身体倾斜时胫骨骨微血管血流动力学与胫前动脉血流的比较

Tibia Bone Microvascular Flow Dynamics as Compared to Anterior Tibial Artery Flow During Body Tilt.

作者信息

Becker Rachel L, Siamwala Jamila H, Macias Brandon R, Hargens Alan R

出版信息

Aerosp Med Hum Perform. 2018 Apr 1;89(4):357-364. doi: 10.3357/AMHP.4928.2018.

DOI:10.3357/AMHP.4928.2018

PMID:29562965

Abstract

BACKGROUND

We compared microvascular and macrovascular blood flows of the tibia and anterior tibial artery during graded whole-body tilt. We hypothesized equal responses for bone microvascular and macrovascular blood flows during varying angles of tilt.

METHODS

There were 18 volunteers who were randomly positioned in the following postures: supine, 15° head-up tilt, 6° head-up tilt, 6° head-down tilt, and 15° head-down tilt using an inversion table with reference to seated posture (baseline control). Ultrasonography quantified anterior tibial arterial diameter and peak systolic velocity, enabling calculation of macrovascular blood flow to the tibia. Tibial bone microvascular blood flow was measured noninvasively using photoplethysmography in the same leg.

RESULTS

Transitioning from a seated position to a supine position, macrovascular blood flow did not change significantly (1.81 ± 1.18 to 2.80 ± 1.74cm 3 · s-1). However, bone microvascular flow increased significantly (0.36 ± 0.23 to 1.11 ± 0.79 V) from the seated to the supine position. Transitioning from a seated posture to 15° head-down tilt, both arterial macrovascular and bone microvascular flows increased significantly (1.81 ± 1.18 to 3.32 ± 2.08 cm3 · s-1 and 0.36 ± 0.23 V to 2.99 ± 2.71 V, respectively). The normalized flow for microvascular blood flow as a function of body tilt was significantly greater than that for macrovascular blood flow at 6° and 15° head-down tilt.

DISCUSSION

These data do not support our hypothesis that bone microvascular flow and arterial macrovascular flow share equal responses to altered body tilt. Therefore, for a given decrease in local blood pressure in the leg with head-down body tilt, the magnitude of increase in blood flow is greater in the microcirculation as compared to the feeding artery.Becker RL, Siamwala JH, Macias BR, Hargens AR. Tibia bone microvascular flow dynamics as compared to anterior tibial artery flow during body tilt. Aerosp Med Hum Perform. 2018; 89(4):357-364.

摘要

背景

我们比较了分级全身倾斜过程中胫骨和胫前动脉的微血管和大血管血流情况。我们假设在不同倾斜角度下，骨微血管和大血管血流的反应相同。

方法

18名志愿者被随机安排在以下姿势：仰卧位、头向上倾斜15°、头向上倾斜6°、头向下倾斜6°以及头向下倾斜15°，使用翻转台以坐姿（基线对照）为参考。超声检查量化胫前动脉直径和收缩期峰值流速，从而计算出流向胫骨的大血管血流。在同一条腿上使用光电容积描记法无创测量胫骨骨微血管血流。

结果

从坐姿转变为仰卧位时，大血管血流无显著变化（1.81±1.18至2.80±1.74cm³·s⁻¹）。然而，从坐姿到仰卧位，骨微血管血流显著增加（0.36±0.23至1.11±0.79V）。从坐姿转变为头向下倾斜15°时，动脉大血管血流和骨微血管血流均显著增加（分别为1.81±1.18至3.32±2.08cm³·s⁻¹以及0.36±0.23V至2.99±2.71V）。在头向下倾斜6°和15°时，微血管血流相对于身体倾斜的归一化血流显著大于大血管血流。