Optimized Carbon Monoxide Rebreathing Method Research Articles

Effect of Fluid Intake on Acute Changes in Plasma Volume: A Randomized Controlled Crossover Pilot Trial.

Plasma volume (PV) undergoes constant and dynamic changes, leading to a large intra-day variability in healthy individuals. Hydration is known to induce PV changes; however, the response to the intake of osmotically different fluids is still not fully understood. In a randomized controlled crossover trial, 18 healthy individuals (10 females) orally received an individual amount of an isotonic sodium-chloride (ISO), Ringer (RIN), or glucose (GLU) solution. Hemoglobin mass (Hbmass) was determined with the optimized carbon monoxide re-breathing method. Fluid-induced changes in PV were subsequently calculated based on capillary hemoglobin concentration ([Hb]) and hematocrit (Hct) before and then every 10 minutes until 120 min (t0-120) after the fluid intake and compared to a control trial arm (CON), where no fluid was administered. Within GLU and CON trial arms, no statistically significant differences from baseline until t120 were found (p > 0.05). In the ISO trial arm, PV was significantly increased at t70 (+138 mL, p = 0.01), t80 (+191 mL, p < 0.01), and t110 (+182 mL, p = 0.01) when compared to t0. Moreover, PV in the ISO trial arm was significantly higher at t70 (p = 0.02), t110 (p = 0.04), and t120 (p = 0.01) when compared to the same time points in the CON trial arm. Within the RIN trial arm, PV was significantly higher between t70 and t90 (+183 mL, p = 0.01) and between t110 (+194 mL, p = 0.03) and t120 (+186 mL, p < 0.01) when compared to t0. These results demonstrated that fluids with a higher content of osmotically active particles lead to acute hemodilution, which is associated with a decrease in [Hb] and Hct. These findings underpin the importance of the hydration state on PV and especially on PV constituent levels in healthy individuals.

Application of the optimized carbon monoxide rebreathing method for the measurement of total haemoglobin mass in chronic liver disease.

BackgroundAnemia is common in liver cirrhosis. This generally infers a fall in total hemoglobin mass (tHb‐mass). However, hemoglobin concentration ([Hb]) may fall due to an expansion in plasma volume (PV). The “optimized carbon monoxide rebreathing method” (oCOR) measures tHb‐mass directly and PV (indirectly using hematocrit). It relies upon carboxyhemoglobin (COHb) distribution throughout the entire circulation. In healthy subjects, such distribution is complete within 6–8 min. Given the altered circulatory dynamics in cirrhosis, we sought in this pilot study, to assess whether this was true in cirrhosis. The primary aim was to ascertain if the standard timings for the oCOR were applicable to patients with chronic liver disease and cirrhosis. The secondary aim was to explore the applicability of standard CO dosing methodologies to this patient population.MethodsSixteen patients with chronic liver parenchymal disease were studied. However, tHb‐mass was determined using the standard oCOR technique before elective paracentesis. Three subjects had an inadequate COHb% rise. In the remaining 13 (11 male), mean ± standard deviation (SD) age was 52 ± 13.8 years, body mass 79.1 ± 11.4 kg, height 175 ± 6.8 cm. To these, mean ± SD dose of carbon monoxide (CO) gas administered was 0.73 ± 0.13 ml/kg COHb values at baseline, 6 and 8 min (and “7‐min value”) were compared to those at 10, 12, 15 and 20 min after CO rebreathing.ResultsThe “7‐min value” for median COHb% (IQR) of 6.30% (6.21%–7.47%) did not differ significantly from those at subsequent time points (8 min: 6.30% (6.21%–7.47%), 10 min: 6.33% (6.00%–7.50%), 12 min: 6.33% (5.90%–7.40%), 15 min: 6.37% (5.80%–7.33%), 20 min: 6.27% (5.70%–7.20%)). Mean difference in calculated tHb‐mass between minute 7 and minute 20 was only 4.1 g, or 0.6%, p = .68. No subjects reported any adverse effects.ConclusionsThe oCOR method can be safely used to measure tHb‐mass in patients with chronic liver disease and ascites, without adjustment of blood sample timings. Further work might refine and validate appropriate dosing regimens.

Applying the Optimized CO Rebreathing Method for Measuring Blood Volumes and Hemoglobin Mass in Heart Failure Patients.

Introduction: Determination of blood volume, red cell volume, and plasma volume contributes to the understanding of the pathophysiology in heart failure, especially concerning anemia and volume load. The optimized carbon monoxide (CO)-rebreathing method (oCORM) is used to determine these parameters and hemoglobin mass (Hbmass) in exercise physiology. The applicability of oCORM to determine the intravascular volumes and Hbmass in heart failure patients is currently undetermined because assumptions concerning CO kinetics with oCORM rely on healthy subjects with a normal ejection fraction. Therefore, the aim of the present study is to determine the applicability and the systematic error of oCORM arising from a reduced EF when oCORM is used for measurement of intravascular volumes and Hbmass in heart failure patients.Methods: oCORM was performed in 21 patients with heart failure and a reduced ejection fraction (EF) of < 30% (EFsev) and 25 controls (CONT). CO kinetics in capillary blood was studied 3–15 min after commencement of CO rebreathing. Differences in CO kinetics between the groups were assessed using a generalized linear model. The systematic error for determination of Hbmass with oCORM arising from differences in CO kinetics was assessed using the Monte Carlo method.Results: The CO kinetics was significantly different between EFsev and CONT. In both groups, exposure to CO led to a COHb increase to 6.0 ± 1.0% 3 min after CO rebreathing. There were no CO related side effects or any clinical symptoms. Monte Carlo simulation quantifies the systematic error for determination of Hbmass arising from an impaired ejection fraction to be −0.88%.Conclusion: Our results indicate an impaired vascular mixing of CO when EF is severely reduced. When Hbmass is determined using the original oCORM protocol in heart failure patients with a reduced EF, the systematic underestimation of about 1% should be considered. However, the error arising from this impaired vascular mixing appears small and clinically negligible. Furthermore, application of oCORM was safe and not related to any side effects resulting from CO exposure. In conclusion, oCORM can be used for assessing intravascular volumes and Hbmass in patients with a reduced EF.

Impact of Energy Availability, Health, and Sex on Hemoglobin-Mass Responses Following Live-High-Train-High Altitude Training in Elite Female and Male Distance Athletes.

The authors investigated the effects of sex, energy availability (EA), and health status on the change in hemoglobin mass (ΔHbmass) in elite endurance athletes over ∼3-4 wk of live-high-train-high altitude training in Flagstaff, AZ (2135m; n = 27 women; n = 21 men; 27% 2016 Olympians). Precamp and postcamp Hbmass (optimized carbon monoxide rebreathing method) and iron status were measured, EA was estimated via food and training logs, and a Low Energy Availability in Females Questionnaire (LEAFQ) and a general injury/illness questionnaire were completed. Hypoxic exposure (h) was calculated with low (<500h), moderate (500-600h), and high (>600h) groupings. Absolute and relative percentage ΔHbmass was significantly greater in women (6.2% [4.0%], P < .001) than men (3.2% [3.3%], P = .008). %ΔHbmass showed a dose-response with hypoxic exposure (3.1% [3.8%] vs 4.9% [3.8%] vs 6.8% [3.7%], P = .013). Hbmasspre was significantly higher in eumenorrheic vs amenorrheic women (12.2 [1.0] vs 11.3 [0.5]g/kg, P = .004). Although statistically underpowered, %ΔHbmass was significantly less in sick (n = 4, -0.5% [0.4%]) vs healthy (n = 44, 5.4% [3.8%], P < .001) athletes. There were no significant correlations between self-reported iron intake, sex hormones, or EA on Hbmass outcomes. However, there was a trend for a negative correlation between LEAFQ score and %ΔHbmass (r = -.353, P = .07). The findings confirm the importance of baseline Hbmass and exposure to hypoxia on increases in Hbmass during altitude training, while emphasizing the importance of athlete health and indices of EA on an optimal baseline Hbmass and hematological response to hypoxia.

Individual hemoglobin mass response to normobaric and hypobaric "live high-train low": A one-year crossover study.

The purpose of this research was to compare individual hemoglobin mass (Hbmass) changes following a live high-train low (LHTL) altitude training camp under either normobaric hypoxia (NH) or hypobaric hypoxia (HH) conditions in endurance athletes. In a crossover design with a one-year washout, 15 male triathletes randomly performed two 18-day LHTL training camps in either HH or NH. All athletes slept at 2,250 meters and trained at altitudes <1,200 meters. Hbmass was measured in duplicate with the optimized carbon monoxide rebreathing method before (pre) and immediately after (post) each 18-day training camp. Hbmass increased similarly in HH (916-957 g, 4.5 ± 2.2%, P < 0.001) and in NH (918-953 g, 3.8 ± 2.6%, P < 0.001). Hbmass changes did not differ between HH and NH (P = 0.42). There was substantial interindividual variability among subjects to both interventions (i.e., individual responsiveness or the individual variation in the response to an intervention free of technical noise): 0.9% in HH and 1.7% in NH. However, a correlation between intraindividual ΔHbmass changes (%) in HH and in NH (r = 0.52, P = 0.048) was observed. HH and NH evoked similar mean Hbmass increases following LHTL. Among the mean Hbmass changes, there was a notable variation in individual Hbmass response that tended to be reproducible.NEW & NOTEWORTHY This is the first study to compare individual hemoglobin mass (Hbmass) response to normobaric and hypobaric live high-train low using a same-subject crossover design. The main findings indicate that hypobaric and normobaric hypoxia evoked a similar mean increase in Hbmass following 18 days of live high-train low. Notable variability and reproducibility in individual Hbmass responses between athletes was observed, indicating the importance of evaluating individual Hbmass response to altitude training.

Effect Of Low Dose Cobalt Administration On Erythropoiesis

Before recombinant EPO became available cobalt chloride has been used as a therapeutic drug to treat anemic patients. Nowadays, cobalt (Co) is offered as nutritional supplement for endurance athletes as it is supposed to stimulate erythropoiesis also in small dosages. As a consequence, WADA has put cobalt on the list of prohibited substances although no information is available on the efficacy of low dose Co application on red cell production. PURPOSE: To evaluate the effect of low dose oral Co administration on erythropoietic activity. METHODS: Three studies were performed: 1. application of a single dose of either 5mg Co (n=6) or 10mg Co (n=7); 2. application of 5mg (n=9) or 10 mg (n=7) per day for 5 days, and 3. application of 5 mg Co/day for 3 weeks followed by a 3-week wash-out period (n=16). In all studies a control group was included. Venous EPO concentration was determined in all studies, reticulocytes (ret%) and immature reticulocyte fraction (IRF) in study 2 and 3 and tHbmass in study 3 by the optimized carbon monoxide re-breathing method. RESULTS: 10 mg Co significantly increased plasma EPO until 7h after the single dose (from 8.7 ±2.6 to 11.5 ±2.4 mU/ml) and after the 5-day administration (from 10.6 ±2.6 to 13.1 ±4.2 mU/ml, p<0.05). 5 mg Co had only a slight effect 5h after a single application (from 8,8 ±4,3 to 10,6 ±5,5 mU/ml, p<0.05). During the 3-week administration 5mg Co transiently increased EPO by 30% (from 9.5 ±3.0 to 12.4 ±5.2 mU/ml after 2 weeks, p=0.01). IRF increased after 5 days of 10mg Co administration (from 0.60 ±0.22 to 0.87 ±0.27, p<0.001), but not after short or long-term dosage of 5 mg. Ret% slightly increased in study 3 after 2 weeks (from 1.16 ±0.42 to 1.25 ±0.41%, p<0.05). In study 3, Hbmass slightly increased until week 2 (+17.2 ±22.1g, p=0.01) and remained at higher level thereafter. CONCLUSIONS: Low dose cobalt administration which can be achieved with nutritional supplements slightly increases erythropietic activity and total hemoglobin mass. Supported by WADA Grant 13D21DS.

Total haemoglobin mass, but not haemoglobin concentration, is associated with preoperative cardiopulmonary exercise testing-derived oxygen-consumption variables

BackgroundCardiopulmonary exercise testing (CPET) measures peak exertional oxygen consumption ( V˙O2peak) and that at the anaerobic threshold ( V˙O2 at AT, i.e. the point at which anaerobic metabolism contributes substantially to overall metabolism). Lower values are associated with excess postoperative morbidity and mortality. A reduced haemoglobin concentration ([Hb]) results from a reduction in total haemoglobin mass (tHb-mass) or an increase in plasma volume. Thus, tHb-mass might be a more useful measure of oxygen-carrying capacity and might correlate better with CPET-derived fitness measures in preoperative patients than does circulating [Hb]. MethodsBefore major elective surgery, CPET was performed, and both tHb-mass (optimized carbon monoxide rebreathing method) and circulating [Hb] were determined. ResultsIn 42 patients (83% male), [Hb] was unrelated to V˙O2 at AT and V˙O2peak (r=0.02, P=0.89 and r=0.04, P=0.80, respectively) and explained none of the variance in either measure. In contrast, tHb-mass was related to both (r=0.661, P<0.0001 and r=0.483, P=0.001 for V˙O2 at AT and V˙O2peak, respectively). The tHb-mass explained 44% of variance in V˙O2 at AT (P<0.0001) and 23% in V˙O2peak (P=0.001). ConclusionsIn contrast to [Hb], tHb-mass is an important determinant of physical fitness before major elective surgery. Further studies should determine whether low tHb-mass is predictive of poor outcome and whether targeted increases in tHb-mass might thus improve outcome.

Decreased arterial PO2, not O2 content, increases blood flow through intrapulmonary arteriovenous anastomoses at rest.

The mechanism(s) that regulate hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA ) are currently unknown. Our previous work has demonstrated that the mechanism of hypoxia-induced QIPAVA is not simply increased cardiac output, pulmonary artery systolic pressure or sympathetic nervous system activity and, instead, it may be a result of hypoxaemia directly. To determine whether it is reduced arterial PO2 (PaO2) or O2 content (CaO2) that causes hypoxia-induced QIPAVA , individuals were instructed to breathe room air and three levels of hypoxic gas at rest before (control) and after CaO2 was reduced by 10% by lowering the haemoglobin concentration (isovolaemic haemodilution; Low [Hb]). QIPAVA , assessed by transthoracic saline contrast echocardiography, significantly increased as PaO2 decreased and, despite reduced CaO2 (via isovolaemic haemodilution), was similar at iso-PaO2. These data suggest that, with alveolar hypoxia, low PaO2 causes the hypoxia-induced increase in QIPAVA , although where and how this is detected remains unknown. Alveolar hypoxia causes increased blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA ) in healthy humans at rest. However, it is unknown whether the stimulus regulating hypoxia-induced QIPAVA is decreased arterial PO2 (PaO2) or O2 content (CaO2). CaO2 is known to regulate blood flow in the systemic circulation and it is suggested that IPAVA may be regulated similar to the systemic vasculature. Thus, we hypothesized that reduced CaO2 would be the stimulus for hypoxia-induced QIPAVA . Blood volume (BV) was measured using the optimized carbon monoxide rebreathing method in 10 individuals. Less than 5days later, subjects breathed room air, as well as 18%, 14% and 12.5% O2 , for 30min each, in a randomized order, before (CON) and after isovolaemic haemodilution (10% of BV withdrawn and replaced with an equal volume of 5% human serum albumin-saline mixture) to reduce [Hb] (Low [Hb]). PaO2 was measured at the end of each condition and QIPAVA was assessed using transthoracic saline contrast echocardiography. [Hb] was reduced from 14.2±0.8 to 12.8±0.7gdl(-1) (10±2% reduction) from CON to Low [Hb] conditions. PaO2 was no different between CON and Low [Hb], although CaO2 was 10.4%, 9.2% and 9.8% lower at 18%, 14% and 12.5% O2 , respectively. QIPAVA significantly increased as PaO2 decreased and, despite reduced CaO2, was similar at iso-PaO2. These data suggest that, with alveolar hypoxia, low PaO2 causes the hypoxia-induced increase in QIPAVA . Whether the low PO2 is detected at the carotid body, airway and/or the vasculature remains unknown.

Four-day Head-down Tilt Bed Rest as a Model for Studying Rapid Alterations in Hemoglobin Mass

Rapid decreases in hemoglobin mass (Hbmass) have been reported in healthy humans with spaceflight and following descent from high altitude. It has been proposed that a selective increase in the destruction of young red blood cells (RBCs) mediates these decreases but conclusive evidence demonstrating neocytolysis is lacking. Based on the proposed triggers and time course of adaptation during spaceflight, we hypothesized that 4 days of −6° head-down tilt bed rest (HDTBR) would cause a rapid decrease in Hbmass that would be associated with evidence of increased RBC destruction. PURPOSE: To examine changes in Hbmass before (PRE), 5 hours after (POST), and 5 days after (POST5) 4 days of HDTBR. METHODS: Seven healthy, recreationally active men (age: 21 ± 3 years, peak oxygen uptake: 50 ± 6 mL kg-1 min-1) completed 4 days of HDTBR. Hbmass was assessed using the optimized carbon monoxide rebreathing method. Markers of RBC production and destruction assessed included [erythropoietin] ([EPO]), [soluble transferrin receptor] ([sTfr]), reticulocyte count, [ferritin], [haptoglobin], and [bilirubin]. RESULTS: [EPO] decreased by 30 ± 33% from PRE to POST (p = 0.028). Contrary to our hypothesis, Hbmass was increased by 4.0 ± 4.3% from PRE to POST (p = 0.014) before decreasing to a level 3.6 ± 2.4% below PRE at POST5 (p = 0.027). From PRE to POST, [haptoglobin] increased 66 ± 73% (p = 0.013), [bilirubin] decreased 26 ± 34% (p = 0.054), [ferritin] increased 17 ± 17 % (p = 0.012), and reticulocyte count remained stable. From PRE to POST5, sTfr decreased 17 ± 5% (p = 0.018) but there were no significant alterations in [ferritin], [haptoglobin], [bilirubin] or reticulocyte count. CONCLUSION: Our findings suggest that 4-day HDTBR results in a transient increase in Hbmass that may be influenced by decreased RBC destruction. However, since the POST measurement occurred following re-ambulation, a potential role for other factors (i.e., spleen contraction) on the increase in Hbmass cannot be excluded. The decrease in Hbmass at POST5 appears to be mediated by decreased RBC production rather than increased RBC destruction. These findings highlight the need to re-examine the time course and mechanisms of Hbmass alterations with short-term spaceflight and simulated microgravity.

Decreased Arterial PO 2 , not O 2 Content, Increases Blood Flow Through Intrapulmonary Arteriovenous Anastomoses at Rest

Alveolar hypoxia, not increased pulmonary artery pressure, causes increased blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA) in humans. However, it is unknown whether the hypoxic stimulus for QIPAVA is decreased arterial PO2 (PaO2) or arterial O2 content (CaO2). CaO2 is known to regulate blood flow in the systemic circulation and it is suggested that QIPAVA is regulated similar to the systemic vasculature. Thus, we hypothesized that reduced CaO2 would be the stimulus for hypoxia-induced QIPAVA. Blood volume (BV) was measured using the optimized carbon monoxide rebreathing method in 8 healthy subjects, 1 female. Less than 5 days later subjects breathed 18%, 14%, and 12.5% O2 for 30 min each, in a randomized order, before and after isovolemic hemodilution (IH; 10% of BV withdrawn and replaced with an equal volume of 5% human serum albumin). PaO2 was obtained at the end of each trial and QIPAVA was assessed using saline contrast echocardiography. Hemoglobin concentration was reduced from 14.2 ± 0.7 to 12.8 ± 0.5 g/dL with IH. PaO2 did not change pre- and post-IH at any FIO2, but CaO2 was 10.1, 11.3, and 5.4% lower at 18, 14, and 12.5% O2, respectively. QIPAVA was significantly increased as PaO2 decreased and despite reduced CaO2, was similar at iso-PO2. These data suggest that with alveolar hypoxia, low PaO2 causes the hypoxia-induced increase in QIPAVA. Support: Department of Defense

Comparison of total haemoglobin mass measured with the optimized carbon monoxide rebreathing method across different Radiometer™ ABL-80 and OSM-3 hemoximeters

A new Radiometer™ hemoximeter (ABL-80) has recently become available to measure carboxyhaemoglobin concentration for the optimized CO-rebreathing method (oCOR-method). Within the English Institute of Sport (EIS), hemoximeters are used in three different laboratories; therefore, precision and agreement of total haemoglobin mass (tHbmass) determination across sites is essential, and comparison to the previous model OSM-3 is desirable. Six male and one female (age 30 ± 6 years, body mass 78.1 ± 10.6 kg) undertook the oCOR-method. Venous blood (~2 ml) was sampled immediately before and at 7 min during the oCOR-method; with seven replicates from each time point simultaneously analysed on five different Radiometer™ hemoximeters [OSM-3(1), OSM-3(2), ABL-80(1), ABL-80(2) and ABL-80(3)]. There were no differences (p > 0.05) between Δ%HbCO or mean tHbmass analysed with five different hemoximeters (OSM-3(1): 886 ± 167 g; OSM-3(2): 896 ± 160 g: ABL-80(1): 904 ± 157 g; ABL-80(2): 906 ± 163 g: ABL-80(3): 906 ± 162 g). However, the Bland–Altman plot revealed that there was closer agreement between ABL-80 machines for tHbmass than for the OSM-3. The variance (i.e. % error) across replicate samples decreased as the number of samples increased, with the error derived from the ‘worse-case’ scenario (single samples) being 1.2 to 1.6 fold greater in the OSM-3 than the ABL-80. Although there were no differences in the average tHbmass measured with five different hemoximeters, the new ABL-80 were in better agreement with each other compared to the old OSM-3. Previously, five replicates were required to achieve a low error using the OSM-3; however, three replicates are sufficient with the ABL-80 model to produce an error of ≤ 1% in tHbmass.

NO ASSOCIATION BETWEEN tHbmass AND POLYMORPHISMS IN THE HBB GENE IN ENDURANCE ATHLETES.

The aim of this study was to examine the association between tHbmass and HBB gene polymorphisms in athletes of endurance disciplines. Eighty-two well-trained athletes (female n=36, male n=46), aged 19.3 ± 2.7 years, representing cross country skiing (n=37) and middle- and long-distance running (n=45), participated in the study. Genotyping for 2 polymorphisms in the HBB gene (- 551C/T and intron 2, +16 C/G) was performed using restriction fragment length polymorphism analysis. Total haemoglobin mass (tHbmass) was determined by the optimized carbon monoxide rebreathing method. Blood morphology, indices of iron status (ferritin, transferrin receptor and total iron binding capacity) and C reactive protein were also determined. No differences were found in the HBB genotype and allele frequencies between male and female athletes. Regardless of the polymorphisms, no relationships were found between HBB genotypes as well as alleles and relative values of tHbmass, expressed per body mass (g · kg-1 BM), both in female and male athletes. Our results demonstrated that -551 C/T and intron 2, +16 C/G polymorphisms of the HBB gene have no association with total haemoglobin mass in endurance athletes. It cannot be ruled out that several polymorphisms, each with a small but significant contribution, may be responsible for the amount of haemoglobin.

Haemoglobin Mass and Running Time Trial Performance after Recombinant Human Erythropoietin Administration in Trained Men

Recombinant human erythropoietin (rHuEpo) increases haemoglobin mass (Hbmass) and maximal oxygen uptake ( O2 max).PurposeThis study defined the time course of changes in Hbmass, O2 max as well as running time trial performance following 4 weeks of rHuEpo administration to determine whether the laboratory observations would translate into actual improvements in running performance in the field.Methods19 trained men received rHuEpo injections of 50 IU•kg−1 body mass every two days for 4 weeks. Hbmass was determined weekly using the optimized carbon monoxide rebreathing method until 4 weeks after administration. O2 max and 3,000 m time trial performance were measured pre, post administration and at the end of the study.ResultsRelative to baseline, running performance significantly improved by ∼6% after administration (10∶30±1∶07 min:sec vs. 11∶08±1∶15 min:sec, p<0.001) and remained significantly enhanced by ∼3% 4 weeks after administration (10∶46±1∶13 min:sec, p<0.001), while O2 max was also significantly increased post administration (60.7±5.8 mL•min−1•kg−1 vs. 56.0±6.2 mL•min−1•kg−1, p<0.001) and remained significantly increased 4 weeks after rHuEpo (58.0±5.6 mL•min−1•kg−1, p = 0.021). Hbmass was significantly increased at the end of administration compared to baseline (15.2±1.5 g•kg−1 vs. 12.7±1.2 g•kg−1, p<0.001). The rate of decrease in Hbmass toward baseline values post rHuEpo was similar to that of the increase during administration (−0.53 g•kg−1•wk−1, 95% confidence interval (CI) (−0.68, −0.38) vs. 0.54 g•kg−1•wk−1, CI (0.46, 0.63)) but Hbmass was still significantly elevated 4 weeks after administration compared to baseline (13.7±1.1 g•kg−1, p<0.001).ConclusionRunning performance was improved following 4 weeks of rHuEpo and remained elevated 4 weeks after administration compared to baseline. These field performance effects coincided with rHuEpo-induced elevated O2 max and Hbmass.

Total haemoglobin mass, blood volume and morphological indices among athletes from different sport disciplines

IntroductionHaemoglobin is a key determinant of maximal oxygen uptake. This study's objective was to assess total haemoglobin mass (tHb-mass), as well as blood volume and morphological indices in athletes training different sports disciplines.Material and methodsThis study was conducted on 176 endurance and non-endurance athletes (males and females). tHb-mass, blood volume (BV), plasma volume (PV), and red cell volume (RCV) were determined by optimized carbon monoxide rebreathing method. Haemoglobin concentration (Hb), haematocrit (Hct), red blood count (RBC) were also determined.ResultsIn endurance sports, gender regardless, no significant differences in relative mean values of tHb-mass (12.8–13.1 g/kg – males; 10.4–10.6 g/kg – females), BV (90.8–94.0 ml/kg – males; 82.7–86.9 ml/kg – females), RCV (36.6–38.0 ml/kg – males; 31.1–31.5 ml/kg – females) or of PV in males (54.2–56.4 ml/kg) were observed. The above indices’ relative values, gender regardless, were significantly lower in judo (11.2 ±0.7 g/kg, 81.8 ±5.9 ml/kg, 48.6 ±4.5 ml/kg and 33.1 ±2.0 ml/kg – males; 9.3 ±0.7 g/kg, 74.3 ±5.6 ml/kg, 46.4 ±4.0 ml/kg and 27.9 ±2.1 ml/kg – females) compared to endurance sports (p < 0.001). No substantial differences were observed in morphological blood indices in males, whereas this differentiation was found between certain sports in female athletes.ConclusionsThe lack of differences in tHb-mass, BV, PV and RCV in endurance sports and presence of this differentiation between various sports shows that the types of training might affect levels of mentioned indices. Measurements of tHb-mass and BV parameters prove Hb, Hct and RBC to have limited value for haematological status evaluations.

Precision of the optimized carbon monoxide rebreathing method to determine total haemoglobin mass and blood volume

The aim of this study was to evaluate the influence of different apparatuses, procedures and calculations on the precision of the optimized carbon monoxide method. Total haemoglobin mass was determined twice on consecutive days in 11 subjects using both venous and capillary blood samples. To estimate loss of carbon monoxide due to exhalation, carbon monoxide concentration was measured by two portable carbon monoxide analysers (Fluke CO-220, Fluke, Norwich, UK and Pac 7000 Carbon Monoxide, Draeger Safety, Northumberland, UK) and alveolar ventilation was specified using an automated metabolic gas analysis system (Cosmed Quark b2, Cosmed, Rome, Italy). Blood volume was derived from total haemoglobin mass using haemoglobin concentration and haematocrit obtained in both the supine and the seated position. Two different formulae to calculate blood volume were also compared. Precision was good for both total haemoglobin mass and blood volume measurements performed on consecutive days (typical error < 2%). Using Fluke CO-220 analyser, an estimated alveolar ventilation and capillary blood, total haemoglobin mass (917±136 g) was similar when compared to the Pac 7000 Draeger CO-analyser (904±137 g; mean bias –13 g with 95% limits of agreement –26 to + 1 g, P=0.76), specified alveolar ventilation (911±132 g, mean bias –6 g with 95% limits of agreement –18 g to + 6 g, P =0.87) and venous blood (917±134 g, mean bias 0 g with 95% limits of agreement –38 to + 38 g, P=0.99), respectively. Blood volume determination was also not significantly affected by the supine vs. seated position (6.7±0.8 l vs. 6.6±0.8 l, P=0.56) but can deviate by ~0.6 l (P=0.01) depending on the formula applied. Thus, the good precision of the assessment of total haemoglobin mass and blood volume using the optimized carbon monoxide rebreathing method is not significantly influenced by the make of CO analyser, method of obtaining alveolar ventilation, blood sampling method and subject position, but should for longitudinal monitoring purposes use the same formula.

Stability of Hemoglobin Mass During a 6-Day UCI ProTour Cycling Race

Blood doping in endurance sport is a growing problem. The purpose of this study was to determine the reliability of total hemoglobin mass (Hb(mass)) measurement in the field and to establish the variability of Hb(mass) during a cycling race, to assess its viability as an additional antidoping detection parameter. Control-matched longitudinal study. International Cycling Union's (UCI) ProTour stage race. Six professional cyclists and 5 recreationally active controls. Seventy-two Hb(mass) tests using the optimized carbon monoxide rebreathing method were performed over 7 consecutive days, before and throughout the tour. Fasted venous blood was obtained for measurement of hematocrit (Hct) and hemoglobin concentration [Hb] in the morning before stages 1, 3, and 6 (D1, D3, and D6). Reliability of Hb(mass) measurement was established using typical error calculated from 2 baseline measures. Individual change scores and coefficients of variation were used to assess stability during racing. Typical error for Hb(mass) was 1.3% [95% confidence limits (CL): 0.9%, 2.5%]. Calculated 95% and 99.99% CL for percent change in Hb(mass) were +/-3.6% and +/-7.2%, respectively. Mean Hb(mass) remained within +/-1.9% of baseline in cyclists and +/-0.5% in controls. In all cases, individual change scores for both cyclists and controls fell within the 95% CL. There was a decrease in Hct (8.1% +/- 2.8%) and [Hb] (9.7% +/- 3.2%) throughout the tour in cyclists but not in controls. We demonstrate that Hb(mass) can be measured reliably via CO-rebreathing during a cycling tour. Unlike [Hb] and Hct, Hb(mass) remains stable over 6 days of racing in professional cyclists and may have potential in an antidoping context.

Total Hemoglobin Mass, Iron Status, and Endurance Capacity in Elite Field Hockey Players

The aims of this study were as follows: To evaluate total hemoglobin mass (tHbmass) in international field hockey players; to examine the correlation between tHbmass and maximum oxygen uptake (VO2max); and to assess influences of iron status on tHbmass and on VO2max. The players of the German women's (N = 17, aged 24.8 +/- 3.0 [21-31] years) and men's (N = 17, aged 24.2 +/- 2.9 [19-32] years) national field hockey team were investigated. tHbmass was measured by an optimized carbon monoxide rebreathing method. The following parameters were measured in venous blood: Hemoglobin concentration (Hbconc), hematocrit (Hct), number and percentage of reticulocytes, reticulocyte hemoglobin content, serum iron, serum ferritin, serum transferrin, unsaturated iron-binding capacity, and serum soluble transferrin receptor concentration. VO2max was determined in a treadmill test. tHbmass (women: 10.6 +/- 1.1 g/kg; men: 12.5 +/- 0.9 g/kg) correlated to VO2max (women: 46.6 +/- 2.9 mL/min/kg; men: 55.8 +/- 4.0 mL/min/kg) in women (r = 0.56, p < 0.05) and in men (r = 0.57, p < 0.05), whereas Hbconc and Hct did not. The investigated parameters of iron status showed no association to tHbmass or to VO2max. In conclusion, tHbmass can be used as an indicator for endurance capacity in elite field hockey players, whereas Hbconc may not. tHbmass or VO2max were not influenced by the actual iron status of the investigated athletes.