TY - JOUR
T1 - Differentiating compensatory mechanisms associated with low tolerance to central hypovolemia in women
AU - Schlotman, Taylor Elyse
AU - Akers, Kevin S.
AU - Nessen, Shawn C.
AU - Convertino, Victor A.
N1 - Publisher Copyright:
© 2019 the American Physiological Society.
PY - 2019/3
Y1 - 2019/3
N2 - Women generally display lower tolerance to acute central hypovolemia than men. The measurement of compensatory reserve (CRM) is a novel metric that provides information about the sum total of all mechanisms that together work to compensate for the relative blood volume deficit. Hemodynamic decompensation occurs with depletion of the CRM (i.e., 0% CRM). In the present study, we hypothesized that the lower tolerance to progressive central hypovolemia reported in women can be explained by a faster reduction rate in CRM compared with men rather than sex differences in absolute integrated compensatory responses. Continuous, noninvasive measures of CRM were collected from 208 healthy volunteers (107 men and 85 women) who underwent progressive stepwise central hypovolemia induced by lower body negative pressure to the point of presyncope. Comparisons revealed shorter (P < 0.01) times in female participants compared with male participants to reach 30% and 0% CRM. Similarly, the lower body negative pressure level, represented by the cumulative stress index, was less at 30% and 0% CRM in women compared with men (P < 0.01). Changes in hemodynamic responses and frequency-domain data (oscillations in cerebral blood flow velocity and mean arterial blood pressure) were similar between men and women at 0% CRM (P > 0.05). We conclude that compensatory responses to central hypovolemia in women were similar to men but were depleted at a faster rate compared with men. The earlier depletion of the compensatory reserve in women appears to be influenced by failure to maintain adequate cerebral oxygen delivery.
AB - Women generally display lower tolerance to acute central hypovolemia than men. The measurement of compensatory reserve (CRM) is a novel metric that provides information about the sum total of all mechanisms that together work to compensate for the relative blood volume deficit. Hemodynamic decompensation occurs with depletion of the CRM (i.e., 0% CRM). In the present study, we hypothesized that the lower tolerance to progressive central hypovolemia reported in women can be explained by a faster reduction rate in CRM compared with men rather than sex differences in absolute integrated compensatory responses. Continuous, noninvasive measures of CRM were collected from 208 healthy volunteers (107 men and 85 women) who underwent progressive stepwise central hypovolemia induced by lower body negative pressure to the point of presyncope. Comparisons revealed shorter (P < 0.01) times in female participants compared with male participants to reach 30% and 0% CRM. Similarly, the lower body negative pressure level, represented by the cumulative stress index, was less at 30% and 0% CRM in women compared with men (P < 0.01). Changes in hemodynamic responses and frequency-domain data (oscillations in cerebral blood flow velocity and mean arterial blood pressure) were similar between men and women at 0% CRM (P > 0.05). We conclude that compensatory responses to central hypovolemia in women were similar to men but were depleted at a faster rate compared with men. The earlier depletion of the compensatory reserve in women appears to be influenced by failure to maintain adequate cerebral oxygen delivery.
KW - Cerebral blood flow velocity
KW - Compensatory reserve
KW - Hypovolemia
KW - Lower body negative pressure
KW - Sex difference
UR - http://www.scopus.com/inward/record.url?scp=85063462822&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.00420.2018
DO - 10.1152/ajpheart.00420.2018
M3 - Article
C2 - 30592899
AN - SCOPUS:85063462822
SN - 0363-6135
VL - 316
SP - H609-H616
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 3
ER -