BACKGROUND

Determination of serum bicarbonate (HCO3 - ) using arterial blood gas analysis in patients with diabetic ketoacidosis allows for the evaluation of the severity of the condition, determines whether HCO3 - therapy is required, and tracks the progression and resolution of the disease. Serum carbon dioxide combining power (CO2CP) from venous chemistry analysis has often been used as an indicator of metabolic acidosis. This study investigated the relationship between HCO3 - and CO2CP and developed an approximation formula for serum bicarbonate concentration using its predictor variables, as this may lessen the need to repeat arterial blood gas analysis or be used in settings in which blood gas analyzers are unavailable.

METHODOLOGY

This single-center, retrospective, cross-sectional study investigated a total of 77 patients diagnosed with diabetic ketoacidosis. Assessment of the bivariate correlations between serum HCO3 - and serum CO2CP as well as other potential predictor variables was done via Pearson’s correlation coefficient. Predictor variables that were significantly correlated with serum HCO3 - were identified and an approximation formula was developed by regression analysis. Evaluation of the correlation between the approximated HCO3 - value and the actual serum HCO3 - concentration was performed using correlation coefficient and residual statistics to assess agreement.

RESULTS

Serum CO2CP had significant correlation with serum HCO3 - (r = 0.768, p < 0.05). By multiple regression analysis, the following approximation formula was therefore expressed: HCO3 - = 12.682 + (0.612 x CO2CP) – [ketones] + (0.085 x BUN) - (0.026 x SGPT) – (1.23 x Creatinine) - (0.067 x Chloride). Examination of residuals revealed a mean of zero (0), indicating no significant difference between the actual and approximated levels of serum HCO3 -

CONCLUSION

The predictor variables included in the formula collectively contribute significantly to the approximation of serum HCO3 - . The approximated serum HCO3 - values also showed significant correlation with actual serum HCO3 - concentration; thus, the formula may be utilized to derive an approximation of serum bicarbonate concentration in patients with diabetic ketoacidosis.

Human ; Male ; Female ; Adolescent: 13-18 Yrs Old ; Young Adult: 19-24 Yrs Old ; Adult: 25-44 Yrs Old ; Attention ; Bicarbonates ; Carbon Dioxide ; Diabetic Ketoacidosis ; Ketosis ; Patients ; Carbon ; Power (psychology) ; Power, Psychological ; Serum

End-tidal carbon dioxide monitoring is an important means of evaluating human lung function and is widely used in fields such as clinical emergency treatment and cardiopulmonary resuscitation. This paper develops a microstream end-tidal carbon dioxide monitoring system. It adopts an integrated gas circuit design to further reduce the size of the equipment. The system uses the method of calculating the root mean square (RMS) of differential pressure signals to regulate the gas circuit flow, enabling the system to stably operate at a flow state of 30 mL/min. In addition, by simultaneously detecting multiple environmental parameters such as temperature and pressure, the system realizes system state monitoring and gas parameter compensation. The test results show that various indicators of the system meet the requirements of relevant standards, laying a good foundation for subsequent engineering applications.
Carbon Dioxide/analysis* ; Equipment Design ; Monitoring, Physiologic/methods* ; Humans

Ecological cultivation is an important way for the sustainable production of traditional Chinese medicine in the context of the carbon peaking and carbon neutrality goals. Facility cultivation and simulative habitat cultivation modes have been developed and applied to develop the endangered Dendrobium huoshanense on the basis of protection. However, the differences in the greenhouse gas emissions and global warming potential of these cultivation modes remain unexplored, which limits the accurate assessment of carbon-friendly ecological cultivation modes of D. huoshanense. Greenhouse gas emission flux monitoring based on the static chamber method provides an effective way to solve this problem. Therefore, this study conducted a field experiment in the facility cultivation and simulative habitat cultivation modes at a D. huoshanense cultivation base in Dabie Mountains, Anhui Province. From April 2023 to March 2024, samples of greenhouse gases were collected every month, and the concentrations of CO_2, CH_4, and N_2O of the samples were then detected by gas chromatography. The greenhouse gas emission fluxes, cumulative emissions, and global warming potential were further calculated, and the following results were obtained.(1)The two cultivation modes of D. huoshanense showed significant differences in greenhouse gas emission fluxes, especially the CO_2 emission flux, with a pattern of facility cultivation>simulative habitat cultivation [(35.60±11.70)mg·m~(-2)·h~(-1) vs(2.10±4.59)mg·m~(-2)·h~(-1)].(2) The annual cumulative CO_2 emission flux in the case of facility cultivation was significantly higher than that of simulative habitat cultivation[(3 077.00±842.00)kg·hm~(-2) vs(221.00±332.00)kg·hm~(-2)], while no significant difference was found in annual cumulative CH_4 and N_2O emission fluxes.(3) The facility cultivation mode had a significantly higher global warming potential than the simulative habitat cultivation mode [(3 053.00±847.00)kg·hm~(-2) vs(196.00±362.00)kg·hm~(-2)]. Overall, the simulative habitat cultivation of D. huoshanense has obvious carbon-friendly characteristics compared with facility cultivation, which is in line with the concept of ecological cultivation of medicinal plants. This study is of great reference significance for the implementation and promotion of the ecological cultivation mode of D. huoshanense under carbon peaking and carbon neutrality goals.
Dendrobium/chemistry* ; Greenhouse Gases/metabolism* ; Carbon/analysis* ; Ecosystem ; Carbon Dioxide/metabolism* ; China ; Global Warming

In this study, high-throughput promoter screening was employed to optimize the heterologous expression of Mesorhizobium loti carbonic anhydrase (MlCA) in order to reduce the costs associated with carbon capture and storage (CCS). To simplify the complexity of traditional vectors, a fusion protein expression system was constructed using superfolder green fluorescent protein (sfGFP) and MlCA. The synthetic promoter library in Escherichia coli was utilized for efficient one-step screening. Based on fluorescence intensity on agar plates, a total of 143 monoclonal colonies were identified, forming a library with varying expression levels. The top four recombinants with the highest fluorescence intensity were selected, among which MlCA driven by the promoter 342042/+ exhibited the highest enzymatic activity, with a specific activity of the 34.6 Wilbur-Anderson units (WAU)/mg. Optimization experiments revealed that MlCA exhibited the best performance when cultured for 4 days under pH 7.0 and 40 ℃ conditions. The Michaelis constant (K_m·hdy) and maximum reaction rate (V_max·hdy) for CO₂ hydration were determined to be 62.46 mmol/L and 0.164 mmol/(s·L), respectively. For esterase hydrolysis, MlCA showed the K_m and V_max of 639.8 mmol/L and 0.035 mmol/(s·L), respectively. MlCA accelerated the CO₂ hydration process, promoting CO₂ mineralized into CaCO₃ within 9 min at low pH and room temperature conditions. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses confirmed that the precipitated product was calcite. This study provides a low-cost and environmentally friendly alternative for future CCS applications.
Carbonic Anhydrases/biosynthesis* ; Promoter Regions, Genetic/genetics* ; Escherichia coli/metabolism* ; Carbon Sequestration ; Carbon Dioxide/metabolism* ; Green Fluorescent Proteins/metabolism*

OBJECTIVE: To explore the effects of veno-venous extra corporeal carbon dioxide removal (V-V ECCO₂R) on local mechanical power and gas distribution in the lungs of patients with mild to moderate acute respiratory distress syndrome (ARDS) receiving non-invasive ventilation. METHODS: Retrospective research methods were conducted. Sixty patients with mild to moderate ARDS complicated with renal insufficiency who were transferred to the respiratory intensive care unit (RICU) through the 96195 platform critical care transport green channel from January 2018 to January 2020 at the collaborative hospitals of Henan Provincial People's Hospital were enrolled. According to different treatment methods, they were divided into a conventional treatment group and an ECCO₂R group, with 30 patients in each group. Both groups received standard treatments including primary disease treatment, airway management, and non-invasive ventilation. The conventional treatment group received bedside continuous renal replacement therapy (CRRT), and the ECCO₂R group received V-V ECCO₂R treatment. General information of patient such as gender, age, cause of disease, and acute physiology and chronic health evaluation II (APACHE II) were recorded; arterial blood gas analysis was performed before treatment and at 12 hours and 24 hours during treatment, recording arterial partial pressure of oxygen (PaO₂), arterial partial pressure of carbon dioxide (PaCO₂), and oxygenation index (PaO₂/FiO₂). Respiratory mechanics parameters [tidal volume, respiratory rate, maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP)] were recorded, and the rapid shallow breathing index (RSBI) was calculated; electrical impedance tomography (EIT) was used to measure regional of interest (ROI) values in different lung areas at 12 hours and 24 hours of treatment, and the pulmonary mechanical energy was calculated. RESULTS: The arterial blood gas analysis indicators, respiratory mechanics parameters, and pulmonary mechanical energy of patients in the conventional treatment group and ECCO₂R group improved significantly after 24 hours of treatment compared to 12 hours of treatment (all P < 0.05). The levels of PaCO₂, RSBI, total mechanical power, and non-dependent zone mechanical power in the ECCO₂R group were significantly lower than those in the conventional treatment group at both 12 hours and 24 hours during the treatment [PaCO₂ (mmHg, 1 mmHg ≈ 0.133 kPa): 44.03±2.96 vs. 49.96±2.50 at 12 hours, 41.65±3.21 vs. 48.53±2.33 at 24 hours; RSBI (times×min^-1×L^-1): 88.67±4.05 vs. 92.35±4.03 at 12 hours, 77.66±4.64 vs. 90.98±4.21 at 24 hours; total mechanical power (mJ): 10.40±1.15 vs. 12.93±1.68 at 12 hours, 11.13±1.18 vs. 14.05±1.69 at 24 hours; non-dependent zone mechanical power (mJ): 7.15±0.84 vs. 7.98±0.75 at 12 hours, 7.77±0.93 vs. 9.13±1.10 at 24 hours], and MEP and MIP in the ECCO₂R group were significantly higher than those in the conventional treatment group at both 12 hours and 24 hours during the treatment [MEP (cmH₂O, 1 cmH₂O ≈ 0.098 kPa): 89.88±5.04 vs. 86.09±5.57 at 12 hours, 96.57±2.59 vs. 88.66±2.98 at 24 hours; MIP (cmH₂O): 47.64±2.82 vs. 41.93±2.44 at 12 hours, 60.11±6.53 vs. 43.63±2.80 at 24 hours], the differences were statistically significant (all P < 0.05). CONCLUSIONS V-V ECCO₂R combined with non-invasive ventilation can effectively reduce the regional tidal volume, mechanical power, and respiratory rate in the non-gravitational dependent zones of patients with mild to moderate ARDS, and improve respiratory distress and oxygenation status.
Humans ; Respiratory Distress Syndrome/physiopathology* ; Retrospective Studies ; Carbon Dioxide ; Blood Gas Analysis ; Lung/physiopathology* ; Intensive Care Units ; Male ; Female ; Noninvasive Ventilation/methods* ; Continuous Renal Replacement Therapy/methods* ; APACHE ; Middle Aged

Prehospital emergency care is the primary stage in the treatment of critically ill patients, where efficient and accurate monitoring methods are crucial for patient survival and prognosis. End-tidal carbon dioxide (EtCO₂) monitoring is a real-time, non-invasive method that can sensitively capture the status of respiratory, circulatory, and metabolic functions, particularly in the urgent and complex pre-hospital environment, a immediate detection and non-invasive method, can sensitively capture the respiratory, circulatory, and metabolic status of patients. It provides valuable guidance for rapid decision-making and precise interventions. This is particularly valuable in the complex and urgent prehospital environment, providing critical data for rapid decision-making and precise intervention. This paper systematically reviews the advancements in the application of EtCO₂ monitoring across various fields, including sepsis identification, trauma assessment, cardiac arrest, respiratory critical care, endotracheal intubation confirmation, and management of metabolic diseases, aiming to explore its application value and prospects in pre-hospital emergency care.
Humans ; Emergency Medical Services/methods* ; Carbon Dioxide/analysis* ; Monitoring, Physiologic/methods* ; Critical Illness ; Capnography/methods*

OBJECTIVES: To evaluate the immunogenicity and osteogenic ability of animal-derived bone graft material decellularized with supercritical carbon dioxide. METHODS: Porcine femurs were randomly divided into two groups after preliminary treatment, and decellularized with conventional method (control group) or supercritical carbon dioxide (experimental group). Allogenic demineralized bone matrix was used as positive control. Clearance rate of galactose-α-1, 3-galactose (α-Gal) antigen was determined by enzyme-linked immunosorbent assay and residual DNA was detected by a fluorescence method. Nine SPF-grade male athymic nude mice of 6 weeks old were randomly divided into experimental, control and positive control groups. Samples were implanted over biceps femoris muscle of athymic nude mice. The explants were collected 4 weeks post implantation. Hematoxylin and eosin (HE) staining and immunohistochemistry were applied to determine the osteogenic ability and bone tissue-associated protein expressions of the implants. RESULTS: The clearance rates of α-Gal antigen in the experimental group and the control group were (99.09±0.26)% and (30.18±2.02)%, respectively (t=58.67, P<0.01). The residual DNA of the experimental, control and positive control groups were (13.49±0.07), (15.20±0.21) and (14.70±0.17) ng/mg. The residual DNA in the experimental group was significantly lower than that in the control group (t=－13.41, P<0.01) and positive control group (t=－11.30, P<0.01). HE staining results showed that multiple bone formation centers with active osteogenesis and rich bone marrow were observed in experimental group 4 weeks after implantation, but only a small number of bone formation centers were observed in the control and positive control groups, with no obvious osteoblasts present. Immunohistochemistry results indicated that the expressions of alkaline phosphatase, Runt-related transcription factor 2, collagen typeⅠand osteocalcin in the experimental group showed an increasing trend compared with those in the control and positive control groups. CONCLUSIONS Compared with clinically used allogenic demineralized bone matrix and bone graft material decellularized with conventional method, bone graft material decellularized with supercritical carbon dioxide exhibits lower immunogenicity and better osteogenic ability.
Animals ; Mice ; Swine ; Male ; Bone Transplantation/methods* ; Mice, Nude ; Carbon Dioxide ; Osteogenesis/drug effects* ; Femur ; Bone Substitutes ; Tissue Engineering/methods*

OBJECTIVE: To investigate the association between short-term exposure to indoor total volatile organic compounds (TVOC) and nocturnal heart rate variability (HRV) among young female adults. METHODS: This panel study recruited 50 young females from one university in Beijing, China from December 2021 to April 2022. All the participants underwent two sequential visits. During each visit, real time indoor TVOC concentration was monitored using an indoor air quality detector. The real time levels of indoor temperature, relative humidity, noise, carbon dioxide and fine particulate matter were monitored using a temperature and humidity meter, a noise meter, a carbon dioxide meter and a particulate counter, respectively. HRV parameters were measured using a 12-lead Holter. Mixed-effects models were used to evaluate the association between the TVOC and HRV parameters and establish the exposure-response relationships, and two-pollutant models were applied to examine the robustness of the results. RESULTS: The mean age of the 50 female subjects was (22.5±2.3) years, and the mean body mass index was (20.4±1.9) kg/m². During this study, the median (interquartile range) of indoor TVOC concentrations was 0.069 (0.046) mg/m³, the median (interquartile range) of indoor temperature, relative humidity, carbon dioxide concentration, noise level and fine particulate matter concentration were 24.3 (2.7) ℃, 38.5% (15.0%), 0.1% (0.1%), 52.7 (5.8) dB(A) and 10.3 (21.5) μg/m³, respectively. Short-term exposure to indoor TVOC was associated with significant changes in time-domain and frequency-domain HRV parameters, and the exposure metric for most HRV parameters with the most significant changes was 1 h-moving average. Along with a 0.01 mg/m³ increment in 1 h-moving average concentration of indoor TVOC, this study observed decreases of 1.89% (95%CI: -2.28%, -1.50%) in standard deviation of all normal to normal intervals (SDNN), 1.92% (95%CI: -2.32%, -1.51%) in standard deviation of average normal to normal intervals (SDANN), 0.64% (95%CI: -1.13%, -0.14%) in percentage of adjacent NN intervals differing by more than 50 ms (pNN50), 3.52% (95%CI: -4.30%, -2.74%) in total power (TP), 5.01% (95%CI: -6.21%, -3.79%) in very low frequency (VLF) power, and 4.36% (95%CI: -5.16%, -3.55%) in low frequency (LF) power. The exposure-response curves showed that indoor TVOC was negatively correlated with SDNN, SDANN, TP, and VLF when the concentration exceeded 0.1 mg/m³. The two-pollutant models indicated that the results were generally robust after controlling indoor noise and fine particulate matter. CONCLUSION Short-term exposure to indoor TVOC was associated with significant negative changes in nocturnal HRV of young women. This study provides an important scientific basis for relevant prevention and control measures.
Humans ; Female ; Adult ; Young Adult ; Air Pollutants/analysis* ; Heart Rate/physiology* ; Volatile Organic Compounds/analysis* ; Carbon Dioxide ; Particulate Matter/adverse effects* ; Environmental Pollutants

Introduction: Laparoscopic Cholecystectomy uses carbon dioxide (CO2) which affects the respiratory, cardiovascular and renal system. The residual CO2 induces phrenic nerve irritation, manifesting as shoulder and abdominal pain. Recruitment maneuvers opens the lungs and helps expelling this residual carbon dioxide. However, there are limited studies on its role to hemodynamics especially in patients undergoing abdominal laparoscopic procedures. Methods: Sixty patients (51 15.1) scheduled for laparoscopic cholecystectomy under General Endotracheal Anesthesia were randomly allocated to two groups. The control group (Group C) underwent standard laparoscopic cholecystectomy procedures. The experimental group (Group R) was placed in a Trendelenburg and was given 4-5 manual pulmonary inflations at a pressure of 40cmH20. The blood pressure, heart rate, respiratory rate and oxygen saturation, as well as the post operative site pain and shoulder pain were measured using the Numerical Pain Scale (NPS) were monitored at 0, 1 and 2 hours post operatively. Results: The demographics and preoperative vital signs were comparable. The mean systolic blood pressure [119.5 vs 131.5; p=0.002], mean arterial pressure [91.8 vs 95.3; p=0.049], heart rate [74.9 vs 87.5; p <0.001] and respiratory rate [15.7 vs 16.2; p=0.02] were all differrent only during the immediate post operative period. The mean shoulder pain was lower in Group R immediately [1.9 ± 1.2; p=0.01] and 1 hour after surgery [0.7 ± 0.8; p=0.01]. Conclusion Recruitment maneuver significantly reduces the shoulder pain scores after laparoscopic cholecystectomy. It causes a decrease in blood pressure, heart rate and mean arterial pressure in the immediate post operative period.
Cholecystectomy, Laparoscopic ; Shoulder Pain ; Hemodynamics ; Carbon Dioxide

INTRODUCTION: Laryngeal mask airway (LMA), which is used in difficult airway maintenance conditions during emergencies, is rarely used in prolonged surgery despite its advantages over endotracheal tube (ETT). In this study, we conducted a comparative analysis of intraoperative gas exchanges between second-generation LMA and ETT during prolonged laparoscopic abdominal surgery. METHODS: Prolonged surgery was defined as a surgery lasting more than 2 h. In total, 394 patients who underwent laparoscopic liver resection via either second-generation LMA or ETT were retrospectively analysed. The following parameters were compared between the two groups of patients: end-tidal pressure of carbon dioxide (ETCO₂), tidal volume (TV), respiratory rate (RR), peak inspiratory pressure (PIP), arterial partial pressure of carbon dioxide (PaCO₂), pH and ratio of arterial partial pressure of oxygen to fractional inspired oxygen (PFR) during surgery. In addition, the incidence of postoperative pulmonary complications (PPCs), including pulmonary aspiration, was compared. RESULTS: The values of ETCO₂, TV, RR and PIP during pneumoperitoneum were comparable between the two groups. Although PaCO₂ at 2 h after induction was higher in patients in the LMA group (40.5 vs. 38.5 mmHg, P < 0.001), the pH and PFR values of the two groups were comparable. The incidence of PPC was similar. CONCLUSION During prolonged laparoscopic abdominal surgery, second-generation LMA facilitates adequate intraoperative gas exchange and may serve as an alternative to ETT.
Humans ; Laryngeal Masks ; Carbon Dioxide ; Retrospective Studies ; Intubation, Intratracheal ; Laparoscopy/adverse effects* ; Postoperative Complications/etiology* ; Oxygen