Association between mechanical power and intensive care unit mortality in Korean patients under pressure-controlled ventilation.

BACKGROUND: Mechanical power (MP) has been reported to be associated with clinical outcomes. Because the original MP equation is derived from paralyzed patients under volume-controlled ventilation, its application in practice could be limited in patients receiving pressure-controlled ventilation (PCV). Recently, a simplified equation for patients under PCV was developed. We investigated the association between MP and intensive care unit (ICU) mortality. METHODS: We conducted a retrospective analysis of Korean data from the Fourth International Study of Mechanical Ventilation. We extracted data of patients under PCV on day 1 and calculated MP using the following simplified equation: MPPCV = 0.098 ∙ respiratory rate ∙ tidal volume ∙ (ΔPinsp + positive end-expiratory pressure), where ΔPinsp is the change in airway pressure during inspiration. Patients were divided into survivors and non-survivors and then compared. Multivariable logistic regression was performed to determine association between MPPCV and ICU mortality. The interaction of MPPCV and use of neuromuscular blocking agent (NMBA) was also analyzed. RESULTS: A total of 125 patients was eligible for final analysis, of whom 38 died in the ICU. MPPCV was higher in non-survivors (17.6 vs. 26.3 J/min, P<0.001). In logistic regression analysis, only MPPCV was significantly associated with ICU mortality (odds ratio, 1.090; 95% confidence interval, 1.029-1.155; P=0.003). There was no significant effect of the interaction between MPPCV and use of NMBA on ICU mortality (P=0.579). CONCLUSIONS: MPPCV is associated with ICU mortality in patients mechanically ventilated with PCV mode, regardless of NMBA use.

Full-Color Generation via Phototunable Mono Ink for Fast and Elaborate Printings.

Unlike pigment-based colors, which are determined by their molecular structure, diverse colors can be expressed by a regular arrangement of nanomaterials. However, existing techniques for constructing such nanostructures have struggled to combine high precision and speed, resulting in a narrow gamut, and prolonged color fabrication time. Here, this work reports a phototunable mono ink that can generate a wide range of colors by controlling regularly arranged nanostructure. Core-shell growth controlled by polymerization time precisely regulates the distance between arranged particles at a nanometer-scale, enabling the generation of various colors. Moreover, the wide and thin arrangement induces constrained out-of-plane growth, thus facilitating the intricate color generation at the desired location via photopolymerization. Upon terminating polymerization by oxygen gas, the generated colors are readily fixed and kept stable. Utilizing programmed ultraviolet illumination, large-scale and high-resolution (≈1 µm) full-color printings are demonstrated at high speed (100 mm2 s-1 ).

Triboresistive Touch Sensing: Grid-Free Touch-Point Recognition Based on Monolayered Ionic Power Generators.

Recent growing pursuit of skin-mountable devices has been impeded by the complicated structures of most sensing systems, containing electrode grids, stacked multilayers, and even external power sources. Here, a type of touch sensing, termed "triboresistive touch sensing", is introduced for gridless touch recognition based on monolayered ionic power generators. A homogeneous monolayer, i.e., ionic poly(dimethylsiloxane) (PDMS), generates electricity based on the electric field generated by touch. Voltages generated at each corner of the ionic PDMS rely on resistance between touch points and each corner, ensuring recognition of the touch positions without the need for electrode grid layers and external power sources. With notable advantages of high transparency (96.5%), stretchability (539.1%), and resilience (99.0%) of the ionic PDMS, epidermal triboresistive sensing is demonstrated to express touch position and readily play a musical instrument. A gridless system of triboresistive sensing allows rearrangement of the touch sections according to a given situation without any physical modification, and thus easily completes consecutive missions of controlling position, orientation, and gripping functions of a robot.

Change in management and outcome of mechanical ventilation in Korea: a prospective observational study.

BACKGROUND/AIMS: There are few studies describing contemporary status of mechanical ventilation in Korea. We investigated changes in management and outcome of mechanical ventilation in Korea. METHODS: International, prospective observational cohort studies have been conducted every 6 years since 1998. Korean intensive care units (ICUs) participated in 2010 and 2016 cohorts. We compared 2016 and 2010 Korean data. RESULTS: Two hundred and twenty-six patients from 18 ICUs and 275 patients from 12 ICUs enrolled in 2016 and 2010, respectively. In 2016 compared to 2010, use of non-invasive ventilation outside ICU increased (10.2% vs. 2.5%, p = 0.001). Pressure-control ventilation was the most common mode in both groups. Initial tidal volume (7.1 mL/kg vs. 7.4 mL/kg, p = 0.372) and positive end-expiratory pressure (6 cmH2O vs. 6 cmH2O, p = 0.141) were similar, but peak pressure (22 cmH2O vs. 24 cmH2O, p = 0.011) was lower in 2016. More patients received sedatives (70.7% vs. 57.0%, p = 0.002) and analgesics (86.5% vs. 51.1%, p < 0.001) in 2016. The awakening (48.4% vs. 31.0%, p = 0.002) was more frequently attempted in 2016. The accidental extubation rate decreased to one tenth of what it was in 2010 (1.1% vs. 10.2%, p < 0.001). The ICU mortality did not change (31.4% 35.6%, p = 0.343) but ICU length of stay showed a decreasing trend (9 days vs. 10 days, p = 0.054) in 2016. CONCLUSION: There were temporal changes in care of patients on mechanical ventilation including better control of pain and agitation, and active attempt of awakening.

Soft artificial electroreceptors for noncontact spatial perception.

Elasmobranch fishes, such as sharks, skates, and rays, use a network of electroreceptors distributed on their skin to locate adjacent prey. The receptors can detect the electric field generated by the biomechanical activity of the prey. By comparing the intensity of the electric fields sensed by each receptor in the network, the animals can perceive the relative positions of the prey without making physical contact. Inspired by this capacity for prey localization, we developed a soft artificial electroreceptor that can detect the relative positions of nearby objects in a noncontact manner by sensing the electric fields that originate from the objects. By wearing the artificial receptor, one can immediately receive spatial information of a nearby object via auditory signals. The soft artificial electroreceptor is expected to expand the ways we can perceive space by providing a sensory modality that did not evolve naturally in human beings.

Ionic spiderwebs.

Spiders use adhesive, stretchable, and translucent webs to capture their prey. However, sustaining the capturing capability of these webs can be challenging because the webs inevitably invite contamination, thus reducing its adhesion force. To overcome these challenges, spiders have developed strategies of using webs to sense prey and clean contaminants. Here, we emulate the capturing strategies of a spider with a single pair of ionic threads based on electrostatics. Our ionic spiderwebs completed consecutive missions of cleaning contamination on itself, sensing approaching targets, capturing those targets, and releasing them. The ionic spiderwebs demonstrate the importance of learning from nature and push the boundaries of soft robotics in an attempt to combine mutually complementary functions into a single unit with a simple structure.

The increased amount of coffee consumption lowers the incidence of fatty liver disease in Korean men.

BACKGROUND AND AIMS: Coffee is known to have a beneficial effect on various liver diseases. The aim of this retrospective longitudinal study was to investigate an association between the amount of coffee consumption and the incidence of fatty liver disease in Korean adults. METHODS AND RESULTS: Data from a total of 91,436 male and female subjects with the mean follow-up period of 2.8 years were analyzed. The incidence of fatty liver was not associated with the amount of coffee consumption at baseline, but it was associated with the change in the amount of coffee consumption at the follow-up period. Multiple linear regression analyses showed that hazard ratios for incidence of fatty liver disease were significantly low in "increase" group comparing with "no change" group in fully adjusted model. When a subgroup analysis by gender was conducted, similar significant results were observed in male subjects, but not in females. CONCLUSIONS: The increment in the amount of coffee consumption is associated with the lower incidence of fatty liver in Korean men and suggests that increasing the coffee consumption may have a protective effect on fatty liver.

Natural course of fatty liver in 36,195 South Korean adults.

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver disease, and yet the natural course remains unclear. Study population included 36,195 individuals who participated in a health-screening program and diagnosed with fatty liver by abdominal ultrasound. Participants were provided written information regarding fatty liver and advised to make lifestyle changes. Ultrasound was repeated after at least 6 months. After a mean follow up of 4.9 years (±3.4), 19.6% resolved their fatty liver. Individuals who resolved were more likely female (22.9% vs. 12.3%), thinner (body mass index [BMI], 25.2 ± 2.7 vs. 26 ± 2.7), and with lower HOMA-IR (1.4 vs. 1.7) (P .70.001). Decrease in BMI predicted resolution of fatty liver with 42% of those in the top quartile of BMI decline resolving compared with 5.7% in the lowest quartile (odds ratio [OR] (95% confidence interval [CI]) 15.65 (14.13-17.34), P < 0.001)). Baseline HOMA-IR also predicted resolution with those in the top quartile (most insulin resistant) being least likely to resolve (12%) vs. those in the lowest quartile (25%) (OR 0.36 [0.31-0.42], P < 0.001). Fatty liver disease is persistent. Individuals with higher degree of insulin resistance are also the most likely to have persistent steatosis at follow up.

Decreased lung function is associated with risk of developing non-alcoholic fatty liver disease: A longitudinal cohort study.

BACKGROUND: Decreased lung function is associated with non-alcoholic fatty liver disease (NAFLD), based on linking mechanisms such as insulin resistance and systemic inflammation However, its association with the risk of developing NAFLD is unclear. Our aim was to investigate whether baseline lung function is associated with incident NAFLD in middle-aged healthy Koreans. METHODS: A cohort study of 96,104 subjects (mean age: 35.7 years) without NAFLD were followed up from 2002 to 2015. NAFLD was diagnosed by ultrasound after the exclusion of other possible causes of liver diseases. Baseline percent predicted forced expiratory volume in one second (FEV1%) and forced vital capacity (FVC%) were categorized in quartiles. Adjusted hazard ratios (aHR) and 95% confidence intervals (CIs) (using the highest quartile as reference) were calculated for incident NAFLD at follow-up, controlling for covariates and potential confounders. RESULTS: During 579,714.5 person-years of follow-up, 24,450 participants developed NAFLD (incidence rate, 42.2 per 1,000 person-years). The mean follow-up period was 5.9±3.4 years. Regardless of smoking history, the risk for incident NAFLD increased with decreasing quartiles of FEV1 (%) and FVC (%) in a dose-response manner (p for trend<0.001). In never smokers, the aHRs (95% CIs) for incident NAFLD were 1.15 (1.08-1.21), 1.11 (1.05-1.18), and 1.08 (1.02-1.14) in quartiles 1-3 for FEV1 (%) and 1.12 (1.06-1.18), 1.11 (1.05-1.18), and 1.09 (1.03-1.15) in quartiles 1-3 for FVC (%), compared with the highest quartile reference. Similar inverse association was present in smoke-exposed subjects (aHR for incident NAFLD were 1.14, 1.21, 1.13 and 1.17, 1.11, 1.09 across FEV1(%) and FVC(%) quartile in increasing order, respectively). CONCLUSIONS: Reduced lung function was a risk factor for incident NAFLD in a large middle-aged Korean cohort with over half a million person-years of follow-up.

Clinical implications of differentiating between types of post-tracheostomy tracheal stenosis.

BACKGROUND: Post-tracheostomy tracheal stenosis (PTTS) can be divided into four types according to stenosis mechanism and site: subglottic, stoma, cuff, and tip granuloma. However, there is little information available regarding clinical differences among types of PTTS; therefore, we evaluated the clinical differences between these types. METHODS: We retrospectively evaluated 99 PTTS patients who underwent interventional bronchoscopy between 2004 and 2014. Patients were divided into two groups according to pathophysiological similarities as follows: subglottic or stoma type (n=59) and cuff or tip type (n=40). RESULTS: There were no differences in baseline characteristics between groups. However, silicone stents were more frequently needed in patients with subglottic or stoma type stenosis (76%) than those with cuff or tip type stenosis (55%, P=0.031) to maintain airway patency. On the contrary, permanent tracheostomy was more frequently performed in patients with cuff or tip type stenosis (50%) than those with subglottic or stoma type stenosis (19%, P=0.002). Finally, successful removal of the tracheostomy tube without surgery and procedure- or disease-related mortality were more frequently achieved in patients with subglottic or stoma type stenosis (71%) than those with cuff or tip type stenosis (45%, P=0.012). CONCLUSIONS: Although there were no significant differences in baseline characteristics between PTTS types, patients with subglottic or stoma type stenosis had more favorable outcomes than those with cuff or tip type stenosis. Therefore, it could be important to distinguish between types of PTTS when assessing prognosis.

Clinical significance of differentiating post-intubation and post-tracheostomy tracheal stenosis.

BACKGROUND AND OBJECTIVE: Post-intubation tracheal stenosis (PITS) and post-tracheostomy tracheal stenosis (PTTS) are serious complications in mechanically ventilated patients. Although the aetiologies and mechanisms of PITS and PTTS are quite different, little is known about the clinical impact of differentiating one from the other. METHODS: We retrospectively conducted a chart review of 117 patients with PITS and 88 patients with PTTS who were treated with interventional bronchoscopy at Samsung Medical Center between January 2004 and December 2013. RESULTS: Compared to patients with PITS, patients with PTTS had a lower BMI, poorer performance status and more frequent neurological aetiologies, mid-to-lower tracheal lesions, total obstruction and mixed stenosis types. Although there were no differences in the number of patients who received silicone stents between the two groups, Montgomery T-tubes were more frequently used in the PTTS group than in the PITS group. The final success rate without surgery, mortality or tracheostomy in situ was higher in the PITS group than in the PTTS group (76.9% vs 63.6%, P = 0.043). Additionally, airway prosthesis removal was achieved in 46.2% of patients in the PITS group and in 33.0% of the PTTS group (P = 0.063). CONCLUSION: There were significant differences between PITS and PTTS in terms of patient and stenosis characteristics, treatment modalities and clinical outcomes. Therefore, PITS and PTTS should be considered two different entities.

Clinical Utility of Additional Measurement of Total Lung Capacity in Diagnosing Obstructive Lung Disease in Subjects With Restrictive Pattern of Spirometry.

BACKGROUND: Total lung capacity (TLC), forced expiratory flow between 25 and 75% (FEF25-75%), peak expiratory flow (PEF), or post-bronchodilator volume response is recommended to detect obstructive abnormalities in the lung. The present study was performed to evaluate the usefulness of these pulmonary function test (PFT) parameters to diagnose obstructive lung disease in subjects with a restrictive pattern of spirometry. METHODS: A retrospective study was conducted in 64 subjects with a restrictive pattern of spirometry (normal FEV1/FVC and low FVC) out of 3,030 patients who underwent all pre- and post-bronchodilator spirometry and lung volume measurement between April 2008 and December 2010. After subjects were clinically classified into those with obstructive lung disease, restrictive lung disease, and mixed lung disease, the agreements between the clinical diagnosis and PFT classification according to TLC, FEF(25-75%), PEF, and post-bronchodilator response criteria were compared. RESULTS: Of 64 subjects, 18 (28.1%) were classified with obstructive lung disease, 39 (60.9%) had restrictive lung disease, 1 (1.6%) had mixed lung disease, and 6 (9.4%) had no clinical lung disease. Among the 58 subjects with clinical lung disease, 22 (37.9%), 37 (63.8%), 33 (56.9%), and 3 (5.2%) were classified as having obstructive pattern based on TLC, FEF25-75%, PEF, and post-bronchodilator response criteria, respectively. The kappa coefficients for the agreement between the clinical classification and PFT classification using TLC, FEF25-75%, PEF, and post-bronchodilator response criteria in 58 subjects were 0.59, 0.18, 0.17, and < 0.01, respectively. CONCLUSIONS: The additional measurement of TLC is more useful than FEF25-75%, PEF, and post-bronchodilator response for diagnosis of obstructive lung disease in subjects with a restrictive pattern of spirometry, when obstructive lung disease is clinically suspected.

Chronic obstructive pulmonary disease severity is associated with severe pneumonia.

CONTEXT: Chronic obstructive pulmonary disease (COPD) is a heterogeneous disorder, and various aspects of COPD may be associated with the severity of pneumonia in such patients. AIMS: We examined the risk factors associated with severe pneumonia in a COPD population. MATERIALS AND METHODS: We performed a retrospective observational study using a prospectively collected database of pneumonia patients who were admitted to our hospital through emergency department between 2008 and 2012. Patients with hospital-acquired pneumonia and those with an immunocompromised status were excluded. RESULTS: Of 148 pneumonia patients with COPD for whom chest computed tomography (CT) scans were available, 106 (71.6%) and 42 (28.4%) were classified as non-severe and severe pneumonia, respectively. Multivariate logistic regression analysis revealed that the severity of airflow limitation [odds ratio (OR), 2.751; 95% confidence interval (CI), 1.074-7.050; P = 0.035] and the presence of emphysema on a chest CT scan (OR, 3.366; 95% CI, 1.104-10.265; P = 0.033) were independently associated with severe pneumonia in patients with COPD. CONCLUSIONS: The severity of COPD including the airflow limitation grade and the presence of pulmonary emphysema were independently associated with the development of severe pneumonia.

Mycobacterium abscessus Lung Disease in a Patient with Kartagener Syndrome.

Primary ciliary dyskinesia (PCD) is characterized by the congenital impairment of mucociliary clearance. When accompanied by situs inversus, chronic sinusitis and bronchiectasis, PCD is known as Kartagener syndrome. The main consequence of impaired ciliary function is a reduced mucus clearance from the lungs, and susceptibility to chronic respiratory infections due to opportunistic pathogens, including nontuberculous mycobacteria (NTM). There has been no report of NTM lung disease combined with Kartagener syndrome in Korea. Here, we report an adult patient with Kartagener syndrome complicated with Mycobacterium abscessus lung disease. A 37-year-old female presented to our hospital with chronic cough and sputum. She was ultimately diagnosed with M. abscessus lung disease and Kartagener syndrome. M. abscessus was repeatedly isolated from sputum specimens collected from the patient, despite prolonged antibiotic treatment. The patient's condition improved and negative sputum culture conversion was achieved after sequential bilateral pulmonary resection.

Pulmonary function assessment in the early phase of patients with smoke inhalation injury from fire.

OBJECTIVES: Fire smoke contains toxic gases and numerous chemical compounds produced by incomplete combustion, and may cause injury to the airways. Increased airway reactivity, as well as a decrease in lung function, has been reported as a sequela of smoke inhalation injury. This study was undertaken to assess lung functions in the early phase of patients with smoke inhalation damage from fires. METHODS: A total of 15 patients with fire smoke inhalation (fire smoke group) and 15 subjects with chronic cough but no previous history of lung disease (chronic cough group) were enrolled. For diagnosis of inhalation injury, we performed bronchoscopy, high-resolution computed tomography (HRCT), as well as arterial carboxyhemoglobin (COHb) at admission. Clinical characteristics, pulmonary function tests (PFTs) and mannitol bronchial provocation tests (BPTs) were analyzed and compared between the two groups. RESULTS: In fire smoke group, initial COHb levels and the PaO2/FiO2 ratio were (14.8±18.49)% and 425.7±123.68, respectively. Of seven patients performing HRCT, 4 (57.1%) showed the CT findings compatible with lung involvement of inhalation injury. Post bronchodilator value of the percent of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were (76.0±24.27)% and (79.8±27.82)%, respectively. Pre-and post- bronchodilator forced expiratory flow between 25% and 75% of the FVC (FEF25-75) and the percent predicted FEF25-75 were 2.41±1.47 vs. 2.65±1.45 L (P=0.045), and (68.7±37.29)% vs. (76.4±36.70)% (P=0.031), respectively. Two patients (13.3%) had positive bronchodilator response (BDR). In fire smoke and chronic cough group, all the subjects showed mannitol BPTs within normal limits. CONCLUSIONS: Fire smoke inhalation leads to mild obstructive small airway disease pattern of pulmonary function in the early phase of patients with fire smoke damage. Further studies, however, need to be followed to identify the relationship between airway narrowing to inhaled mannitol and smoke inhalation injury.

Fabrication of transparent Al:LiF composite/MoO3 interconnecting layers for tandem white organic light emitting devices.

We report transparent Al:LiF composite/molybdenum oxides (MoO3) as interconnecting layers for tandem white organic light emitting diodes (WOLEDs) consisting of blue and red phosphorescent unit devices. The Al:LiF (3 nm)/MoO3 (10 nm) interconnecting layers show a high transmittance, good carrier generation and injection capability for tandem WOLEDs. The performance of tandem WOLEDs is sensitive to the LiF doping concentration, which is mainly attributed to the difference in efficiency of carrier injection into the adjoining electroluminescent units. For 10~20% LiF concentration, the external quantum efficiency of tandem device is almost equal to the sum of the efficiencies of blue and red OLEDs at high current density; furthermore, a small variation of Commission Internationale de l'Eclairage (CIE) coordinates with the current density is obtained.

A case of synchronous presentation of primary non-small cell lung carcinoma and pheochromocytoma.

We report a rare synchronous presentation of primary lung cancer and adrenal pheochromocytoma. A 59-year-old woman was diagnosed with right upper lobe non-small cell lung carcinoma measuring 2.8 cm and a right adrenal gland mass measuring 3.5 cm, which displayed increased metabolic activity on (18)F-fluorodeoxyglucose positron emission tomography-computed tomography. The adrenal lesion was revealed to be asymptomatic. The patient underwent right adrenalectomy and histological examination revealed a pheochromocytoma. Ten days later, right upper lobectomy was performed for lung cancer. This case indicates that incidental adrenal lesions found in cases of resectable primary lung cancer should be investigated.

Familial Mediterranean fever: the first adult case in Korea.

Familial Mediterranean fever (FMF) is known to be a genetic disorder that prevalent among populations surrounding the Mediterranean Sea. Since Mediterranean fever gene (MEFV) was discovered at 1997, some cases have been reported in countries not related or close to this area like Japan. In addition it has been generally accepted that the clinical onset of FMF begins before 20 yr of age in most patients. Onset of the disease at an older age may occur but is rare. Adult-onset FMF may be a form of disease with distinct clinical, demographic and molecular characteristics. We describe a case of adult-onset FMF confirmed by DNA analysis of the MEFV gene in a Korean patient. A 32-yr-old man, who has no family history of FMF, presented with periodic fever, abdominal pain and vomiting. Though several various tests were thoroughly performed to evaluate the cause of his symptoms, there was no evidence of infectious, autoimmune or neoplastic diseases. Several gene analysis of periodic fever syndrome was finally performed and two point mutations (p.Leu110Pro, p.Glu148Gln) were identified. We confirmed the first adult case of FMF through detection of MEFV gene mutations in Korea and describe his clinical characteristics.

Simultaneous total occlusion of multiple distal coronary arteries in acute myocardial infarction.

Simultaneous multiple coronary artery thrombosis is a rare finding in ST segment elevation myocardial infarction (STEMI). We report a case of myocardial infarction with multiple ST segment elevation on the electrocardiography and total occlusions of the distal left anterior descending artery (dLAD), as well as of the second and third obtuse marginal artery on emergency coronary angiography. Thrombus aspiration was performed at dLAD and systemic glycoprotein IIb/IIIa inhibitor was used successfully. In patients with STEMI, multiple coronary thromboses are unusual and associated with patient fatality. However, assertive thrombus aspiration and antiplatelet therapy could be effective in STEMI patients with multiple distal coronary artery occlusions.