Ultrasound during Advanced Life Support-Help or Harm?

Ultrasound is used in cardiopulmonary resuscitation (CPR) and advanced life support (ALS). However, there is divergence between the recommendations of many emergency and critical care societies who support its use and the recommendations of many international resuscitation organizations who either recommend against its use or recommend it only in limited circumstances. Ultrasound offers potential benefits of detecting reversable causes of cardiac arrest, allowing specific interventions. However, it also risks interfering with ALS protocols and increasing unhelpful interventions. As with many interventions in ALS, the evidence base for ultrasound use is weak, and well-designed randomized trials are needed. This paper reviews the current theory and evidence for harms and benefits.

Echoscopy in scanning cardiac diseases in critical care medicine.

BACKGROUND AND AIMS: Targeted ultrasound examinations with a portable ultrasound device ("handheld ultrasound system"; HHUS) have been defined as "echoscopy" by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). Cardiac scanning with HHUS is feasible. Echoscopy could play a major role in emergency and intensive care medicine, but adequate data on its effectiveness are still lacking. Sonographic examinations in the field of emergency and intensive care medicine can often not be carried out under standardized examination conditions. Thus, the aim of this study is to show that the use of HHUS for echocardiography in emergency medicine is possible and that for this setting HHUS is not inferior to a high-end ultrasound system (HEUS) for detecting cardiac pathologies. METHODS: The examinations were carried out with a Vscan™ (GE Medical Systems, Solingen, Germany) and a high-end ultrasound device (Acuson X­300 or X­700). The examinations were randomized and blinded to two examiners within 30 min. The examinations took place in the intensive care unit, the emergency room and the ambulance service. The results were recorded in an examination sheet. RESULTS: In all, 93 patients (61 men and 32 women, age 69 ± 14.76 [33-95] years). In 32.6% (30/93) of examinations with HEUS the examination conditions were optimal and in 29.03% (27/93) when the HHUS was used. Of the examinations, 50.08% (31/61) were carried out by both examiners in the same patient position. Using HHUS, the following sensitivity and specificities (respectively) were found: pericardial effusion (73.68%; 96.97%), hemodynamically relevant effusion (50%; 97.67%), right heart strain (90,91%; 96,72%), arrest of the right ventricle (100%; 87,5%), limitation of left ventricular pump function (91.49%; 86.11%), wall movement disorders (WMD, 97.29%; 78.95%), aortic valve sclerosis (42.86%; 86.67%), aortic regurgitation (60%; 95%), mitral valve sclerosis (60%; 100%), mitral reguritation (66.67%; 82.86%), tricuspid valve regurgitation (48%; 81,48%). Measurements of the dimensions of pericardial effusion, the left ventricle, the left atrium and the left ventricular posterior wall each had a positive correlation between the examination with HHUS and HEUS (Κ = 0.45 to 0.91). The diameters determined by HHUS and HEUS for the septum and aortic root, however, correlated negatively (κ = -0.61 to -0.86). CONCLUSIONS: The use of echoscopy in emergency and intensive care medicine is not inferior to HEUS for detecting defined cardiac pathologies.

Echoscopy in scanning abdominal diseases in a critical care setting.

BACKGROUND AND AIMS: Targeted ultrasound examinations with portable ultrasound device (handheld ultrasound system [HHUS]) have been defined as "echoscopy" by the European Federation of Societies of Ultrasound in Medicine and Biology (EFSUMB). For abdominal diseases it has been shown that echoscopy is sensitive and specific. The aim of this study is to show that the use of HHUS for abdominal ultrasonography is possible under the conditions prevailing in emergency and intensive care medicine and that it is not inferior to high-end devices (high-end ultrasound systems [HEUS]). METHODS: Examinations were carried out with a first-generation Vscan™ (GE Medical Systems, Solingen, Germany) and HEUS device (Siemens Acuson X­300 or X­700, Siemens Healthcare, Erlangen, Germany). The HEUS device was seen as standard. The examinations were randomized and blinded and carried out by two examiners within 30 min in order to avoid falsifications due to time delay. They took place in the intensive care unit, the emergency room and the emergency medical service. The results had to be recorded in an examination sheet. RESULTS: In all, 86 patients (54 men and 32 women, aged 73 ± 14.58 [28-95] years) were included. In 45.35% (39/86) of the ultrasound examinations using HEUS and in 41.86% (36/89) of the cases using HHUS the examination conditions were optimal. Furthermore, 76.19% of the examinations were carried out by both examiners in the same scanning position. For the detection of liver tumours, HHUS shows a sensitivity of 70% and specificity of 100%. With regard to identifying signs of cholecystitis, i.e., evidence of surrounding inflammation (a) or hydrops (b), HHUS shows a sensitivity of 66.67% (a) and 60% (b) and a specificity of 97.06% (a) and 96.86% (b). The diagnosis of an ileus is successful with a sensitivity of 87.5% and a specificity of 60%. The respiratory variability of the inferior vena cava has a sensitivity of 100% and a specificity of 40% using HHUS. Ascites and pleural effusions can be diagnosed with a sensitivity of 89% and a specificity of 93.1%. When using the FAST (Focused Assessment with Sonography for Trauma) protocol, HHUS has a sensitivity of 80% and a specificity of 90.9%. With the exception of kidney cysts and inferior vena cava, the measurement of the diameter has a positive correlation. CONCLUSION: Echoscopy of the abdomen in emergency and intensive care medicine is possible despite restrictive circumstances. The inferior vena cava can only be assessed to a limited extent with the first generation of Vscan™. In order to use sonography in emergency and intensive care medicine, a standardized procedure is to be aimed for and training in emergency sonography is necessary.

EchoScopy in scanning abdominal diseases; a prospective single center study.

BACKGROUND AND AIMS: The introduction of a new type of small handheld ultrasound device brings greater portability and affordability in a different setting. The basic ultrasound approach with these handheld devices has been defined by European Federation of Societies of Ultrasound in Medicine and Biology (EFSUMB) as "EchoScopy". The current study aimed to assess the image quality, indications and limitations of a portable pocket "EchoScopy" performed first compared with a high-end ultrasound system (second) in abdominal diseases. MATERIAL AND METHODS: Three hundred consecutive patients (158 males and 142 females, age 55±19 [18-96]) years) were included. The ultrasound examinations were performed firstly by an EchoScope (Vscan™ Dual Probe) and secondly with a high-end ultrasound system (HEUS, GE Logiq E9). Compared with the always excellent image quality using HEUS, the image quality of the EchoScope was graded as good, sufficient or non-sufficient. RESULTS: Out of all 300 patients, 221 had focal lesions, 31 patients were found with diffuse pathological findings, 20 with ascites, 25 after liver puncture and 45 without any pathological findings. The image quality of the pocket device was considered as being good or sufficient to delineate the pathology in 265/300 (88%). The detection rate of the EchoScope for abdominal focal lesion was 172/221 (78%). The higher frequency of the Dual Probe was helpful in 35/300 (12%). CONCLUSIONS: EchoScopy has proven to display sufficient image quality to answer specific questions, e.g., detection of ascites, splenomegaly, bile duct enlargement, hydronephrosis and other pathological findings which can be judged by "yes/no".

Ambient atomic resolution atomic force microscopy with qPlus sensors: Part 1.

Atomic force microscopy (AFM) is an enormous tool to observe nature in highest resolution and understand fundamental processes like friction and tribology on the nanoscale. Atomic resolution in highest quality was possible only in well-controlled environments like ultrahigh vacuum (UHV) or controlled buffer environments (liquid conditions) and more specified for long-term high-resolution analysis at low temperatures (∼4 K) in UHV where drift is nearly completely absent. Atomic resolution in these environments is possible and is widely used. However, in uncontrolled environments like air, with all its pollutants and aerosols, unspecified thin liquid films as thin as a single molecular water-layer of 200 pm or thicker condensation films with thicknesses up to hundred nanometer, have been a problem for highest resolution since the invention of the AFM. The goal of true atomic resolution on hydrophilic as well as hydrophobic samples was reached recently. In this manuscript we want to review the concept of ambient AFM with atomic resolution. The reader will be introduced to the phenomenology in ambient conditions and the problems will be explained and analyzed while a method for scan parameter optimization will be explained. Recently developed concepts and techniques how to reach atomic resolution in air and ultra-thin liquid films will be shown and explained in detail, using several examples. Microsc. Res. Tech. 80:50-65, 2017. © 2016 Wiley Periodicals, Inc.

Influence of PEGylation on nanoparticle mobility in different models of the extracellular matrix.

Nanoparticle transport inside the extracellular matrix (ECM) is a crucial factor affecting the therapeutic success. In this work, two in vitro ECM models - a neutrally charged collagen I network with an effective pore size of 0.47µm and Matrigel, a basement membrane matrix with strong negative charge and effective pore size of 0.14µm - were assessed for barrier function in the context of diffusing nanoparticles. Nanoparticles with a size of 120nm were coated with poly(ethylene glycol) (PEG) of different molecular weights - 2, 5 and 20kDa - over a range of gradually increasing coating densities - precisely 0.2, 2, 8 and 20PEG/nm2. The PEG corona was imaged in its native state without any drying process by atomic force microscopy, revealing that the experimentally determined arrangement of PEG at the surface did not match with what was theoretically expected. In a systematic investigation of nanoparticle mobility via fluorescence recovery after photobleaching, increasing both PEG MW and PEGylation density gradually improved diffusion properties predominately in collagen. Due to its smaller pore size and electrostatic obstruction, diffusion coefficients were about ten times lower in Matrigel than in the collagen network and an extension of the PEG MW and density did not necessarily lead to better diffusing particles. Consequently, collagen gels were revealed to be a poor model for nanoparticle mobility assessment, as neither their pore size nor their electrostatic properties reflect the expected in vivo conditions. In Matrigel, diffusion proceeded according to a sigmoidal increase with gradually increasing PEG densities showing threshold zeta potentials of 11.6mV (PEG2kDa) and 13.8mV (PEG5kDa), below which particles were regarded as mobile. Irrespective of the molecular weight particles with a PEGylation density lower than 2PEG/nm2 were defined as immobile and those with a PEG coverage of more than 8PEG/nm2 as mobile.

Lung B-line artefacts and their use.

BACKGROUND: The analysis of lung artefacts has gained increasing importance as markers of lung pathology. B-line artefact (BLA), caused by a reverberation phenomenon, is the most important lung artefact. In this review, we discuss the current role of BLA in pneumology and explore open questions of the published consensus. METHODS: We summarized current literature about BLA. Also, we presented observations on healthy subjects and patients with interstitial syndrome (pulmonary fibrosis and edema), to investigate technical factors influencing BLA visualization. RESULTS: BLA imaging is influenced by more factors than recently assumed. When multiple BLA is visualized in the lung, they represent a sign of increased density due to the loss of aeration in the lung periphery. This condition may indicate different diseases including cardiogenic pulmonary edema, diffuse or focal interstitial lung diseases (ILD), infections and acute respiratory distress syndrome (ARDS). Correct interpretation of BLA in lung ultrasound is strongly influenced by associated sonographic signs and careful integration of all relevant clinical information. CONCLUSIONS: BLA is useful to monitor clinical response, and may become crucial in directing the diagnostic process. Further research is warranted to clarify technical adjustments, different probe and machine factors that influence the visualization of BLA.

[Rapid diagnostic in the emergency unit: bedside sonography]. / Bettseitige Bildgebung.

Using bedside ultrasound in the emergency room includes point of care sonography (echoscopy) and several protocols (RUSH, FATE, etc.). The aim of these protocols is to evaluate the life threatening emergency care situation without interrupting the clinical work flow. This article also compares the definition of emergency care echocardiography and focused ultrasound of the heart. In addition this article gives an overview about compression sonography of veins. Examples are presented on how to use bedside ultrasound in clinical settings.

Oligolayer-coated nanoparticles: impact of surface topography at the nanobio interface.

Layer-by-layer coating of nanoparticles with a layer number in the single-digit range has gained increasing attention in the field of nanomedicinal research. However, the impact of using various polyelectrolytes on oligolayer formation and, more importantly, their influence on the interaction with the biological system has not often been considered in the past. Hence, we investigated the polyelectrolyte deposition profiles and resulting surface topographies of up to three polyelectrolyte layers on a flat gold sensor surface using three different polycations, namely, poly(ethylene imine) (PEI), poly(allylamine hydrochloride) (PAH), and poly(diallylammonium chloride) (PD), each in combination with poly(styrenesulfonate) (PSS). Surface plasmon resonance spectroscopy and atomic force microscopy revealed that the PEI/PSS pair in particular showed a so-called overshoot phenomenon, which is associated with partial polyelectrolyte desorption from the surface. This is also reflected by a significant increase in the surface roughness. Then, after having transferred the oligolayer assembly onto nanoparticles of ∼32 nm, we realized that quite similar surface topographies must have emerged on a curved gold surface. A major finding was that the extent of surface roughness contributes significantly to the fashion by which the oligolayer-coated nanoparticles interact with serum proteins and associate with cells. For example, for the PEI/PSS system, both the surface roughness and protein adsorption increased by a factor of ∼12 from the second to third coating layer and, at the same time, the cell association massively decreased to only one-third. Our study shows that surface roughness, along with other particle properties such as size, shape, zeta potential, and hydrophobicity, is another decisive factor for nanoparticles in a biological context, which has indeed been discussed previously but has not to date been investigated for oligolayers.

Atomic Resolution of Calcium and Oxygen Sublattices of Calcite in Ambient Conditions by Atomic Force Microscopy Using qPlus Sensors with Sapphire Tips.

Characterization and imaging at the atomic scale with atomic force microscopy in biocompatible environments is an ongoing challenge. We demonstrate atomically resolved imaging of the calcite (101̅4) surface plane using stiff quartz cantilevers ("qPlus sensors", stiffness k = 1280 N/m) equipped with sapphire tips in ambient conditions without any surface preparation. With 10 atoms in one surface unit cell, calcite has a highly complex surface structure comprising three different chemical elements (Ca, C, and O). We obtain true atomic resolution of calcite in air at relative humidity ranging from 20% to 40%, imaging atomic steps and single atomic defects. We observe a great durability of sapphire tips with their Mohs hardness of 9, only one step below diamond. Depending on the state of the sapphire tip, we resolve either the calcium or the oxygen sublattice. We determine the tip termination by comparing the experimental images with simulations and discuss the possibility of chemical tip identification in air. The main challenges for imaging arise from the presence of water layers, which form on almost all surfaces and have the potential to dissolve the crystal surface. Frequency shift versus distance spectra show the presence of at least three ordered hydration layers. The measured height of the first hydration layer corresponds well to X-ray diffraction data and molecular dynamic simulations, namely, ∼220 pm. For the following hydration layers we measure ∼380 pm for the second and third layer, ending up in a total hydration layer thickness of at least 1 nm. Understanding the influence of water layers and their structure is important for surface segregation, surface reactions including reconstructions, healing of defects, and corrosion.

Influence of matrix and filler fraction on biofilm formation on the surface of experimental resin-based composites.

The aim of this study was to investigate the impact of resin matrix chemistry and filler fraction on biofilm formation on the surface of experimental resin-based composites (RBCs). Specimens were prepared from eight experimental RBC formulations differing in resin matrix blend (BisGMA/TEGDMA in a 7:3 wt% ratio or UDMA/aliphatic dimethacrylate in a 1:1 wt% ratio) and filler fraction (no fillers; 65 wt% dental glass with an average diameter of 7 or 0.7 µm or 65 wt% SiO2 with an average diameter of 20 nm). Surface roughness, surface free energy, and chemical surface composition were determined; surface topography was visualized using atomic force microscopy. Biofilm formation was simulated under continuous flow conditions for a 48 h period using a monospecies Streptococcus mutans and a multispecies biofilm model. In the monospecies biofilm model, the impact of the filler fraction overruled the influence of the resin matrix, indicating lowest biofilm formation on RBCs with nano-scaled filler particles and those manufactured from the neat resin blends. The multispecies model suggested a more pronounced effect of the resin matrix blend, as significantly higher biofilm formation was identified on RBCs with a UDMA/dimethacrylate matrix blend than on those including a BisGMA/TEGDMA matrix blend but analogous filler fractions. Although significant differences in surface properties between the various materials were identified, correlations between the surface properties and biofilm formation were poor, which highlights the relevance of surface topography and chemistry. These results may help to tailor novel RBC formulations which feature reduced biofilm formation on their surface.

Atomically resolved graphitic surfaces in air by atomic force microscopy.

Imaging at the atomic scale using atomic force microscopy in biocompatible environments is an ongoing challenge. We demonstrate atomic resolution of graphite and hydrogen-intercalated graphene on SiC in air. The main challenges arise from the overall surface cleanliness and the water layers which form on almost all surfaces. To further investigate the influence of the water layers, we compare data taken with a hydrophilic bulk-silicon tip to a hydrophobic bulk-sapphire tip. While atomic resolution can be achieved with both tip materials at moderate interaction forces, there are strong differences in force versus distance spectra which relate to the water layers on the tips and samples. Imaging at very low tip-sample interaction forces results in the observation of large terraces of a naturally occurring stripe structure on the hydrogen-intercalated graphene. This structure has been previously reported on graphitic surfaces that are not covered with disordered adsorbates in ambient conditions (i.e., on graphite and bilayer graphene on SiC, but not on monolayer graphene on SiC). Both these observations indicate that hydrogen-intercalated graphene is close to an ideal graphene sample in ambient environments.

Streptococcus mutans biofilm formation and release of fluoride from experimental resin-based composites depending on surface treatment and S-PRG filler particle fraction.

PURPOSE: To evaluate fluoride release and biofilm formation on resin-based composites (RBCs) including surface pre-reacted glass ionomer (S-PRG) filler particles. MATERIALS AND METHODS: Specimens were prepared from experimental RBCs including different fractions of S-PRG fillers (0/10/30/50/70% w/v). RBCs were light cured against mylar strips (MYL), and 50% of the specimens were additionally polished to a high gloss (POL). Surface roughness (SR), surface free energy (SFE) and fluoride release were determined. Streptococcus mutans biofilm formation (SMBF) was simulated for 48 h and 120 h; adherent viable biomass was assessed using an MTT-based assay. RESULTS: The highest SR was identified for POL specimens manufactured from the RBC with a filler fraction of 70%. For all specimens and surface treatments, polishing caused an increase in surface free energy. For both MYL and POL specimens, increasing the filler fraction coincided with an increased release of fluoride; a higher release of fluoride was identified for POL specimens with filler fractions of 50% and 70% in comparison to their MYL counterparts. Release of fluoride was lower after 120 h than after 48 h. No differences in SMBF were identified between MYL and POL specimens with identical filler fractions after 48 h of biofilm formation; with increasing filler fractions, a tendency towards decreasing SMBF was observed. After 120 h, less SMBF was identified for POL specimens with filler fractions of 30%, 50% and 70% in comparison to corresponding MYL specimens. CONCLUSION: The inclusion of S-PRG fillers and an effective surface treatment may reduce biofilm formation on RBCs.

Observation of 4 nm pitch stripe domains formed by exposing graphene to ambient air.

We study epitaxial graphene on the 6H-SiC(0001) surface under ambient conditions using frequency-modulation atomic force microscopy. We observe large terraces with a self-assembled stripe structure within a highly adsorbate covered surface on top of the graphene. To identify the origin of the structure, we compare the experimental data on graphene with calculations and experiments on graphite that predict the formation of a solid-gas monolayer in the solid-liquid interface of hydrophobic surfaces.

qPlus magnetic force microscopy in frequency-modulation mode with millihertz resolution.

Magnetic force microscopy (MFM) allows one to image the domain structure of ferromagnetic samples by probing the dipole forces between a magnetic probe tip and a magnetic sample. The magnetic domain structure of the sample depends on the alignment of the individual atomic magnetic moments. It is desirable to be able to image both individual atoms and domain structures with a single probe. However, the force gradients of the interactions responsible for atomic contrast and those causing domain contrast are orders of magnitude apart, ranging from up to 100 Nm(-1) for atomic interactions down to 0.0001 Nm(-1) for magnetic dipole interactions. Here, we show that this gap can be bridged with a qPlus sensor, with a stiffness of 1800 Nm(-1) (optimized for atomic interaction), which is sensitive enough to measure millihertz frequency contrast caused by magnetic dipole-dipole interactions. Thus we have succeeded in establishing a sensing technique that performs scanning tunneling microscopy, atomic force microscopy and MFM with a single probe.

CD133+CD34+ stem cells are mobilized after musculoskeletal surgery and target endothelium activated by surgical wound fluid.

PURPOSE: CD133+CD34+ hematopoietic stem cells (HSCs) have been shown to differentiate into cell types of nonhematopoietic lineage. It is unclear whether HSCs target and repair damaged musculoskeletal tissue. We aimed to analyze if HSCs are mobilized after musculoskeletal surgery to circulation, home to surgical wound fluid (SWF)-activated endothelium, and are chemoattracted by SWF under in vitro conditions. METHODS: Circulating HSC levels were measured at t = 3, 8, 24, 48 h postoperatively using fluorescence-activated cell sorting (FACS) and compared with preoperative levels (t = 0) and normal volunteers. For adhesion experiments, HSCs were incubated on SWF-activated human umbilical vein endothelial cells (HUVECs) and HSC/HUVEC ratios determined by FACS. Adhesion receptor expression on HSC (L-selectin, lymphocyte function-associated antigen 1 (LFA-1), very late antigen-4) and SWF-activated HUVECs (P-selectin, E-selectin, V-cell adhesion molecules (CAM), I-CAM) was determined and HSC adhesion measured again after blocking upregulated receptors. Using a modified Boyden chamber, HSC chemotaxis was analyzed for an SWF and cytokine-neutralized SWF (vascular endothelial growth factor (VEGF), stromal-derived factor-1, interleukin-8) gradient. RESULTS: Circulating HSCs were significantly increased 8 h after surgery. Increasing HSC adhesion to HUVECs was shown for SWF isolated at any postoperative time point, and chemoattraction was significantly induced in an SWF gradient with SWF isolated 8 and 24 h postoperatively. Receptor and cytokine blockade experiments with monoclonal antibodies revealed decreased HSC adhesion to SWF-activated endothelium and showed lower chemotaxis after blocking the LFA-1-I-CAM-1 receptor axis (adhesion) and neutralizing VEGF-165 (chemotaxis). CONCLUSIONS: Our data demonstrate that HSCs are mobilized after trauma, target to wound-associated endothelium via the LFA-1-I-CAM-1 axis, and are chemoattracted by VEGF-165 under in vitro conditions.

Surgical Wound Fluid From Elderly Patients Shows a Dramatically Reduced Potential to Stimulate In-vitro Recruitment and Differentiation of Endothelial Progenitor Cells: Role of VEGF-165 and TGF-ß1.

UNLABELLED: Purpose. Elderly patients are susceptible to wound healing problems due to impaired neovascularisation in tissue repair. We investigated influence of surgical wound fluid (WF) obtained from both young and aged patients after musculoskeletal surgery on in-vitro recruitment and differentiation of endothelial progenitor cells (EPCs). Further, VEGF and TGF-b1 in WF were measured and blockade experiments were performed to analyze the role of both cytokines in EPC recruitment. METHODS: WF was obtained from young (28 ± 5 years, n = 14) and elderly (74 ± 8 years, n = 15) patients at 3, 8, and 24 hours after surgery. EPCs were isolated from healthy donors and incubated (72 hours) in medium substituted by WF. EPC number/differentiation was determined by fluorescence-microscopy and flow-cytometry after staining for DiLDL and lectin. CBF or ELISA was used to measure VEGF and TGF-b1 in WF. For blockade experiments, WF was mixed with antibodies against VEGF/TGF-b1 before incubation. RESULTS: A significantly higher number and increased differentiation of EPC can be observed after incubation with WF from young compared to elderly individuals. VEGF and TGF-b1 were higher in young patients' WF, and blockade of both cytokines reduced EPC numbers significantly. CONCLUSION: Impaired wound healing in the elderly could be a result of dampened recruitment of EPC to site of affliction, possibly due to low VEGF/TGF-b1 levels.  .