Investigation of Optimal Needle Position for Radiofrequency Ablation-Based Blockade of Interspace between the Popliteal Artery and the Posterior Capsule of the Knee: A Cadaveric Study.

Background and Objectives: The interspace between the popliteal artery and the posterior capsule of the knee (iPACK) block has been widely used in perioperative settings to control posterior knee pain and can additionally be used for chronic knee pain. In this cadaveric study, we aimed to investigate the needle tip position and its proximity to the articular branch of the tibial nerve (ABTN) during an iPACK-targeted radiofrequency procedure. Materials and Methods: An ultrasound-guided iPACK block was performed on 20 knees of 10 cadavers. We injected 0.1 mL each of blue and green gelatinous dye near the tibial artery (point A) and posterior knee capsule (point B), respectively, and evaluated the spread of both around the ABTN. For a hypothetical conventional radiofrequency ablation (RFA) lesion (diameter, 2.95 mm) and cooled RFA lesion (diameter, 4.9 mm), we counted the number of specimens in which the ABTNs would be captured. Results: The percentage of specimens in which the ABTN would be captured by a cooled RFA lesion was 64.71% at point A and 43.75% at point B (p = 0.334). Meanwhile, the percentage of specimens in which the ABTN would be captured by a conventional RFA lesion was 58.82% from point A and 25% from point B (p = 0.065). Conclusions: When performing an RFA-based iPACK block, the needle tip may be positioned either lateral to the tibial artery or in the space between the posterior knee capsule and the tibial artery. However, more studies with larger samples are needed to verify these results before the clinical use of this procedure can be recommended.

Investigation of the existence of and a block technique for the inferior lateral genicular nerve: cadaveric study.

Background: Among the four genicular nerves innervating the anterior aspect of the knee, the inferior lateral genicular nerve has been omitted as a target of blocking. Some authors have suggested that the inferior lateral genicular nerve of the knee might pass beneath the lateral collateral ligament of knee. The authors aimed to study the location of the inferior lateral genicular nerve and the spread of injectate during the inferior lateral genicular nerve block. Methods: In ten knees from fresh frozen cadavers, the authors performed on each an ultrasound-guided block of the inferior lateral genicular nerve of the knee just below the lateral collateral ligament. The needle was inserted below the lateral collateral ligament, and 2 mL of blue dye was injected. A week later, the cadavers were dissected, and the existence of the inferior lateral genicular nerve and the spread of dye around it was investigated. Results: The proportion of inferior lateral genicular nerves branching from the common peroneal nerve was found in 8 of 10 (80.0%) cadavers. Of these eight cadavers with inferior lateral genicular nerve, five specimens (62.5%) were stained with blue dye. The common peroneal nerve was not infiltrated with dye in any specimens. Conclusions: When 2 mL of dye was inserted inferiorly to the lateral collateral ligament, the inferior lateral genicular nerve could be blocked in 62.5% of specimens. Because the common peroneal nerve was not involved in any specimen, motor weakness would be avoided with this method.

Ultrasound diagnosis and treatment of intractable anterior chest pain from golf - A case report.

BACKGROUND: Pleurisy is an inflammation of the parietal pleura and is characterized by pleuritic pain. The most common cause of pleurisy is infection; other causes include rheumatoidarthritis, malignancy, rib fractures, or trauma. Possible causes of chest pain associated withgolf include costochondritis, stress fractures of the ribs, intercostal muscle strain, or, rarely,Tietze's syndrome and slipping rib syndrome. CASE: A 64-year-old female presented with intractable chest pain that began 4 months priorwhile playing golf. No specific cause was found after various examinations. There was persistent pain despite medical treatment. Ultrasonography (US) was performed over the painful areas, which revealed focal pleural effusions. A mixture of ropivacaine and triamcinolonewas injected into the focal pleural effusions using US guidance, which dramatically relievedher pain. CONCLUSIONS: This case demonstrates that US can be used as a diagnostic and therapeuticmodality for intractable chest pain with an undetected pathology.

The effect of ultrasound-guided transversus abdominis plane block on pulmonary function in patients undergoing laparoscopic cholecystectomy: a prospective randomized study.

BACKGROUND: Transversus abdominis plane block (TAPB) is commonly used for postoperative pain control after laparoscopic cholecystectomy. However, few studies have analyzed its effect on pulmonary function. The goal of this study was to elucidate the effect of ultrasound-guided bilateral TAPB on pulmonary function preservation and analgesia after laparoscopic cholecystectomy. METHODS: We enrolled 58 patients who underwent laparoscopic cholecystectomy. Among them, 53 were randomized to group T (n = 27) and group C (n = 26). Group T and group C received ultrasound-guided bilateral TAPB with 40 ml of 0.375% ropivacaine and 40 ml of 0.9% normal saline, respectively. Visual analog scale (VAS) scores, patient-controlled analgesia (PCA) consumption, forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, peak expiratory flow rate (PEF), and modified Borg scale scores were measured until 24 h post-surgery. RESULTS: The VAS scores were significantly lower in group T than in group C at 1 and 8 h after the surgery. PCA consumption was significantly lower in group T than in group C at all postoperative time points. FEV1, PEF, and FEV1/FVC were more preserved in group T than in group C at 1 h. Group T had significantly lower modified Borg scale scores than did group C at 1 and 8 h. CONCLUSION: Ultrasound-guided TAPB is effective in pulmonary function preservation and pain control after laparoscopic cholecystectomy. Therefore, it could be a great option for multimodal analgesia, preservation of pulmonary function, prevention of pulmonary complications including atelectasis, and promotion of postoperative recovery after laparoscopic cholecystectomy. CLINICAL REGISTRATION: This study was enrolled in the Clinical Research Information Service (Clinical Research Information Service, KCT0004435, Hwa Yong Shin, 2019-08-19).

Recent update on epidural blood patch.

Epidural blood patch (EBP) is the injection of autologous blood into the epidural space with the intent of sealing off a dural tear and stopping the leakage of cerebrospinal fluid (CSF). EBP may cause an increase in intracranial pressure (ICP) due to the mass effect of the injected blood volume, causing CSF from the spinal compartment to enter the intracranial compartment. EBP is usually considered in the management of moderate to severe headache (HA) attributed to low CSF pressure, such as post-dural puncture HA (PDPH), CSF fistula HA, and HA attributed to spontaneous intracranial hypotension (SIH) that does not respond to conservative management. However, prophylactic administration of EBP after accidental dural puncture can hardly be substantiated at present. EBP is generally safe but may rarely be associated with serious complications. Therefore, it should be carefully planned and performed under C-arm fluoroscopic guidance. Although many studies on PDPH and SIH have been conducted until recently, only few reviews have summarized the effectiveness of EBP from the perspective of a pain physician. This article reviews the current literature on the indication, contraindication, procedural consideration, post-procedural management, outcomes, and complications of EBP and the considerations for EBP in patients with COVID-19.

Pharmacological and non-pharmacological strategies for preventing postherpetic neuralgia: a systematic review and network meta-analysis.

BACKGROUND: Postherpetic neuralgia (PHN) is a refractory complication of herpes zoster (HZ). To prevent PHN, various strategies have been aggressively adopted. However, the efficacy of these strategies remains controversial. Therefore, we aimed to estimate the relative efficacy of various strategies used in clinical practice for preventing PHN using a network meta-analysis (NMA). METHODS: We performed a systematic and comprehensive search to identify all randomized controlled trials. The primary outcome was the incidence of PHN at 3 months after acute HZ. We performed both frequentist and Bayesian NMA and used the surface under the cumulative ranking curve (SUCRA) values to rank the interventions evaluated. RESULTS: In total, 39 studies were included in the systematic review and NMA. According to the SUCRA value, the incidence of PHN was lower in the order of continuous epidural block with local anesthetics and steroids (EPI-LSE), antiviral agents with subcutaneous injection of local anesthetics and steroids (AV + sLS), antiviral agents with intracutaenous injection of local anesthetics and steroids (AV + iLS) at 3 months after acute HZ. EPI-LSE, AV + sLS and AV + iLS were also effective in preventing PHN at 1 month after acute HZ. And paravertebral block combined with antiviral and antiepileptic agents was effective in preventing PHN at 1, 3, and 6 months. CONCLUSIONS: The continuous epidural block with local anesthetics and steroid, antiviral agents with intracutaneous or subcutaneous injection of local anesthetics and a steroid, and paravertebral block combined with antiviral and antiepileptic agents are effective in preventing PHN.

Hypertrophic osteoarthropathy in renal cell carcinoma - A case report.

BACKGROUND: Hypertrophic osteoarthropathy (HOA) is a rare clinical condition including an abnormal periosteal reaction in the long bones that causes painful swelling and tenderness of the extremities, digital clubbing, arthritis, synovitis, and joint effusions. Most cases are associated with tumorous conditions and most commonly with lung cancer. HOA has been rarely reported in association with other cancers. CASE: A patient with a history of recurrent renal cell carcinoma was referred to our clinic with bilateral leg pain, knee joint effusion, and arthritis. Simple radiography and bone scintigraphy confirmed a diagnosis of HOA. Oral non-steroidal anti-inflammatory drugs, joint fluid aspiration, and intra-articular injection of pain medications were found to be effective in the management of HOA pain. CONCLUSIONS: HOA prognosis depends on the underlying disease, therefore, cancer treatment is critical. This case demonstrates the need to consider HOA in patients with various malignancies who present with bone or joint pain of the extremities.

Diagnosis and treatment of nerve injury following venipuncture - A report of two cases.

BACKGROUND: Venipuncture is one of the one of the most commonly performed, minimally-invasive procedures; however, it may lead to peripheral nerve injury. Here, we describe the diagnosis, treatment, and prognosis of two self-reported cases of nerve injury during venipuncture with the aim of drawing attention to possible needle-related nerve injuries. CASE: Two anesthesiologists in our hospital experienced an injury of the lateral antebrachial cutaneous branch of the musculocutaneous nerve during venipuncture. Immediately, they underwent ultrasound examinations and nerve blocks with oral medication, resulting in full recovery. CONCLUSIONS: Ultrasonography is important for the early and confirmative diagnosis of a nerve injury during venipuncture, and for immediate treatment with a nerve block. Moreover, it is imperative for both the practitioner and the patient to be aware of the possible complication of nerve injury after venipuncture.

Ultrasound-guided treatment of common peroneal neuropathy caused by Baker's cyst: a clinical note - A case report.

BACKGROUND: Baker's cysts are usually located in the posteromedial side of the knee and seldom cause neuropathy. CASE: We describe the rare case of a 57-year-old woman with a popliteal cyst who presented with limping gait and pain in her lower leg. She was electronically diagnosed with common peroneal neuropathy and transferred to our pain clinic. On ultrasound examination, about 2.0 × 1.2 cm sized popliteal cyst was found to extend to the fibular head, compressing the common peroneal nerve. Therefore, ultrasound-guided aspiration of the cyst and a common peroneal nerve block were performed. Immediately after the procedure, the pain, dysesthesia, and limping gait were relieved. Although her pain and dysesthesia were relieved, she underwent the surgery because of limping gait. CONCLUSIONS: In this case, we found the Baker's cyst, the cause of the common peroneal neuropathy, and treated it immediately by just simple ultrasound examination and aspiration.

Relationship between Surgery under General Anesthesia and the Development of Dementia: A Systematic Review and Meta-Analysis.

OBJECTIVE: To investigate the association between exposure to general anesthesia and the development of Alzheimer's disease (AD) and dementia by reviewing and integrating the evidence from epidemiological studies published to date. METHODS: We searched MEDLINE, EMBASE, and Google Scholar to identify all relevant articles up to April 2018 reporting the risk of AD/dementia following exposure to general anesthesia and finally updated in February 2020. We included patients older than 60 or 65 years who had not been diagnosed with dementia or AD before the study period. The overall pooled effect size (ES) was evaluated with a random-effect model. Subgroup analyses were conducted and possibility of publication bias was assessed. RESULTS: A total of 23 studies with 412253 patients were included in our analysis. A statistically significant positive association between exposure to general anesthesia and the occurrence of AD was detected in the overall analysis (pooled ES = 1.11, 95%confidence interval = 1.07-1.15), but with substantial heterogeneity (p χ 2 < 0.001, I 2 = 79.4). Although the overall analysis revealed a significant association, the results of the subgroup analyses were inconsistent, and the possibility of publication bias was detected. CONCLUSION: s. This meta-analysis demonstrated a significant positive association between general anesthesia and AD. However, considering other results, our meta-analysis must be interpreted with caution. Particularly, it should be considered that it was nearly impossible to discriminate the influence of general anesthesia from the effect of surgery itself on the development of AD. Further, large-scale studies devised to reduce the risk of bias are needed to elucidate the evidence of association between general anesthesia and AD. Trial registration. PROSPERO International prospective register of systematic reviews CRD42017073790.

The analgesic efficacy of the continuous adductor canal block compared to continuous intravenous fentanyl infusion with a single-shot adductor canal block in total knee arthroplasty: a randomized controlled trial.

BACKGROUND: The adductor canal block (ACB) is an effective intervention for postoperative analgesia following total knee arthroplasty (TKA). However, the ideal ACB regimen has not yet been established. We compared the analgesic effects between a continuous ACB group and fentanyl-based intravenous patient-controlled analgesia (IV-PCA) with a single-shot ACB group. METHODS: Patients who underwent TKA were randomly allocated to either a continuous ACB group (Group CACB) or IV-PCA with a single-shot ACB group (Group IVACB). Before the surgery, ultrasound guided ACB with 0.5% ropivacaine 20 cc was provided to all patients. Before skin incision, the infusion system (0.2% ropivacaine through an adductor canal catheter in group CACB vs. intravenous fentanyl in group IVACB) was connected. The postoperative pain severity; the side effects of local anesthetics and opioids; administration of rescue analgesics and anti-emetics; and sensorimotor deficits were measured. RESULTS: Postoperative pain severity was significantly higher in the IVACB group at 30 min, 4 h, 24 h, and 48 h after surgery. The averages and standard deviations (SD) of the NRS score of postoperative pain were 0.14 ± 0.37, 4.57 ± 2.37, 6.00 ± 1.63, and 4.28 ± 1.49, respectively in the IVACB group. Rescue analgesic requirements and quadriceps muscle strength were not statistically different between the groups throughout the postoperative period. Moreover, rescue antiemetic requirements were higher in group IVACB than group CACB. CONCLUSIONS: In this study, the continuous ACB provided superior analgesia and fewer side effects without any significant motor deficit than the IV-PCA with a single-shot ACB.

Retrospective Outcome Evaluation of Cervical Nucleoplasty Using Digital Infrared Thermographic Imaging.

OBJECTIVE: Percutaneous cervical nucleoplasty (PCN) is used to treat cervical disc herniation. Radiological imaging studies, including plain radiography, computed tomography (CT), and magnetic resonance imaging (MRI), have been used to make early predictions of cervical spinal surgery outcomes. However, simple radiological studies do not provide sufficiently detailed information; moreover, CT and MRI are highly expensive. Herein, we aimed to elucidate the usefulness of digital infrared thermography imaging (DITI) as an outcome marker after cervical nucleoplasty by correlating the changes in thermal difference (ΔTD) with the changes in pain intensity after PCN expressed as visual analogue scale (ΔVAS) scores. METHODS: For this study, 255 patients treated with PCN at Thomas Hospital between March 2012 and August 2014 were included. For each patient, demographic and clinical data, including preoperative MRI results, ΔVAS, ΔTD at the disc level treated with PCN, subjective symptom improvement, procedure-related discomfort, overall satisfaction, and adverse effects, were collected and evaluated for up to 3 months retrospectively. RESULTS: Thermal difference (TD) and VAS scores improved after PCN (p<0.05), but ΔTD showed no significant correlation with ΔVAS. If the preoperative TD was larger, the postoperative VAS was worse and there was less pain relief (ΔVAS) after PCN (p<0.05). Only few adverse effects were noticeable after PCN. CONCLUSION: In DITI, which was used to evaluate the outcomes after cervical nucleoplasty, the ΔTD did not seem to reflect the ΔVAS after PCN. However, preoperative DITI findings could be useful for predicting VAS reduction and clinical improvements after PCN.

Comparison of Epidural Spreading Patterns and Clinical Outcomes of Transforaminal Epidural Steroid Injection with High-Volume Injectate via the Subpedicular Versus the Retrodiscal Approach.

BACKGROUND: The effect of transforaminal epidural steroid injection (TFESI) appears to be influenced by the volume of the injected material because there is a positive correlation between injection volume and extent of pain relief. OBJECTIVES: The purpose of this study was to examine how many vertebral segments are covered by the subpedicular (SP) approach and the retrodiscal (RD) approach and to compare the clinical outcomes of the 2 approaches in TFESI with high-volume injectates. STUDY DESIGN: A randomized, active control trial. SETTING: Medical University centers. METHODS: Fifty patients were randomly assigned to either the SP group or the RD group. TFESI was performed with high-volume injectates. A total of 9 mL injectate was divided into 3 injections (0.5 mL, 2.5 mL, and 6 mL) given at 10-second intervals. The primary outcome measure was injectate distribution. The spreading patterns were described as unilateral, bilateral, ventral, or dorsal. Ventral or dorsal flow was also described as being cephalad or caudad, respectively. The secondary outcome measures were pain relief and reduction of functional disability at 4 weeks after the procedure. RESULTS: The total numbers of vertebral segments and median levels of contrast spread from the injection site were not significantly different between the 2 groups. However, in 3 mL of injectate, the injectate spread showed more extensive bilateral distribution in the RD group. At 4 weeks after treatment, both groups demonstrated statistically significant pain relief and improvement in functional status. No significant differences were observed between the 2 groups. LIMITATIONS: We enrolled only a small number of patients and did not analyze long-term outcomes. Patients with severe spinal stenosis or herniated nucleus pulposus were included. Slightly different methods were used in the 2 groups to determine the number of levels at which the injectate was spread. CONCLUSIONS: Epidural spreading patterns and clinical outcomes of lumbar TFESI with high-volume injectate were not significantly different between the SP approach and the RD approach.Institutional Review Board (IRB) approval: Institutional Review Board of Ewha Womans University Hospital (EUMC 2015-05-003-003). Clinical trials registration number: Clinical Research Information Service (CRIS, registration number: KCT0002288; RCT URL: https://cris.nih.go.kr/cris/search/search_result_st01.jsp?seq=7309)KEY WORDS: Epidural injections, epidural space, low back pain, radiating pain, disability evaluation, steroids, local anesthetics, intervertebral disc disease, spinal stenosis.

Antinociceptive and anti-inflammatory effects of ginsenoside Rf in a rat model of incisional pain.

BACKGROUND: Ginseng saponin has long been used as a traditional Asian medicine and is known to be effective in treating various kinds of pain. Ginsenoside Rf is one of the biologically active saponins found in ginseng. We evaluated ginsenoside Rf's antinociceptive and anti-inflammatory effects, and its mechanism of action on adrenergic and serotonergic receptors, in an incisional pain model. METHODS: Mechanical hyperalgesia was induced via plantar incision in rats followed by intraperitoneal administration of increasing doses of ginsenoside Rf (vehicle, 0.5 mg/kg, 1 mg/kg, 1.5 mg/kg, and 2 mg/kg). The antinociceptive effect was also compared in a Positive Control Group that received a ketorolac (30 mg/kg) injection, and the Naïve Group, which did not undergo incision. To evaluate the mechanism of action, rats were treated with prazosin (1 mg/kg), yohimbine (2 mg/kg), or ketanserin (1 mg/kg) prior to receiving ginsenoside Rf (1.5 mg/kg). The mechanical withdrawal threshold was measured using von Frey filaments at various time points before and after ginsenoside Rf administration. To evaluate the anti-inflammatory effect, serum interleukin (IL)-1ß, IL-6, and tumor necrotizing factor-α levels were measured. RESULTS: Ginsenoside Rf increased the mechanical withdrawal threshold significantly, with a curvilinear dose-response curve peaking at 1.5 mg/kg. IL-1ß, IL-6, and tumor necrotizing factor-α levels significantly decreased after ginsenoside Rf treatment. Ginsenoside Rf's antinociceptive effect was reduced by yohimbine, but potentiated by prazosin and ketanserin. CONCLUSION: Intraperitoneal ginsenoside Rf has an antinociceptive effect peaking at a dose of 1.5 mg/kg. Anti-inflammatory effects were also detected.

Myoclonic movement after general anesthesia: A case report and review of the literature.

RATIONALE: Myoclonic movement is a rare side effect after general anesthesia. Since we use various intravenous agents during general anesthesia recently, it is troublesome to find out the exact cause of this neurologic complication. PATIENT CONCERNS: A 31-year-old female patient without any past medical history underwent hip arthroscopic surgery under general anesthesia. DIAGNOSES: Although there was no specific event during the operation, she showed a sudden myoclonic movement confined to left upper extremity in recovery room. INTERVENTIONS: We administered anticonvulsant agents intrvenously, the myoclonus was stopped shortly but recurred over again. As we stopped the patient-controlled analgesia due to nausea, the symptom halted. OUTCOMES: There was no significant abnormality in electroencephalography or brain diffusion magnetic resonance imaging, which was taken after the event. LESSONS: Clinicians should carefully consider the pharmacologic characteristics and neurologic adverse effects of all administered agents when myoclonus occurs after general anesthesia.

Comparison of the accuracy of noninvasive hemoglobin monitoring for preoperative evaluation between adult and pediatric patients: a retrospective study.

We measured noninvasive hemoglobin (SpHb) levels during the pre-anesthesia visit in patients planning elective surgery. Differences between SpHb and laboratory-measured hemoglobin (Hblab) were compared between adult and pediatric patients. In the pre-anesthesia visiting office, we routinely monitor noninvasive Hb levels with oxygen saturation and heart rate using Masimo Radical-7® Pulse CO-Oximetry (Masimo Corp., Irvine, CA, USA). We attached the R1 20 (body weight, 10-50 kg) or R1 25 (body weight > 30 kg) probe on the index finger. After signal stabilization, SpHb and perfusion index (PI) were recorded. We retrospectively reviewed the recorded data and included patients who visited the anesthesiologist within 24 h after venous sampling. Bias was calculated by subtracting Hblab from SpHb. We compared the biases of adult and pediatric patients (< 18 years) and evaluated correlation coefficients between the bias and Hblab. Records of 105 patients were reviewed and 100 data points of 50 patients in each group were analyzed. The median ± interquartile range bias was - 2.6 ± 2.2 and - 1.2 ± 1.5 g/dL in adult and pediatric patients, respectively (P < 0.001); the corresponding mean ± standard deviation PIs were 4.4 ± 3.1 and 5.9 ± 2.7, respectively (P = 0.19). Bias was inversely proportional to Hblab irrespective of age. The correlation coefficient between the bias and Hblab was - 0.81 in adults and - 0.54 in pediatric patients (P < 0.001). SpHb and Hblab measured during pre-anesthesia visits showed a smaller difference in pediatric than in adult patients. Lower Hblab corresponded to higher accuracy.

Effect of Stellate Ganglion Block on the Regional Hemodynamics of the Upper Extremity: A Randomized Controlled Trial.

BACKGROUND: The success of stellate ganglion block (SGB) is traditionally determined on the basis of findings such as Horner's syndrome, temperature rise in the face, hyperemia of the tympanic membrane, and nasal congestion. However, decreases in vascular resistance and increases in blood flow in the arm may be more meaningful findings. To date, the effect of SGB on the regional hemodynamics of the arm has not been evaluated using pulsed-wave Doppler ultrasound. METHODS: A total of 52 patients who were to undergo orthopedic surgery of the forearm were randomly assigned to either the mepivacaine group (SGB with 5 mL of 0.5% mepivacaine) or the saline group (SGB with 5 mL of normal saline). Before surgery, a single anesthesiologist performed a SGB under ultrasound guidance. The temperature of the upper extremity and the resistance index and blood flow in the brachial artery were measured before SGB, 15 and 30 minutes after SGB, and 1 hour after surgery. The severity of pain, requirement for rescue analgesics, and side effects of the local anesthetic agent were all documented. RESULTS: After SGB, the resistance index decreased significantly and the blood flow increased significantly in the brachial artery of members of the mepivacaine group (15 minutes: P = .004 and P < .001, respectively; 30 minutes: P < .001 and P < .001, respectively). However, these values normalized after surgery. The severity of pain, need for rescue analgesics, and incidence of adverse effects were not significantly different between the 2 groups. CONCLUSIONS: Although SGB did not decrease the pain associated with forearm surgery, ultrasound-guided SGB did increase blood flow and decrease vascular resistance in the arm. Therefore, pulsed-wave Doppler may be used to monitor the success of SGB.

Effects of a Lidocaine-Loaded Poloxamer/Alginate/CaCl2 Mixture on Postoperative Pain and Adhesion in a Rat Model of Incisional Pain.

BACKGROUND: Pain and adhesion are problematic issues after surgery. Lidocaine has analgesics and anti-inflammatory properties, and poloxamer/alginate/CaCl2 (PACM) is a known antiadhesive agent. We hypothesized that the novel combination of lidocaine as chemical barrier and PACM as physical barrier would be beneficial for both postoperative pain and adhesion. The purpose of this study was to investigate the effects of lidocaine-loaded PACM in a rat model of incisional pain. Primary outcome was to evaluate between-group differences for the mechanical withdrawal threshold (MWT) measured by von Frey filament in various concentrations of lidocaine-loaded PACM applied, PACM applied, and sham-operated groups. METHODS: Male Sprague-Dawley rats were used for the postoperative pain model. After plantar incision and adhesion formation, 0.5%, 1%, 2%, and 4% lidocaine-loaded PACM, PACM only, nothing, and 4% lidocaine only were applied at the incision site in groups PL0.5, PL1, PL2, PL4, P, S, and L4, respectively. MWT using a von Frey filament and serum levels of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and high-sensitivity C-reactive protein were measured. Rats were euthanized 2 weeks after surgery, and inflammation and fibrosis were assessed with microscopy. Data were analyzed using the Kruskal-Wallis test, multivariate analysis of variance, and linear mixed-effect model. To compare MWT at each time point, analysis of variance with Bonferroni correction was used. RESULTS: Multivariate analysis of variance showed that 4% lidocaine-loaded PACM significantly raised the MWT up to 6 and 8 hours after surgery compared with lidocaine-unloaded groups S and P, respectively; 2% lidocaine-loaded PACM significantly increased the MWT at 4 hours after surgery compared with groups S and C. Linear mixed-effect model showed that the MWT (estimated difference in means [95% confidence interval]) was significantly increased in groups PL2 and PL4 (6.58 [2.52-10.63], P = .002; 11.46 [7.40-15.51], P < .001, respectively) compared with group P. Inflammation and fibrosis seen on microscopic evaluation were significantly decreased in groups PL2 and PL4 compared with group S. Four percent of lidocaine only showed a significant reduction in inflammation. Serum levels of tumor necrosis factor-α, IL-1ß, IL-6, and high-sensitivity C-reactive protein were decreased in lidocaine-loaded groups compared with group S or P at 1, 2, and 48 hours, and 2 weeks after surgery, respectively. CONCLUSIONS: Lidocaine-loaded PACM reduced postoperative pain, and lidocaine strengthened the antiadhesive effect of PACM.

Evaluation of Lung Function and Clinical Features of the Ultrasound-Guided Stellate Ganglion Block With 2 Different Concentrations of a Local Anesthetic: A Randomized Controlled Trial.

BACKGROUND: One possible complication of stellate ganglion block (SGB) is respiratory compromise. No study has yet addressed the comparison of its effect on lung function and clinical features, including Horner's syndrome, changes in temperature, sensory and motor functions, and adverse events of lower versus higher concentrations (LC and HC, respectively) of local anesthetics in an ultrasound-guided SGB. METHODS: Fifty patients were randomized into 1 of 2 groups: the LC group (5 mL of 0.5% mepivacaine) and the HC group (5 mL of 1% mepivacaine). One anesthesiologist performed a C6- SGB under ultrasound guidance. Our primary objective was to compare LC and HC of a local anesthetic in terms of its effect on lung function, and the secondary objective was to compare the clinical features between LC and HC of a local anesthetic. Lung function was compared between the 2 groups using the Mann-Whitney U test. RESULTS: The forced vital capacity at 20 minutes post-SGB was not significantly different between the HC and the LC groups (P = .360); the median difference (95% confidence intervals [CI]) was 1 (-1 to 8). Other parameters of lung function were comparable with the forced vital capacity. Patients in the HC group had significantly greater sensory changes than those in the LC group (% decrease compared with the unblocked side); 95.4 ± 2.1 (CI: 91.11-99.73) vs 87.3 ± 3.5 (CI: 80.12-94.49). CONCLUSIONS: Lung function between the LC and HC groups after SGB did not differ significantly. Clinical features between the 2 groups also did not differ clinically, except that patients in the HC group had significantly greater sensory loss in the C6 dermatomes.

Optimal dose of intravenous oxycodone for attenuating hemodynamic changes after endotracheal intubation in healthy patients: A randomized controlled trial.

BACKGROUND: Intravenous oxycodone has been used as an adjunct to anesthetic agents. This study aimed to assess the optimal dose of intravenous oxycodone for the attenuation of the hemodynamic responses to laryngoscopy and endotracheal intubation. METHODS: A prospective, randomized, double-blind study was conducted. Ninety-five patients were randomly divided into 5 groups based on the oxycodone dose: 0, 0.05, 0.1, 0.15, 0.2 mg/kg. After administering the assigned dose of intravenous oxycodone, anesthesia was induced with thiopental. Heart rate (HR) and blood pressure (BP) were measured at baseline, before intubation, and 1, 2, and 3 minutes after intubation. The percentage increase of BP was calculated as (highest BP after intubation - baseline BP)/baseline BP × 100 (%). The percentage increase of HR was calculated in same formula as above. Hypertension was defined as a 15% increase of systolic BP from baseline, and probit analysis was conducted. RESULTS: Hemodynamic data from 86 patients were analyzed. The percentage increase of mean arterial pressure after intubation in groups 0.05, 0.1, 0.15, and 0.2 was significantly different from that in the control (P < 0.001). For HR, the percentage increase was lower than control group when oxycodone was same or more than 0.1 mg/kg (P < 0.05). Using probit analysis, the 95% effective dose (ED95) for preventing hypertension was 0.159 mg/kg (95% confidence interval [CI], 0.122-0.243). In addition, ED50 was 0.020 mg/kg (95% CI, -0.037 to 0.049). However, oxycodone was not effective for maintaining the HR in our study dosage. There were no significant differences in the incidence of hypotension during induction between groups. CONCLUSIONS: Using 0.1 mg/kg of intravenous oxycodone is sufficient to attenuate the increase of BP and HR during induction period in healthy patients. The ED95, which was 0.159 mg/kg, can be useful to adjust the dosage of IV oxycodone for maintain stable BP during induction of general anesthesia.