BackgroundThe intubation difficulty scale (IDS) has been used as a validated difficulty score to define difficult intubation (DI). The purpose of this study is to identify airway assessment factors and total airway score (TAS) for predicting DI defined by the IDS.MethodsThere were 305 ASA physical status 1-2 patients, aged 19-70 years, who underwent elective surgery with endotracheal intubation. During the pre-anesthetic visit, we evaluated patients by 7 preoperative airway assessment factors, including the following: Mallampati classification, thyromental distance, head & neck movement, body mass index (BMI), buck teeth, inter-incisor gap, and upper lip bite test (ULBT). After endotracheal intubation, patients were divided into 2 groups based on their IDS score estimated with 7 variables: normal (IDS < 5) and DI (IDS ≥ 5) groups. The incidence of TAS (> 6) and high score of each airway assessment factor was compared in two groups: odds ratio, confidence interval (CI) of 95%, with a significant P value ≤ 0.05.ResultsThe odds ratio of TAS (> 6), ULBT (class III), head & neck movement (< 90°), inter-incisor gap (< 4 cm), BMI (≥ 25 kg/m2) and Mallampati classification (≥ class III) were respectively 13.57 (95% CI = 2.99-61.54, P < 0.05), 12.48 (95% CI = 2.50-62.21, P < 0.05), 3.11 (95% CI = 0.87-11.13), 2.32 (95% CI = 0.75-7.19), 2.22 (95% CI = 0.81-6.06), and 1.22 (95% CI = 0.38-3.89).ConclusionsWe suggest that TAS (> 6) and ULBT (class III) are the most useful factors predicting DI.

An 81-year-old male patient was scheduled for a laparoscopic cholecystectomy due to acute cholecystitis. About 50 minutes into the operation, the arterial blood pressure suddenly decreased and ventricular fibrillation appeared on the electrocardiography. The patient received cardiopulmonary resuscitation and recovered a normal vital sign. We suspected a carbon dioxide embolism as the middle hepatic vein had been injured during the surgery. We performed a transesophageal echocardiography and were able to confirm the presence of multiple gas bubbles in all of the cardiac chambers. After the operation, the patient presented a stable hemodynamic state, but showed weaknesses in the left arm and leg. There were no acute lesions except for a chronic cerebral cortical atrophy and chronic microvascular encephalopathy on the postoperative brain-computed tomography, 3D angiography and magnetic resonance image. Fortunately, three days after the operation, the patient's hemiparesis had entirely subsided and he was discharged without any neurologic sequelae.

BackgroundThe aim of this study was to investigate whether a small dose of midazolam and lessening the propofol dosage could prevent cardiovascular change at tracheal intubation for induction in aged patients.MethodsEighty patients over 65 years (ASA physical status 1, 2) scheduled for elective surgery received general anesthesia with remifentanil and propofol or midazolam. Patients in group P (n = 40) were induced with 0.9% NaCl 0.03 ml/kg, propofol 1. 2 mg/kg and remifentanil. Patients in group MP (n = 40) were induced with midazolam 0.03 mg/kg, propofol 0.8 mg/kg and remifentanil. The time taken to reach loss of consciousness (LOC) and the value of bispectral index score (BIS) at LOC were recorded. After LOC, 0.8 mg/kg of rocuronium was given and tracheal intubation was performed. The mean blood pressure (MBP) and heart rate (HR) were recorded before induction as the base value, before intubation, immediately post-intubation and 3 minutes after intubation.ResultsCompared with the base values, MBP at before intubation and 3 minutes after intubation was significantly decreased in group P and group MP (P < 0.05). Compared with group P, the decrease of MBP was significantly less at before intubation, immediately after intubation and 3 minutes after intubation in group MP (P < 0.05). The time taken to reach LOC was significantly decreased in group MP compared with that in group P (P < 0.05). There were no significant differences of HR at any time between the two groups.ConclusionsCo-induction with midazolam and propofol could prevent a marked BP decrease at tracheal intubation for induction in aged patients.

BackgroundG protein-coupled receptor, family C, group 5 (GPRC5B), a retinoic acid-inducible orphan G-protein-coupled receptor (GPCR), is a member of the group C metabotropic glutamate receptor family proteins presumably related in non-canonical Wnt signaling. In this study, we investigated altered GPRC5B expression in the dorsal horn of the spinal cord after spinal nerve injury and its involvement in the development of neuropathic pain.MethodsAfter induction of anesthesia by intraperitoneal injection of pentobarbital (35 mg /kg), the left L5 spinal nerve at the level of 2 mm distal to the L5 DRG was tightly ligated with silk and cut just distal to the ligature. Seven days after nerve injury, animals were perfused with 4% paraformaldehyde, and the spinal cords were extracted and post-fixed at 4℃ overnight. To identify the expression of GPRC5B and analyze the involvement of GPRC5B in neuropathic pain, immunofluorescence was performed using several markers for neurons and glial cells in spinal cord tissue.ResultsAfter L5 spinal nerve ligation (SNL), the expression of GPRC5B was decreased in the ipsilateral part, as compared to the contralateral part, of the spinal dorsal horn. SNL induced the downregulation of GPRC5B in NeuN-positive neurons in the spinal dorsal horn. However, CNPase-positive oligodendrocytes, OX42-positive microglia, and GFAP-positive astrocytes were not immunolabeled with GPRC5B antibody in the spinal dorsal horn.ConclusionsThese results imply that L5 SNL-induced GPRC5B downregulation may affect microglial activation in the spinal dorsal horn and be involved in neuropathic pain.

Photonic fibers are important raw materials for structurally colored fabrics. In particular, the mechanochromic fibers potentially provide color‐tunable clothes, like chameleon skins. Herein, microfluidic jetting to continuously produce mechanochromic fibers in a controlled manner is used. The jet is produced by flow‐focusing the photocurable dispersions in a surfactant‐laden carrier fluid using microfluidic devices. The dispersions contain monodispersed silica particles in an elastomer‐forming resin. As the silica particles have repulsive interparticle potential in the resin, they spontaneously organize into a nonclose‐packed regular array, developing structural colors. The jet of the dispersions is photocured in situ by irradiation of ultraviolet at the exit of the microfluidic channel, continuously producing the photonic fibers. As the interparticle separation among silica particles is shortened along the radial direction by stretching the elastic fibers, the structural colors are dynamically blue shifted. Also, the original colors are reversibly recovered by relaxing the fibers as the deformation is fully elastic. The nonclose‐packed array of inelastic silica particles provides a wide range of color tuning and high reversibility. Moreover, microfluidic jetting enables the production of Janus fibers composed of two distinct color domains, which enriches the available structural colors through color mixing.