Optimal effect-site concentration of remifentanil to prevent hemodynamic changes during nasotracheal intubation using a video laryngoscope

Background@#Nasotracheal intubation is the most commonly used method to secure the field of view when performing surgery on the oral cavity or neck. Like orotracheal intubation, nasotracheal intubation uses a laryngoscope. Hemodynamic change occurs due to the stimulation of the sympathetic nervous system. Recently, video laryngoscope with a camera attached to the end of the direct laryngoscope blade has been used to minimize this change. In this study, we investigated the optimal effect-site concentration (Ce) of remifentanil for minimizing hemodynamic responses during nasotracheal intubation with a video laryngoscope. @*Methods@#Twenty-one patients, aged between 19 and 60 years old, scheduled for elective surgery were included in this study. Anesthesia was induced by slowly injecting propofol. At the same time, remifentanil infusion was initiated at 3.0 ng/ml via target-controlled infusion (TCI). When remifentanil attained the preset Ce, nasotracheal intubation was performed using a video laryngoscope. The patient's blood pressure and heart rate were checked pre-induction, right before and after intubation, and 1 min after intubation. Hemodynamic stability was defined as an increase in systolic blood pressure and heart rate by 20% before and after nasotracheal intubation. The response of each patient determined the Ce of remifentanil for the next patient at an interval of 0.3 ng/ml. @*Results@#The Ce of remifentanil administered ranged from 2.4 to 3.6 ng/ml for the patients evaluated. The estimated optimal effective effect-site concentrations of remifentanil were 3.22 and 4.25 ng/ml, that were associated with a 50% and 95% probability of maintaining hemodynamic stability, respectively. @*Conclusion@#Nasotracheal intubation using a video laryngoscope can be successfully performed in a hemodynamically stable state by using the optimal remifentanil effect-site concentration (Ce50 , 3.22 ng/ml; Ce95 , 4.25 ng/ml).

Neurotoxicity of local anesthetics in dentistry

During dental treatment, a dentist usually applies the local anesthesia. Therefore, all dentists should have expertisein local anesthesia and anesthetics. Local anesthetics have a neurotoxic effect at clinically relevant concentrations.Many studies have investigated the mechanism of neurotoxicity of local anesthetics but the precise mechanismof local anesthetic-induced neurotoxicity is still unclear. In addition, it is difficult to demonstrate the directneurotoxic effect of local anesthetics because perioperative nerve damage is influenced by various factors, suchas the anesthetic, the patient, and surgical risk factors. This review summarizes knowledge about the pharmacologyof local anesthetics, nerve anatomy, and the incidence, risk factors, and possible cellular mechanisms of localanesthetic-induced neurotoxicity.

Pain, Disability, Emotional Status and Educational Needs between Acute and Chronic Low Back Pain Groups

PURPOSE: This study aimed to identify pain, disability, anxiety, depression and educational needs between acute and chronic low back pain groups. METHODS: A total of 153 patients aged 18 to 64, recruited from S-neurosurgical clinic for low back pain in Gyeonggi-do. Out of 153 subjects, 70 were Acute Low Back Pain (ALBP) group and 83 were Chronic Low Back Pain (CLBP) group. The collected data was analyzed using the SAS System V 9.4 program by chi-square test/Fisher's exact test and t-test. RESULTS: The pain and disability scores were higher in ALBP group while the depression score was higher in CLBP group. The educational needs score in the area for the time for lumbar operation was higher in CLBP group. In the Low Back Pain (LBP) treatment management, ALBP group visited clinic (60.0%) most frequently and CLBP group visited both clinic & traditional medicine (66.3%) regularly. CONCLUSION: In order to minimize the progression from acute to chronic LBP, it is necessary for patients who visited the clinic to be accompanied with an education program that reflects educational needs of patients and with proven alternative therapy.

Remifentanil promotes osteoblastogenesis by upregulating Runx2/osterix expression in preosteoblastic C2C12 cells

BACKGROUND: The imbalance between osteoblasts and osteoclasts can lead to pathological conditions such as osteoporosis. It has been reported that opioid adversely affect the skeletal system, but it is inconsistent. Remifentanil is currently used as an adjuvant analgesic drug in general anesthesia and sedation. The aim of the present study was to investigate the effect of remifentanil on the osteoblast differentiation and mechanism involved in this effect. METHODS: The C2C12 cells (mouse pluripotent mesenchymal cell line) were used as preosteoblast. Osteoblastic differentiation potency was determined by alkaline phosphatase (ALP) staining. C2C12 cell migration by remifentanil was evaluated using Boyden chamber migration assay. The expression of Runx2 and osterix was evaluated by RT-PCT and western blot analysis to investigate the mechanism involved in remifentanil-mediated osteoblast differentiation. RESULTS: ALP staining showed that remifentanil increased significantly osteoblast differentiation. In Boyden chamber migration assay, C2C12 cell migration was increased by remifentanil. RT-PCR and western blot analysis showed that the expression of Runx2 and osterix was upregulated by remifentanil. CONCLUSIONS: We demonstrated that remifentanil increased osteoblast differentiation in vitro by upregulation of Runx2 and osterix expression. Therefore, remifentanil has the potential for assisting with bone formation and bone healing.

Anti-inflammatory effect of remifentanil in lipopolysaccharide–stimulated amniotic epithelial cells

BACKGROUND: Sometimes general anesthesia is required for dental surgery in pregnant women. Facial bone fractures or neck abscess should be treated immediately. Dental surgery, however, creates a stressful situation that can cause inflammation. Inflammatory responses are a well-known major cause of preterm labor and preterm birth. Here we demonstrate the effects of remifentanil on the factors related to preterm labor and its mechanism of action on amniotic-derived epithelial cells (WISH cells). METHODS: WISH cells were exposed to lipopolysaccharide (LPS) for 24 h and co-treated with various concentrations of remifentanil. MTT assays were performed to measure cell viability. To explain the effects of remifentanil on the factors related to inflammation in WISH cells, activation of nuclear factor kappa B (NF-κB) and p38 and the expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, cyclooxygenase (COX)2, and prostaglandin E (PGE)2 were quantified using western blotting and RT-PCR, respectively. RESULTS: Remifentanil did not affect WISH cell viability. In western blot analysis, co-treatment with remifentanil resulted in decreased phosphorylation of NF-κB, and expression of COX2 and PGE2 in LPS-induced inflammation, but the results were statistically significant only at low concentrations. Reduction of IL-1β and TNF-α expression was also observed with RT-PCR. CONCLUSION: Co-treatment with remifentanil does not affect the viability of WISH cells, but reduces the expression of the factors related to inflammation, which can induce uterine contraction and preterm labor. These findings provide evidence that remifentanil may inhibit uterine contraction and preterm labor in clinical settings.

Propofol Suppresses LPS-Induced Inflammation in Amnion Cells via Inhibition of NF-κB Activation

BACKGROUND: Preterm labor is a leading risk factor for neonatal death and long-term impairment and linked closely with inflammation. Non-obstetric surgery is occasionally needed during pregnancy and the anesthetic drugs or surgery itself can give rise to inflammation. Here, we examined the influence of propofol pretreatment on the expression of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) after lipopolysaccharide (LPS) stimulation. In addition, we evaluated the expression of pro-inflammatory cytokines and nuclear factor kappa B (NF-κB). METHODS: Human amnion-derived WISH cells were used to investigate the effect of propofol on the LPS-induced expression of inflammatory substances involved in preterm labor. For the experiment, WISH cells were pretreated with various concentrations propofol (0.01–10 µg/ml) for 1 h and then treated with LPS (1 µg/ml) for 24 h. Cytotoxicity was evaluated using MTT assay. PGE2 concentration was assessed by ELISA. Protein expressions of COX-2, PGE2 and NF-κB were analyzed by western blotting analysis. RT-PCR was used for analysis of mRNA expression of COX-2, PGE2, interlukin (IL)-1β and tumor necrosis factor (TNF)-α. RESULTS: Propofol showed no cytotoxicity on the WISH cells. LPS-induced PGE2 production and COX-2 and PGE2 expression were decreased after propofol pretreatment. Propofol also attenuated the LPS-induced mRNA expression of IL-1β and TNF-α. Moreover, the activation of NF-jB was inhibited by propofol pretreatment on LPS-stimulated WISH cells. CONCLUSION: We demonstrated that propofol suppresses the expression of inflammatory substances enhanced by LPS stimulation. Furthermore, this inhibitory effect of propofol on the inflammatory substance expression is mediated by suppression of NF-κB activation.

Effects of remifentanil preconditioning on factors related to uterine contraction in WISH cells

BACKGROUND: Preterm labor and miscarriage may occur in stressful situations, such as a surgical operation or infection during pregnancy. Pharyngeal and buccal abscess and facial bone fractures are inevitable dental surgeries in pregnant patients. Remifentanil is an opioid analgesic that is commonly used for general anesthesia and sedation. Nonetheless, no study has investigated the effects of remifentanil on amniotic epithelial cells. This study evaluated the effects of remifentanil on the factors related to uterine contraction and its mechanism of action on amniotic epithelial cells.METHODS: Amniotic epithelial cells were preconditioned at various concentrations of remifentanil for 1 h, followed by 24-h lipopolysaccharide (LPS) exposure. MTT assays were performed to assess the cell viability in each group. The effects of remifentanil on factors related to uterine contractions in amniotic epithelial cells were assessed using a nitric oxide (NO) assay, western blot examinations of the expression of nuclear factor-kappa B (NF-κB), cyclooxygenase 2 (COX2), and prostaglandin E2 (PGE₂), and RT-PCR examinations of the expression of the proinflammatory cytokines interleukin (IL)-1β and tumor necrosis factor-alpha (TNF-α).RESULTS: Remifentanil did not affect viability and nitric oxide production of amniotic epithelial cells. Western blot analysis revealed that remifentanil preconditioning resulted in decreased expressions of NF-κB and PGE2 in the cells in LPS-induced inflammation, and a tendency of decreased COX2 expression. The results were statistically significant only at high concentration. RT-PCR revealed reduced expressions of IL-1β and TNF-α.CONCLUSION: Preconditioning with remifentanil does not affect the viability of amniotic epithelial cells but reduces the expression of factors related to uterine contractions in situations where cell inflammation is induced by LPS, which is an important inducer of preterm labor. These findings provide evidence that remifentanil may inhibit preterm labor in clinical settings.

Fatal vocal cord granuloma after orthognathic surgery

Endotracheal intubation is commonly associated with laryngeal injury that often resolves spontaneously without any complication. However, stenosis or granulomatous lesions are generally found on the tracheal wall or vocal process at the tube cuff level, caused by excessive cuff pressure. We present a case of fatal vocal cord granuloma leading to dyspnea following orthognathic surgery and sustained intubation for 14 hours.

Optimal effective-site concentration of remifentanil for sedation during plate removal of maxilla

BACKGROUND: Removal of the plate following Le Fort I osteotomy and BSSO (bilateral sagittal split osteotomy) is a common procedure. However, patients who undergo plate removal experience intense pain and discomfort. This study investigated the half-maximal effective concentration (Ce50 ) of remifentanil in the prevention of plate removal pain under sedation using dexmedetomidine. METHODS: The study evaluated 18 patients, between 18 and 35 years of age, scheduled for elective surgery. Remifentanil infusion was initiated after sedation using dexmedetomidine, and started at a dose of 1.5 ng/mL on the first patient via target-controlled infusion (TCI). Patients received a loading dose of 1.0 µg/kg dexmedetomidine over 10 min, followed by a maintenance dose of 0.7 µg/kg/h. When the surgeon removed the plate, the patient Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score was observed. RESULTS: The Ce of remifentanil ranged from 0.9 to 2.1 ng/mL for the patients evaluated. The estimated effect-site concentrations of remifentanil associated with a 50% and 95% probability of reaching MOAA/S score of 3 were 1.28 and 2.51 ng/mL, respectively. CONCLUSIONS: Plate removal of maxilla can be successfully performed without any pain or adverse effects by using the optimal remifentanil effect-site concentration (Ce50 , 1.28 ng/mL; Ce95 , 2.51 ng/mL) combined with sedation using dexmedetomidine.

Medical adhesive related skin injury after dental surgery

An 87-year-old woman was referred for the extraction of residual teeth and removal of tori prior to prosthetic treatment. After surgery under general anesthesia, the surgical tape was removed to detach the bispectral index sensor and the hair cover. After the surgical tape was removed, skin injury occurred on the left side of her face. After epidermis repositioning and ointment application, a dressing was placed over the injury. Her wound was found to have healed completely on follow-up examination. Medical adhesive related skin injury (MARSI) is a complication that can occur after surgery and subjects at the extremes of age with fragile skin are at a higher risk for such injuries. Careful assessment of the risk factors associated with MARSI is an absolute necessity.

Warfarin-Induced Eosinophilic Pleural Effusion

A 29-year-old man suffering from dyspnea and eosinophilic pleural effusion after being on warfarin for pulmonary thromboembolism for a period of one month, was readmitted to our hospital. Etiology of pleural effusion other than warfarin was excluded. To the best of our knowledge, this is the first case of warfarin-induced pleural effusion reported in Korea.

Warfarin-Induced Eosinophilic Pleural Effusion

A 29-year-old man suffering from dyspnea and eosinophilic pleural effusion after being on warfarin for pulmonary thromboembolism for a period of one month, was readmitted to our hospital. Etiology of pleural effusion other than warfarin was excluded. To the best of our knowledge, this is the first case of warfarin-induced pleural effusion reported in Korea.

A Case of Pulmonary Arterial Hypertension Associated With Hyperthyroidism, Persistent After Euthyroidism Was Obtained

Cardiovascular manifestations in hyperthyroidism occur frequently with various phenotypes. An association between hyperthyroidism and pulmonary arterial hypertension has been reported. In previously reported cases, the hemodynamic and symptomatic recovery of pulmonary arterial hypertension is usually concomitant with achievement of euthyroidism. We report a patient who had pulmonary arterial hypertension associated with Graves' disease, which persisted after euthyroidism was obtained.