Olsen H, Länne T
Departments of Endocrinology, Lund University, Malmö University Hospital, S-205 02 Malmö, Sweden.
Am J Physiol. 1998 Sep;275(3):H878-86. doi: 10.1152/ajpheart.1998.275.3.H878.
Venous compliance in the calf of humans and its importance for capacitance function in relation to age were studied with the aid of 22, 44, and 59 mmHg lower body negative pressure (LBNP). Negative pressure transmission to the calf as well as changes in calf volume were studied, and venous compliance was calculated [change in volume with pressure change (dV/dP)]. The change in capacitance response of the calf with age (20-70 yr) was evaluated during LBNP 44 mmHg. Transmission of negative pressure to the subcutaneous tissue was almost full without any changes with age (92%). However, it was reduced to 80% in the underlying muscle tissue, irrespective of depth. Venous compliance in the young was 0.051 ml . 100 ml-1 . mmHg-1 and was reduced by 45% to 0.029 ml . 100 ml-1 . mmHg-1 in the old (P < 0.05). Accordingly, the capacitance response was reduced by 0.015 ml . 100 ml-1 . yr-1 (P < 0.005). Furthermore, the hemodynamic response to hypovolemic circulatory stress was attenuated with age. The reduced pressure transmission in muscle tissue is probably due to restriction of the muscle fascia envelope. The reduced venous compliance with age and the concomitant reduction in capacitance response during LBNP have implications for both the sympathetic reflex responses as well as the capacitance response during acute hypovolemic circulatory stress, which might be defected in aging humans.
借助22、44和59 mmHg的下体负压（LBNP），研究了人类小腿的静脉顺应性及其与年龄相关的容量功能的重要性。研究了负压向小腿的传递以及小腿体积的变化，并计算了静脉顺应性[体积随压力变化的变化量（dV/dP）]。在44 mmHg的LBNP期间，评估了小腿容量反应随年龄（20 - 70岁）的变化。负压向皮下组织的传递几乎是完全的，且不随年龄变化（92%）。然而，在深层肌肉组织中，无论深度如何，负压传递都降至80%。年轻人的静脉顺应性为0.051 ml·100 ml⁻¹·mmHg⁻¹，老年人则降至0.029 ml·100 ml⁻¹·mmHg⁻¹，降低了45%（P < 0.05）。相应地，容量反应以0.015 ml·100 ml⁻¹·岁⁻¹的速度降低（P < 0.005）。此外，对低血容量循环应激的血流动力学反应随年龄减弱。肌肉组织中压力传递的降低可能是由于肌肉筋膜包膜的限制。随着年龄增长静脉顺应性降低以及LBNP期间容量反应随之降低，这对交感反射反应以及急性低血容量循环应激期间的容量反应都有影响，而这在老年人中可能存在缺陷。
