Chemical and isotopic vertical profiles from the volcanic lakes of Sete Cidades, Santiago, Fogo, Congro and Furnas (Island of Sao Miguel, Azores Archipelago, Portugal) were studied to investigate the ...biogeochemical processes acting at different depths, with a focus on the CO2 and CH4 dynamics. These lakes are fed by meteoric water affected by seawater spray and interacting with volcanic rocks at a relatively low extent. In addition to volcanogenic gas inputs, the biogeochemical processes are influenced by microbial activities since the lakes offer specialized ecological niches for oxic and anoxic metabolism. The lakes were sampled in 2 extreme conditions of (partial) mixing (winter) and stratification (summer), respectively. The seasonal thermal stratification favored the development of anaerobic hypolimnia, showing relatively high concentrations of NH4+, NO3–, P and other minor species (Fe, Mn, Zn, As) controlled by microbial activity and minerogenetic processes occurring within the lake sediments. The strongly negative δ13C-TDIC values measured in almost all the studied lakes suggest dominant contribution of organic carbon. Dissolved gases were mostly consisting of atmospheric compounds with significant concentrations of CO2 and CH4. The δ13C-CO2 values were intermediate between those measured in the hydrothermal fluids and those typical of biogenic CO2. Dissolved CH4, which was the most abundant extra-atmospheric gas in the anoxic waters, was measured at significant concentrations even in the aerobic layers, especially in the winter season. This unexpected feature may tentatively be explained by admitting i) convective mixing of shallow and deep waters, and/or ii) aerobic CH4 production. Further investigations, focusing on the recognition of microbial populations able to produce CH4 at different redox conditions, may be useful to corroborate these intriguing hypotheses.
The present study is aimed at providing a brief overview of the Italian acidic waters based on literature and unpublished data. Acidic waters in Italy, as elsewhere, are relatively common and ...associated with extremely variable geological settings. Owing to their peculiar features, these waters may seriously affect the environment and the ecosystems. Along the Apennine belt, the western and inner sectors of the Italian peninsula record an anomalous geothermal gradient, mostly overlapping with the Neogene-to-present magmatism, that explains the presence of a huge amount of CO2(H2S)-rich gas and thermal water discharges, geothermal fields (e.g. Larderello and Mt. Amiata) and ore deposits (e.g. Fe- and polymetallic sulfides, e.g. Elba Island and Colline Metallifere). Acidic waters (pH ≤5) from volcanic and geothermal areas show outlet temperatures and Total Dissolved Solids (TDS) from 10 to 96°C and <1 to ≈30 g/L, respectively, with a chemical composition usually belonging to the Ca-SO4, NH4-SO4 or Na-Cl facies. Frequently, they are related to bubbling and boiling pools due to the interaction between deepsourced gases and shallow aquifers or meteoric waters. Concentrations of heavy metals and metalloids are in most cases high. Extremely high contents of metals are also recorded for those acidic waters that characterize the main Italian mining districts, mostly located in Sardinia (not included in the present study), Tuscany and NW Alps, where they are related to Acid Mine Drainage l.s. or Acid Rock Drainage. The pH values are as low as 2.08, with variable TDS concentrations. Compositionally, they are Na-SO4, Ca(Mg)-SO4, and/or Mg(Ca)-SO4 waters, prevalently due to oxidative processes affecting polymetallic sulfides.
Background:
Femorally inserted central catheters are increasingly used, especially after the COVID-19 pandemic, also thanks to widespread of tunneling techniques that allow the exit site to be moved ...away from the groin.
Methods:
In this retrospective observational study, femorally inserted catheters, with exit site at mid-thigh and the tip in Inferior vena cava or in Inferior vena cava at the junction with right atrium, have been observed and complications have been analyzed. All catheters were inserted by trained Nurses of a tertiary hospital Vascular Access Team.
Results:
In 142 catheters (126 inserted via common femoral vein and 16 inserted via superficial femoral vein) and 3060 catheter days, we observed an infection rate of 1.3 events/1000 catheter days (all of them in oncologic patients and up to 30 days of catheterization), 2 cases of thrombotic events (1.41%) and 17 cases of accidental removal (11.97%). Other rare complications, as primary malposition, tip migration, arterial pseudoaneurysm, have been recorded. The average length of catheters inserted, from the exit site to the tip, was 47.6 ± 2.4 cm.
Conclusion:
The attention to the correct position of the tip, the exit site at mid-thigh and the new techniques during insertion make these femoral catheters as safe as other central vascular access devices. For this kind of central access device, a catheter at least 50 cm long is needed.
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Introduction:
Midline catheters are widely used in clinical practice. Proper placement of midline catheter tip is usually assessed only by aspirating blood and flushing with normal saline without ...resistance.
Purpose:
To describe the ultrasound-guided tip location for midline catheters and its feasibility and to compare incidence of catheter-related venous thrombosis associated with or without ultrasound tip localization.
Methods:
The ultrasound-guided tip location is described step by step. Feasibility of the technique and incidence of catheter-related venous thrombosis were measured (study group) and compared with two historical groups: study group, 20-cm midline catheters inserted with ultrasound-guided tip location; group 1, 25-cm midline catheters inserted without ultrasound-guided tip location and group 2, 20-cm midline catheters inserted without ultrasound-guided tip location.
Results:
In the study group, ultrasound-guided tip location was easily feasible in 98.9% of patients. Incidence of catheter-related venous thrombosis was 2.42% in control group 1, 9% in control group 2 and 2.62% in the study group.
Discussion:
In the study group and control group 1, the tip was placed in the axillary vein, about 3 cm distal to the clavicle and in the subclavian vein. In control group 2, the tip was probably located at the transition between the axillary and the subclavian vein. It is possible that such position may have been associated with an increased incidence of catheter-related venous thrombosis.
Conclusion:
The ideal position of the tip of a midline catheter might be inside the axillary vein, about 3 cm distal to the axillary-subclavian transition or inside the subclavian vein. Ultrasound-guided tip location is safe, inexpensive, easy and potentially useful during midline catheters insertion.
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We report evidences of active seabed doming and gas discharge few kilometers offshore from the Naples harbor (Italy). Pockmarks, mounds, and craters characterize the seabed. These morphologies ...represent the top of shallow crustal structures including pagodas, faults and folds affecting the present-day seabed. They record upraise, pressurization, and release of He and CO2 from mantle melts and decarbonation reactions of crustal rocks. These gases are likely similar to those that feed the hydrothermal systems of the Ischia, Campi Flegrei and Somma-Vesuvius active volcanoes, suggesting the occurrence of a mantle source variously mixed to crustal fluids beneath the Gulf of Naples. The seafloor swelling and breaching by gas upraising and pressurization processes require overpressures in the order of 2-3 MPa. Seabed doming, faulting, and gas discharge are manifestations of non-volcanic unrests potentially preluding submarine eruptions and/or hydrothermal explosions.
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Extracorporeal membrane oxygenation (ECMO) is required for patients with refractory cardiac or respiratory failure. Inadequate securement of ECMO cannulae may lead to adverse events, ranging from ...line kinking to catastrophic accidents, such as air entrainment into the circuit or massive bleeding. Furthermore, the micro-motion of the cannulae at the entry site might increase the risk of local infections. Since 2015, we implemented a written protocol for management of ECMO cannulae and tubing, which specifically includes the securement of each cannula with three sutureless devices. The aim of the present study was to retrospectively assess cannulae micro-motion and the rate of bleeding events at the insertion site. Secondarily we aimed to evaluate the impact of prone positioning maneuvers during ECMO on these events. We performed a single-centre retrospective analysis of prospectively collected data on nursing care of ECMO cannulae. We included adult patients treated with veno-venous (V-V) or veno-arterial (V-A) ECMO between 2015 and 2018 in our general intensive care unit. The distance between the insertion site and the end of the wire-wound part of the cannula was recorded daily. Variations of this distance (defined as “cannula micro-motion”) were recorded. Forty-five ECMO consecutive adult patients (40 V-V and 5 V-A) were included. No accidental cannula dislodgement was recorded. Median daily “cannula micro-motion” was 0.0 (−0.5 to 0.2) cm, without any significant difference between ECMO configuration, cannula type, and insertion site. Twelve patients (26%) presented at least one bleeding episode at cannula insertion site, none of which required surgical intervention. In the subgroup of patients who underwent prone positioning, no difference in cannulae micro-motion was recorded. An ECMO nursing protocol for cannulae management providing sutureless devices for cannula and tubing securement allows safe line stabilization, with the potential to reduce complications related to ECMO vascular access.
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Peripherally Inserted Central Catheters play an increasingly important role in Central Venous Access Devices. However, the use of these devices should be carefully considered in specific situations ...such as central catheterisation in patients with chronic kidney disease. When evaluating the feasibility of placement for a patient undergoing dialysis, the relationship between changes in circulating volume before and after dialysis treatment, and potential variations in the size of deep veins in the upper limbs, should be considered.
Upper limb veins, specifically the basilic or brachial veins, were identified and measured before and after dialysis treatment. Patient data and weight loss data during dialysis treatment were also collected. Linear regression analysis was performed to assess the correlation between the variables.
The average variation in vein size for the entire sample was +0.17 ± 0.43 mm. The mean volume removed was 2.2 ± 0.8 l. In subgroup 1 (fluid volume loss <2000 ml), the population experienced a decrease in the measured vein size after dialysis. In subgroup 2 (fluid volume loss ⩾2000 ml), the population experienced an increase in the measured vein size after dialysis.
Upper arm vascular access placement in dialysed patients with fluid removal of less than 2000 ml should be performed after the dialysis session. Conversely, in dialysed patients with fluid removal of more than 2000 ml, where a significant increase in vein size was observed, vascular access placement should be performed before the dialysis session when the veins are smaller. Additionally, it should be noted that in patients with chronic kidney disease, the venous system of the upper limbs should be preserved as much as possible to prevent thrombosis and stenosis in potential arteriovenous fistula creation.
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Introduction:
Peripherally inserted central catheters are very common devices for short, medium and long-term therapies. Their performance is strictly dependent on the correct tip location, at the ...junction between the upper caval vein and the right atrium. It is very important to obtain an estimated measure of the catheter, in order to reach the cavo-atrial junction and optimize the catheter length. Estimated measures are often obtained using cutaneous landmarks.
Objective:
Evaluate the reliability of cutaneous landmark-based length estimation during catheter insertion. Identify any patient’s related factors that may affect cutaneous landmarks reliability.
Methods:
We used two distinct techniques and collected data about cutaneous landmark-based length estimation, electrocardiographic guided intravascular length, age, weight and height. We studied the reliability of possible correcting factors, balancing the error average by regression models, and we found and tested two different models of prediction.
Results:
A total number of 519 patients were studied. The average bias, between the two studied length assessment by cutaneous landmarks and electrocardiographic guided catheter length, were 3.77 ± 2.44 cm and 3.28 ± 2.57 cm, respectively. The analysed prediction models (deviance explained 43.5%, Akaike information criterion = 1313.67% and 43.4%, Akaike information criterion = 1313.92), fitted on the validation set, showed a root mean square error of 3.07 and 3.06.
Conclusion:
Landmark-based length estimation for preventive catheter length assessment seems to be unreliable, when associated with post-procedural tip location. They are useful for distal trimming catheters to optimize the ‘out of skin’ portion when associated with electrocardiographic tip location. Models identified for balancing bias are probably not useful.
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Arterial lines and central venous catheter (CVC) allow to monitor patients' acid-base status and gas exchange. Their placement and maintenance may however be burdened by severe complications. Midline ...Catheters (MC) are peripheral venous accesses that are less invasive and easier to insert compared to CVC and arterial lines.
A prospective observational study was performed including stabilized critical patients with clinical indication to midline positioning before intensive care unit (ICU) discharge. The primary aim was to assess if venous sampling from MCs can be a reliable alternative to CVC for pH and CO
monitoring. The secondary aim was to evaluate the correlation between samplings from MC, CVC and arterial line with regards to pH, carbon dioxide tension (pCO
), lactates and electrolytes. Three samples from CVC, arterial line and MC were collected simultaneously. Agreement and correlation of the studied parameters between different sampling sites were explored.
40 patients were included in the analysis. A good agreement for pH and pCO
was recorded between MC and CVC: mean differences were 0.001 (95% CI -0.006 to 0.007) and 0.7 (-0.1 to 1.5), percentage error 0.4% and 11.2%, respectively. Correlation between MC and both central venous and arterial samples for pH, pCO
, lactates and electrolytes was found to be moderate-to-strong (Pearson's
coefficient range 0.59-0.99,
< 0.001 for all these parameters).
In stabilized critical patients, midline catheters represent a reliable alternative to CVC and arterial lines to monitor acid-base disturbances, CO
levels and electrolytes. The present findings add to the known advantages of MC, which might be considered a first-line vascular access for non-critical or stabilized patients who do not require infusion of vesicant or irritant drugs.
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In 2001–2002, two ground collapses occurred in the island of Nisyros (Aegean Sea, Greece), which formed a 600 m long and up to 5 m wide fissure in the vegetated central part of the Lakki Plain ...caldera. The fissure was alternatively ascribed to tensional stress release and hydrothermal alteration. In this study, we present original data of diffuse CO
2
soil fluxes, soil temperatures, mineralogical and chemical composition of the caldera-filling deposits exposed on the fissure walls, and chemical and isotopic composition of interstitial soil gases collected from: the bottom of the fissure, the adjacent vegetated areas, the hydrothermal craters, and selected sites outside the caldera. The occurrence of intense hydrothermal alteration was shown by both mineralogical and chemical analyses of the fissure walls material. Typical mineral assemblage and enrichments in incompatible elements related to advanced argillic alteration, characterizing steam-heated hydrothermal environments, were recognized. Although the low-permeable sediment cover in the Lakki Plain concealed the underneath hydrothermal gas flow, preventing anomalous soil temperatures and CO
2
fluxes, the chemical and isotopic composition of the interstitial soil gases revealed an active hydrothermal fluids circulation below the collapsed area, likely controlled by buried structural lineaments. Hydrothermal alteration can then be invoked as the most likely trigger mechanism for the 2001–2002 collapse event.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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