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

When do benefits turn to risks? Impact of a 900 mL whole blood donation on Special Forces performance

BACKGROUND

Special Forces (SF) teams operate in remote environments with limited medical support. As a result, they may need to rely on buddy transfusions to treat bleeding teammates. Considering that 450 mL has no direct impact on their combat performances, it might be tempting to take more blood from a compatible donor to save a hemorrhaging teammate. This study investigates the effect of a 900 mL blood donation on SF operator performance and recovery time following this donation.

STUDY DESIGN AND METHODS

Participants underwent a multifactorial assessment including measures of physiological parameters, vigilance, and physical performance. Results from the day of blood donation were compared with baseline values obtained 1 week earlier (i.e., immediate effect), as well as repeated testing at 7, 14, and approximately 30 days after blood donation (i.e., recovery period).

RESULTS

Hemoglobin levels and heart rate were affected by giving blood. The participants also experienced a significant decrease in physical performance of more than 50% immediately after blood donation. Recovery was slow over the following weeks, remaining significantly different from baseline until full recovery around day 30. However, participants were still able to respond to a simple stimulus and adjust their response, if necessary, even immediately after donating blood.

DISCUSSION

A 900 mL blood donation greatly affects the physical fitness of SF operators. A donation may be worthwhile if it is the only life-saving procedure available and does not endanger the donor's life. The donor would then become a patient and unable to complete the mission.

Vasovagal syncope after blood donation in active duty military personnel of the Spanish Army

BACKGROUND

All studies of vasovagal syncope (VVS) after blood donation have been performed with civilian donors. We hypothesized that military donors have a lower incidence of VVS and a particular set of predisposing factors.

STUDY DESIGN AND METHODS

Retrospective case-control study matching every case of VVS seen from 2011 to 2019 with two controls without VVS from the same blood drive. We used the odds ratio (OR) and its 95% confidence interval (CI), estimated by multivariate logistic regression, to identify independent predictors of VVS.

RESULTS

There were 105 episodes of VVS among 65.481 whole blood donations (0.15%). VVS was more frequent among donors from military academies than from other military units (0.37% vs. 0.10%, p < .001) and in collections conducted in mobile inside setups than in mobile buses (0.23% vs. 0.06%, p < .001). In the multivariate analysis, the only independent predictors of VVS were the status of first-time donor (OR 2.6, 95% CI 1.5-4.4; p < .001) and pre-donation systolic blood pressure (SBP) < 120 mm Hg (OR 1.9, 95% CI 1.1-3.3; p = .01). Donors with both risk factors had a 5.5-fold increased risk of VVS than donors without any risk factor. Age and female sex were not predictive of VVS.

DISCUSSION

Active duty military blood donors have a lower incidence of VVS than that reported in civilian donors. First-time donors and donors with SBP < 120 mm Hg should be temporarily deferred when immediate reincorporation to hazardous or strenuous duty tasks after donation is inescapable.