Propylene glycol-induced side effects during intravenous nitroglycerin therapy

Propylene glycol, an alcohol frequently used as a solvent in medical preparations, is considered non-toxic. We found that this solvent, used in a commercially available IV nitroglycerin solution, may cause hyperosmolality, hemolysis and lactic acidosis. The influence of kidney function as the main determinant in causing accumulation of this solvent and consequently hyperosmolality is emphasized. A review of the literature dealing with propylene glycol is given. The possible mechanisms of neurological disturbances occurring during IV nitroglycerin therapy are discussed.     

Hemolyzed Laboratory Specimens in the Emergency Department: An Underappreciated,but Frequent Problem

IntroductionHemolysis of blood samples from emergency department (ED) patients leads to delays in treatment and disposition. The aim of this study is to determine the frequency of hemolysis and variables predictive of hemolysis.MethodsThis observational cohort study was conducted among three institutions: academic tertiary care center and two suburban community EDs, with an annual census of over 270,000 ED visits. Data were obtained from the electronic health record. Adults requiring laboratory analysis with at least one peripheral intravenous catheter (PIVC) inserted within the ED were eligible. Primary outcome was hemolysis of lab samples and secondary outcomes included variables related to PIVC failure.ResultsBetween January 8, 2021 and May 9, 2022, 141,609 patient encounters met inclusion criteria. The average age was 55.5 and 57.5% of patients were female. Hemolysis occurred in 24,359 (17.2%) samples. In a multivariate analysis, when compared to 20-gauge catheters, smaller 22-gauge catheters had an increased odds of hemolysis (OR 1.78, 95% confidence interval (CI) 1.65-1.91; P < .001), while larger 18-gauge catheters had a lower odds of hemolysis (OR 0.94; 95% CI 0.90-0.98; P = .0046). Additionally, when compared to antecubital placement, hand/wrist placement demonstrated increased odds of hemolysis (OR 2.06; 95% CI 1.97-2.15; P < .001). Finally, hemolysis was associated with a higher rate of PIVC failure (OR 1.06; 95%CI 1.00-1.13; P = 0.043).DiscussionThis large observational analysis demonstrates that lab hemolysis of is a frequent occurrence among ED patients. Given the added risk of hemolysis with certain placement variables, clinicians should consider catheter gauge/placement location to avoid hemolysis that may result in patient care delays and prolonged hospital stays.     

New indicators in evaluation of hemolysis,elevated liver enzymes,and low platelet syndrome: A case-control study

BACKGROUNDIndices such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), mean platelet volume (MPV), platelet distribution width (PDW), and red cell distribution width (RDW) are considered new markers of the systemic inflammatory response (SIR), and have been widely implemented for the diagnosis of patients with inflammatory diseases. These new indicators have also been widely investigated in preeclampsia (PE) but less analyzed in hemolysis, elevated liver enzymes, and low platelet (HELLP) syndrome.AIMTo compare SIR markers among HELLP patients, PE only patients, and healthy gravidae.METHODSThis retrospective case-control study enrolled 630 cases, including 210 patients with HELLP syndrome (HELLP group), 210 patients with only PE (PE group) and 210 healthy gravidae (control group). The three groups were matched by age, parity, status of assisted reproduction, and multiple pregnancies. Birthweight, gestational age at complete blood count collection, gestational age at delivery, mode of delivery, etc. were recorded. The main indices as NLR, PLR, MPV, PDW, and RDW among the groups were compared, as well as some secondary outcomes including neutrophil, platelets, and hemoglobin.RESULTSThe NLR (6.4 vs 4.3 vs 3.5), MPV (11.9 vs 11.2 vs 10.7), PDW (16.4 vs 13.3 vs 14.2), leukocyte (12.4 × 10⁹/L vs 9.7 × 10⁹/L vs 8.7 × 10⁹/L) and neutrophil count (9.9 × 10⁹/L vs 7.3 × 10⁹/L vs 6.1 × 10⁹/L) were highest in the HELLP group, lower in the PE group, and lowest in the control group. Both the overall comparisons between the three groups (all ^bP < 0.01) and pairwise comparisons between every two groups elicited statistically significant differences (all ^dP < 0.01, except control vs PE: ^cP < 0.05 in PDW). The average lymphocyte counts were 1.4 (1.1, 2.0) × 10⁹/L in the HELLP group, 1.6 (1.3, 2.0) × 10⁹/L in the PE group and 1.7 (1.4, 2.0) × 10⁹/L in the control group. The overall comparison of lymphocyte count within the three groups had statistically significant differences (P = 0.000). The pairwise comparisons between every two groups demonstrated that the HELLP group had a lower lymphocyte count than both the PE (P = 0.019) and control groups (P = 0.000), but the difference between the PE and control groups was not statistically significant (P = 0.432). The overall comparisons on platelet counts and the PLR among these three groups also showed statistically significant differences (both P = 0.000), from low to high being those in the HELLP group (43.4 × 10⁹/L, 64.0), control group (180.5 × 10⁹/L, 103.6) and PE group (181.5 × 10⁹/L, 112.8). Pairwise comparisons of neither index displayed statistically significant differences between the PE and control groups (both P > 0.05), while the differences in the two indices between the HELLP group and the two other groups were still statistically significant (all P = 0.000). RDW values were highest in the HELLP group (14.5% [13.6, 15.3]), lower in the control group (14.1% [13.5, 14.8]) and lowest in the PE group (13.9% [13.4, 14.9]). The difference between the PE and control group did not show statistical significance (P = 1.000), while RDW values in the HELLP group were higher than those in the other two groups (^cP < 0.05 vs control, ^dP < 0.01 vs PE).CONCLUSIONSIR markers such as NLR, RDW, MPV, and PDW were increased and PLR was decreased in HELLP. These SIR markers may become new indicators in the evaluation of HELLP syndrome.     

Reevaluation of the harboe assay as a standardized method of assessment for the hemolytic performance of ventricular assist devices

The Harboe spectrophotometric assay is regarded as one of the safest and most reproducible methods for measuring plasma free hemoglobin (pfHb). However, there is still some ambiguity in the application of the assay when assessing the hemolytic performance of ventricular assist devices (VADs). The purpose of this study was to reexamine and compare values of pfHb obtained using different concentrations of plasma diluent (Na(2) CO(3) ) as cited by various studies such that a standard practice may be recommended for the application of the Harboe assay in the hemolytic evaluation of VADs, allowing reliable comparisons to be made between laboratories. As a means to examine the Harboe assay, a BioMedicus BPX-80 was tested using both whole blood and a washed suspension of red blood cells (RBCs). Results show that for whole blood, the pfHb may be underestimated by 13-23%, dependent upon the concentration of Na(2) CO(3) diluent solution. This trend was not observed for the washed suspension of RBCs. Furthermore, it is shown that the concentration of diluent influences the stability of a sample. The results of this study show that the problems associated with the incongruity of pfHb readings are a direct result of the precipitation of proteins from the plasma under alkaline conditions; as the molarity of the diluent controls pH, it becomes essential to use the appropriate concentration of Na(2) CO(3) diluent in order to avoid turbidity of the solution and the consequent misrepresentation of pfHb values. Such standardization is pertinent when measuring the very low levels of pfHb observed during the in vivo testing of modern ventricular assist devices.     

Progress on the design and development of the continuous-flow total artificial heart

Cleveland Clinic's continuous‐flow total artificial heart has one motor and one rotating assembly supported by a hydrodynamic bearing. The right hydraulic output is self regulated by passive axial movement of the rotating assembly to balance itself with the left output. The purpose of this article is to present progress in four areas of development: the automatic speed control system, self‐regulation to balance right/left inlet pressures and flows, hemolysis testing using calf blood, and coupled electromagnetics (EMAG) and computational fluid dynamics (CFD) analysis. The relationships between functions of motor power and speed, systemic flow, and systemic vascular resistance (SVR) were used for the sensorless speed control algorithm and demonstrated close correlations. Based on those empirical relationships, systemic flow and SVR were calculated in the system module and showed good correlation with measured pump flow and SVR. The automatic system adjusted the pump's speed to obtain the target flow in response to the calculated SVR. Atrial pressure difference (left minus right atrial pressure) was maintained within ±10 mm Hg for a wide range of SVR/pulmonary vascular resistance ratios, demonstrating a wide margin of self‐regulation under fixed‐speed mode and 25% sinusoidally modulated speed mode. Hemolysis test results indicated acceptable values (normalized index of hemolysis <0.01 mg/dL). The coupled EMAG/CFD model was validated for use in further device development.     

G-6-PD缺乏症和新生儿高胆红素血症

葡萄糖-6-磷酸脱氢酶缺乏症是一种常见的单基因遗传性疾病,在全球范围内分布非常广泛,而且人群中携带者频率很高。患者突然出现的急性溶血会导致血清总胆红素升高,引起高胆红素血症,甚至胆红素脑病。新生儿高胆红素血症是儿科医生经常遇到的问题,需要及时发现和处理。     

The antioxidant tempol decreases acute pulmonary thromboembolism-induced hemolysis and nitric oxide consumption

Introduction

Acute pulmonary thromboembolism (APT) is a critical condition associated with acute pulmonary hypertension. Recent studies suggest that oxidative stress and hemolysis contribute to APT-induced pulmonary hypertension, possibly as a result of increased nitric oxide (NO) consumption. We hypothesized that the antioxidant tempol could attenuate APT-induced hemolysis, and therefore attenuate APT-induced increases in plasma NO consumption.

Materials and Methods

APT was induced in anesthetized sheep with autologous blood clots. The hemodynamic effects of tempol infused at 1.0 mg/kg/min 30 min after APT were determined. Hemodynamic measurements were carried out every 15 min. To assess oxidative stress, serum 8-isoprostanes levels were measured by ELISA. Plasma cell-free hemoglobin concentrations and NO consumption by plasma samples were determined. An in vitro oxidative AAPH-induced hemolysis assay was used to further validate the in vivo effects of tempol.

Results

APT caused pulmonary hypertension, and increased pulmonary vascular resistance in proportion with the increases in 8-isoprostanes, plasma cell-free hemoglobin concentrations, and NO consumption by plasma (all P < 0.05). Tempol attenuated the hemodynamic alterations by approximately 15-20% and blunted APT-induced increases in 8-isoprostanes, in cell-free hemoglobin concentrations, and the increases in NO consumption by plasma (P < 0.05). Tempol dose-dependently attenuated AAPH-induced in vitro hemolysis (P < 0.05).

Conclusions

Our findings are consistent with the idea that antioxidant properties of tempol decrease APT-induced hemolysis and nitric oxide consumption, thus attenuating APT-induced pulmonary hypertension.     

自动监测样品状态在临床生化检测中的应用

目的拓展全自动生化分析仪的功能,利用其自动判别样品的脂血、黄疸与溶血(LIH)状态,比较其与传统的肉眼判定结果的差异。方法编制特定的LIH检测程序,采用生理盐水作测定LIH级别的试剂,每日监测样品的LIH状态,460余份异常者同时测定其三酰甘油(TG)、总胆红素(TB il)及血红蛋白(Hb)含量。将95份仪器判别为存在LIH的样品与30份明显LIH的样品进行单盲人工判别,比较两者的一致性。结果仪器与人工判别样品有无黄疸和溶血及其严重程度差异无显著性;2种方法判断脂血状态有一定差异,对低TG水平[(3.02±1.81)mmol/L]的样品判别两者符合率较低;但TG浓度较高[(8.77±5.34)mmol/L]的样品,两者的符合率可达93.33%。明显溶血[Hb为(4.23±1.65)g/L]与黄疸[TB il为(198.61±132.95)μmol/L]的样品,两法判别的符合率均为100%。结论采用仪器自动判别样品的LIH状态结果比传统的手工法更为可靠,同时又极大地提高检验工作效率,具有很好的实用价值。     

Enhancement of Hemocompatibility of the MERA Monopivot Centrifugal Pump: Toward Medium‐Term Use

The MERA monopivot centrifugal pump has been developed for use in open‐heart surgery, circulatory support, and bridge‐to‐decision for up to 4 weeks. The pump has a closed‐type, 50‐mm diameter impeller with four straight paths. The impeller is supported by a monopivot bearing and is driven by a radial‐flux magnet‐coupling motor. Because flow visualization experiments have clarified sufficient pivot wash and stagnation at the sharp corner of the pivot support was suggested, sharp corners were removed in the design stage. The index of hemolysis of the pump operating at more than 200 mm Hg was found to be lower than that of a commercial pump. Four‐week animal tests were then conducted two times; improvement of thrombus formation was seen in the female pivot through modification of female pivot geometry. Overall antithrombogenicity was also recorded. Finally, to assure mid‐term use, an additional 4‐week durability test revealed that the rate of the axial pivot wear was as small as 1.1 µm/day. The present in vitro and in vivo studies revealed that the MERA monopivot centrifugal pump has sufficient hemocompatibility and durability for up to 4 weeks.