Angular change in the line of vision to the larynx: implications for determining the laryngoscopic view.

BACKGROUND: We measured the angular change from the line of vision to the larynx around the upper incisors under defined laryngoscopic forces and investigated its association with the laryngoscopic view. METHODS: Laryngoscopy was performed under general anesthesia with muscle paralysis in male patients with a difficult laryngoscopy (DLG, n = 11) and in male patients matched for age and body mass index with an easy laryngoscopy (ELG, n = 11). A Macintosh blade #3 was used for the procedure. The line of vision was marked on lateral photographs during laryngoscopy by simultaneously delineating two straight lines: a line from the upper incisors to the lowest surface of the laryngoscope blade and a line from the upper incisors to the thyroid notch. The angle difference, defined as the angle between those two lines, was measured at laryngoscopic forces of 10-50 N. RESULTS: The angle difference was significantly greater in the DLG than in the ELG at 50 N [median, 18.0° (range, 16.5-21.0°) vs 12.0° (12.0-13.5°), respectively; P < 0.001] and at lower forces (10-40 N; P ≤ 0.001). A higher Cormack-Lehane grade was associated with a greater angle difference at 50 N (P < 0.001). CONCLUSIONS: Compared with ELG, DLG is associated with a larger angle difference, i.e., a larger gap between the underside of the blade and the thyroid notch at all laryngoscopic forces (10-50 N). The concept of angle difference, based on the angular change in the line of vision around the upper incisors, may provide a new approach to understanding DLG. This study was registered with the Clinical Research Information Service, registration number KCT0000433.

Previsional space during direct laryngoscopy: Implication in the difficult laryngoscopy.

The laryngoscope should displace oral soft tissues forward out of the operator's vision. Therefore, the space in front of the view may be critical for determining the laryngoscopic view. The aim was to investigate the difference in the previsional space during difficult versus easy laryngoscopy (EL).Under general anesthesia, digital photographs of the lateral view of the head and neck were taken in the horizontal sniffing position, after head extension, and during laryngoscopy with a defined force (50 N). Three points (thyroid notch (T), maxillary incisor (I), and mandibular mentum (M)) were marked on the photograph. The previsional space was defined as the TIM triangle. We compared these areas and other variables of the TIM triangle between male patients with difficult laryngoscopy (DL: Cormack-Lehane III-IV, n = 12) versus those of age- and body mass index-matched male patients with EL (Cormack-Lehane I-II, n = 12).When the head was extended, the areas TIM triangle in DL were significantly smaller than in EL. During laryngoscopy, all values of the TIM triangle in DL, including the TIM area (16.4 ±â€Š3.7 vs 22.6 ±â€Š2.8 cm, P < .01), were significantly smaller than the values in EL.The previsional space was smaller in patients with DL than in those with EL. The TIM triangle could suggest new way to explain the mechanism underlying DL.

The grain growth behavior of NiO in thermally-stable mesoporous gadolinium-doped ceria network for intermediate-temperature solid oxide fuel cell anode materials.

The grain growth behavior of NiO nano grains in mesoporous gadolinium-doped ceria (GDC) network was investigated for anode materials of intermediate-temperature solid oxide fuel cell (SOFC). Both mesoporous GDC and NiO-GDC powders were synthesized using tri-block copolymer, Pluronic F127 as a structure-directing agent, and then X-ray diffraction, N2 adsorption/desorption isotherms, thermo gravimetric analysis, field-emission scanning electron microscopy and transmission electron microscopy were used for characterization of the mesoporous structure. Mesoporous GDC synthesized using pluronic F127 triblock copolymer had ordered double mesoporous structure with an average pore size of 9.68 nm and was thermally stable up to 700 degrees C. NiO grains in the mesoporous GDC network grew to have an octahedral shape with truncated-edges, but massive NiO agglomeration occurred as the calcination temperature increases up to 850 degrees C.