Cerebral Blood Flow Response to Simulated Hypovolemia in Essential Hypertension

Figures

• 

  Figure 1.. Physiological responses to lower body negative pressure (LBNP). A, Mean arterial blood pressure (MAP; mmHg) was unchanged during LBNP but higher in the uncontrolled hypertensives (uHTN). B, Heart rate (beats per minute) increased during LBNP at −50 mmHg with no difference between the groups. C, Systolic blood pressure (mmHg) showed a significant reduction at −50 mmHg, as well as a consistently higher pressure in the uHTN compared with normotensives (NTN). D, Diastolic blood pressure (mmHg) was significantly increased at −40 and −50 mmHg LBNP, as well as being higher in the uHTN group. E, cardiac output (L/min) decreased during LBNP with no difference between the groups. F, Total peripheral resistance (mmHg/L per min) increased with LBNP in all groups and was persistently higher in the uHTN, P above the line refers to ANOVA main effect of LBNP. * & $ P<0.05, ** & $$ P<0.01, *** & $$$ P<0.001 are multiple comparison P where * is NTN vs uHTN and $ LBNP vs rest. ns indicates nonsignificant.

• 

  Figure 2.. Cerebral blood flow (CBF) during lower body negative pressure (LBNP) to −50 mmHg. A, total cerebral blood flow (tCBF) (L/min) decreased with LBNP. B, Normalized CBF (nCBF) decreased with LBNP. C, Percentage of the cardiac output (CO) to the brain (%) increased with LBNP. D, Cerebrovascular conductance (mL/min per mmHg) decreased with LBNP and showed a lower conductance in the uncontrolled hypertensives (uHTN) at −40 and −50 mmHg compared with the normotensives (NTN). P above the line refers to ANOVA main effect of LBNP. * & $ P<0.05, ** & $$ P<0.01, *** & $$$ P<0.001 are multiple comparison P where * is NTN vs uHTN and $ LBNP vs rest.