Female sex and young age predicted lower tolerance to simulated blood loss (time to presyncope) during lower body negative pressure testing.
Observational (n=187)
Do demographic characteristics and physiological variables predict time to presyncope during simulated hemorrhage?
Young age and female sex are predictors of low tolerance to simulated blood loss, suggesting they should be considered for early triage in prehospital settings.
Lower body negative pressure (LBNP) simulates hemorrhage, and tolerance to LBNP (time to presyncope TTP) is indicative of tolerance to blood loss. The purpose of this study was to predict TTP based on demographic characteristics (sex, age, height, and body mass index) and physiological variables (heart rate HR, systolic arterial pressure, diastolic arterial pressure DAP, pulse pressure, stroke volume, total peripheral resistance TPR, and baroreflex sensitivity BRS) at baseline, and during 2 levels of LBNP (-15, -30 mm Hg). Multiple linear regression analysis was used to create a model to predict TTP (range: 670 to 2516 seconds, n=187) based on demographic characteristics and physiological variables changes (Δ) from baseline to -30 mm Hg LBNP. The prediction model revealed that TTP (seconds)=1667.5+(5.1×Age)+(61.1×Sex)-(21.5×ΔHR)+(55.3×ΔDAP)-(88.2×ΔTPR)-(4.9×ΔBRS). Most significantly, our analysis demonstrated a lesser survival trajectory for females given the same rate and magnitude of hemorrhage compared to males. Young age and female sex are predictors of low tolerance to blood loss, and should be considered for early triage in the prehospital setting.
Hinojosa‐Laborde et al. (Sun,) conducted a observational in Hypovolemia-induced hemodynamic instability (n=187). Female sex and young age vs. Male sex and older age was evaluated on Time to presyncope (TTP) during lower body negative pressure. Female sex and young age predicted lower tolerance to simulated blood loss (time to presyncope) during lower body negative pressure testing.