Abstract Title

THE IMPACT OF ACUTE CENTRAL HYPOVOLEMIA ON CEREBRAL HEMODYNAMICS: DOES SEX MATTER?

Presenter Name

AJ Rosenberg

RAD Assignment Number

415

Abstract

Trauma-induced hemorrhage is a leading cause of disability and death due, in part, to impaired perfusion and oxygenation of the brain. While cerebrovascular function is known to differ between males and females, it is not clear if cerebrovascular responses to blood loss are differentiated based on sex. Purpose: To examine the effect of sex on cerebral blood velocity and oxygenation responses following simulated hemorrhage induced via application of lower body negative pressure (LBNP) to presyncope. Methods: Healthy males (n=11, 25±1 yr) and females (n=7, 27±1 yr) participated in a LBNP ramp protocol (-3 mmHg/min) until presyncope. Middle cerebral artery velocity (MCAv), cerebral oxygen saturation (ScO2), end-tidal CO2 (etCO2), heart rate (HR), arterial pressure (MAP) and stroke volume (SV) were measured continuously. Results: Baseline MCAv was higher in females vs. males (70.3±5.8 vs. 57.8 ± 2.1 cm/s, p=0.03), despite a lower etCO2 (37.9±0.9 vs. 44.4±1.5 mmHg, p=0.02). While LBNP tolerance was higher for males compared with females (1675.5±123.1 vs. 1315.9±140.0 s; p=0.08), the absolute and relative (% change) increases in HR and decreases in MCAv, MAP, SV, and etCO2 were similar between males and females at presyncope (p≥0.11). Males exhibited a lower rate of change in MCAv over LBNP time (-0.56±0.10 vs. -0.92±0.09 cm/s/min, p=0.03) and a greater maximum decrease in ScO2 (-7.6±1.3 vs -5.3±0.9 %, p=0.08) when compared with females, most likely due to the higher tolerance in this group. Conclusions: These findings suggest that sex may influence the cerebral hemodynamic responses to simulated blood loss in young healthy adults.

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Research Area

Cardiovascular

Presentation Type

Oral

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THE IMPACT OF ACUTE CENTRAL HYPOVOLEMIA ON CEREBRAL HEMODYNAMICS: DOES SEX MATTER?

Trauma-induced hemorrhage is a leading cause of disability and death due, in part, to impaired perfusion and oxygenation of the brain. While cerebrovascular function is known to differ between males and females, it is not clear if cerebrovascular responses to blood loss are differentiated based on sex. Purpose: To examine the effect of sex on cerebral blood velocity and oxygenation responses following simulated hemorrhage induced via application of lower body negative pressure (LBNP) to presyncope. Methods: Healthy males (n=11, 25±1 yr) and females (n=7, 27±1 yr) participated in a LBNP ramp protocol (-3 mmHg/min) until presyncope. Middle cerebral artery velocity (MCAv), cerebral oxygen saturation (ScO2), end-tidal CO2 (etCO2), heart rate (HR), arterial pressure (MAP) and stroke volume (SV) were measured continuously. Results: Baseline MCAv was higher in females vs. males (70.3±5.8 vs. 57.8 ± 2.1 cm/s, p=0.03), despite a lower etCO2 (37.9±0.9 vs. 44.4±1.5 mmHg, p=0.02). While LBNP tolerance was higher for males compared with females (1675.5±123.1 vs. 1315.9±140.0 s; p=0.08), the absolute and relative (% change) increases in HR and decreases in MCAv, MAP, SV, and etCO2 were similar between males and females at presyncope (p≥0.11). Males exhibited a lower rate of change in MCAv over LBNP time (-0.56±0.10 vs. -0.92±0.09 cm/s/min, p=0.03) and a greater maximum decrease in ScO2 (-7.6±1.3 vs -5.3±0.9 %, p=0.08) when compared with females, most likely due to the higher tolerance in this group. Conclusions: These findings suggest that sex may influence the cerebral hemodynamic responses to simulated blood loss in young healthy adults.