Risk factors of emergency reoperations.

BACKGROUND: Emergency reoperation is considered to be a quality indicator in surgery. We analyzed the risk factors for emergency reoperations. METHODS: Patients who underwent emergency operations from January 1, 2017, to December 31, 2017, at our hospital were reviewed in this retrospective study. Multivariate logistic regression was performed for the perioperative risk factors for emergency reoperation. RESULTS: A total of 1,481 patients underwent emergency operations during the study period. Among them, 79 patients received emergency reoperations. The variables related to emergency reoperation included surgeries involving intracranial and intraoral lesions, highest mean arterial pressure ≥ 110 mmHg, highest heart rate ≥ 100 beats/min, anemia, duration of operation >120 min, and arrival from the intensive care unit (ICU). CONCLUSIONS: The type of surgery, hemodynamics, hemoglobin values, the duration of surgery, and arrival from ICU were associated with emergency reoperations.

Oral administration of Ulmus davidiana extract suppresses interleukin-1ß expression in LPS-induced immune responses and lung injury.

BACKGROUND: Ulmus davidiana (UD) is a traditional Korean herb medicine that is used to treat inflammatory disorders. UD has been shown to modulate a number of inflammatory processes in vitro or in vivo studies. However, the molecular mechanisms of UD on lipopolysaccharide (LPS)-induced acute lung injury remain to be understood. OBJECTIVE: The primary objective of this study is to determine the effect of UD bark water extract on LPS-induced immune responses and lung injury using both in vitro and in vivo models. METHODS: RAW 264.7 cells and a rat model of acute lung injury (ALI) were used to study the effects of UD on several parameters. Nitrite level, lactate dehydrogenase (LDH) level, and superoxide dismutase (SOD) activities were measured. Tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and plasma transaminase activities in blood were also determined. Pathological investigations were also performed. RESULTS: LPS infusion resulted in elevated IL-1ß mRNA expression, nitrite levels, TNF-α expression, and IL-1ß expression in RAW 264.7 cells. LPS infusion also increased levels of nitrite/nitrate, total protein, LDH, and TNF-α in bronchoalveolar lavage fluid, but reduced SOD levels in ex vivo and in vivo models. UD administration ameliorated all these inflammatory markers. In particular, treatment with UD reduced LPS-induced nitrite production in RAW 264.7 cells in a dose-dependent manner. UD treatment also counteracted the LPS-induced increase in alanine aminotransferase (ALT) and aspartate transaminase (AST) activity in rat plasma, leading to a significant reduction in ALT and AST activity. CONCLUSIONS: The results revealed that UD treatment reduces LPS-induced nitrite production, IL-1ß mRNA expression, and TNF-α expression. In addition, LPS-induced decrease in SOD level is significantly elevated by UD administration. These results indicate that UD extract merits consideration as a potential drug for treating and/or preventing ALI.

Targeted Transforaminal Epidural Blood Patch for Postdural Puncture Headache in Patients with Postlaminectomy Syndrome.

Postdural puncture headache is a leak of cerebrospinal fluid that lowers intracranial pressure and usually presents as a positional headache. If conservative treatments are not successful, the epidural blood patch is the gold standard of the treatment for dural puncture. The interlaminar approach is the most commonly used technique for an epidural blood patch. This case report describes a patient who was treated with a transforaminal epidural blood patch for postdural puncture headache following an acupuncture procedure on his lower back after two epidural blood patches using an interlaminar approach had failed. The patient underwent an acupuncture therapy for management of chronic low back pain due to postlaminectomy syndrome. After the procedure, the patient had a severe headache and the conservative treatment was not effective. The two interlaminar epidural blood patches at the L2-3 level and at the L3-4 level were failed. We performed transforaminal epidural blood patch at the L3-4 and L4-5 levels on the left side, the site of leakage in the MRI myelogram. His symptoms finally subsided without complication. This case demonstrates that targeted transforaminal epidural blood patch is a therapeutic option for the treatment of postdural puncture headache when epidural blood patch using an interlaminar approach is ineffective.

Global trend analysis in primary and secondary production of marine aerosol and aerosol optical depth during 2000-2015.

The global trends in sea spray aerosol (SSA) emissions, dimethyl sulfide (DMS) flux from sea to air, and aerosol optical depth (AOD) during 2000-2015 were analyzed using the satellite-based, ECMWF reanalysis, and model-predicted data. The SSA emissions were estimated using a widely used whitecap method with a sea surface temperature (SST) dependence. The sea-to-air DMS fluxes were estimated by a thin film model based on the DMS concentration in seawater and its gas transfer velocity. The yearly global mean anomaly in DMS fluxes showed a significant downward trend during the study period, whereas the SSA emissions showed an upward trend. In terms of regional trends, the increases in SSA emissions during 2000-2015 occurred over the tropical southeastern Pacific Ocean and Southern Ocean, whereas any downward trends in SSA emissions were localized. The DMS fluxes during the study period showed a clear downward trend over most oceans, except for the strong upward trend at low latitudes. In general, the AOD from the MODerate resolution Imaging SpectroRadiometer (MODIS) showed upward trends across the entire Southern Hemisphere (SH), whereas there were downward trends in most areas of the Northern Hemisphere (NH). Therefore, the upward trend of AOD in the SH were derived mainly from the SSA emission trend, due to smaller contribution of anthropogenic sources in the SH.

Reducing radiation dose by application of optimized low-energy x-ray filters to K-edge imaging with a photon counting detector.

K-edge imaging with photon counting x-ray detectors (PCXDs) can improve image quality compared with conventional energy integrating detectors. However, low-energy x-ray photons below the K-edge absorption energy of a target material do not contribute to image formation in the K-edge imaging and are likely to be completely absorbed by an object. In this study, we applied x-ray filters to the K-edge imaging with a PCXD based on cadmium zinc telluride for reducing radiation dose induced by low-energy x-ray photons. We used aluminum (Al) filters with different thicknesses as the low-energy x-ray filters and implemented the iodine K-edge imaging with an energy bin of 34-48 keV at the tube voltages of 50, 70 and 90 kVp. The effects of the low-energy x-ray filters on the K-edge imaging were investigated with respect to signal-difference-to-noise ratio (SDNR), entrance surface air kerma (ESAK) and figure of merit (FOM). The highest value of SDNR was observed in the K-edge imaging with a 2 mm Al filter, and the SDNR decreased as a function of the filter thicknesses. Compared to the K-edge imaging with a 2 mm Al filter, the ESAK was reduced by 66%, 48% and 39% in the K-edge imaging with a 12 mm Al filter for 50 kVp, 70 kVp and 90 kVp, respectively. The FOM values, which took into account the ESAK and SDNR, were maximized for 8, 6 to 8 and 4 mm Al filters at 50 kVp, 70 kVp and 90 kVp, respectively. We concluded that the use of an optimal low-energy filter thickness, which was determined by maximizing the FOM, could significantly reduce radiation dose while maintaining image quality in the K-edge imaging with the PCXD.

Quantitative material decomposition using spectral computed tomography with an energy-resolved photon-counting detector.

Dual-energy computed tomography (CT) techniques have been used to decompose materials and characterize tissues according to their physical and chemical compositions. However, these techniques are hampered by the limitations of conventional x-ray detectors operated in charge integrating mode. Energy-resolved photon-counting detectors provide spectral information from polychromatic x-rays using multiple energy thresholds. These detectors allow simultaneous acquisition of data in different energy ranges without spectral overlap, resulting in more efficient material decomposition and quantification for dual-energy CT. In this study, a pre-reconstruction dual-energy CT technique based on volume conservation was proposed for three-material decomposition. The technique was combined with iterative reconstruction algorithms by using a ray-driven projector in order to improve the quality of decomposition images and reduce radiation dose. A spectral CT system equipped with a CZT-based photon-counting detector was used to implement the proposed dual-energy CT technique. We obtained dual-energy images of calibration and three-material phantoms consisting of low atomic number materials from the optimal energy bins determined by Monte Carlo simulations. The material decomposition process was accomplished by both the proposed and post-reconstruction dual-energy CT techniques. Linear regression and normalized root-mean-square error (NRMSE) analyses were performed to evaluate the quantitative accuracy of decomposition images. The calibration accuracy of the proposed dual-energy CT technique was higher than that of the post-reconstruction dual-energy CT technique, with fitted slopes of 0.97-1.01 and NRMSEs of 0.20-4.50% for all basis materials. In the three-material phantom study, the proposed dual-energy CT technique decreased the NRMSEs of measured volume fractions by factors of 0.17-0.28 compared to the post-reconstruction dual-energy CT technique. It was concluded that the proposed dual-energy CT technique can potentially be used to decompose mixtures into basis materials and characterize tissues according to their composition.

A Monte Carlo simulation study of the effect of energy windows in computed tomography images based on an energy-resolved photon counting detector.

The energy-resolved photon counting detector provides the spectral information that can be used to generate images. The novel imaging methods, including the K-edge imaging, projection-based energy weighting imaging and image-based energy weighting imaging, are based on the energy-resolved photon counting detector and can be realized by using various energy windows or energy bins. The location and width of the energy windows or energy bins are important because these techniques generate an image using the spectral information defined by the energy windows or energy bins. In this study, the reconstructed images acquired with K-edge imaging, projection-based energy weighting imaging and image-based energy weighting imaging were simulated using the Monte Carlo simulation. The effect of energy windows or energy bins was investigated with respect to the contrast, coefficient-of-variation (COV) and contrast-to-noise ratio (CNR). The three images were compared with respect to the CNR. We modeled the x-ray computed tomography system based on the CdTe energy-resolved photon counting detector and polymethylmethacrylate phantom, which have iodine, gadolinium and blood. To acquire K-edge images, the lower energy thresholds were fixed at K-edge absorption energy of iodine and gadolinium and the energy window widths were increased from 1 to 25 bins. The energy weighting factors optimized for iodine, gadolinium and blood were calculated from 5, 10, 15, 19 and 33 energy bins. We assigned the calculated energy weighting factors to the images acquired at each energy bin. In K-edge images, the contrast and COV decreased, when the energy window width was increased. The CNR increased as a function of the energy window width and decreased above the specific energy window width. When the number of energy bins was increased from 5 to 15, the contrast increased in the projection-based energy weighting images. There is a little difference in the contrast, when the number of energy bin is increased from 15 to 33. The COV of the background in the projection-based energy weighting images is only slightly changed as a function of the number of energy bins. In the image-based energy weighting images, when the number of energy bins were increased, the contrast and COV increased and decreased, respectively. The CNR increased as a function of the number of energy bins. It was concluded that the image quality is dependent on the energy window, and an appropriate choice of the energy window is important to improve the image quality.