Search

Background: Patients with sepsis with low albumin levels and high red blood cell distribution width levels have poor prognoses. Red blood cell distribution width to albumin ratio (RAR) has recently attracted attention as an innovative inflammation biomarker. We aimed to explore the association between RAR and the prognosis of patients with sepsis. Methods: This retrospective observational study included 402 patients meeting the sepsis-3 standards admitted to Yantai Yuhuangding Hospital's intensive care units (ICUs) between January 2020 and December 2022. The relationship between RAR and mortality in patients with sepsis was examined using regression analysis, Kaplan–Meier analyses, and a receiver operating characteristic curve. Subgroup and sensitivity analyses were conducted to assess the results' robustness. Results: RAR, when considered as a continuous variable, was a significant independent in-hospital mortality risk factor (adjusted odds ratio [OR]: 1.383; 95% confidence interval [CI]: 1.164–1.645; P < 0.001). When considering RAR as a categorical variable, the ORs (95% CIs) of hospital mortality for quartile 2 (Q2), Q3, and Q4 compared with Q1 were 1.027 (0.413–2.551), 3.632 (1.579–8.354), and 4.175 (1.625–10.729), respectively, P < 0.001. Similar outcomes were observed for 28- and 90-day mortalities. Conclusions: RAR may indicate clinical prognosis for patients with sepsis in the ICU, potentially providing a low-cost, easily repeatable, and accessible biomarker for risk categorization for these patients. [ABSTRACT FROM AUTHOR]

Duplicate measure of hemoglobin mass by carbon monoxide (CO)-rebreathing is a logistical challenge as recommendations prompt several hours between measures to minimize CO-accumulation. This study investigated the feasibility and reliability of performing duplicate CO-rebreathing procedures immediately following one another. Additionally, it was evaluated whether the obtained hemoglobin mass from three different CO-rebreathing devices is comparable. Fifty-five healthy participants (22 males, 23 females) performed 222 duplicate CO-rebreathing procedures in total. Additionally, in a randomized cross-over design 10 participants completed three experimental trials, each including three CO-rebreathing procedures, with the first and second separated by 24 h and the second and third separated by 5–10 min. Each trial was separated by >48 h and conducted using either a glass-spirometer, a semi-automated electromechanical device, or a standard three-way plastic valve designed for pulmonary measurements. Hemoglobin mass was 3 ± 22 g lower (p < 0.05) at the second measure when performed immediately after the first with a typical error of 1.1%. Carboxyhemoglobin levels reached 10.9 ± 1.3%. In the randomized trial, hemoglobin mass was similar between the glass-spirometer and three-way valve, but ∼6% (∼50 g) higher for the semi-automated device. Notably, differences in hemoglobin mass were up to ∼13% (∼100 g) when device-specific recommendations for correction of CO loss to myoglobin and exhalation was followed. In conclusion, it is feasible and reliable to perform two immediate CO-rebreathing procedures. Hemoglobin mass is comparable between the glass-spirometer and the three-way plastic valve, but higher for the semi-automated device. The differences are amplified if the device-specific recommendations of CO-loss corrections are followed. [ABSTRACT FROM AUTHOR]

An indispensable precondition for the determination of hemoglobin mass (Hbmass) and blood volume by CO rebreathing is complete mixing of CO in the blood. The aim of this study was to demonstrate the kinetics of CO in capillary and venous blood in different body positions and during moderate exercise. Six young subjects (4 male, 2 female) performed three 2-min CO rebreathing tests in seated (SEA) & supine (SUP) positions as well as during moderate exercise (EX) on a bicycle ergometer. Before, during, and until 15 min after CO rebreathing cubital venous and capillary blood samples were collected simultaneously and COHb% was determined. COHb% kinetics were significantly slower in SEA than in SUP or EX. Identical COHb% in capillary and venous blood were reached in SEA after 5.0 ± 2.3 min, in SUP after 3.2 ± 1.3 min and in EX after 1.9 ± 1.2 min (EX vs. SEA p <.01, SUP vs. SEA p <.05). After 7th min, Hbmass did not differ between the resting positions (capillary: SEA 766 ± 217 g, SUP 761 ± 227 g; venous: SEA 759 ± 224 g, SUP 744 ± 207 g). Under exercise, however, a higher Hbmass (p <.05) was determined (capillary: 823 ± 221 g, venous: 804 ± 226 g). In blood, the CO mixing time in the supine position is significantly shorter than in the seated position. By the 6th minute complete mixing is achieved in either position giving similar Hbmass determinations. CO-rebreathing under exercise conditions, however, leads to ∼7% higher Hbmass values. [ABSTRACT FROM AUTHOR]

Purpose: This investigation quantified the effect of changes in plasma osmolality on the measurement of hematocrit (Hct) and the implications for the subsequent use of these data to calculate changes in plasma volume and application to the World Anti-Doping Agency Athlete Biological Passport. Methods: Two groups of eight male volunteers visited the laboratory after an overnight fast. In study 1, a 20-mL blood sample was collected and aliquoted into collection tubes containing saline of varying concentrations to alter the sample osmolality. In study 2, plasma osmolality was manipulated in vivo through prolonged exercise. Samples were analyzed for hemoglobin concentration and Hct using manual methods and using an automated hematology analyzer (AHA). Results: Changes in blood, plasma, and red cell volumes were calculated. Although AHA Hct values did not change (P = 0.652), spun packed cell volume fell progressively as the osmolality of the sample increased (P < 0.001, study 1). Consequently, there was a significant increase in apparent plasma volume as osmolality increased (P < 0.001): regression analysis revealed that a 10 mOsm⋅kg-1 change in plasma osmolality produced a difference of 0.8 Hct units and a 1.6% change in plasma volume. In study 2, exercise produced a 12 ± 3 mOsm⋅kg-1 increase in plasma osmolality. No difference in Hct was apparent at rest (P = 0.659), but spun packed cell volume was 1.0 ± 0.9 Hct units lower during exercise compared with AHA data (P < 0.001). There was a difference in the degree of plasma volume change calculated, with a reduction of 8.7% ± 3.4% and 11.3% ± 3.5% reported with the manual and AHA methods, respectively (P = 0.002). Conclusions: Conditions or interventions that result in a marked change in plasma osmolality produce a discrepancy in Hct measured using an AHA, consequently introducing errors into any calculation of changes in plasma volume using these data. These findings may also have implications for the measurement of Hct by World Anti-Doping Agency-accredited laboratories. [ABSTRACT FROM AUTHOR]

Objective: Fetal alloimmune anemia is associated with increased blood flow velocities and cardiomegaly. In severe cases, hydrops can develop. We investigated whether the decrease of red blood cell volume is associated with a reduction or expansion of plasma volume. Methods: In 86 alloimmunized fetuses that received a first intrauterine transfusion, we calculated fetal total blood volumes (i.e. fetoplacental blood volumes) using a dilutional principle of fetal hemoglobin with adult hemoglobin. The relation between total blood volume and estimated fetal weight, severity of anemia and hydrops was analyzed. Results: Gestational age ranged from 17 to 35 weeks. Mean hemoglobin deficit was 6.8 standard deviations (range 2.1–11.7) below the normal mean. Fetal total blood volume was significantly related to estimated fetal weight (p < 0.001). Mean total blood volume in nonhydropic fetuses was 123 ml/kg (n = 74) and in hydropic fetuses 144 ml/kg (n = 12). There was a significant relation between total blood volume per kg body weight and hydrops (p = 0.035); however, there was no relation with severity of anemia (p = 0.94). Conclusion: In the human nonhydropic fetus with severe hemolytic anemia, total blood volume is maintained: the decrease in red blood cell volume is thus compensated by an increase in plasma volume. In hydropic fetuses, however, total blood volume seems to be increased. This is in accordance with the hypothesis that congestive heart failure plays a role in the pathophysiology of hydrops in anemic fetuses. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Space flight anemia is a widely recognized phenomenon in astronauts. Reduction in circulating red blood cells and plasma volume results in a 10% to 15% decrement in circulatory volume. This effect appears to be a normal physiologic adaptation to weightlessness and results from the removal of newly released blood cells from the circulation. Iron availability increases, and (in the few subjects studied) iron stores increase during long-duration space flight. The consequences of these changes are not fully understood. [ABSTRACT FROM AUTHOR]