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The surgical site for the creation of an arteriovenous fistula at the lateral aspect of the distal forearm may be faster and more effectively blocked with the infraclavicular coracoid approach than with the axillary approach for brachial plexus block.Sixty uremic patients scheduled for the creation of an arteriovenous fistula at the forearm were randomized to receive a single-injection brachial plexus block with 35 to 50 mL mepivacaine 0.95% with epinephrine using the infraclavicular coracoid approach (IC group) or the perivascular axillary approach (AX group). A distal muscular contraction elicited by a nerve stimulator at current0.5 mA was used in all patients.At 30 and 45 minutes, complete loss of sensation was observed more often in group IC than AX in the cutaneous distribution of musculocutaneous nerve (62% v 30% [P.05] and 69% v 40%, respectively [P.05]), but at 60 minutes the difference was not statistically significant. In other areas, analgesia and motor block were achieved at a similar rate. In 3 patients surgery could not be performed under the block due to changes in schedule or the use of a brachial tourniquet. Patient satisfaction was equally high in both groups.Blockade of the musculocutaneous nerve developed faster with the infraclavicular coracoid approach than with the axillary approach. The infraclavicular coracoid approach may be preferable in patients scheduled for the creation of an arteriovenous fistula at the forearm.

Adequate intraoperative analgesia combined with faster mobilization might be achieved by replacing hyperbaric ropivacaine partly with fentanyl.Sixty spinal anesthesia patients were randomized into 2 groups of either fentanyl 20 microg mixed with hyperbaric ropivacaine 10 mg (group FR10) or hyperbaric ropivacaine 15 mg (group R15). Forty-five patients underwent inguinal hernia repair and 15 patients had lower extremity surgery. Sensory block was tested by pinprick, and motor block was tested by use of a modified Bromage scale at 5-minute intervals for 30 minutes, 15-minute intervals for 60 minutes, and at 30-minute intervals until full recovery.The groups did not differ significantly regarding success (27 of 30 [group FR10] and 29 of 30 [group R15]), median onset time (10 [5 to 25] v 10 [5 to 20] minutes) or median duration of T10 sensory block (55 [20 to 115] v 80 [5 to 170] minutes), respectively. Recovery from spinal block was significantly quicker in group FR10 than in group R15, recorded in ability to walk (2.5 hours v 3 hours [P=.017]), full motor recovery (1 hour v 1.5 hour [ P.001]), and sensory recovery to S1 (2.5 hours v 3.3 hours [ P=.026]). Pruritus occurred in 18 (60%) of group FR10 v 0 of group R15 patients ( P.001). This symptom was mild in all except 1 patient, who received ondansetron 8 mg IV. In the OR, the groups did not differ hemodynamically: 9 (30%) of the group FR10 and 10 (33%) of the group R15 patients, respectively, required medication for hypotension and/or bradycardia. Full motor block (Bromage 3) developed less frequently (P.001) in group FR10 patients than in group R15 patients (1 [3%] v 14 [47%]), and the group FR10 patients recovered faster in a median time of 60 v 90 minutes (P.001). In both groups, sensory and motor blocks were more extensive on the operative side compared with the nonoperative side ( P.001).Faster mobilization but equal onset and duration of analgesia were achieved with intrathecal hyperbaric ropivacaine 10 mg plus fentanyl 20 microg as compared with hyperbaric ropivacaine 15 mg.

The current recommendations regarding maximum doses of local anesthetics presented in textbooks, or by the responsible pharmaceutical companies, are not evidence based (ie, determined by randomized and controlled studies). Rather, decisions on recommending certain maximum local anesthetic doses have been made in part by extrapolations from animal experiments, clinical experiences from the use of various doses and measurement of blood concentrations, case reports of local anesthetic toxicity, and pharmacokinetic results. The common occurrence of central nervous system toxicity symptoms when large lidocaine doses were used in infiltration anesthesia led to the recommendation of just 200 mg as the maximum dose, which has remained unchanged for more than 50 years. In most cases, there is no scientific justification for presenting exact milligram doses or mg/kg doses as maximum dose recommendations. Instead, only clinically adequate and safe doses (ranges) that are block specific are justified, taking into consideration the site of local anesthetic injection and patient-related factors such as age, organ dysfunctions, and pregnancy, which may influence the effect and the pharmacokinetics of the local anesthetic. Epinephrine in concentrations of 2.5 to 5 microg/mL should be added to the local anesthetic solution when large doses are administered, providing there are no contraindications for the use of epinephrine. As a rule, conditions (eg, end-stage pregnancy, high age in epidural, or spinal block) or diseases (uremia) that may increase the rate of the initial uptake of the local anesthetic are indications to reduce the dose in comparison to one normally used for young, healthy, and nonpregnant adults. On the other hand, the reduced clearance of local anesthetics associated with renal, hepatic, and cardiac diseases is the most important reason to reduce the dose for repeated or continuous administration. The magnitude of the reduction should be related to the expected influence of the pharmacodynamic or pharmacokinetic change.

Background and Objectives: The combined spinal and epidural (CSE) technique can reduce or eliminate some of the disadvantages of spinal and epidural anesthesia, while still preserving their advantages. CSE anesthesia is now commonly performed with a single-segment needle-through-needle technique; however, this technique involves some controversies about needle handling and the risk of catheter migration. To avoid some of these potential problems, special CSE sets have been produced. In the present study, 2 of these sets were compared with the traditional double-segment technique. Methods: Ninety patients undergoing orthopedic surgery of the lower extremity were randomly allocated into 3 groups of equal size: Group 1, CSE set with an interlocking device between the spinal and epidural needle; group 2, CSE set with a “backeye” at the epidural needle curve for the passage of the spinal needle; group 3, double-segment technique. All epidural needles were 18-gauge, and spinal needles were 27-gauge with a pencil-point tip. In groups 1 and 2, the puncture was performed at the L3-4 interspace, and in group 3 the epidural catheter was first inserted at the L2-3 interspace followed by spinal puncture one interspace lower. Hyperbaric 0.5% bupivacaine, 2 mL, was used for the spinal block, and 4 mL of 2% lidocaine with epinephrine through the epidural catheter was used as a test dose. The block performance characteristics were recorded, and the level of analgesia was studied in a blinded fashion. Postoperatively, a bolus of epidural morphine 2 to 4 mg was used for the control of postoperative pain. All patients were interviewed on the 1st and the 7th postoperative days. Afterwards, the needles and catheters were examined by microscopy. Results: The frequency of the successful CSE block was higher in groups 3 (100%) and 2 (90%) than in group 1 (63%) (P < .05). The mean duration of successful block performance, as well as the median level of analgesia, were similar in all the groups. One case of epidural catheter migration intrathecally was observed (group 1). Postoperative nausea and vomiting occurred in 23% of patients, and the incidence of postdural puncture headache was 2.2%. The incidence of backache at the puncture site was similar in the groups. Microscopy showed 6 distorted spinal needle tips (all in group 1), but no material damage to the epidural catheters. Conclusions: The use of the CSE sets does not seem to save time compared with the double-segment technique. Technical problems, unsuccessful CSE block, and damaged spinal needle tip were noted relatively often with the interlocking CSE set. Anesthetic characteristics in the successful blocks were similar with the different techniques. Reg Anesth Pain Med 2001;26:17-23.

Background and Objectives: Major complications after spinal or epidural anesthesia are extremely rare. The occurrence of less serious and transient sequelae and complaints may be underestimated if there is no established organization for the systematic and continuous surveillance of patients after anesthesia. This study was designed to evaluate the possible relationship between various block-related occurrences and the intra- and postoperative side effects and complaints. Methods: This prospective study included 3,230 orthopedic patients operated on under neuraxial block. The block was performed by single-dose (single-shot spinal anesthesia [SPIN], 80.6%), continuous spinal anesthesia (CSA, 10.3%), or combined spinal and epidural anesthesia (CSE, 9.1%) technique. The patient position during surgery and a detailed description of block performance and equipment, as well as all intraoperative problems, were immediately recorded. Every patient was given a standardized questionnaire to be completed and returned after 1 week. Results: The overall incidence of paresthesia was 12.8%, being most frequent during spinal catheter insertion with multiple attempts. Postoperative sensory disturbances (numbness, dysesthesia) occurred unrelated to paresthesia elicited by the puncture or catheterization. The failure rates (SPIN, 1.0%; CSA, 1.5%; and CSE, 1.0%) were quite low. Asystole with successful resuscitation, occurred in 1 patient with CSE but, overall, hemodynamic perturbations were more common with the continuous techniques. On the first postoperative day, decreased sensation of the skin was significantly more frequent after the continuous techniques, still present in 6.5% of SPIN patients, 6.1% of CSA patients, and 17.2% of CSE patients 1 week after surgery. These disturbances were also related to the use of a tourniquet and lateral position of the patient during surgery. The frequency of postdural puncture headache (PDPH) was similar for the different techniques (SPIN, 0.9%; CSA, 1.5%; and CSE, 1.7%). About one third of the patients reported strong postoperative pain on the day after the operation, and 5.6% continued to report this at 1 week. Conclusions: Although sensory changes were quite frequent, they were mild and transient. Rather than having been caused by the anesthetic technique, per se, a “nonanesthetic” reason (position, tourniquet, immobilization) should also be considered as their origin. Sensory disturbances, as well as strong pain for at least a week, were reported by several patients, and to become aware of these problems and improve the quality of treatment, a universal regional anesthesia follow-up system is recommended. Reg Anesth Pain Med 2000;25:488-497.

Background and Objectives Previous studies have shown the vulnerability of the tips of cutting type thin spinal needles and the possibility of foreign material passing into the subarachnoid space during the lumbar puncture. We made a microscopic analysis to compare two commonly used noncutting pencil-point spinal needles with different tip designs. Needles with a cutting tip design were included as reference. Methods Four fresh cadavers were placed in the lateral position and their backs were scrubbed with disinfectant solution containing 0.1% fluorescein. Thirty-two spinal needles (27 gauge) of each type (modified Quincke, modified Sprotte, and modified Whitacre) were inserted through an introducer at interspaces L2-5 into the subarachnoid space. Under visual control (spinal canal opened ventrally) all the needle tips were cut after successful subarachnoid puncture; 16 needles of each tip design were investigated under a fluorescence microscope, and another 16 needle tips were collected into test tubes and cytocentrifuged smears were prepared. The tips and smears with the most obvious findings were photographed under a microscope. Results On microscopy, only 2 needle tips were damaged (1 modified Quincke and 1 modified Whitacre). Visible fluorescent tissue particles were more frequently seen on modified Quincke needles (56%) compared with modified Sprotte (37%) and Whitacre (37%) needles (NS). In the cytocentrifugation smears, the largest clusters of epithelioid cells and muscle fibers were observed in the Quincke group. In the Whitacre group many fewer and smaller cell clusters including small muscle particles were seen, and only minor epithelioid cells were found in the Sprotte group. Conclusions Tissue coring seems to be a common phenomenon during lumbar puncture. The most prominent attachments appeared with a cutting Quincke-type spinal needle.

Background and Objectives The use of thin single-hole pencil-point (SHPP) spinal needles may be a reason for subarachnoid maldistribution of local anesthetic. A new double-hole pencil-point (DHPP) needle may be preferable because of a theoretic more uniform initial distribution of local anesthetic. Methods This was a prospective, double-blinded study of 50 patients randomly selected to have spinal anesthesia using either single-hole 27-gauge (B. Braun, Melsungen, Germany) or double-hole 26-gauge (A.L.B. Medical Inc., U.S.A.) pencil-point needles. The former were inserted with the side port directed caudally and the latter with openings in both caudal and cranial direction. Two milliliters of hyperbaric 0.5% bupivacaine were injected in 1 minute, and sensory and motor block were studied at regular intervals during spinal anesthesia. All patients were interviewed on the first (personal) and the seventh (mailed questionnaire) postoperative day. Furthermore, microscopic inspection of the spinal needles was performed. Results There were no statistically significant differences in sensory or motor block levels between the two needle types at any time during spinal anesthesia. Likewise, there was no difference in the duration of spinal block. The postanesthetic side effects (headache, backache, pricking, numbness, weakness) were similar in both groups. Light and electron microscopic examination showed resistance of the SHPP needles to tip damage. On the other hand, the DHPP needle tips seemed to be distorted quite frequently, and, even in unused needles, the tip was blunt and asymmetric. Conclusion There was no difference between the spread of analgesia using either SHPP or DHPP spinal needles. The DHPP needles appear to be vulnerable to tip damage from mechanical contact.

Background and Objectives Interpleural anesthesia blocks pain perception from the thoracoabdominal wall without impairment of leg function. Bilateral interpleural anesthesia is not recommended because of possible bilateral impairment of respiratory function. Infiltration of the retromediastinum with local anesthetic might cause bilateral thoracoabdominal somatic block and block of sympathetic afferents from the abdominal cavity without impairing respiration. Method Distribution of stained fluid was studied after injection into the retromediastinum through a catheter placed about 10 cm cephalad to the diaphragm via the esophageal hiatus in three human cadavers of normal size and in six anesthetized pigs of 20-30 kg. In the pigs, serum levels of bupivacaine were measured after injection of 10 mL of 0.5% bupivacaine stained with 1 mL of methylene blue. Results The injected Dye stained intercostal nerves 6-11 in cadavers and 5-12 in pigs symmetrically on both sides, along with the adjacent parts of the sympathetic chain and both vagal nerves but not the phrenic nerves. During the sampling period of 50-60 minutes, bupivacaine serum concentrations rose slowly to a maximum of 4.2 μg/mL. Conclusions Block of pain perception from the abdominal wall and cavity is possible by injection of local anesthetic into the retromediastinum via a catheter introduced through the esophageal diaphragm hiatus. The block would not be expected to impair respiratory or leg function. Its efficacy and safety have yet to be established.