A Comparison of Anesthetic Quality between Single and Septum-based Double Injection for Ultrasound-Guided Costoclavicular Block: A Randomized Controlled Trial.

BACKGROUND: In a costoclavicular (CC) approach of an ultrasound (US)-guided infraclavicular brachial plexus block (BPB), a septum between the lateral and the medial/posterior cords can result in an incomplete block. We hypothesized that double injections in each compartment between the septum would result in a higher success rate of BPB than a single injection in the center of the CC space. OBJECTIVES: This study was conducted to confirm the superiority of block quality achieved by septum-based double injections (experimental group; group E) over single injection in the center of the CC space (control group; group C). STUDY DESIGN: A randomized, controlled trialSETTING: Department of Anesthesiology and Pain Medicine, Korea University College of Medicine, Anam Hospital. METHODS: Sixty-eight patients who underwent upper extremity surgery randomly received a single (SI group, n = 34) or a septum-based double injection (DI group, n = 34) using the CC approach. Ten milliliters of 2% lidocaine, 10 mL of 0.75% ropivacaine, and 5 mL of normal saline were used for BPB in each group (total 25 mL). Sensory-motor blockade of the ipsilateral median, radial, ulnar, and musculocutaneous nerves was assessed by a blinded observer at 5-minute intervals for 30 minutes immediately after local anesthesia administration. The assessed variables were the success rate, the rate of all 4 nerves blockade, and onset time. RESULTS: Thirty minutes after the block, the success rate was significantly higher in the DI group than in the SI group (64.7% in the SI group vs 91.2% in the DI group, P = 0.009), and the rate of all 4 nerves blockade also significantly increased in the DI group compared to the SI group (44.1% in the SI group vs 91.2% in the DI group, P = 0). The onset time was significantly shortened in the DI group compared with the SI group (26.3 ± 5.6 min in the SI group vs 21.3 ± 6.2 min in the DI group, P = 0.010). LIMITATIONS: We considered that the location of the septum was always between the lateral cord superficially and the medial/posterior cords below it. In some patients in whom the septum was not visible, a superficial lateral cord was injected first, and then deep medial and posterior cords were injected, assuming that the 2 compartments were divided by the septum. CONCLUSIONS: Compared with the SI, the septum-based DI of CC approach increased the success rate and the rate of all 4 nerves blockade and shortened the onset time.

A Comparison of Anesthetic Quality Between Interscalene Block and Superior Trunk Block for Arthroscopic Shoulder Surgery: A Randomized Controlled Trial.

BACKGROUND: Interscalene block is the most commonly used nerve block for shoulder surgery, and superior trunk block has been investigated as a phrenic-sparing alternative. This randomized controlled trial compared ultrasound-guided interscalene block and superior trunk block as anesthesia for arthroscopic shoulder surgery. OBJECTIVES: Our aims were to determine the superiority of anesthesia quality and compare the risk of hemidiaphragmatic paralysis between these 2 blocks. STUDY DESIGN: A randomized, controlled trial. SETTING: Department of Anesthesiology and Pain Medicine, Korea University Anam Hospital. METHODS: Forty-eight patients undergoing elective arthroscopic shoulder surgery under an ultrasound guided brachial plexus block were randomized to receive either an interscalene block (ISB group, n = 24) or a superior trunk block (STB group, n = 24) for surgery. Ten milliliters of 2% lidocaine and 10 mL of 0.75% ropivacaine were used as local anesthesia in both brachial plexus block groups (total 20 mL). In the ISB group, the local anesthesia was injected between the C5-C6 root and at the upper part of C5 with equally divided doses. In the STB group, the local anesthesia was injected into the anterior and posterior parts of the superior trunk with equally divided doses. Sensory blockade of each trocar's insulting site (supraclavicular, axillary, and suprascapular nerve areas) and motor blockade of the axillary nerve (shoulder abduction) and the suprascapular nerve (shoulder external rotation) were assessed by a blinded observer at 5-minute intervals for 30 minutes after the block. Anesthesia quality was assessed using 3 grades (excellent/insufficient/failure). The blinded investigator also assessed the grade of hemidiaphragmatic paralysis (normal/partial/complete) by comparing pre- and postoperative chest radiographs. Primary outcome variables were anesthesia grade and rate of hemidiaphragmatic paralysis. Secondary outcome variables were performance time and anesthesia onset time. RESULTS: The anesthetic grade was significantly different between the 2 groups (22/2/0 in the ISB group vs. 16/3/5 in the STB group, P = 0.046). Both groups displayed equivalent incidence of hemidiaphragmatic paralysis (12/6/6 in the ISB group vs. 7/14/3 in the STB group, P = 0.063). No intergroup differences were found in terms of performance time and anesthesia onset time. LIMITATIONS: Our sensory and motor function test was not applied to the subscapular nerve, which serves internal rotation of the humeral head so may be difficult to evaluate in patients with rotator cuff tears. We assessed the diaphragmatic movement by chest radiographs instead of by ultrasound. CONCLUSIONS: The superior trunk block provided lower quality of surgical anesthesia than the interscalene block and did not effectively decrease the risk of hemidiaphragmatic paralysis during arthroscopic shoulder surgery for rotator cuff syndrome.

Clinical efficacy of adductor canal block in medial open wedge high tibial osteotomy.

BACKGROUND: To evaluate the effect of adductor canal block (ACB) on short-term postoperative outcomes in patients who underwent medial open-wedge high tibial osteotomy (MOWHTO) compared to that of a placebo. METHODS: 35 patients who underwent unilateral MOWHTO between 2017 and 2019 were prospectively reviewed and randomly divided into two groups: 19 patients who received a single-shot ACB and 16 patients who received a saline injection (a placebo group). Primary outcomes were (1) pain measured using the visual analog scale and range of motion, (2) patient satisfaction, (3) postoperative need for additional opioids, (3) quadriceps strength (the time to straight leg raising [SLR]), (4) clinical outcomes, and (5) complications. RESULTS: The pain score was lower in the ACB group than in the placebo group in the first 12 h (p = 0.04). ACB did not exhibit significantly less quadriceps strength weakness postoperatively. There was no statistical difference in the time to SLR (23.5 ± 17.7 h in ACB vs. 27.6 ± 11.4 in placebo, p = 0.520). The opioid consumption rate within postoperative 12 h was significantly decreased after ACB (16.7% in ACB, 70% in placebo, p = 0.017). The proportion of patients with more than 5 opioid injections within 72 h postoperatively was lower in the ACB group (8.3% in ACB, 50% in placebo, p = 0.043). Both groups did not show any localized and systemic complications. CONCLUSION: ACB following MOWHTO exhibited better outcomes than a placebo with respect to opioid consumption with no changes in the quadriceps strength and complications. LEVEL OF EVIDENCE: II, Prospectively comparative study.

A Randomized Comparison Between Two Injections from Two Planes versus Two Injections with a Uniplanar Approach for Ultrasound-Guided Supraclavicular Block.

BACKGROUND: The brachial plexus courses along the lateral to posterior aspect of the subclavian artery located within the supraclavicular region as a trunk or division. Therefore we hypothesized that 2 injections, one along the lateral and one along the posterior aspect of the brachial plexus, could be performed by changing the angle of the ultrasound probe, thereby achieving a 3-dimensional (3-D) even distribution of local anesthetics. Previously, we confirmed the efficacy of this type of approach with that of a single cluster approach. These findings represent a subsequent study. OBJECTIVES: This study was conducted to confirm the superiority of block quality achieved by 2 injections from 2 planes (control group; group C) over 2 injections in one plane (experimental group; group E). STUDY DESIGN: A randomized, controlled trial. SETTING: Department of Anesthesiology and Pain Medicine, Gachon University Gil Medical Center. METHODS: In group C (n = 35), the brachial plexus sheath was penetrated in 2 planes by anteriorly altering the angle of the ultrasound probe without changing its position. In group E (n = 35), the upper and lower portions of the brachial plexus sheath were penetrated in one plane. A total of 15 mL of lidocaine 1.5% containing epinephrine (1:200,000) was injected at each point in both groups. The ultrasound-guided supraclavicular brachial plexus block was evaluated every 5 minutes for 30 minutes. The main outcome variables were rates of blockage of all 4 nerves and ulnar nerve sparing. RESULTS: The rate of blockage of all 4 nerves (median, ulnar, radial, and musculocutaneous nerves) was not significantly different between the 2 groups (94% in group C vs. 86% in group E, respectively; P = 0.232). The number of spared ulnar nerves was similar (1 vs. 5, respectively; P = 0.088). Group procedure times, onset times, and Visual Analog Scale scores for the blocks were similar. LIMITATIONS: For the 2 plane, 2 injection approach, only 2-D imaging was performed rather than 3-D imaging. CONCLUSIONS: Two injections performed in one plane offered similar benefits to 2 injections performed in 2 planes. The 2 techniques provided comparable block qualities and could be viewed as equally effective alternatives.

Efficacy of a single injection compared with triple injections using a costoclavicular approach for infraclavicular brachial plexus block during forearm and hand surgery: A randomized controlled trial.

OBJECTIVES: It was recently proposed that a costoclavicular (CC) approach can be used in ultrasound (US)-guided infraclavicular brachial plexus block (BPB). In this study, we hypothesized that triple injections in each of the 3 cords in the CC space would result in a greater spread in the 4 major terminal nerves of the brachial plexus than a single injection in the CC space without increasing the local anesthetic (LA) volume. METHODS: Sixty-eight patients who underwent upper extremity surgery randomly received either a single injection (SI group, n = 34) or a triple injection (TI group, n = 34) using the CC approach. Ten milliliters of 2% lidocaine, 10 mL of 0.75% ropivacaine, and 5 mL of normal saline were used for BPB in each group (total 25 mL). Sensory-motor blockade of the ipsilateral median, radial, ulnar, and musculocutaneous nerves was assessed by a blinded observer at 5 minutes intervals for 30 minutes immediately after LA administration. RESULTS: Thirty minutes after the block, the blockage rate of all 4 nerves was significantly higher in the TI group than in the SI group (52.9% in the SI group vs 85.3% in the TI group, P = .004). But there was no significant difference in the anesthesia grade between the 2 groups (P = .262). The performance time was similar in the 2 groups (3.0 ±â€Š0.9 minutes in the SI group vs 3.2 ±â€Š1.2 minutes in the TI group, respectively; P = .54). DISCUSSION: The TI of CC approach increased the consistency of US-guided infraclavicular BPB in terms of the rate of blocking all 4 nerves without increasing the procedure time despite administering the same volume of the LA.

Ultrasound-guided sciatic nerve block at the midthigh level in a porcine model: A descriptive study.

BACKGROUND AND OBJECTIVE: There are a growing number of porcine models being used for orthopaedic experiments for human beings. Therefore, pain management of those research pigs using ultrasound (US)-guided nerve block can be usefully performed. The aim of this study is to determine optimal US approaches for accessing and localizing the sciatic nerve at the midthigh level, a relevant block site for hindlimb surgery in female Yorkshire pigs. METHODS: As a first step, we dissected the intubated, blood-washed out pigs (n = 3) and confirmed the anatomical position of the sciatic nerve at midthigh level. After dissection, we found the sciatic nerve, connected with nerve stimulator, and checked the dorsiflexion or plantar flexion of the hindlimb. We matched the sciatic nerve location with the US image. After the pigs were euthanized, the neural structures of the sciatic nerve were confirmed by histological examination with H&E staining. In second step, a main US-guided sciatic nerve block study was done in the intubated, live pigs (n = 8) based on the above study. RESULTS: In lateral position, the effective US-guided nerve block site was about 6 cm from the patella crease level; immediately proximal to the bifurcation of the sciatic nerve into the tibial nerve and common peroneal nerve. The distal femur was selected as the landmark. There were no vessels or other nerves surrounding the sciatic nerve. The needle-tip was positioned less than 1 cm lateral from the distal femur and about 2 cm deep to skin. 'Donut sign' in US images was confirmed in all 16 nerves. CONCLUSIONS: Midthigh level sciatic nerve is located superficially, which enables nerve block to be easily performed using US. This is the first study to describe midthigh sciatic nerve block in the lateral position under US guidance in a porcine model from a clinical perspective.

The Effect of Interfascial Injection on Obturator Nerve Block Compared with Nerve Stimulating Approach by Ultrasound-Guide: A Randomized Clinical Trial.

PURPOSE: This study was conducted to evaluate whether the ultrasound-guided interfascial injection technique is really compatible with the ultrasound-guided nerve stimulating technique for obturator nerve block (ONB) at the inguinal crease after bifurcation of the obturator nerve. MATERIALS AND METHODS: A total 62 ONBs were performed for transurethral resection of bladder tumors under spinal anesthesia, and divided into two groups, that is, to an ultrasound-guided ONB with nerve stimulation control group (the US-NS group) or an ultrasound-guided interfascial injection experimental group (the US-IFI group). In the US-IFI group, complete ONB was confirmed using a nerve stimulator at 5 min after completing the injection, and if residual twitching remained, another local anesthetic was injected; in such cases blocks were considered to have 'failed'. During TURB surgeries, two urology assistants determined obturator reflex grade (I-IV) at 15 min after injection completion in both groups. RESULTS: We assumed that the US-NS group achieved complete ONB in all cases. Six cases in the US-IFI group failed to achieve complete ONB (failure rate: 0% versus 19.4%, P = .012). There was one case of grade II obturator reflex in each group. CONCLUSION: The ultrasound-guided interfascial injection technique was not compatible with the ultrasound-guided nerve stimulating technique for ONB at the inguinal crease.

Sonographic Guidance for Supraclavicular Brachial Plexus Blocks: Single vs. Double Injection Cluster Approach.

BACKGROUND: The cluster approach for supraclavicular brachial plexus block (SC-BPB) can be easily performed but may result in asymmetric local anesthetic (LA) spread. The authors hypothesized that the use of a cluster approach in each of the 2 planes would achieve better 3-dimensional LA distribution than the traditional single cluster approach. OBJECTIVES: The purpose of the present study was to compare a double injection (DI) in 2 planes (one injection in each plane) with the traditional single injection (SI) cluster approach for ultrasound-guided SC-BPB. STUDY DESIGN: A randomized, controlled trial. SETTING: Department of Anesthesiology and Pain Medicine, Gachon University Gil Medical Center. METHODS: In the SI group (n = 18), 30 mL of LA was injected into the main neural cluster after penetrating the brachial plexus sheath laterally. In the DI group (n = 18), the needle penetrated the sheath in a downward direction at the first skin puncture, and 15 mL of LA was injected, and at the second skin puncture (behind the initial puncture site), the needle penetrated the sheath in an upward direction, and 15 mL was again injected. Ultrasound-guided SC-BPB was evaluated from immediately after the block every 5 minutes to 30 minutes by sensory and motor testing. The main outcome variables were procedural time; onset time (time for complete sensory and motor block of the median, radial, ulnar, and musculocutaneous nerves); and rate of blockage of all 4 nerves. RESULTS: Procedure times (medians [interquartile range]) were similar in the DI and SI groups (5.5 [4.75 - 8] vs. 5 [4 - 7] minutes, respectively; P = 0.137). Block onset time in the DI group was not significantly different from that in the SI group (10 [5 - 17.5] vs. 20 [6.25 - 30] minutes, P = 0.142). However, the rate of blockage of all 4 nerves was significantly higher in the DI group (94% vs. 67%, P = 0.035). LIMITATIONS: Although the results of this study indicate LA distribution in the DI group was more evenly spread within brachial plexus sheaths than in the SI group, this was not confirmed by ultrasonography or contrast radiography. CONCLUSION: The DI approach can be performed easily as single cluster approach and increases the consistency of ultrasound-guided SC-BPB over the SI approach in terms of the rate of blocking of all 4 nerves. Key words: Brachial plexus block, corner pocket approach, cluster approach, multiple injection, supraclavicular block, ultrasound.

Changes in cerebral oxygen saturation and early postoperative cognitive function after laparoscopic gastrectomy: a comparison with conventional open surgery.

BACKGROUND: Laparoscopic gastrectomy requires a reverse-Trendelenburg position and prolonged pneumoperitoneum and it could cause significant changes in cerebral homeostasis and lead to cognitive dysfunction. We compared changes in regional cerebral oxygen saturation (rSO2), early postoperative cognitive function and hemodynamic variables in patients undergoing laparoscopic gastrectomy with those patients that underwent conventional open gastrectomy. METHODS: Sixty patients were enrolled in this study and the patients were distributed to receive either laparoscopic gastrectomy (laparoscopy group, n = 30) or open conventional gastrectomy (open group, n = 30). rSO2, end-tidal carbon dioxide tension, hemodynamic variables and arterial blood gas analysis were monitored during the operation. The enrolled patients underwent the mini-mental state examination 1 day before and 5 days after surgery for evaluation of early postoperative cognitive function. RESULTS: Compared to baseline value, rSO2 and end-tidal carbon dioxide tension increased significantly in the laparoscopy group after pneumoperitoneum, whereas no change was observed in the open group. No patient experienced cerebral oxygen desaturation or postoperative cognitive dysfunction. Changes in mean arterial pressure over time were significantly different between the groups (P < 0.001). CONCLUSIONS: Both laparoscopic and open gastrectomy did not induce cerebral desaturation or early postoperative cognitive dysfunction in patients under desflurane anesthesia. However, rSO2 values during surgery favoured laparoscopic surgery, which was possibly related to increased cerebral blood flow due to increased carbon dioxide tension and the effect of a reverse Trendelenburg position.

The Influence of Genotype Polymorphism on Morphine Analgesic Effect for Postoperative Pain in Children.

BACKGROUND: Although opioids are the most commonly used medications to control postoperative pain in children, the analgesic effects could have a large inter-individual variability according to genotypes. The aim of this study was to investigate the association between single nucleotide polymorphisms and the analgesic effect of morphine for postoperative pain in children. METHODS: A prospective study was conducted in 88 healthy children undergoing tonsillectomy, who received morphine during the operation. The postoperative pain score, frequency of rescue analgesics, and side effects of morphine were assessed in the post-anesthesia care unit. The children were genotyped for OPRM1 A118G, ABCB1 C3435T, and COMT Val158Met. RESULTS: Children with at least one G allele for OPRM1 (AG/GG) had higher postoperative pain scores compared with those with the AA genotype at the time of discharge from the post-anesthesia care unit (P = 0.025). Other recovery profiles were not significantly different between the two groups. There was no significant relationship between genotypes and postoperative pain scores in analysis of ABCB1 and COMT polymorphisms. CONCLUSIONS: Genetic polymorphism at OPRM1 A118G, but not at ABCB1 C3435T and COMT Val158Met, influences the analgesic effect of morphine for immediate acute postoperative pain in children.

Ultrasound-guided central cluster approach for the supraclavicular brachial plexus block: a case series.

There are many different approaches to ultrasound-guided supraclavicular brachial plexus block (US-SCBPB), and each has a different success rate and complications. The most commonly performed US-SCBPB is the corner pocket approach in which the needle is advanced very close to the subclavian artery and pleura. Therefore, it may be associated with a risk of subclavian artery puncture or pneumothorax. We advanced the needle into the central part of the neural cluster after penetrating the sheath of the brachial plexus in US-SCBPB. We refer to this new method as the "central cluster approach." In this approach, the needle does not have to advance close to the subclavian artery or pleura. The aim of this study was to evaluate the clinical outcomes of the central cluster approach in US-SCBPB.

The effect of clonidine pretreatment on epidural resiniferatoxin in a neuropathic pain rat model.

Resiniferatoxin (RTX) is an ultrapotent synthetic TRPV1 (transient receptor potential vanilloid subtype 1) agonist with significant initial transient hyperalgesia followed by a prolonged analgesic effect in response to thermal stimulus. Using a rat model of neuropathic pain, we evaluated the effect of pretreatment with clonidine-which has been shown to relieve intradermal capsaicin-induced hyperalgesia-on the initial hyperalgesic response and the thermal analgesic property of RTX. Thirty-six male rats were divided into 6 treatment groups (n=6 each):RTX 500 ng, RTX 1 µg, clonidine 20 µg (Cl), Cl＋RTX 500 ng, Cl＋RTX 1 µg, or normal saline 20 µL (control). We evaluated the short-term (180 min) and long-term (20 days) analgesic effects of RTX after thermal stimulation and mechanical stimulation. RTX had significant initial transient hyperalgesia followed by a prolonged analgesic effect in response to the thermal stimulus, but the RTX 500 ng and RTX 1 µg groups showed no initial short-term thermal hyperalgesic responses when pretreated with clonidine. The Cl＋RTX 1 µg rats' behavior scores indicated that they were more calm and comfortable compared to the RTX 1 µg rats. Even though we cannot precisely confirm that pretreatment with clonidine potentiates or adds to the analgesic effect of RTX, clonidine pretreatment with epidural RTX eliminated the initial RTX-associated hyperalgesic response and systemic toxicity in this neuropathic pain rat model.

Effect of pneumoperitoneum on the recovery from intense neuromuscular blockade by rocuronium in healthy patients undergoing laparoscopic surgery.

BACKGROUND: This study investigated the effect of pneumoperitoneum on the recovery from intense neuromuscular blockade by rocuronium in healthy patients undergoing laparoscopic abdominal surgery. METHODS: Thirty adult patients undergoing laparoscopic abdominal surgery were studied. Anesthesia was induced with 1.5 mg/kg of propofol, 12 ug/kg of alfentanil and 0.6 mg/kg of rocuronium and maintained with 2 vol% of sevoflurane and 0.05-0.2 µg/kg/min remifentanil. The neuromuscular relaxation was monitored by Train-of-Four (TOF) and post-tetanic count (PTC). Additional rocuronium of 0.2 mg/kg was administered for deep neuromuscular blockade at 30 min after pneumoperitoneum. Before (PPpre) and 30 min after pneumoperitoneum (PPpost), PTC was measured at 6 min intervals. The relationship between PTC and the time interval to reappearance of T1 response was observed. RESULTS: The mean ± SD of the intervals between the detection of 4 counts of the PTC and the first response to TOF stimulation was 13.0 ± 1.1 min and 16.4 ± 6.3 min PPpre and PPpost, respectively (P = 0.20). There were significant negative relationships between PTC observed and the time interval to reappearance of T1 response (adjusted R(2) = 0.869, P < 0.001 for PPpre data, and adjusted R(2) = 0.561, P < 0.001 for PPpost data). Comparing the difference of regression equation between PPpre and PPpost data using a parallelism test, there was no statistically significant difference (P = 0.193). CONCLUSIONS: This study showed that PP with intra-abdominal pressure at the level of 13-14 mmHg did not affect the recovery from intense neuromuscular blockade by rocuronium in healthy patients undergoing laparoscopic abdominal surgery.

Effects of incrementally increasing tidal volume on the cross-sectional area of the right internal jugular vein.

BACKGROUND: Different tidal volume (TV) settings during mechanical ventilation alter intrathoracic blood volume, and these changes could alter central venous pressure and the cross sectional area (CSA) of the right internal jugular vein (RIJV). The aim of this study was to determine the optimal TV for maximizing the CSA of the RIJV in the supine and Trendelenburg positions in anesthetized patients. METHODS: Forty patients were randomly allocated to a supine group (Group S, n = 20) or a Trendelenburg group (Group T, n = 20) by computer generated randomization. RIJV CSAs were measured repeatedly after increasing the inspiratory volume in 1 ml/kg increments from a TV of 8 ml/kg to 14 ml/kg using ultrasound images. RESULTS: Peak inspiratory pressure increased significantly on increasing TV from 11 ml/kg to 14 ml/kg and between baseline (TV 8 ml/kg) and 11 ml/kg in both groups (P < 0.05). RIJV CSA was not increased versus baseline even after TV changes in either group and no intergroup difference was found. CONCLUSIONS: TV increases do not increase the CSA of the RIJV within the TV range 8 to 14 ml/kg in the supine or 10° Trendelenburg position.

Profound hypotension after an intradermal injection of indigo carmine for sentinel node mapping.

Intradermal injections of indigo carmine for sentinel node mapping are considered safe and no report of an adverse reaction has been published. The authors described two cases of profound hypotension in women that underwent breast-conserving surgery after an intradermal injection of indigo carmine into the periareolar area for sentinel node mapping.

Effect of palonosetron on postanesthetic shivering after propofol-remifentanil total intravenous anesthesia.

PURPOSE: The authors conducted a prospective, randomized, double-blind study to evaluate the anti-shivering efficacy of palonosetron for patients after gynecological laparoscopy under total intravenous propofol-remifentanil anesthesia. METHODS: Sixty female patients were randomly assigned to one of two groups and administered palonosetron 0.075 mg (palonosetron group, n = 30) or the same volume of normal saline (control group, n = 30) immediately after anesthesia induction. Anesthesia was induced and maintained with propofol and remifentanil, using a target-controlled infusion device. Esophageal and index finger temperatures were measured immediately after anesthesia induction (baseline) and at 15-min intervals until the end of the surgery. Postanesthetic shivering and side effects were assessed in a postanesthetic care unit. RESULTS: Incidence of shivering was comparable in the control and palonosetron groups (10/30 vs. 8/30, respectively, P = 0.779). No significant intergroup differences were observed between esophageal and index finger temperatures. Compared with baseline values, esophageal temperatures decreased immediately after pneumoperitoneum in the control group and from 30 min after pneumoperitoneum in the palonosetron group. CONCLUSION: Use of palonosetron (0.075 mg) did not reduce the incidence of postanesthetic shivering after gynecological laparoscopy under propofol-remifentanil anesthesia. Further study including other 5-HT3 antagonists or male patients would elucidate the effect of palonosetron on shivering after propofol-remifentanil anesthesia.

The effect of epidural resiniferatoxin in the neuropathic pain rat model.

BACKGROUND: Resiniferatoxin (RTX) is a potent synthetic agonist for transient receptor potential vanilloid subtype 1 (TRPV1), which has a selectivity for antinociception. The analgesic effect of epidural RTX in a rat model of neuropathic pain has not yet been studied. OBJECTIVES: The purpose of this study was to evaluate the analgesic effect of epidural RTX on neuropathic pain in a rat model to mechanical and thermal stimulation. The dose-related behavior changes and side effects were also studied. STUDY DESIGN: A randomized, experimental trial. SETTING: Department of Anesthesiology and Pain Medicine, Korea University Guro Hospital METHODS: A spinal nerve ligation model was prepared using male Sprague-Dawley rats (7 weeks old, weight 230-250 g). An epidural catheter was placed at the L4-L5 level. Each study group (n = 6) received a different dose of RTX: 100 ng, 500 ng, 1 µg, 2 µg, 4 µg and 10 µg. All substances were administered in 20 µL volume doses. The control group (n = 6) received 20 µL of normal saline. We evaluated the response to mechanical and thermal stimuli as well as the sedation score at both short-term (3 hours) and long-term (20 days) after the epidural RTX injection. RESULTS: Prolonged analgesia to thermal stimulation was preceded by a transient dose-dependent hyperalgesia (500 ng, 1 µg) or sedation (>/= 2 µg) during the initial 60 minutes after RTX administration. Marked sedation and hyperventilation were noted at higher doses (>/= 2 µg), while 2 out of 6 rats died with a 10 µg dose. ED50 for epidural RTX was 265 ng (95% confidence interval 216.1-324.9 ng). The increased latency to thermal stimulation continued for 20 days at RTX >/=1 µg. But the threshold to mechanical stimulation increased only in the acute period and returned to the baseline after 3-5 days, regardless of the administered dose. LIMITATIONS: A histological examination by electron-microscopic staining was not performed. The observation period was not very long (20 days). CONCLUSION: RTX has potential to be used in an epidural route for neuropathic pain in a rat model with a relatively small amount, which produces transitory improvement of mechanical hypersensitivity and prolonged thermal analgesic response.

The clinical effective dose of alfentanil for suppressing cough during emergence from desflurane anesthesia.

BACKGROUND: The administration of short-acting opioids before emergence is useful for preventing emergence cough induced by an endotracheal tube. This study examined the clinically effective dose of alfentanil for suppressing cough during emergence from desflurane anesthesia. METHODS: Twenty-nine adult patients undergoing elective oral surgery were enrolled in this study. During emergence from anesthesia, the patients received alfentanil diluted in 10 ml normal saline when the end-tidal vol% of desflurane decreased to 3%. The initial alfentanil dose was 16 µg/kg. The alfentanil dose for consecutive patients, determined by Dixon's up-and-down method, increased or decreased by 2 µg/kg according to a previous patient's result. RESULTS: The 50% effective dose (ED(50)) of alfentanil for suppressing cough during emergence from desflurane anaesthesia was 9.3 ± 1.5 µg/kg according to Dixon's up-and-down method. Isotonic regression revealed an ED(50) and ED(95) (95% confidence interval) of alfentanil 10.0 µg/kg (6.8-13.2 µg/kg) and 14.0 µg/kg (7.7-19.4 µg/kg), respectively. CONCLUSIONS: The ED(95) of alfentanil for suppressing emergence cough was 14.0 µg/kg. A single bolus administration of alfentanil during emergence from anesthesia was useful for suppressing emergence cough.

Thoracic spinal cord stimulation for neuropathic pain after spinal meningioma removal: a case report.

Spinal cord stimulation (SCS) is highly successful for treating neuropathic pain but its effect is limited for central origin pain caused by cord injury. The authors describe a case in which pain was successfully controlled by SCS implantation in a patient with intractable chronic neuropathic pain after T5 meningioma removal. The authors tried lead insertion over the T5 level passing through postoperative adhesions to produce adequate stimulation to the patient's painful areas fully enough without any complications. This case showed good response to SCS even though it was a central type of neuropathic pain by spinal cord injury.