Search

Abstract 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

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]

We wanted to determine the influence of total blood volume (BV) and blood lactate quantity on lactate concentrations during incremental exercise. Twenty-six healthy, nonsmoking, heterogeneously trained females (27.5 ± 5.9 ys) performed an incremental cardiopulmonary exercise test on a cycle ergometer during which maximum oxygen uptake ( V · O2max), lactate concentrations ([La−]) and hemoglobin concentrations ([Hb]) were determined. Hemoglobin mass and blood volume (BV) were determined using an optimised carbon monoxide-rebreathing method. V · O2max and maximum power (Pmax) ranged between 32 and 62 mL·min−1·kg−1 and 2.3 and 5.5 W·kg−1, respectively. BV ranged between 81 and 121 mL·kg−1 of lean body mass and decreased by 280 ± 115 mL (5.7%, p = 0.001) until Pmax. At Pmax, the [La−] was significantly correlated to the systemic lactate quantity (La−, r = 0.84, p < 0.0001) but also significantly negatively correlated to the BV (r = −0.44, p < 0.05). We calculated that the exercise-induced BV shifts significantly reduced the lactate transport capacity by 10.8% (p < 0.0001). Our results demonstrate that both the total BV and La− have a major influence on the resulting [La−] during dynamic exercise. Moreover, the blood La− transport capacity might be significantly reduced by the shift in plasma volume. We conclude, that the total BV might be another relevant factor in the interpretation of [La−] during a cardio-pulmonary exercise test. [ABSTRACT FROM AUTHOR]

Raman spectroscopy, infrared spectroscopy and laser interference microscopy revealed both morphological changes and changes in the conformation of hemoglobin in the erythrocyte as a result of an increase in the ratio of [Na+]in and [K+]in when cellular Na+/K+-ATPase was inhibited. It was found that the Na+/K+-ATPase inhibition led not only to an increase in [Na+]in in the cell, it also increased the positive charge on the cytoplasmic surface of the plasma membrane. Under these conditions, changes in the conformation of both heme and the protein globule of hemoglobin were detected, namely there was a decrease in the packing density of the hemoglobin molecule, which could be associated with both the sorption of Na+ (or Ca2+) with hemoglobin, and with an increase in the number of water molecules in the cell and the redistribution of hemoglobin. It is likely that the redistribution of hemoglobin and the change in the packing density of globin affected the conformation of heme; this increased the probability of hemoglobin heme to be in a "dome-shaped form" and, thus, increased its ability to bind O2. [ABSTRACT FROM AUTHOR]

We wanted to determine the influence of total blood volume (BV) and blood lactate quantity on lactate concentrations during incremental exercise. Twenty-six healthy, nonsmoking, heterogeneously trained females (27.5 ± 5.9 ys) performed an incremental cardiopulmonary exercise test on a cycle ergometer during which maximum oxygen uptake (V·O2max), lactate concentrations ([La−]) and hemoglobin concentrations ([Hb]) were determined. Hemoglobin mass and blood volume (BV) were determined using an optimised carbon monoxide-rebreathing method. V·O2max and maximum power (Pmax) ranged between 32 and 62 mL·min−1·kg−1 and 2.3 and 5.5 W·kg−1, respectively. BV ranged between 81 and 121 mL·kg−1 of lean body mass and decreased by 280 ± 115 mL (5.7%, p = 0.001) until Pmax. At Pmax, the [La−] was significantly correlated to the systemic lactate quantity (La−, r = 0.84, p < 0.0001) but also significantly negatively correlated to the BV (r = −0.44, p < 0.05). We calculated that the exercise-induced BV shifts significantly reduced the lactate transport capacity by 10.8% (p < 0.0001). Our results demonstrate that both the total BV and La− have a major influence on the resulting [La−] during dynamic exercise. Moreover, the blood La− transport capacity might be significantly reduced by the shift in plasma volume. We conclude, that the total BV might be another relevant factor in the interpretation of [La−] during a cardio-pulmonary exercise test.

Purpose: To investigate the association between blood volume, hemoglobin mass (Hbmass), and peak oxygen uptake (VO2peak) in healthy older adults.Methods: Fifty fit or unfit participants from the prospective randomized Generation 100 Study (n = 1,566) were included (age- and sex-specific VO2peak above or below average values). Blood, plasma, and erythrocyte volume and Hbmass were tested using the carbon monoxide rebreathing method within 1 week after VO2peak testing.Results: Mean age, BMI, Hbmass, blood volume, and VO2peak were 73.0 ± 2.1 years, 24.8 ± 3.3 kg·m2, 10.0 ± 1.7 g·kg−1, 76.4 ± 11.8 mL·kg−1, and 33.5 ± 8.4 mL·kg−1·min−1. VO2peak in fit and unfit participants and women and men were 38.6 ± 6.5 and 25.8 ± 3.8 mL·kg−1·min−1, 30.7 ± 7.6 mL·kg−1·min−1, and 35.5 ± 8.5 mL·kg−1·min−1, respectively. Women were shorter (Δ14 cm), leaner (Δ13 kg), and with less muscle mass (Δ9%) than men (P < 0.05). Relative erythrocyte volume and Hbmass were lower in women, and blood and erythrocyte volume and Hbmass were higher in the fit participants (P < 0.05). Hbmass and erythrocyte volume explained 40 and 37%, respectively, of the variability in VO2peak, with a limited effect of physical-activity adjustment (40 and 38%, respectively). Blood and plasma volume explained 15 and 25%, respectively, of VO2peak variability, and the association was strengthened adjusting for physical activity (25 and 31%, respectively), indicating a training-dependent adaptation in plasma but not erythrocyte volume (p ≤ 0.006).Conclusions: Blood and plasma volumes were moderately associated with VO2peak in healthy older men and women, and the association was strengthened after adjustment for physical activity. Hbmass and erythrocyte volume were strongly associated with VO2peak but unrelated to physical activity.

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]

In a previous study, our laboratory showed that young dogs born at sea level (SL) and raised from 2.5 mo of age to beyond somatic maturity at a high altitude (HA) of 3,100 m show enhanced resting lung function (Johnson RL Jr, Cassidy SS, Grover RF, Schutte JE, and Epstein RH. J Appl Physiol 59: 1773–1782, 1985). To examine whether HA-induced adaptation improves pulmonary gas exchange during exercise and whether adaptation is reversible when animals return to SL before somatic maturity, we raised 2.5-mo-old foxhounds at HA (3,800 m) for 5 mo (to age 7.5 mo) before returning them to SL. Lung function was measured under anesthesia 1 mo and 2 yr after return to SL and during exercise ∼1 yr after return. In animals exposed to HA relative to simultaneous litter-matched SL controls, resting circulating blood and erythrocyte volumes, lung volumes, septal volume estimated by a rebreathing technique, and lung tissue volume estimated by high-resolution computed tomography scan were persistently higher. Lung diffusing capacity, membrane diffusing capacity, and pulmonary capillary blood volume estimated at a given cardiac output were significantly higher in animals exposed to HA, whereas maximal oxygen uptake and hematocrit were similar between groups. We conclude that relatively short exposure to HA during somatic maturation improves long-term lung function into adulthood. [ABSTRACT FROM AUTHOR]

While it is well established that highlanders have optimized their oxygen transport system, little is known about the acclimatization of those who move between different altitudes. The purpose of this study was to establish whether the acclimatization to long-term intermittent hypoxic exposure in members of the Chilean Army who frequently move from sea level to 3,550 m altitude is correlated with acute acclimatization or chronic adaptation to hypoxia. A group of officers was exposed intermittently to hypoxia for about 22 years (OI, officers at intermittent hypoxia) and a group of soldiers for 6 months (SI, soldiers at intermittent hypoxia). Both groups were compared to residents at altitude (RA) and to soldiers at sea level (SL). When compared to SL, we observed an 11% increase in total hemoglobin mass (tHb) as well as a corresponding increase in red cell volume (RCV), hemoglobin concentration and hematocrit in all three groups at altitude. Plasma volume (PV) and blood volume (BV) decreased at altitude but increased when OI and SI returned to sea level. Moreover, intermittent hypoxic exposure of OI and SI resulted in increased plasma erythropoietin (Epo) levels, which peaked on day 2 at high altitude followed by decreasing levels during the successive days, and reaching pre-altitude values in SI even when staying at altitude. In conclusion, with regard to tHb and RCV, the acclimatization to long-term intermittent hypoxia resembles the adaptation to chronic hypoxia, while PV and BV regulation mimicked acclimatization to acute hypoxia. Remarkably, finely controlled regulation of Epo expression still occurs after up to 22 years of weekly exposure to altitude. [ABSTRACT FROM AUTHOR]

Copyright of Anaesthesist is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study examined the erythrocyte height/length, hematocrit, total blood hemoglobin concentration and mean cellular hemoglobin content of diploid and triploid transgenic and non-transgenic Atlantic salmon, to clarify the interaction between metabolic rate and hematology in these fish. Triploid erythrocytes were significantly longer and proportionately thinner than diploid erythrocytes for both genotypes. These morphological differences gave triploid erythrocytes an elliptical appearance with the width being ∼53% of the length, whereas diploid erythrocytes tended to be more rounded with the width being ∼62% of the length. As well, diploid and triploid transgenic erythrocytes were significantly shorter and thinner ( P<0.0001) than their non-transgenic counterparts. Although not significant, observations using a Channelized Coulter Counter showed that transgenic erythrocytes tended to be higher in count and smaller in volume than non-transgenic erythrocytes of the same ploidy. Transgenics likely produce erythrocytes with higher surface area to volume ratio in response to their elevated metabolic rates. No other major hematological differences were observed between transgenics and non-transgenics of the same ploidy. [ABSTRACT FROM AUTHOR]

An inverse relationship exists between erythrocyte size and the aerobic swimming ability of teleosts. A functional basis for this relationship is found in larger surface area to volume ratios and shorter diffusion distances allowing more rapid oxygen transfer as erythrocyte volume decreases. However, this apparently simple functional relationship is confounded by a more general direct relationship between cell size and nuclear volume. Nuclear DNA content, which is directly proportional to nuclear volume, is known to vary at least 11 fold among teleost species. Therefore a question arises as to the relative contributions of nuclear volume and the demands of the blood oxygen delivery system in determining erythrocyte volume. These relationships were investigated by regressing erythrocyte volume against nuclear volume and whole blood haemoglobin concentration (as an index of aerobic scope) for 52 species of teleost fish from 25 families. This analysis shows that erythrocyte volume is more highly correlated with oxygen delivery than with nuclear volume. However, much of the variation in erythrocyte volume is unexplained. [ABSTRACT FROM AUTHOR]

In the diagnosis of polycytemia vera, estimation of erythrocyte volume (EV) from plasma volume (PV) and venous hematocrit (Hct) is usually thought unadvisable, because the ratio of whole body hematocrit to venous hematocrit ( f ratio) is higher in patients with splenomegaly than in normal subjects, and varies considerably between individuals. We determined the mean f ratio in 232 consecutive patients suspected of polycytemia vera ( $$\bar f = {\text{0}}{\text{.967}}$$ ;SD 0.048) and used it with each patient's PV and Hct to calculate an estimated normalised EV. With measured EV as a reference value, EV was investigated as a diagnostic test. By means of two cut off levels the EV values could be divided into EV elevated, EV not elevated (both with high predictive values), and an EV borderline group. The size of the borderline EV group ranged from 5% to 46% depending on position of the cut off levels, i.e. with the efficiency demanded from the diagnostic test. EV can safely and rapidly be estimated from PV and Hct, if $$\bar f$$ is determined from the relevant population, and if the results in an easily defineable borderline range of EV values are supplemented by direct EV determination. [ABSTRACT FROM AUTHOR]

Twenty-one women completed a longitudinal study of glycosylated haemoglobin in normal pregnancy. Glycosylated haemoglobin levels were measured using two independent techniques (ion-exchange column and colorimetric). Concurrent serial oral glucose tolerance tests (75-g glucose load) and erythrocyte indices were obtained. Changes in mean glycosylated haemoglobin were similar with both techniques with a nadir at 17 weeks, a peak at delivery ( p<0.002 versus 17 weeks) and a fall post-partum. Glycosylated haemoglobin levels in abnormal pregnancies, e. g. diabetic, should be interpreted in the knowledge of these physiological changes. [ABSTRACT FROM AUTHOR]

Fatiguing muscular exercise of short duration (7-9 min) with the arms produced large increments of pCO (>+30 mm Hg) and hydrogen ion concentration in venous blood from the working limbs. On the basis of these biochemical changes it might be expected to find a volumetric increase in the red cell of venous blood, since more osmotically active ions entered the erythrocytes through the chloride shift mechanism. However simultaneous measurements of mean corpuscular red cell volume (MVC) and mean corpuscular hemoglobin concentration (MCHC) failed to demonstrate a measurable change in the size of the erythrocyte in the acidified venous blood. The concomitantly determined significant elevation of the plasma osmolarity (+7.7%) suggests that in vivo the human red cells from venous blood in exercising limbs maintain a constant volume through counteracting osmotic forces in spite of large hematological changes. [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]

At rest, rat erythrocyte electrophoretic mobility varied independently on cell volume. Emotional and physical stress gave rise to a short-lived moderate negative correlation between erythrocyte volume and the coefficient of asymmetry of electrophoretic mobility distribution, probably originating from accompanying metabolic and systemic influences. [ABSTRACT FROM AUTHOR]

Erytyrocyte volume in neonates is 25.8% greater than in women. Electrophoretic erythrocyte mobility was the same in neonates and in parturient women. The results obtained indicate that the more heterogeneous the hemoglobin system, the more heterogenous are erythrocyte membrane electrical characteristics. [ABSTRACT FROM AUTHOR]