Department of Anaesthesia, Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
Physiol Rep. 2022 Jul;10(14):e15216. doi: 10.14814/phy2.15216.
Volume responsiveness can be evaluated by tilting maneuvers such as head-down tilt (HDT) and passive leg raising (PLR), but the two procedures use different references (HDT the supine position; PLR the semi-recumbent position). We tested whether the two procedures identify "normovolemia" by evaluating the stroke volume (SV) and cardiac output (CO) responses and whether the peripheral perfusion index (PPI) derived from pulse oximetry provides similar information. In randomized order, 10 healthy men were exposed to both HDT and PLR, and evaluations were made also when the subjects fasted. Central cardiovascular variables were derived by pulse contour analysis and changes in central blood volume assessed by thoracic electrical admittance (TEA). During HDT, SV remained stable (fasted 110 ± 16 vs. 109 ± 16 ml; control 113 ± 16 vs. 111 ± 16 ml, p > 0.05) with no change in CO, TEA, PPI, or SV variation (SVV). In contrast during PLR, SV increased (fasted 108 ± 17 vs. 117 ± 17 ml; control 108 ± 18 vs. 117 ± 18 ml, p < 0.05) followed by an increase in TEA (p < 0.05) and CO increased when subjects fasted (6.7 ± 1.5 vs. 7.1 ± 1.5, p = 0.007) with no change in PPI or SVV. In conclusion, SV has a maximal value for rest in supine men, while PLR restores SV as CBV is reduced in a semi-recumbent position and the procedure thereby makes healthy volunteers seem fluid responsive.
容量反应性可以通过倾斜试验来评估，如头低位倾斜（HDT）和被动抬腿（PLR），但这两种方法使用不同的参考值（HDT 是仰卧位，PLR 是半卧位）。我们通过评估每搏量（SV）和心输出量（CO）的反应，以及脉搏血氧饱和度衍生的外周灌注指数（PPI）是否提供相似的信息，来测试这两种方法是否能识别“血容量正常”。10 名健康男性以随机顺序接受 HDT 和 PLR 两种方法，且在受试者禁食时也进行了评估。中心心血管变量通过脉搏轮廓分析得出，中心血容量的变化通过胸腔电导（TEA）评估。在 HDT 期间，SV 保持稳定（禁食时 110±16 比 109±16ml；对照时 113±16 比 111±16ml，p>0.05），CO、TEA、PPI 或 SV 变异（SVV）无变化。相比之下，在 PLR 期间，SV 增加（禁食时 108±17 比 117±17ml；对照时 108±18 比 117±18ml，p<0.05），随后 TEA 增加（p<0.05），当受试者禁食时 CO 增加（6.7±1.5 比 7.1±1.5，p=0.007），PPI 或 SVV 无变化。总之，在仰卧位男性中，SV 在休息时达到最大值，而 PLR 在半卧位时降低 CBV 以恢复 SV，从而使健康志愿者看起来对液体有反应性。
