Hyo-Jin Byon

A randomised trial comparing the i-gel (TM) with the LMA Classic (TM) in children.

We performed a prospective, randomised trial comparing the i‐gelTM with the LMA ClassicTM in children undergoing general anaesthesia. Ninety‐nine healthy patients were randomly assigned to either the i‐gel or the LMA Classic. The outcomes measured were airway leak pressure, ease of insertion, time taken for insertion, fibreoptic examination and complications. Median (IQR [range]) time to successful device placement was shorter with the i‐gel (17.0 (13.8−20.0 [10.0−20.0]) s) compared with the LMA Classic (21.0 (17.5−25.0 [15.0−70.0]) s, p = 0.002). There was no significant difference in oropharyngeal leak pressure between the two devices. A good fibreoptic view of the glottis was obtained in 74% of the i‐gel group and in 43% of the LMA Classic group (p < 0.001). There were no significant complications. In conclusion, the i‐gel provided a similar leak pressure, but a shorter insertion time and improved glottic view compared with the LMA Classic in children.

Usefulness of ultrasound for selecting a correctly sized uncuffed tracheal tube for paediatric patients

The purpose of this study was to assess whether ultrasonography is useful for determining uncuffed tracheal tube sizes for paediatric patients. The equation for selecting the correctly sized tracheal tube was developed using data on the subglottic diameter measured by ultrasonography and air leak test. The efficacy of the new equation was evaluated by comparing it with the conventional age‐based formula (4 + age/4) in another 100 patients. Tracheal tube sizes were selected using two methods, and air leakage pressure was measured after each intubation. The ultrasonographic method allowed the correct tube size to be selected in 60% of cases, whereas the age‐based method enabled this in 31% of cases (p < 0.001). Ultrasound can offer a useful means of selecting correct tracheal tube size compared with the age‐based formula in paediatric patients. However, even using ultrasound, the success rate of correct tube size selection is still not very high.

Predicting the optimal depth of left-sided central venous catheters in children

The aim of this study was to predict the optimal depth for insertion of a left‐sided central venous catheter in children. Using 3D chest computed tomography angiography, we measured the distance from a point where the internal jugular vein is at the superior border of the clavicle, and from a point where the subclavian vein is inferior to the anterior border of the clavicle, to the junction of the superior vena cava and the right atrium in 257 children. Linear regression analysis revealed that the distances correlated with age, weight and height. Simple formulae for the depth of a central venous catheter via the left internal jugular vein (0.07 × height (cm)) and the left subclavian vein (0.08 × height (cm)) were developed to predict placement of the central venous catheter tip at the junction of the superior vena cava with the right atrium. Using these fomulae, the proportion of catheter tips predicted to be correctly located was 98.5% (95% CI 96.8–100%) and 94.0% (95% CI 90.8–97.3%), respectively.

Lipid Emulsion Inhibits Vasodilation Induced by a Toxic Dose of Bupivacaine via Attenuated Dephosphorylation of Myosin Phosphatase Target Subunit 1 in Isolated Rat Aorta

Lipid emulsions are widely used for the treatment of systemic toxicity that arises from local anesthetics. The goal of this in vitro study was to examine the cellular mechanism associated with the lipid emulsion-mediated attenuation of vasodilation induced by a toxic dose of bupivacaine in isolated endothelium-denuded rat aorta. The effects of lipid emulsion on vasodilation induced by bupivacaine, mepivacaine, and verapamil were assessed in isolated aorta precontracted with phenylephrine, the Rho kinase stimulant NaF, and the protein kinase C activator phorbol 12,13-dibutyrate (PDBu). The effects of Rho kinase inhibitor Y-27632 on contraction induced by phenylephrine or NaF were assessed. The effects of bupivacaine on intracellular calcium concentrations ([Ca2+]i) and tension induced by NaF were simultaneously measured. The effects of bupivacaine alone and lipid emulsion plus bupivacaine on myosin phosphatase target subunit 1 (MYPT1) phosphorylation induced by NaF were examined in rat aortic vascular smooth muscle cells. In precontracted aorta, the lipid emulsion attenuated bupivacaine-induced vasodilation but had no effect on mepivacaine-induced vasodilation. Y-27632 attenuated contraction induced by either phenylephrine or NaF. The lipid emulsion attenuated verapamil-induced vasodilation. Compared with phenylephrine-induced precontracted aorta, bupivacaine-induced vasodilation was slightly attenuated in NaF-induced precontracted aorta. The magnitude of the bupivacaine-induced vasodilation was higher than that of a bupivacaine-induced decrease in [Ca2+]i. Bupivacaine attenuated NaF-induced MYPT1 phosphorylation, whereas lipid emulsion pretreatment attenuated the bupivacaine-induced inhibition of MYPT1 phosphorylation induced by NaF. Taken together, these results suggest that lipid emulsions attenuate bupivacaine-induced vasodilation via the attenuation of inhibition of MYPT1 phosphorylation evoked by NaF.

Dexmedetomidine-induced contraction involves c-Jun NH2-terminal kinase phosphorylation through activation of the 5-lipoxygenase pathway in the isolated endothelium-denuded rat aorta

Vasoconstriction induced by dexmedetomidine, a highly selective alpha‐2 adrenoceptor agonist, mainly involves c‐Jun NH2‐terminal kinase (JNK) phosphorylation in the isolated endothelium‐denuded aorta. We carried out an in vitro study to determine the main arachidonic acid metabolic pathway that is involved in dexmedetomidine‐induced JNK activation. Cumulative dexmedetomidine concentration‐contractile response curves were generated in the endothelium‐denuded rat aorta in the presence or absence of the following inhibitors: the JNK inhibitor SP600125, the phospholipase A2 inhibitor quinacrine dihydrochloride, the non‐specific lipoxygenase (LOX) inhibitor nordihydroguaiaretic acid, the 5‐LOX inhibitor AA‐861, the dual 5‐LOX and cyclooxygenase (COX) inhibitor phenidone, the non‐specific COX inhibitor indomethacin, the cytochrome p450 epoxygenase inhibitor fluconazole, the COX‐1 inhibitor SC‐560, and the COX‐2 inhibitor NS‐398. The effect of the alpha‐2 adrenoceptor inhibitor rauwolscine and other inhibitors, such as quinacrine dihydrochloride, nordihydroguaiaretic acid, AA‐861, phenidone, indomethacin and the protein kinase C inhibitor GF 109203X, on dexmedetomidine‐induced JNK phosphorylation was investigated in rat aortic vascular smooth muscle cells with western blotting. The effect of dexmedetomidine on 5‐LOX and COX‐2 expression was investigated in vascular smooth muscle cells. SP600125, quinacrine dihydrochloride, nordihydroguaiaretic acid, AA‐861, phenidone, rauwolscine and chelerythrine attenuated dexmedetomidine‐induced contraction. Indomethacin slightly attenuated dexmedetomidine‐induced contraction. Fluconazole and SC‐560 had no effect on dexmedetomidine‐induced contraction, whereas NS‐398 attenuated contraction. SP600125, rauwolscine, quinacrine dihydrochloride, nordihydroguaiaretic acid, AA‐861, phenidone and GF 109203X attenuated dexmedetomidine‐induced JNK phosphorylation. 5‐LOX and COX‐2 were upregulated by dexmedetomidine. Thus, dexmedetomidine‐induced alpha‐2 adrenoceptor‐mediated contraction is mediated mainly by 5‐LOX and partially by COX‐2, which leads to JNK phosphorylation.

Comparison between Glidescope and Lightwand for tracheal intubation in patients with a simulated difficult airway.

Background Although Lightwand and Glidescope have both shown high success rates for intubation, there has been no confirmation as to which device is most effective for difficult endotracheal intubation. We compared the Glidescope and Lightwand devices in terms of duration of intubation and success rate at the first attempt in a simulated difficult airway situation. Methods Fifty-eight patients were randomized to undergo tracheal intubation with either the Glidescope (Glidescope group, n = 29) or the Lightwand (Lightwand group, n = 29). All patients were fitted with a semi-hard cervical collar in order to simulate a difficult airway, and intubation was attempted with the assigned airway device. The data collected included the rate of successful endotracheal intubation, the number of attempts required, the duration of the intubation, as well as the interincisor distance, hemodynamic variables, and adverse effects. Results There was no difference between Glidescope group (92.6%) and Lightwand group (96.4%) in terms of success rate for the first attempt at intubation. The duration of successful intubation for the first tracheal intubation attempt was significantly longer in Glidescope group than in Lightwand group (46.9 sec vs 29.5 sec, P = 0.001). All intubations were completed successfully within two intubation attempts. The incidence of hypertension was significantly higher in Glidescope group than in Lightwand group (51.9% vs 17.9%, P = 0.008). Conclusions In a simulated difficult airway situation, endotracheal intubation using Lightwand yielded a shorter duration of intubation and lower incidence of hypertension than when using Glidescope.

The Effects of Shoulder Rotation on the Acoustic Window for Thoracic Paramedian Epidural Approach in the Lateral Decubitus Position.

Background and Objectives The aim of this study was to examine whether shoulder rotation increases the length of the posterior longitudinal ligament (PLL) in the lateral decubitus position. Methods Thirty-four adult male volunteers were placed in the right or left lateral decubitus and flexion position on a horizontal operating table. Thoracic spinal ultrasonography was performed using the paramedian oblique sagittal plane to obtain the optimal ultrasound view for the PLL on the dependent side. The lengths of the PLL were measured at the T6/7 and T9/10 interspaces before and after ipsilateral 30-degree shoulder rotation. Results In the right lateral decubitus position, the ipsilateral shoulder rotation increased the mean (SD) of the PLL from 7.4 (2.8) to 8.4 (2.6) mm (P = 0.006) at the T6/7 level and from 8.4 (2.9) to 10.6 (2.8) mm (P < 0.0001) at the T9/10 level. Similarly, in the left lateral decubitus position, the ipsilateral shoulder rotation increased the mean (SD) of the PLL from 8.0 (2.6) to 9.1 (2.6) mm (P = 0.001) at the T6/7 level and from 9.3 (2.8) to 11.8 (3.1) mm (P < 0.0001) at the T9/10 level. Conclusions Shoulder rotation significantly increased the dimension of the acoustic target window for paramedian thoracic epidural access in the lateral decubitus position at both T6/7 and T9/10 levels. Further clinical studies are needed to investigate the effect of shoulder rotation on thoracic epidural access.

Measuring the depth of the caudal epidural space to prevent dural sac puncture during caudal block in children

Caudal blocks are performed through the sacral hiatus in order to provide pain control in children undergoing lower abdominal surgery. During the block, it is important to avoid advancing the needle beyond the sacrococcygeal ligament too much to prevent unintended dural puncture. This study used demographic data to establish simple guidelines for predicting a safe needle depth in the caudal epidural space in children.

An Open-label Comparison of a New Generic Sevoflurane Formulation With Original Sevoflurane in Patients Scheduled for Elective Surgery Under General Anesthesia

PURPOSE To compare the stability, effectiveness, and safety profiles of a new generic sevoflurane with those of the original sevoflurane formulation in patients undergoing elective surgery. METHODS An accelerated 3-month storage test was performed to evaluate the compositional changes in generic sevoflurane stored in glass bottles. In addition, 182 patients were randomly allocated to receive generic (n = 89 [54 men and 35 women]; mean [SD] age, 49.9 [11.6] years) or original (n = 93 [61 men and 32 women]; mean [SD] age, 49.6 [11.1] years) sevoflurane at a gas flow of 3 L/min for approximately 3 hours. The mean minimum alveolar concentration (MAC) during sevoflurane anesthesia was evaluated, and gas samples for measuring compound A were collected from the inspiratory limb of the circuit at preset intervals. Blood samples for measuring serum inorganic fluoride were obtained at preset intervals (pharmacokinetic group: generic/original sevoflurane = 45/46). Renal biomarkers, such as N-acetyl-β-glucosaminidase, α- and π-glutathione-S-transferase, albumin, urine protein and osmolality, serum creatinine and osmolality, creatinine clearance, and blood urea nitrogen, were measured at preset intervals (renal biomarker group: generic/original sevoflurane = 44/47). Adverse reactions were monitored for 72 hours after discontinuation of sevoflurane use. FINDINGS Generic sevoflurane contained in glass bottles was stable for 3 months. The mean MAC was similar for generic and original sevoflurane (median [range], 0.93 [0.67-1.29] vs 0.94 [0.63-1.5] vol%). Adverse event rates were similar (90.3% vs 84.3%), as were the AUClast of inorganic fluoride (333.7 [112.7-1264.7] vs 311.9 [81.5-1266.5] hours·μmol/L) and compound A (51.8 [6.3-204.5] vs 55.3 [10.8-270.6] hours·ppm). Biomarkers associated with renal injury were not significantly different between the 2 formulations. IMPLICATIONS No significant difference was found in the mean MAC between generic and original sevoflurane. ClinicalTrials.gov identifier: NCT01096212.

Safety and Efficacy of Off-label and Unlicensed Medicines in Children

Background The aim of this study was to explore the use of off-label/unlicensed drugs to confirm the safety and efficacy of their prescription in children in Korea. Methods In this retrospective study, we analyzed data of patients who received any of the 32 drugs between January–December 2014 in tertiary hospitals in Korea, including demographics, diagnoses, reasons for the medication, administration route, and details of adverse drug reactions. Additionally, the mortality in the cohort was assessed. The primary outcomes were efficacy and safety, including mortality, of these drugs in pediatric patients. The secondary outcomes were the current statuses of the use of off-label/unlicensed drugs in two centers. Results Totally, 5,130 prescriptions were found in 2,779 patients. Age (73.5%) and indication (11.7%) were the most frequent reasons for prescriptions being off-labeled/unlicensed. Approximately 88% of the prescriptions were effective, and 19% of the patients developed adverse drug reactions. The number of prescriptions was significantly higher in children with adverse drug reactions than it was in those without (2.8 vs. 1.5; P < 0.001). The number of prescribed off-label/unlicensed medicines and age at prescription were independently associated with adverse drug events (odds ratio, 1.55 and 1.1; P < 0.001 and 0.034, respectively). Conclusion Children are still prescribed medicines that are not authorized in terms of age, weight, indications, or routes of administration. Therefore, many old products require re-assessment of authorization. More prospective clinical studies should be performed to confirm the efficacy and safety of drugs in the pediatric population.