and sternal bone marrow in humans.

Ofloxacin penetration into heart tissue (valve and myocardium), mediastinal fat, and sternal bone marrow was the object of a prospective nonrandomized study. Thirty-six patients undergoing mitral and/or aortic valve replacement were included. Patients were divided into two groups of 18 patients each. Group 1 patients were administered a single 400-mg intravenous dose of ofloxacin over a 30-min period upon anesthesia (n = 6) or at 1 h (n = 6) or 6 h (n = 6) prior to surgery. Group 2 patients received a 200-mg oral dose of ofloxacin every 12 h during the 48 h preceding surgery. In this group, the final dose of ofloxacin was administered 3 h (n = 9) or 8 h (n = 9) before anesthesia. Plasma and tissue ofloxacin concentrations were assayed by high-pressure liquid chromatography. In group 1 patients, the peak level in plasma was 15.9 +/- 2.5 micrograms/ml. Peak ofloxacin levels in tissue were reached by hour 1 and were 8.89 +/- 2.16 micrograms/g in myocardium and 5 +/- 0.75 micrograms/g in heart valves. A significant decrease in ofloxacin levels in heart valve tissue and sternal bone marrow was observed after hour 3. Nevertheless, ofloxacin myocardial, heart valve, and sternal bone marrow levels remained higher than the MICs for the usually susceptible pathogens for at least 3 h. In group 2 patients, myocardial levels were long lasting (6.46 +/- 1.92 micrograms/g [4 to 8 h] and 5.92 +/- 0.95 micrograms/g [8 to 12 h]) and remained higher than those observed in the other tissues over the entire study period. A progressive but insignificant decrease in ofloxacin heart valve levels was observed (from 2.46 +/- 0.40 micrograms/g [4 to 8 h] to 1.57 +/- 0.22 micrograms/g [8 to 12 h]). In both groups, concentration in mediastinal fat were lower and tended to decrease with time. These were 1.83 +/- 0.61 micrograms/g with the first hour and 0.85 +/- 0.43 micrograms/g between hours 8 and 12 in group 1 and 1.74 +/- 0.52 micrograms/g between hours 4 and 8 and 0.67 +/- 0.11 micrograms/g between hours 8 and 12 in group 2. In conclusion, satisfactory diffusion of ofloxacin into heart tissue seems to favor use of the drug in the treatment of bacterial endocarditis due to susceptible pathogens. Furthermore, the progressively decreasing concentrations observed in heart valve and sternal bone marrow and the poor levels achieved in mediastinal fat suggest the need for renewing injection 3 h following initial infusion if the drug is used as an antibiotic prophylactic agent during cardiovascular surgery.     

Changes in hemodynamics with a combination of epidural anesthesia and propofol sedation in children

Hemodynamic profiles and myocardial contractility were investigated in children aged 3-14 years during epidural anesthesia with propofol. Anesthesia was induced by intravenous bolus propofol (3.5 mg/kg). Ketamine (2.4 mg/kg) was used to potentiate analgesia during intubation. Xilocaine (5 mg/kg) was used for epidural analgesia. Anesthesia was maintained by continuous i.v. propofol infused in a dose of 191-312 micrograms/kg x min (mean dose 243 +/- 30.3 micrograms/kg x min) until the peak of epidural analgesic activity was reached, after which propofol dose was gradually reduced to 53-143 micrograms/kg x min (mean 108.8 +/- 14.6 micrograms/kg x min). This variant of epidural anesthesia with i.v. propofol ensured a hemodynamically stable anesthesia and good analgesia in operations of any complexity. It was however paralleled by a moderate decrease of myocardial contractility.     

Lidocaine and indocyanine green kinetics: effect of hypoxemia and/or hypercapnia

Patients with premature ventricular contractions are also frequently hypoxemic (HO) and/or hypercapnic (HC). The aims of the present study were to document the effect of HO and/or HC on the kinetics of lidocaine, a first choice drug for the i.v. treatment of premature ventricular contractions, and on indocyanine green (ICG), another flow-dependent drug. For this purpose, five groups of rabbits were used: a control group received 2.5 mg/kg i.v. of ICG followed, 30 min later, by 7.5 mg/kg of lidocaine as a bolus. Four other groups received lidocaine as an infusion (261 micrograms/min/kg) for 255 min and ICG (249 micrograms/min/kg) for 8 min, the latter beginning 180 min after the start of the lidocaine infusion. The controls and one test group receiving the lidocaine infusion were breathing air (PaO2 = 89 +/- 2 (S.E.M.) and PaCO2 = 20 +/- 1 mm Hg); the second test group had HO (PaO2 = 51 +/- 1 mm Hg), a third group HC (PaO2 = 68 +/- 1 mm Hg) and the fourth HO combined with HC (HOHC) (PaO2 = 53 +/- 1 and PaCO2 = 61 +/- 2 mm Hg). Multiple blood samples were drawn. Lidocaine and its metabolites and ICG were assayed by high-performance liquid chromatography. Lidocaine volume of distribution was not affected by HO and/or HC. Compared to control values, the clearance of infused lidocaine (CIL) tended to decrease from 65 +/- 2 to 53 +/- 3 ml/min/kg. In animals with HO, HC and HOHC, CIL was 49 +/- 6, 45 +/- 5 and 46 +/- 3 ml/min/kg, respectively, these values not being significantly different from CIL.(ABSTRACT TRUNCATED AT 250 WORDS)     

Profound Prolonged Bradycardia and Hypotension after Interscalene Brachial Plexus Block with Bupivacaine

Background

Interscalene brachial plexus blocks have been a routinely performed method of anesthesia for shoulder surgery that decreases the need for general anesthesia, length of stay, and recovery time. We describe a case of bupivacaine toxicity after an interscalene block.

Transient radiculopathy after 5% lidocaine or 0.75% bupivacaine spinal anesthesia in 3 surgical positions

The present study was conducted to compare the incidence of transient radicular irritation (TRI) after spinal anesthesia with 5% lidocaine or 0.75% bupivacaine in the supine, prone, and lithotomy surgical positions. A non-rAndomized survey approach was used. The convenience sample consisted of 243 adults receiving spinal anesthesia for elective surgery at 1 of 3 hospitals. Patients were questioned by telephone postoperatively to determine whether they had experienced TRI. Statistical analysis using the Fisher exact test revealed no significant difference in TRI incidence between local anesthetics in the supine or prone position groups. In the lithotomy position group, the incidence of TRI was significantly higher in patients receiving 5% lidocaine. Further, chi 2 testing revealed no significant difference in TRI incidence between surgical position groups when position alone was considered. The findings suggest that TRI after spinal anesthesia occurs more frequently with 5% lidocaine than with 0.75% bupivacaine only when patients undergo surgery in the lithotomy position. Providers need to consider the risks and benefits of 5% lidocaine when selecting an agent for spinal anesthesia, especially with patients undergoing surgery in the lithotomy position. When lidocaine is used, providers should discuss TRI as a risk of spinal anesthesia with patients during preanesthetic counseling.