Saturation Pressure Research Articles

CENTRAL VENOUS-TO-ARTERIAL CARBON DIOXIDE PARTIAL PRESSURE DIFFERENCE AS A GUIDING PARAMETER FOR CARDIOTONIC DRUG ADMINISTRATION IN PATIENTS WITH EARLY-STAGE SEPTIC SHOCK.

Objective: This study aimed to investigate the effect of the central venous-to-arterial carbon dioxide partial pressure difference (Pcv-aCO2) on the administration of cardiotonic drugs in patients with early-stage septic shock. Methods: A retrospective study was conducted on 120 patients suffering from septic shock. At admission, the left ventricular ejection fraction (LVEF) and Pcv-aCO2 of the patients were obtained. On the premise of mean arterial pressure ≥ 65 mm Hg, the patients were divided into two groups according to the treatment approaches adopted by different doctors-control group: LVEF ≤50% and observation group: Pcv-aCO2 ≥ 6. Both groups received cardiotonic therapy. Results: The two groups of patients had similar general conditions and preresuscitation conditions ( P > 0.05). Compared with the control group, the observation group had a higher mean arterial pressure, lactic acid clearance rate, and urine output after 6 h of resuscitation ( P < 0.05), but a lower absolute value of lactic acid, total fluid intake in 24 h, and a lower number of patients receiving renal replacement therapy during hospitalization ( P < 0.05). After 6 hours of resuscitation, the percentages of patients meeting central venous oxygen saturation and central venous pressure targets were not significantly different between the control and observation groups ( P > 0.05). There was no difference in the 28-day mortality rate between the two groups ( P > 0.05). Conclusion: Pcv-aCO2 is more effective than LVEF in guiding the administration of cardiotonic drugs in the treatment of patients with septic shock.

Effects of progressive muscle relaxation exercises on the vital signs and fatigue in kidney transplant patients: a randomized controlled trial.

Multiple effective nursing interventions are needed to manage deviations from normal vital signs and fatigue experienced by kidney transplant patients. In this study, we investigated the effect of progressive muscle relaxation (PMR) exercises on vital signs and fatigue in kidney transplant patients. We conducted a randomized controlled experimental study with 52 patients (intervention = 26, control = 26) who underwent kidney transplantation at a university hospital in Turkey and met the inclusion criteria. The "Descriptive Characteristics Form", "Vital Signs Monitoring Form", and "Fatigue Severity Scale" were used to record data on the patients. Then, the patients in the intervention group (baseline assessment) were trained to perform PMR exercises, asked to practice, and followed up (first follow-up). Patients were recommended to perform PMR exercises for 20min every day for four weeks. The second follow-up in the second week after discharge and the third follow-up at the end of the fourth week were performed in the outpatient clinic. We found that the pulse rate, body temperature, and arterial blood pressure decreased over time and oxygen saturation increased in the patients of the intervention group. The PMR exercises decreased fatigue in these patients. The arterial blood pressure and oxygen saturation values differed significantly across different time points among the patients in the control group. The difference in the scores of fatigue severity between the pre-follow-up and the third follow-up in the control group was not significant. PMR exercises were found to be an effective nursing intervention in regulating vital signs and reducing fatigue in renal transplant patients.

A Microfluidic and Numerical Analysis of Non-equilibrium Phase Behavior of Gas Condensates

Conventional assumptions about multiphase flow in gas condensate reservoirs often do not correlate with field production. This discrepancy stems from the various mechanisms influencing the multiphase process, which are inadequately represented in numerical models. One of the least understood mechanisms is the influence of the non-equilibrium thermodynamics on the flow in the wellbore region, where the reservoir pressure is below the dew point pressure. To address this problem, experimental and mathematical analyses were conducted using a microfluidic device designed to replicate the flow dynamics in a gas condensate system. The experimental results showed an 11% deviation from the initial pressure of condensate saturation when compared with the conventional assumption of local equilibrium in numerical models. Similarly, there is a 14% deviation between the experimental and simulated volumes of the condensate. These findings underscore the inadequacy of existing models to accurately predict the saturation profile of the condensate phase. A mathematical model based on a relaxation parameter was applied to account for non-equilibrium phase separation and the fog state of the aerosol as observed in the microfluidic experiment. Incorporating a relaxation parameter (τ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ au$$\\end{document}) enhanced the accuracy of the prediction of the initial pressure of the condensate saturation and an improvement in the prediction of the condensate volumes from 76% to 97.2%. Consequently, it provides a valuable framework and insight on the non-equilibrium phase behavior of gas condensate systems under constant flow regimes.

A novel algorithm for asphaltene precipitation modeling in shale reservoirs with the consideration of capillary pressure during the CCUS processes

Tight and shale reservoirs have markedly expanded their role in global oil and gas production. However, the overall recovery from these reservoirs is suboptimal, leaving much of the shale oil unrecovered. CO2 flooding is a promising enhanced oil recovery (EOR) technique that can improve oil extraction and simultaneously facilitate carbon capture, utilization, and storage (CCUS). However, this method presents challenges, notably the precipitation and deposition of asphaltene, which risks plugging the nanoporous structure characteristic of shale reservoirs. Given that the nanopore sizes in these reservoirs align closely with asphaltene particle dimensions, the risk of pore and throat blockages during gas injection is pronounced. Although various asphaltene precipitation models have been proposed, there is still a lack of robust algorithms accounting for the substantial influence of capillary pressure on asphaltene precipitation in these nanopores. In this study, a novel three-phase vapor–liquid-asphaltene equilibrium calculation algorithm coupled with capillary effect is developed. The algorithm is first validated by comparing with the experimental data of the Px phase diagram and asphaltene precipitation amount. The validated algorithm is then used to conduct example calculations to demonstrate the robustness of the new algorithm and to examine the impact of capillarity on the three-phase vapor–liquid-solid (VLS) equilibria. Computation results show that capillary pressures in nanopores substantially modify the three-phase VLS equilibria, causing shifts in saturation pressure and influencing asphaltene precipitation. Generally, asphaltene precipitation in nanopores occurs at a lower pressure and gas injection concentration. The smaller pore sizes intensify these effects, but the impact diminishes as pressure increases. Additionally, the gas composition also greatly affects asphaltene precipitation. The results reveal that this new algorithm is robust across different conditions, offering an innovative approach that reliably predicts asphaltene precipitation considering the effect of capillary pressures, paving the way for improved EOR and CCUS in shale reservoirs.

Lumbar Paravertebral Muscle Pain Management Using Kinesitherapy and Electrotherapeutic Modalities.

Low back pain is considered a public health problem internationally. Low back pain is a cause of disability that occurs in adolescents and causes negative effects in adults as well. The work environment and physical and psychosocial factors can influence the occurrence and evolution of low back pain. The purpose of this paper is to highlight the physiological and functional changes in young adults with painful conditions of the lumbar spine, after using exercise therapy. The study was of the longitudinal type and was carried out over a period 6 months in an outpatient setting. The rehabilitation treatment included electrotherapeutic modalities and kinesitherapy. The results obtained when evaluating each parameter, for all moments, show statistically significant values in both groups. The results obtained regarding the relationship between the therapeutic modalities specific to rehabilitation medicine and low back pain are consistent with those reported in studies. Depending on the clinical-functional status of each patient, kinesitherapy can accelerate the heart rate and increase the blood pressure and oxygen saturation of the arterial blood, values that can later return to their initial levels, especially through training.

Cavitation-induced pressure saturation: a mechanism governing bubble nucleation density in histotripsy

Objective. Histotripsy is a noninvasive focused ultrasound therapy that mechanically disintegrates tissue by acoustic cavitation clouds. In this study, we investigate a mechanism limiting the density of bubbles that can nucleate during a histotripsy pulse. In this mechanism, the pressure generated by the initial bubble expansion effectively negates the incident pressure in the vicinity of the bubble. From this effect, the immediately adjacent tissue is prevented from experiencing the transient tension to nucleate bubbles. Approach. A Keller–Miksis-type single-bubble model was employed to evaluate the dependency of this effect on ultrasound pressure amplitude and frequency, viscoelastic medium properties, bubble nucleus size, and transducer geometric focusing. This model was further combined with a spatial propagation model to predict the peak negative pressure field as a function of position from a cavitating bubble. Main results. The single-bubble model showed the peak negative pressure near the bubble surface is limited to the inertial cavitation threshold. The predicted bubble density increased with increasing frequency, tissue viscosity, and transducer focusing angle. The simulated results were consistent with the trends observed experimentally in prior studies, including changes in density with ultrasound frequency and transducer F-number. Significance. The efficacy of the therapy is dependent on several factors, including the density of bubbles nucleated within the cavitation cloud formed at the focus. These results provide insight into controlling the density of nucleated bubbles during histotripsy and the therapeutic efficacy.

Two-phase flow thermo-hydro-mechanical modeling for a water flooding field case

Simulation of subsurface energy system involves multi-physical processes such as thermal, hydraulical, and mechanical (THM) processes, and requires a so-called THM coupled modeling approach. THM coupled modeling is commonly performed in geothermal energy production. However, for hydrocarbon extraction, we need to consider multiphase flow additionally. In this paper, we describe a three-dimensional numerical model of non-isothermal two-phase flow in the deformable porous medium by integrating governing equations of two-phase mixture in the porous media flow in the reservoir. To account for inter-woven impacts in subsurface conditions, we introduced a temperature-dependent fluid viscosity and a fluid density along with a strain-dependent reservoir permeability. Subsequently, we performed numerical experiments of a ten-year water flooding process employing the open-source parallelized code, OpenGeoSys. We considered different well patterns with colder water injection in realistic scenarios. Our results demonstrate that our model can simulate complex interactions of temperature, pore pressure, subsurface stress and water saturation simultaneously to evaluate the recovery performance. High temperature can promote fluid flow while cold water injection under non-isothermal conditions causes the normal stress reduction by significant thermal stress. Under different well patterns the displacement efficiency will be changed by the relative location between injection and production wells. This finding has provided the important reference for fluid flow and induced stress evolution during hydrocarbon exploitation under the environment of large reservoir depth and high temperature.

Oxidative Stress Reaction to Hypobaric-Hyperoxic Civilian Flight Conditions.

In military flight operations, during flights, fighter pilots constantly work under hyperoxic breathing conditions with supplemental oxygen in varying hypobaric environments. These conditions are suspected to cause oxidative stress to neuronal organ tissues. For civilian flight operations, the Federal Aviation Administration (FAA) also recommends supplemental oxygen for flying under hypobaric conditions equivalent to higher than 3048 m altitude, and has made it mandatory for conditions equivalent to more than 3657 m altitude. We hypothesized that hypobaric-hyperoxic civilian commercial and private flight conditions with supplemental oxygen in a flight simulation in a hypobaric chamber at 2500 m and 4500 m equivalent altitude would cause significant oxidative stress in healthy individuals. Twelve healthy, COVID-19-vaccinated (third portion of vaccination 15 months before study onset) subjects (six male, six female, mean age 35.7 years) from a larger cohort were selected to perform a 3 h flight simulation in a hypobaric chamber with increasing supplemental oxygen levels (35%, 50%, 60%, and 100% fraction of inspired oxygen, FiO2, via venturi valve-equipped face mask), switching back and forth between simulated altitudes of 2500 m and 4500 m. Arterial blood pressure and oxygen saturation were constantly measured via radial catheter and blood samples for blood gases taken from the catheter at each altitude and oxygen level. Additional blood samples from the arterial catheter at baseline and 60% oxygen at both altitudes were centrifuged inside the chamber and the serum was frozen instantly at -21 °C for later analysis of the oxidative stress markers malondialdehyde low-density lipoprotein (M-LDL) and glutathione-peroxidase 1 (GPX1) via the ELISA test. Eleven subjects finished the study without adverse events. Whereas the partial pressure of oxygen (PO2) levels increased in the mean with increasing oxygen levels from baseline 96.2 mm mercury (mmHg) to 160.9 mmHg at 2500 m altitude and 60% FiO2 and 113.2 mmHg at 4500 m altitude and 60% FiO2, there was no significant increase in both oxidative markers from baseline to 60% FiO2 at these simulated altitudes. Some individuals had a slight increase, whereas some showed no increase at all or even a slight decrease. A moderate correlation (Pearson correlation coefficient 0.55) existed between subject age and glutathione peroxidase levels at 60% FiO2 at 4500 m altitude. Supplemental oxygen of 60% FiO2 in a flight simulation, compared to flying in cabin pressure levels equivalent to 2500 m-4500 m altitude, does not lead to a significant increase or decrease in the oxidative stress markers M-LDL and GPX1 in the serum of arterial blood.

An Analytical Method for Timely Predicting of Coal Seam Pressure during Gas Production for Undersaturated Coalbed Methane Reservoirs

Coal seam pressure is an important parameter for production performance evaluation and prediction of coalbed methane (CBM). CBM production from undersaturated CBM reservoirs can be divided into two stages according to critical desorption pressure. At present, few prediction models of coal seam pressure performance consider the comprehensive influence of critical desorption pressure, dissolved gas, matrix shrinkage, and stress sensitivity. For the purpose of accurately predicting coal seam pressure during gas production for an undersaturated coalbed methane reservoir, the material balance principle is used to establish the analytical method for predicting coal seam pressure, considering the comprehensive influence of the critical desorption pressure, dissolved gas, matrix shrinkage, and stress sensitivity. Then, the proposed method is verified against a numerical simulation case using a computer modelling group (CMG) and two actual coalbed methane wells. Finally, the sensitivities of influencing factors on the coal seam pressure are analyzed. The results show that good agreements were obtained between the calculated coal seam pressures using the proposed method and those from the CMG-GEM simulation case and actual CBM wells, with the relative errors all being less than 1%. When ignoring the influence of critical desorption pressure and mistaking pd for pi as well as ignoring Cs, the relative error can reach as high as 31.3%. The main factors affecting the coal seam pressure are the critical desorption pressure and free gas saturation. The proposed method is simple to use, and without shutting-in the well, it can provide an important basis for production performance evaluation and development strategies.

A modified local thermal non-equilibrium model of transient phase-change transpiration cooling for hypersonic thermal protection

Aiming to efficiently simulate the transient process of transpiration cooling with phase change and reveal the convection mechanism between fluid and porous media particles in a continuum scale, a new two-phase mixture model is developed by incorporating the local thermal non-equilibrium effect. Considering the low-pressure and high overload working conditions of hypersonic flying, the heat and mass transfer induced by capillary and inertial body forces are analyzed for sub-cooled, saturated and super-heated states of water coolant under varying saturation pressures. After the validation of the model, transient simulations for different external factors, including spatially-varied heat flux, coolant mass flux, time-dependent external pressure and aircraft acceleration are conducted. The results show that the vapor blockage patterns at the outlet are highly dependent on the injection mass flux value and the external pressure, and the reduced saturation temperature at low external pressure leads to early boiling off and vapor blockage. The motion of flying has a large influence on the cooling effect, as the inertial force could change the flow pattern of the fluid inside significantly. The comparison of the results from 2-D and 3-D simulations suggests that 3-D simulation shall be conducted for practical application of transpiration cooling, as the thermal protection efficiency may be overestimated by the 2-D results due to the assumption of an infinite width length of the porous plate.

Molecular dynamics simulation of methane hydrates: Prediction of the phase equilibria using extracted microscopic parameters from SAFT-VR Mie EOS

This paper explores the three-phase equilibrium of structure-I methane hydrate by utilizing the extracted Mie potential parameters for non-bonded molecular interactions in the LAMMPS molecular dynamics simulator. An in-house code was developed to numerically solve the SAFT-VR Mie equation of state (EOS). To reduce numerical errors, unlike common practices, we incorporated all partial derivatives analytically in the code. The microscopic simulation parameters for methane and water molecules were selected so that saturation pressure and liquid density data from EOS were fitted on experimental data. Using this approach, the three-phase (V−Lw−H) equilibrium temperatures for pressure values of 30, 70, 100, and 300 bar were calculated. The solubility of methane in the aqueous phase at three-phase equilibrium was also determined. The results were validated against available laboratory data. To evaluate the performance of Mie potential parameters, the MD simulations were repeated using three well-known force fields for methane molecules, namely, Optimized Potentials for Liquid Simulations-United Atom (OPLS-UA), Universal force field (UFF), and General Amber force field (GAFF). The TIP4P/Ice force field was used for water molecules in all cases. The comparison with experimental data reveals that while the accuracy of the UFF force field is the highest, our simulation approach outperforms OPLS-UA and GAFF force fields in predicting methane solubility in the aqueous phase. Besides molecular dynamics simulation, the van der Waals-Platteeuw model was combined with the SAFT VR Mie EOS to account for the hydrate phase. In our case study, the SAFT-VR Mie + vdW-P model proved to be more accurate in predicting the three-phase equilibrium data compared to the MD approach.

Developing statistical and machine learning models for predicting CO2 solubility in live crude oils

CO2 solubility in crude oil primarily affects the viscosity and swelling capacity of oil and determines the displacement efficiency of CO2 flooding during the enhanced oil recovery process. Dissolution of CO2 into crude oil also ensures safe and permanent storage of CO2 in depleted formations via solubility trapping. This study employed statistical and machine learning algorithms to develop precise and stable predictive models for estimating CO2 solubility in crude oils with dissolved gas. Recognizing the limitations of existing experimental data on CO2 solubility for live oils (crude oils with dissolved gas), we introduced a novel approach employing statistical and machine learning techniques for developing accurate and robust predictive models. Our methodology combined regularization, k-fold cross-validation, and statistical significance tests to ensure the robustness of the models, practices not considered in the previous studies. A linear regression model with L2 regularization is developed as the base model and compared with a 2nd order polynomial model and an ensemble feed-forward neural network (FNN) model integrated with gradient boosting (GB). The incorporation of GB into the neural network capitalizes on the additive sequence of FNN models, thereby enhancing the accuracy and reliability of predictions. Moreover, an improved user-accessible and easily implementable correlation is proposed to estimate CO2 solubility in live crude oils at diverse operating conditions as a function of reservoir temperature, saturation pressure, bubble-point pressure, oil molecular weight, and specific gravity. The performances of the developed model and the correlation are compared against the literature models and correlations. The FNN model with an overall R2 score of 0.9978, average absolute relative deviation (AARD) of 1.54 %, and root mean squared error (RMSE) of 0.0083 outperformed the previously published models and correlations. The new correlation, while being relatively simpler than previously published correlations, showed similar predictive performance with an overall R2 score of 0.9817, AARD of 4.98 %, and RMSE of 0.0225. The model and the correlation can be used to estimate CO2 solubility in live crude oils with 0.67 to 0.97 specific gravity for reservoir temperatures and pressures in the range of 28 to 124 °C and 3.23 to 32.76 MPa, respectively.

History matching for geological carbon storage using data-space inversion with spatio-temporal data parameterization

History matching based on monitoring data will enable uncertainty reduction, and thus improved aquifer management, in industrial-scale carbon storage operations. In traditional model-based data assimilation, geomodel parameters are modified to force agreement between flow simulation results and observations. In data-space inversion (DSI), history-matched quantities of interest, e.g., posterior pressure and saturation fields conditioned to observations, are inferred directly, without constructing posterior geomodels. This is accomplished efficiently using a set of O(1000) prior simulation results, data parameterization, and posterior sampling within a Bayesian setting. In this study, we develop and implement (in DSI) a deep-learning-based parameterization to represent spatio-temporal pressure and CO2 saturation fields at a set of time steps. The new parameterization uses an adversarial autoencoder (AAE) for dimension reduction and a convolutional long short-term memory (convLSTM) network to represent the spatial distribution and temporal evolution of the pressure and saturation fields. This parameterization is used with an ensemble smoother with multiple data assimilation (ESMDA) in the DSI framework to enable posterior predictions. A realistic 3D system characterized by prior geological realizations drawn from a range of geological scenarios is considered. A local grid refinement procedure is introduced to estimate the error covariance term that appears in the history matching formulation. Extensive history matching results are presented for various quantities, for multiple synthetic true models, using the new DSI framework. Substantial uncertainty reduction in posterior pressure and saturation fields is achieved in all cases. The framework is also applied to efficiently provide posterior predictions for a range of error covariance specifications. Such an assessment would be very expensive using a traditional model-based approach.

Method of determination of integral and differential nonlinearities of ADC by three histograms during tests of diagnostic channels in complex magnetotherapy

One of the most important components of modern electronic systems in the fields of medical technology, automotive, 5G communications, etc. are microchips containing analog-to-digital converters (ADCs) on a single chip. Aging effects, environment and mechanical vibrations have a significant impact on the operation of electronic systems, so microcircuits need to be periodically verified, calibrated and even replaced. For this reason, in order to control metrological and technical characteristics of hardware and software of the "Multimag-M" complex, which contains diagnostic channels for measuring pulse wave, respiration process, blood pressure and blood oxygen saturation (saturation), it was proposed to introduce an automated block of control, testing and self-calibration into the structure of the chronomagnetotherapy complex [1]. Application of BIST (Build-in Self Test) - built-in means of self-testing is a promising approach to solving problems of reliability improvement of modern microcircuits [2]. Most of the known BIST methods of ADCs require on-chip highly linear test signal generator (TS) [3-4], which is the most complex block. The ability to test ADCs with a large number of digits is limited by the linearity of the TS generator and as the resolution of ADCs increases, it becomes a difficult task to provide linear TS generation on-chip. The aim of the work is to develop a method for determining the integral and differential nonlinearities of ADC independent of the linearity of the test signal. A method for determining the integral and differential nonlinearities of the ADC, taking into account the nonlinear component of the TS, is proposed. This is achieved by sequentially feeding to the input of the tested ADC a periodic TS of triangular shape, a level-shifted down TS and a level-shifted up TS. The first histogram of ADC codes distribution at absence of TS offset, and also the second and the third histograms at TS downward and upward shifting. Using the three linked histograms, the contribution of the nonlinear component of the TS to the integral nonlinearity for each ADC code is determined. Given the nonlinear component of the TS, the integral nonlinearity for each ADC code is further determined, and then the differential nonlinearity of the ADC is determined from the integral nonlinearity. In addition, the method determines the displacement voltages of the TS, which reduces the requirements for the accuracy of the displacement signal reference. The practical value of the research result lies in the application of the method reducing requirements to TS linearity at self-diagnostics and self-calibration of microcircuits containing ADCs will allow to reduce the complexity of crystal design.

Observation on the Analgesic Effect of Different Doses of a Combination of Esketamine and Dexmedetomidine Administered for Percutaneous Endoscopic Transforaminal Discectomy: A Randomized, Double-Blind Controlled Trial.

Percutaneous endoscopic transforaminal discectomy (PETD) is an effective method for treating lumbar disc herniation, and is typically performed under local anesthesia. However, inadequate analgesia during the procedure remains a concern, prompting the search for a medication that can provide optimal pain control with minimal impact on the respiratory and circulatory systems. The aim of this study was to observe the effects of different doses of esketamine combined with dexmedetomidine on reducing visual analog scale (VAS) scores during surgical interventions. One hundred two patients who underwent PETD were randomly divided into a control group (group C: normal saline + dexmedetomidine), an E1 group (0.1 mg kg-1 esketamine + dexmedetomidine), and an E2 group (0.2 mg kg-1 esketamine + dexmedetomidine). The primary outcome was the maximum visual analogue scale (VAS) (score: 0 = no pain and 10 = worst pain) at six time points. The secondary outcomes included the Assessment of Alertness/Sedation Scale (OAA/S) score and mean arterial pressure (BP), heart rate (HR), respiratory rate (RR), and oxygen saturation (SpO2) at 11 time points. The incidence of adverse reactions during and 24 h after the operation and patient satisfaction with the anesthesia were also recorded. Compared with those in group C, the VAS scores of patients in groups E1 and E2 were lower at T6, T7, and T9 (P < 0.05). From T4 to T10, the OAA/S scores of the E1 and E2 groups were both lower than those of group C (P < 0.05), and at the T4-T6 time points, the OAA/S score of the E2 group was lower than that of group E1 (P < 0.05). At T4 and T5, the HR and BP of patients in groups E1 and E2 were greater than those in group C (P < 0.05). Compared with those in group C, the incidences of intraoperative illusion, floating sensation, postoperative dizziness, and hyperalgesia in groups E1 and E2 were significantly greater (P < 0.01). There was no significant difference in patient RR, SpO2, or postoperative satisfaction with anesthesia among the three groups (P > 0.05). The combination of esketamine and dexmedetomidine can reduce VAS scores during certain stages of this type of surgery; it has minimal impact on respiration and circulation. However, this approach is associated with increased incidences of postoperative dizziness and psychiatric side effects, which may also affect patients' compliance with surgical instructions from medical staff. Patient satisfaction was not greater with dexmedetomidine combined with esketamine than with dexmedetomidine alone. http://www.chictr.org.cn . Identifier: ChiCTR2300068206. Date of registration: 10 February 2023.

Remote monitoring of severe heart failure.

Patients with advanced heart failure, due to the instability of their clinical conditions, need close surveillance to avoid dangerous exacerbations or sudden events. Digital technology can be of great help in this contest, thanks to remote monitoring, made possible with the use of wearable or implantable instruments. The latter are currently generally inserted inside defibrillators or resynchronization systems, or inserted inside the pulmonary circulation for monitoring pulmonary pressure. Parameters such as thoracic impedance, physical activity, heart rate variability, atrial and ventricular arrhythmias, blood pressure, and O2 saturation can be controlled remotely. The data relating to the actual benefit in terms of avoidable events (death and hospitalizations) are not definitive, but certainly from an organizational point of view, the benefit is evident, both on the part of the patient and of the organization of care. The latter, provided in the form of televisits, requires a re-modulation of the system, making use of trained personnel, a well-structured network, and digital technologies (platforms, electronic health records) that are not yet perfectly developed. The evolution of the solutions offered by artificial intelligence guarantees a rapid and progressive refinement of telemedicine in this sector.

Chemical additive effect on asphaltenes destabilization and deposition studied using quartz crystal resonator (QCR) sensor: From atmospheric pressure titration to isothermal depressurization of non-diluted crude oil

In this study, the destabilization of asphaltenes in a crude oil sample was analyzed under various pressure conditions using a fully immersed Quartz Crystal Resonator (QCR) sensor. Firstly, oil samples with and without a chemical additive were tested at atmospheric pressure through titration with different liquid n-alkanes (C7, C9, and C12) as antisolvents. Then, high-pressure experiments (HP) were conducted on a recombined crude oil + gas system, involving constant mass expansions from 1000 bar to the saturation pressure point at various fixed temperatures. From these high-pressure experiments, the phase diagrams, including the asphaltene pressure envelope (APE), were constructed and compared for the recombined oil with and without the chemical additive in both P vs T and P vs composition diagrams. The results regarding the impact of the chemical additive under HP conditions were compared with those obtained under atmospheric pressure conditions. The comparison shows an strong agreement between the two sets of experiments, confirming that the test conducted to evaluate the effectiveness of asphaltene inhibitors can be extrapolated to high-pressure applications.

A new method of pulse control in cardiopulmonary resuscitation; Continuous femoral pulse check

ObjectivesThe reliability of manual pulse checks has been questioned but is still recommended in cardiopulmonary resuscitation (CPR) guidelines. The aim is to compare the 10-s carotid pulse check (CPC) between heart massage cycles with the continuous femoral pulse check (CoFe PuC) in CPR, and to propose a better location to shorten the interruption times for pulse check. MethodsA prospective study was conducted on 117 Non-traumatic CPR patients between January 2020 and January 2022. A total of 702 dependent pulse measurements were executed, where carotid and femoral pulses were simultaneously assessed. Cardiac ultrasound, end-tidal CO2, saturation, respiration, and blood pressure were employed for pulse validation. ResultsThe decision time for determining the presence of a pulse in the last cycle of CPR was 3.03 ± 1.26 s for CoFe PuC, significantly shorter than the 10.31 ± 5.24 s for CPC. CoFe PuC predicted the absence of pulse with 74% sensitivity and 88% specificity, while CPC predicted the absence of pulse with 91% sensitivity and 61% specificity. ConclusionCoFe PuC provides much earlier and more effective information about the pulse than CPC. This shortens the interruption times in CPR. CoFe PuC should be recommended as a new and useful method in CPR guidelines.

Assessment of Blood Gas Pattern amongst Artisanal Refinery Operators in Rivers State, Nigeria

Some identified setbacks of the legitimate and illegitimate explorations/exploitations of crude oil and its derivatives in the Niger Delta are degraded environment, weak economy, and deteriorating health of the populace. Therefore, the current study evaluated the effect of artisanal refinery operation on respiratory blood gases and renal functions of its workers in Rivers State. As a cross-sectional investigation with sparse population, the multistage sampling technique (including purposive and snowball tools) was adopted to recruit 203 (including 120 operators of artisanal refinery―OAR-actively exposed and 83 non-OAR- actively exposed) willing and apparently healthy male and female adult subjects. Following receipt of ethical approval and consent, five milliliter of blood was taken from each subject from their antecubital vein after sterilizing the portion of the cubital fossa. The sample was then put into plain sample bottle and centrifuged to recover serum. Thereafter, the automated blood gas analyzer was used to measure the arterial blood gases of the subjects. The result showed marked (P&lt;0.05) reductions in the partial pressure of oxygen (PO2) and oxygen saturation (SO2) levels in artisanal refinery operators (actively exposed) when compared to that of the passively-exposed subjects. Again, there were marked (P&lt;0.05) elevations in the plasma pH and bicarbonate ions (HCO-3) levels in the actively exposed subjects compared to their passively-exposed counterparts. In conclusion, there could be adverse impact on respiratory blood gases and incidences of metabolic alkalosis over chronic exposures to the OAR activities.

Effects of Stepdown Pressure and Wettability on Bubble Nucleation in Gas-Supersaturated Oil-Water Systems

Summary This study investigates the influences of wettability and stepdown pressure on pressure-driven bubble nucleation within a gas-supersaturated oil-water system. Two gases—carbon dioxide (CO2), which is highly soluble in water, and methane (CH4), which is sparingly soluble in water—were used individually for the bubble nucleation experiments. Equal heights of oil (n-decane) and water, in a wettability-controlled glass vial placed in a saturation cell, were saturated with either of the gases at 6000-mbar pressure, followed by applying a stepdown pressure of either 6000 mbar, 500 mbar, or 100 mbar to start the bubble nucleation process. The average bubble nucleation pressures for CO2 and CH4 gases on a hydrophobic vial surface with 500-mbar stepdown pressure were 4333 ± 289 mbar and 3833 ± 289 mbar, respectively. It is important to note that the bubble nucleation took place exclusively on the portion of the solid surface submerged in water. However, bubble nucleation did not take place with 100-mbar stepdown pressure for either gas in the hydrophobic vial despite the pressure being brought down to atmospheric pressure. As expected, bubble nucleation did not take place in the hydrophilic vial for the gases despite the pressure being brought down to atmospheric pressure from the saturation pressure, regardless of the stepdown pressure. In addition, bubble nucleation did not take place in CO2-supersaturated water in the oil-wetted hydrophilic and hydrophobic vials, even at maximum supersaturation.