Improving the Validity of Peripheral Venous Blood Gas Analysis as an Estimate of Arterial Blood Gas by Correcting the Venous Values with SvO2

Background

Peripheral venous blood gas (pVBG) analysis in replacement of arterial blood gas (ABG) is limited by the unpredictable differences between arterial and venous values, especially for PCO₂ and pH (ΔPCO₂ and ΔpH).

Objectives

We hypothesized that, using the theoretical relationship linking SvO₂ and blood flow, we could diminish the effect of local circulatory conditions on ΔPCO₂ and ΔpH and thereby increase pVBG validity.

Methods

This was a prospective cross-sectional study performed in emergency patients requiring a blood gas analysis in which ABG and pVBG were performed simultaneously. The data of 50 randomly selected patients (model group) were used for developing two equations to correct PvCO₂ and pHv according to the peripheral SvO₂ (SpvO₂) level. The formulas derived were PvCO_2cor = PvCO₂ − 0.30 × (75 − SpvO₂), and pHv_cor = pHv + 0.001 × (75 − SpvO₂). The validity of the corrected values was then tested on the remaining population (validation group).

Results

There were 281 patients included in the study, mainly for dyspnea. ΔPCO₂ and ΔpH were strongly correlated with SpvO₂ (r² = 0.62 and r² = 0.53, respectively, p < 0.001). Using the data of the model group, we developed equations that we applied on the validation group. We found that the corrected values were more valid than the raw values for detecting a PaCO₂ > 45 mm Hg (AUC ROC = 0.96 ± 0.01 vs. 0.89 ± 0.02, p < 0.001), a PaCO₂ < 35 mm Hg (AUC = 0.95 ± 0.02 vs. 0.84 ± 0.03, p < 0.001), a pHa < 7.35 (AUC = 0.97 ± 0.01 vs. 0.95 ± 0.02, p < 0.05), or a pHa > 7.45 (AUC = 0.91 ± 0.02 vs. 0.81 ± 0.04, p < 0.001).

Conclusions

The variability of ΔPCO₂ and ΔpH is significantly lowered when the venous values are corrected according to the SpvO₂ value, and pVBG is therefore more accurate and valid for detecting an arterial abnormality.     

Charging Behavior and Stability of the Novel Amino Group Containing Cellulose Ester Cellulose‐4‐[N‐methylamino]butyrate Hydrochloride

The charging behavior of water‐soluble cellulose‐4‐[N‐methylamino]butyrate hydrochloride (CMABH) with different degree of substitution (DS) is investigated by polyelectrolyte titration at different pH values. Samples of high DS (0.92) and low DS (0.31) exhibit a decrease in positively charged groups from pH 2 (3.9 and 1.9 mmol g^?1) to pH 9 (0.81 and 0.65 mmol g^?1) due to the deprotonation of the ammonium groups. The stability of the ester linkage of CMABH is examined as a function of pH value and storage time (up to 28 d). A hydrolysis of the ester moiety is evident after 2 h at pH 8, which is also proved by ATR‐FTIR‐ and Raman spectroscopy.     

危重病三重酸碱失衡发生率及预后分析

目的：了解危重病三重酸碱失衡(TABD)发生率及预后。方法：选择392例危重病患者为研究对象,检测其动脉血气分析值和血电解质,计算阴离子间隙、潜在HC03 -,根据酸碱失衡诊断标准,了解TABD的发生率,并分析其预后情况。结果：392例危重患者中TABD 42例(10.7％),≥60岁TABD发生率较高,TABD组年龄...     

大鼠内囊电毁损痉挛模型的构建及电针干预作用研究

目的：构建一种新的痉挛动物模型以期最大程度地模拟痉挛后的病理生理改变;观察并研究电针的干预作用。方法：应用脑立体定位仪,精确地进行深部内囊的损伤定位,采用电毁损内囊的方式制造大鼠痉挛模型;采用电针督脉＂大椎＂、＂命门＂的方式进行电针治疗。结果：内囊电毁损后,模型组、电针组与空白组和假手术组比较大鼠痉挛侧上肢伸直幅度明显降低,有统计学意义（P〈0.01）;电针治疗后,电针组与模型组比较明显升高,有统计学意义（P〈0.01）。结论：电毁损内囊可作为制作大鼠痉挛性瘫痪的一种优选方案;电针可以使内囊电毁损大鼠增高的肌张力降低,对痉挛有治疗作用。     

Investigation of Post-Processing of Additively Manufactured Nitinol Smart Springs with Plasma-Electrolytic Polishing

Additive manufacturing of Nitinol is a promising field, as it can circumvent the challenges associated with its conventional production processes and unlock unique advantages. However, the accompanying surface features such as powder adhesions, spatters, ballings, or oxide discolorations are undesirable in engineering applications and therefore must be removed. Plasma electrolytic polishing (PeP) might prove to be a suitable finishing process for this purpose, but the effects of post-processing on the mechanical and functional material properties of additively manufactured Nitinol are still largely unresearched. This study seeks to address this issue. The changes on and in the part caused by PeP with processing times between 2 and 20 min are investigated using Nitinol compression springs manufactured by Laser Beam Melting. As a benchmark for the scanning electron microscope images, the differential scanning calorimetry (DSC) measurements, and the mechanical load test cycles, conventionally fabricated Nitinol springs of identical geometry with a medical grade polished surface are used. After 5 min of PeP, a glossy surface free of powder adhesion is achieved, which is increasingly levelled by further polishing. The shape memory properties of the material are retained without a shift in the transformation temperatures being detectable. The decreasing spring rate is primarily attributable to a reduction in the effective wire diameter. Consequently, PeP has proven to be an applicable and effective post-processing method for additively manufactured Nitinol.     

Association of dietary acid-base load and psychological disorders among Iranian women: A cross-sectional study

Metabolic acidosis, which can be affected by dietary acid-base load, seems to be associated with psychological disorders through different pathways. Given limited evidence on dietary acid-base load, we aimed to examine the association of dietary acid-base load with psychological disorders in Iranian women. This cross-sectional study was performed on 447 female subjects (20–50 years old). Dietary intake was assessed using a valid food frequency questionnaire for Iran. Dietary acid-base load was calculated through different indices including potential renal acid load (PRAL), net endogenous acid production (NEAP), and dietary acid load (DAL). To assess psychological disorders, an Iranian validated version of depression, anxiety, and stress scale (DASS-21) was used. The mean value of PRAL, NEAP, and DAL were -8.87mEq/da, 37.94mEq/day, and 30.77mEq/day, respectively. Considering a wide range of confounding variables, compared with the first tertile, a significant positive association was observed between dietary acid-base load and depression (OR_PRAL: 3.63; 95 %CI:1.97, 6.71; P_trend = 0.0001) (OR_NEAP:3.42; 95 %CI: 1.87, 6.23; P_trend = 0.0001) (OR_DAL: 3.02; 95 %CI: 1.64, 5.58; P_trend = 0.0001). Women in the high dietary acid-base load category had higher anxiety (OR_PRAL: 3.31; 95 %CI: 1.81, 6.06; P_trend = 0.0001) (OR_NEAP:3.47; 95 %CI: 1.90, 6.33; P_trend = 0.0001) (OR_DAL: 3.25; 95 %CI: 1.76, 5.98; P_trend = 0.0001). Moreover, there was a strong positive relationship between dietary acid-base load and psychologicaldistress (OR_PRAL: 3.79; 95 %CI: 2.09, 6.90; P_trend = 0.0001) (OR_NEAP: 3.67; 95 %CI: 2.04, 6.58; P_trend = 0.0001) (OR_DAL: 3.00; 95 %CI: 1.66, 5.43; P_trend = 0.0001). Women with higher dietary acid-base load score had greater odds for depression, anxiety, and psychological distress compared to lower ones.     

眼科手术中结膜囊消毒剂的应用与研究

眼内炎是眼科术后最为严重的并发症,结膜囊消毒是目前公认的能有效减少眼内炎发生的重要措施。目前已应用临床或在研究的结膜囊消毒剂主要有：汞剂、庆大霉素、聚维酮碘、酸性电解质水。各类消毒剂通过不同的途径发挥消毒杀菌作用。目前临床应用最为广泛的结膜囊消毒剂是聚维酮碘,汞剂及庆大霉素因其对环境的污染、易产生耐药菌、局部副反应重等原因现已鲜少使用于临床。酸性电解质水目前亦尚未使用于临床。随着眼科手术的普及及发展,眼科医师对患者术后眼部舒适度也越来越关注,未来结膜囊消毒剂的研究与应用将不断更新发展。     

Oxygen-linked hydrogen ion binding of canine blood

Decrease in hemoglobin oxygen saturation without change of true blood baseexcess results in an increase in calculated base-excess because of differences in acidity between oxy- and deoxyhemoglobin. We have determined the mean ± SE canine base-excess correction coefficient to be 0.43±0.01 mmol base per mmol heme, a value approximately 34% higher than the corresponding value for human hemoglobin.New abbreviations base-excess correction coefficient