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Plateau pressure

M Cressoni, C Chiurazzi, D Chiumello, L Gattinoni
Acute respiratory distress syndrome (ARDS) patients need mechanical ventilation to sustain gas exchange. Animal experiments showed that mechanical ventilation with high volume/plateau pressure and no positive end-expiratory pressure (PEEP) damages healthy lungs, while low tidal volumes and the application of higher PEEP levels are protective. PEEP makes the lung homogeneous, reducing the pressure multiplication at the interface between lung units with different inflation statuses and keeps the lung open through the whole respiratory cycle, avoiding intratidal opening and closing...
November 13, 2017: Medizinische Klinik, Intensivmedizin und Notfallmedizin
Cuiying Li, Xiaowei Li, Juan Liu, Xiu Fan, Guoxing You, Lian Zhao, Hong Zhou, Jingqi Li, Huifen Lei
OBJECTIVE: High altitude is characterized by low oxygen pressure, resulting in multiple adaptive responses. Tibetans who have lived in the plateau for thousands of years have developed unique phenotypes, such as downregulation of the HIF pathway through EPAS1 and EGLN1 gene mutation. However, the changes of hemoglobin-oxygen affinity under hypoxia environment remain elusive. METHODS: A blood cell analyzer and a blood oxygen analyzer were used to conduct routine blood tests and measure the oxygen affinity P50 in in the Han population that rapidly entered the plateau (for 3-7 days), the plateau-acclimatized Han population (residing for 30 days on the plateau), the plateau Han population (more than 10 years on the plateau), and the Tibetan population...
November 12, 2017: Hematology (Amsterdam, Netherlands)
Johan A de Bruijn, Aniek P M van Zantvoort, David van Klaveren, Michiel B Winkes, Marike van der Cruijsen-Raaijmakers, Adwin R Hoogeveen, Joep A W Teijink, Marc R Scheltinga
Knowledge about lower leg chronic exertional compartment syndrome (CECS) is largely obtained from highly selected populations. Patient characteristics may therefore not be appropriate for the general population. Our purpose was to describe a heterogeneous population of individuals suspected of lower leg CECS and to identify predictors of CECS. Charts of individuals who were analyzed for exercise-induced lower leg pain in a referral center between 2001 and 2013 were retrospectively studied. Patients were included if history and physical examination were suggestive of CECS and if they had undergone a dynamic intracompartmental pressure measurement...
November 10, 2017: International Journal of Sports Medicine
Mehrdad Behnia, Courtney M Wheatley, Alberto Avolio, Bruce D Johnson
Background: Factors limiting exercise in patients with COPD are complex. With evidence for accelerated pulmonary vascular aging, destruction of alveolar-capillary bed, and hypoxic pulmonary vasoconstriction, the ability to functionally expand surface area during exercise may become a primary limitation. Purpose: To quantify measures of alveolar-capillary recruitment during exercise and the relationship to exercise capacity in a cohort of COPD patients. Methods: Thirty-two subjects gave consent (53% male, with mean ± standard deviation age 66±9 years, smoking 35±29 pack-years, and Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification of 0-4: 2...
2017: International Journal of Chronic Obstructive Pulmonary Disease
Lauren E Wessel, Alexander B Christ, David Helfet, David S Wellman
Nerve traction injuries are common clinical entities that can be confused with nerve palsies secondary to alternate etiologies. Common mechanisms of nerve injury include direct laceration, crush injury, compression injury, elevated compartment pressures, or traction injury. Traction injuries commonly occur after trauma or aberrant patient positioning; however, traction injury following external fixation for lower extremity injury is rare. This case report describes a 42-year-old man who initially sustained a Schatzker VI tibial plateau fracture that required revision of external fixation for pin-site infection as soft tissues recovered from the initial trauma...
November 8, 2017: Orthopedics
Ye-Na Lee, Jong Seok Lee, Seung-Kyu Han, Hye-Kyung Jung
PURPOSE: Our group has reported that negative-pressure wound therapy (NPWT) decreases tissue oxygenation by 84% in the foot of diabetic patients because the pad of the connecting drainage tube and foam sponge of the NPWT system compress the wound bed. The purpose of this study was to determine whether an NPWT modified dressing application reduces tissue oxygenation in the feet of persons with diabetes mellitus. DESIGN: A prospective, clinical, observational study...
November 2017: Journal of Wound, Ostomy, and Continence Nursing
Xiaobo Fan, Agatha Korytowski, Ali Makky, Motomu Tanaka, Michael Wink
Most antimicrobial peptides exert their rapid bactericidal activity through a unique mechanism of bacterial membrane disruption. However, the molecular events that underlie this mechanism remain partly unresolved. In this study, the frequency shift (ΔF) obtained through quartz-crystal microbalance with dissipation (QCM-D) indicated that the initial binding of Ib-AMP4 within the lipid membrane started at a critical Ib-AMP4 concentration that exceeded 100μg/ml. Circular dichroism measurements provided evidence that Ib-AMP4 occurs in a β-sheet configuration which is adapted for insertion into the lipid membrane...
October 26, 2017: Biochimica et Biophysica Acta
Xiang Zhou, Yasushi Yamaguchi, Sanjiwana Arjasakusuma
Distinguishing the vegetation dynamics induced by anthropogenic factors and identifying the major drivers can provide crucial information for designing actionable and practical countermeasures to restore degraded grassland ecosystems. Based on the residual trend (RESTREND) method, this study distinguished the vegetation dynamics induced by anthropogenic factors from the effects of climate variability on the Mongolian Plateau during 1993-2012 using vegetation optical depth (VOD) and normalized difference vegetation index (NDVI), which measure vegetation water content in aboveground biomass and chlorophyll abundance in canopy cover respectively; afterwards, the major drivers within different agricultural zones and socio-institutional periods were identified by integrating agricultural statistics with statistical analysis techniques...
October 31, 2017: Science of the Total Environment
Shaughnessy Brennan Brown, Akel Hashim, Arianna Gleason, Eric Galtier, Inhyuk Nam, Zhou Xing, Alan Fry, Andy MacKinnon, Bob Nagler, Eduardo Granados, Hae Ja Lee
We measure the shock drive capabilities of a 30 J, nanosecond, 527 nm laser system at the matter in extreme conditions hutch of the Linac Coherent Light Source. Using a velocity interferometer system for any reflector, we ascertain the maximum instantaneous ablation pressure and characterize its dependence on a drive laser spot size, spatial profile, and temporal profile. We also examine the effects of these parameters on shock spatial and temporal uniformity. Our analysis shows the drive laser capable of generating instantaneous ablation pressures exceeding 160 GPa while maintaining a 1D shock profile...
October 2017: Review of Scientific Instruments
Christian L Demasi, Francesco Porpiglia, Augusto Tempia, Savino D'Amelio
PURPOSE: Several ischemic optic neuropathies that occurred during robotic-assisted laparoscopic radical prostatectomy (RALRP) have been reported to be due to the Trendelenburg position, which lowers ocular perfusion pressure (OPP). We examined changes in pulsatile ocular blood flow (POBF) and its correlation with OPP during RALRP in the steep Trendelenburg position. METHODS: Pulsatile ocular blood flow and intraocular pressure (IOP) were measured in 50 patients by the OBF Langham System 5 times during RALRP...
October 25, 2017: European Journal of Ophthalmology
Laura J Spece, Kristina H Mitchell, Ellen S Caldwell, Stephanie J Gundel, Sarah E Jolley, Catherine L Hough
PURPOSE: Low tidal volume ventilation (LTVV) reduces mortality in acute respiratory distress syndrome (ARDS) patients. Understanding local barriers to LTVV use at a former ARDS Network hospital may provide new insight to improve LTVV implementation. METHODS: A cohort of 214 randomly selected adults met the Berlin definition of ARDS at Harborview Medical Center between 2008 and 2012. The primary outcome was the receipt of LTVV (tidal volume of ≤6.5mL/kg predicted body weight) within 48h of ARDS onset...
October 18, 2017: Journal of Critical Care
Abdolhamid Anazadehsayed, Nastaran Rezaee, Jamal Naser
The three-dimensional flow in exterior microscale foams including the Plateau borders and nodes are investigated by solving Navier-stoke and continuity equations. First, we show the effect of the interfacial mobility and film thickness on the dimensionless mean velocity of the exterior foams. The velocity of the exterior node-PB is similar to the velocity of single exterior Plateau border. Next, we calculated the pressure difference of each element separately and obtained their hydraulic resistances. We found out that the hydraulic resistance of the exterior Plateau border is always larger than the hydraulic resistance of the exterior node, resulting in a consistent channel-dominated regime...
October 10, 2017: Journal of Colloid and Interface Science
Changkun Ma, Yi Luo, Mingan Shao, Xiangdong Li, Lin Sun, Xiaoxu Jia
Black locust accounts for over 90% of artificial forests in China's Loess Plateau region. However, water use of black locust is an uphill challenge for this semi-arid region. To accurately quantify tree water use and to explain the related hydrological processes, it is important to collect reliable data for application in the estimation of sap flow and its response to environmental factors. This study measured sap flow in black locust in the 2015 and 2016 growth seasons using the thermal dissipation probes technique and laboratory-calibrated Granier's equation...
October 13, 2017: Scientific Reports
Stephen P Juraschek, Mark Woodward, Frank M Sacks, Vincent J Carey, Edgar R Miller, Lawrence J Appel
Both sodium reduction and the Dietary Approaches to Stop Hypertension (DASH) diet lower blood pressure (BP); however, the patterns of their effects on BP over time are unknown. In the DASH-Sodium trial, adults with pre-/stage 1 hypertension, not using antihypertensive medications, were randomly assigned to either a typical American diet (control) or DASH. Within their assigned diet, participants randomly ate each of 3 sodium levels (50, 100, and 150 mmol/d, at 2100 kcal) over 4-week periods. BP was measured weekly for 12 weeks; 412 participants enrolled (57% women; 57% black; mean age, 48 years; mean systolic BP [SBP]/diastolic BP [DBP], 135/86 mm Hg)...
November 2017: Hypertension
Pablo Cruces, Sebastián González-Dambrauskas, Julio Quilodrán, Jorge Valenzuela, Javier Martínez, Natalia Rivero, Pablo Arias, Franco Díaz
BACKGROUND: Analysis of respiratory mechanics during mechanical ventilation (MV) is able to estimate resistive, elastic and inertial components of the working pressure of the respiratory system. Our aim was to discriminate the components of the working pressure of the respiratory system in infants on MV with severe bronchiolitis admitted to two PICU's. METHODS: Infants younger than 1 year old with acute respiratory failure caused by severe bronchiolitis underwent neuromuscular blockade, tracheal intubation and volume controlled MV...
October 6, 2017: BMC Pulmonary Medicine
Ke Wei, Su Min, Jun Cao, Xuechao Hao, Jie Deng
BACKGROUND: Positive end-expiratory pressure (PEEP) is considered essential in protective ventilation, while may lead to hemodynamic impairment. In the present study, we investigated the effect of repeated alveolar recruitment maneuvers (ARMs) with or without additional PEEP on the arterial oxygenation of obese patients who were undergoing bariatric surgery. METHODS: Thirty-six obese adult patients with body mass index (BMI) >40 kg/m2 who were scheduled for laparoscopic sleeve gastrectomy were randomly allocated into three groups: (1) control group, no intraoperative ARMs; (2) ARM+ZEEP group, repeated ARMs every 30 minutes without extra PEEP; or (3) ARM+PEEP group, ARMs followed by 8 cm H2O of PEEP from the onset of pneumoperitoneum...
October 4, 2017: Minerva Anestesiologica
Francesca Lanfranconi, Luca Pollastri, Giovanni Corna, Manuela Bartesaghi, Massimiliano Novarina, Alessandra Ferri, Giuseppe Andrea Miserocchi
Lanfranconi, Francesca, Luca Pollastri, Giovanni Corna, Manuela Bartesaghi, Massimiliano Novarina, Alessandra Ferri, and Giuseppe Andrea Miserocchi. The elusive path of brain tissue oxygenation and cerebral perfusion in harness hang syncope in mountain climbers. High Alt Med Biol. 18:000-000, 2017. AIM: Harness hang syncope (HHS) is a risk that specifically affects wide ranges of situations requiring safety harnesses in mountains. An irreversible orthostatic stasis could lead to death if a prompt rescue is not performed...
October 5, 2017: High Altitude Medicine & Biology
John S Swogger, Shelly G Jain, Andrea K Sawchyn, Gloria P Fleming
A 39-year-old Caucasian man with bilateral narrow angles, a plateau-like iris configuration on gonioscopy and elevated intraocular pressure (IOP) presented with significant asymmetric glaucoma, left eye affected more than right. Initial management with topical medical therapy, laser iridoplasty and peripheral iridotomy in the left eye was ineffective in lowering the IOP or opening the anterior chamber angle. Ultrasound biomicroscopy demonstrated bilateral ciliary body cysts. The patient ultimately required surgical management, consisting of cataract extraction and endoscopic cyclophotocoagulation of ciliary body cysts in the left eye and trabeculectomy in the right eye, for persistent IOP control to prevent further optic nerve damage and subsequent visual field loss...
October 4, 2017: BMJ Case Reports
Guillermo Bugedo, Jaime Retamal, Alejandro Bruhn
Overdistention and intratidal alveolar recruitment have been advocated as the main physical mechanisms responsible for ventilator-induced lung injury. Limiting tidal volume has a demonstrated survival benefit in patients with acute respiratory distress syndrome and is recognized as the cornerstone of protective ventilation. In contrast, the use of high positive end-expiratory pressure levels in clinical trials has yielded conflicting results and remains controversial. In the present review, we will discuss the benefits and limitations of the open lung approach and will discuss some recent experimental and clinical trials on the use of high versus low/moderate positive end-expiratory pressure levels...
April 2017: Revista Brasileira de Terapia Intensiva
Zineb Guennouni, Michel Goldmann, Marie-Claude Fauré, Philippe Fontaine, Patrick Perrin, Denis Limagne, Fabrice Cousin
We describe the surface behavior of PS-b-PAA monolayers at the air/water interface using N,N-dimethyformamide (DMF) as spreading solvent. At low pH, when the PAA blocks are neutral, the surface pressure versus molecular area isotherm shows a pseudoplateau associated with the presence of remaining spreading solvent molecules in the monolayer, as we described in a former study (Guennouni et al., Langmuir, 2016). We show here that the width of the plateau decreases when increasing pH up to its complete disappearance at high pH, when PAA blocks are fully charged, although two regimes of compressibilities on the isotherm still exist...
October 23, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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