Immediate effects of blood donation on physical and cognitive performance—A randomized controlled double-blinded trial

The relationship between hemoglobin and [Formula: see text]: A systematic review and meta-analysis

OBJECTIVE

There is widespread agreement about the key role of hemoglobin for oxygen transport. Both observational and interventional studies have examined the relationship between hemoglobin levels and maximal oxygen uptake ([Formula: see text]) in humans. However, there exists considerable variability in the scientific literature regarding the potential relationship between hemoglobin and [Formula: see text]. Thus, we aimed to provide a comprehensive analysis of the diverse literature and examine the relationship between hemoglobin levels (hemoglobin concentration and mass) and [Formula: see text] (absolute and relative [Formula: see text]) among both observational and interventional studies.

METHODS

A systematic search was performed on December 6th, 2021. The study procedures and reporting of findings followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Article selection and data abstraction were performed in duplicate by two independent reviewers. Primary outcomes were hemoglobin levels and [Formula: see text] values (absolute and relative). For observational studies, meta-regression models were performed to examine the relationship between hemoglobin levels and [Formula: see text] values. For interventional studies, meta-analysis models were performed to determine the change in [Formula: see text] values (standard paired difference) associated with interventions designed to modify hemoglobin levels or [Formula: see text]. Meta-regression models were then performed to determine the relationship between a change in hemoglobin levels and the change in [Formula: see text] values.

RESULTS

Data from 384 studies (226 observational studies and 158 interventional studies) were examined. For observational data, there was a positive association between absolute [Formula: see text] and hemoglobin levels (hemoglobin concentration, hemoglobin mass, and hematocrit (P<0.001 for all)). Prespecified subgroup analyses demonstrated no apparent sex-related differences among these relationships. For interventional data, there was a positive association between the change of absolute [Formula: see text] (standard paired difference) and the change in hemoglobin levels (hemoglobin concentration (P<0.0001) and hemoglobin mass (P = 0.006)).

CONCLUSION

These findings suggest that [Formula: see text] values are closely associated with hemoglobin levels among both observational and interventional studies. Although our findings suggest a lack of sex differences in these relationships, there were limited studies incorporating females or stratifying results by biological sex.

Evaluation of hemostatic capacities among commando candidates: Would their blood suit a hemorrhagic war-injured patient in case of blood donation on the battlefield?

BACKGROUND

In case of a warm fresh whole blood transfusion on the battlefield, the blood donation usually occurs just after a combat phase and often after several days on the fields. To explore the hemostatic capacity of such blood, we analyzed the blood of volunteers attending the commando course of the French Navy, considering this course as an experimental model, placing them into the same physiological conditions as those faced by deployed fighters.

METHODS

Venous blood was collected at the beginning of the course, mimicking their baseline status, and a second time 6 weeks later, from the remaining candidates, during the actual commando training, mimicking the stress conditions. For each candidate, we observed the differences between the two blood samples.

RESULTS

Of the 112 men that attended the first day of the course, only 17 remained 6 weeks later. In the second blood samples, we noted significant increased leucocytes and platelets counts and significant decreased hematocrit and hemoglobin levels. Thrombin generation assays showed significantly lower normalized peak heights (-31%), lower normalized endogenous thrombin potential values (-29%), and lower velocity index (-35%). Normalized lag time and time to peak did not differ. Viscoelastometric testing revealed a significant increasing in clot firmness as assessed by maximum amplitude and amplitude at 6 minutes. The clot speed was significantly increased.

CONCLUSION

This work brings new data on coagulation during prolonged and considerable physical exercise. No obvious deleterious modification of hemostatic properties was observed. The decrease of the endogenous thrombin potentials may reflect a better ability to control the thrombin generation once started. Altogether, these results suggest that this blood could suit well a hemorrhagic war-injured patient.

LEVEL OF EVIDENCE

Prospective observational cohort study, Level III.

Minimal tactical impact and maximal donor safety after a buddy transfusion: A study on elite soldier performances in both laboratory and field environments

BACKGROUND

The major causes of death of combat casualties in austere environments are related to hemorrhage and occur early after injury. The implementation of a walking blood bank may overcome the logistical issues raised using blood component therapy. Nonetheless, it is important to ensure that this buddy transfusion is not going to compromise the mission success by altering the donor's performance. The results available so far cannot rule out this issue with certainty. Therefore, this study aimed at investigating the immediate effect of a 450-ml blood donation on the performances of elite soldiers in laboratory and field environments.

STUDY DESIGN AND METHODS

This double-blind, randomized controlled study included two experiments. For both experiments, subjects were randomly assigned either to a control group (n₁  = n₂  = 7) or to a 450-ml-blood-bag donation group (n₁  = 7 and n₂  = 8). All participants underwent before and after a potential blood donation a multifactorial assessment including adapted physical tasks, hematological variables, vigilance parameters, and subjective assessments.

RESULTS

No significant results were evidenced in this study. There was no impact of blood donation on the participants' performances in both the hospital and the combat-like environments.

CONCLUSION

From a donor's point of view, a 450-ml blood donation has no impact on the required abilities of our elite soldiers to fulfill a demanding tactical mission. Thus, the results of this study support the fact that buddy transfusions could be part of the operational clinical armamentarium in austere environments for elite soldiers when no blood components are available.

Joint Trauma System, Defense Committee on Trauma, and Armed Services Blood Program consensus statement on whole blood

Hemorrhage is the most common mechanism of death in battlefield casualties with potentially survivable injuries. There is evidence that early blood product transfusion saves lives among combat casualties. When compared to component therapy, fresh whole blood transfusion improves outcomes in military settings. Cold-stored whole blood also improves outcomes in trauma patients. Whole blood has the advantage of providing red cells, plasma, and platelets together in a single unit, which simplifies and speeds the process of resuscitation, particularly in austere environments. The Joint Trauma System, the Defense Committee on Trauma, and the Armed Services Blood Program endorse the following: (1) whole blood should be used to treat hemorrhagic shock; (2) low-titer group O whole blood is the resuscitation product of choice for the treatment of hemorrhagic shock for all casualties at all roles of care; (3) whole blood should be available within 30 min of casualty wounding, on all medical evacuation platforms, and at all resuscitation and surgical team locations; (4) when whole blood is not available, component therapy should be available within 30 min of casualty wounding; (5) all prehospital medical providers should be trained and logistically supported to screen donors, collect fresh whole blood from designated donors, transfuse blood products, recognize and treat transfusion reactions, and complete the minimum documentation requirements; (6) all deploying military personnel should undergo walking blood bank prescreen laboratory testing for transfusion transmitted disease immediately prior to deployment. Those who are blood group O should undergo anti-A/anti-B antibody titer testing.

An Analysis of Exertional Safety After Blood Donation in Active Duty Military Personnel-A Feasibility Study

INTRODUCTION

Whole blood (WB) is the optimal resuscitation fluid in hemorrhagic shock. Military research focuses on mortality benefits of WB acquired through walking blood banks (WBBs). Few military-based studies on donation effects exist, almost exclusively performed on small special operation forces. No Department of Defense regulations for postdonation precautions in nonaviation crew members exist. Further study is warranted regarding safety and limitations in postdonation populations.

MATERIALS AND METHODS

A feasibility (n = 25) prospective interventional study examined the safety of exertion (defined as a 1.6-km treadmill run at volunteers' minimum passing pace for the Army Physical Fitness Test) following 1 unit of WB donation. Subjects served as their own controls, performing baseline testing 7 days before donation, with repeat testing 1 h following donation conducted by Armed Services Blood Program personnel. Adverse events, pre- and postexertion vital signs (VS) were evaluated.

RESULTS

There were no adverse events throughout testing. Only resting heart rate (68 vs. 73 beats · min-1, p < 0.01) and postexertion heart rate were significantly different among pre- and postdonation VS. Additional significant findings were time to attain postexertion normocardia (116 vs. 147 seconds, p < 0.01). A small but statistically significant change in Borg perceived exertional scores was noted (10.3 vs. 10.8, p < 0.05).

CONCLUSIONS

This feasibility study demonstrates the first safety test of regular military populations performing exertion immediately following the standardized WB donation. VS changes may translate into a small but significant increase in perceived postdonation exertion. Future studies should expand duration and intensity of exertion to match combat conditions.

"Blood for Blood"? Personal Motives and Deterrents for Blood Donation in the German Population

It is crucial to provide updated knowledge about blood (non-)donors, as it is necessary to design targeted interventions with the aim of retaining blood donors and thus contributing to a functioning health system. This study investigates the prevalence and socio-demographic patterning of lifetime blood donation, assessing blood donation intention within the next 12 months and exploring personal motives and deterrents of blood donation qualitatively in the German population. A face-to-face cross-sectional survey with 2531 respondents was conducted, representative of the German population in terms of age, gender, and residency. Closed as well as open questions were asked. Qualitative content analysis was used for coding the qualitative material. Basic descriptive statistics were conducted to address our research questions. More than one-third of the participants reported that they have donated blood at least once in their lifetime. Motives and deterrents were assigned to 10 domains with 50 main categories and 65 sub-categories. The most frequently stated motives for blood donation were "altruism", "social responsibility", and "charity", whereas the most frequently stated deterrents were "health status", "age", and "lack of time". This study provides information to tailor recruitment and reactivation strategies to address donors at different career steps-from non-donor to loyal donor.

Practical Considerations for a Military Whole Blood Program

INTRODUCTION

Prehospital care in the combat environment has always been of great importance to the U.S. military, and trauma resuscitation has remained a cornerstone. More evidence continues to demonstrate the advantages of intervention with early transfusion of blood products at the point of injury. The military has recognized these benefits; as such, the Department of Defense Joint Trauma System and the Committee on Tactical Combat Casualty Care have developed new advanced resuscitation guidelines, which now encourage the use of whole blood (WB) in the prehospital setting.

MATERIALS AND METHODS

This general review of peer-reviewed journal articles was performed through an extensive electronic search from the databases of PubMed Central (MEDLINE) and the Cochrane Library.

RESULTS

Based on this literature search, the current evidence suggests that transfusion with WB is safe and efficacious. Additionally, soldier function is preserved after donating fresh WB in the field. Currently, the collection and implementation of WB is accomplished through several different protocol-driven techniques.

CONCLUSION

WB has become the favored transfusion product as it provides all of the components of blood in a convenient package that is easy to store and transport. Specifically, group O WB containing low titers of anti-A and -B antibodies has become the transfusion product of choice, offering the ability to universally fluid resuscitate patients despite not knowing their blood group. This new ability to obtain low titer group O WB has transformed the approach to the management of hemorrhagic shock in the prehospital combat environment.

The central blood volume as measured by thoracic electrical impedance and plasma proANP is not compromised by donation of 900 mL of blood in men

OBJECTIVES

To evaluate whether the donation of 900 mL of blood reduces the central blood volume (CBV) assessed by thoracic electrical impedance (TI) and plasma pro-atrial natriuretic peptide (proANP).

BACKGROUND

Donation of 450 mL of blood carries a 1% risk of a vasovagal reaction. Withdrawal of 900 mL of blood decreases cardiac output; however, the effect on CBV remains unknown.

METHODS/MATERIALS

A randomised, single-blinded, placebo-controlled, crossover design was used, where 21 healthy semi-recumbent men donated 2 × 450 mL blood or were sham-phlebotomised. Changes in CBV were estimated by proANP and TI at 1.5 (TI_1.5 ) and 100 (TI₁₀₀ ) kHz, reflecting extracellular volume and (regional) total body water, respectively, and the index value (IDX; 1/T_1.5 -1/TI₁₀₀ ) was used to estimate changes in intracellular (red cell) volume. Systolic, diastolic and mean arterial blood pressure; heart rate; stroke volume; cardiac output; and systemic vascular resistance were monitored. After completion of the study, 1000 mL of isotonic saline was infused.

RESULTS

Changes (mean% ± SD) in TI_1.5 , TI₁₀₀ and IDX were similar after 450 mL (-0.2 ± 1.6%, 0.0 ± 1.1%, -0.4 ± 10.1%) and 900 mL (0.1 ± 1.6%, 0.2 ± 1.5% and -2.0 ± 15.8%) of blood donation compared to after a sham donation of 450 mL (-0.9 ± 1.2%, -0.5 ± 1.5% and -0.1 ± 6.1%) and 900 mL (-1.2 ± 1.5%, -0.6 ± 1.3% and 0.5 ± 9.9%). In addition, changes in plasma proANP were similar after 450 and 900 mL of blood donation (-0.8 ± 6.7% and -7.6 ± 7.9%) as after sham donations (1.3 ± 7.3% and -4.5 ± 5.6%). Monitoring haemodynamic variables revealed that stroke volume decreased after the donation of 900 mL of blood (-12 ± 12 mL) compared to sham donations.

CONCLUSION

During a 900-mL blood loss in semi-recumbent men, CBV measured by TI and plasma proANP is not affected.

Iron supplementation limits the deleterious effects of repeated blood donation on endurance sport performance but not on iron status

BACKGROUND

Every day, blood banks worldwide face the challenge of ensuring an adequate blood supply. Iron deficiency is by far the most common cause of deferral of blood donors. The aim of the present study was to determine the effect of iron supplementation after repeated blood donation on iron status and physiological performance.

MATERIALS AND METHODS

Forty-four moderately trained and iron-replete subjects were randomly divided into a whole blood donation (n=36) and a placebo donation (n=8) group. One third of the donation group received no iron supplementation, whereas one third received 20 mg iron and one third received 80 mg iron daily for 28 days. The subjects were intended to make three donations 3 months apart, and recovery of endurance capacity, assessed by an incremental maximal cycling test, and haematological parameters was monitored up to 28 days after each donation.

RESULTS

Negative effects of repeated blood donation were found for markers of iron storage, markers of functional iron and/or iron metabolism regulation, and physiological markers. Iron supplementation did not affect iron storage but did limit, at the highest dose of 80 mg, the effect of blood donations on functional iron and/or iron metabolism regulation, and at both 20 and 80 mg the negative effects on maximal power output and peak oxygen consumption.

DISCUSSION

Iron supplementation limited the deleterious effects of repeated blood donation on endurance sport performance but not on decline in iron status in iron-replete young men. These results underline the importance of iron supplementation to minimise the deleterious effects of blood donation on physiological functions, and the necessity to optimise the supplementation strategy to preserve iron status.

Cognitive and physical performance are well preserved following standard blood donation: A noninferiority, randomized clinical trial

BACKGROUND

A walking blood bank (WBB) refers to the use of fellow combatants for battlefield blood donation. This requires pretesting combatants for infectious diseases and blood type. A fundamental prerequisite for this technique is that the donating soldier will suffer minimal physiological and mental impact. The purpose of the current study is to assess the effect of blood shedding on battlefield performance.

METHODS

This is a double-blind randomized control trial. Forty Israel Defense Forces combatants volunteered for the study. Participants underwent baseline evaluation, including repeated measurement of vital signs, cognitive evaluation, physical evaluation, and a strenuous shooting test. Three weeks after the baseline evaluation, subjects were randomized to either blood donation or the control group. For blinding purposes, all subjects underwent venous catheterization for the duration of a blood donation. Repeated vital signs and function evaluation were then performed.

RESULTS

Thirty-six patients were available for randomization. Baseline measurements were similar for both groups. Mean strenuous shooting score was 80.5 ± 9.5 for the control group and 82 ± 6.6 for the test group (p = 0.58). No clinically or statistically significant differences were found in tests designed to evaluate cognitive performance or physical functions. Vital signs taken multiple times were also similar between the test and control groups.

CONCLUSIONS

Executive, cognitive, and physical functions were well preserved after blood donation. This study supports the hypothesis that a WBB does not decrease donor combat performance. The categorical prohibition of physical exercise following blood donation might need to be reconsidered in both military and civilian populations.

Fresh Low Titer O Whole Blood Transfusion in the Austere Medical Environment

Massive hemorrhage is an immediate threat to life. The military developed the Tactical Combat Casualty Care guidelines to address the management of acute trauma, including administration of blood products. The guidelines have been expanded to include low titer O whole blood, which is in limited use by the military. This proposal describes how the transfusion of fresh whole blood might be applied to the remote civilian environment. In doing so, this life-saving intervention may be brought to the austere medical environment, allowing critically hemorrhaging patients to survive to reach definitive medical care.