Mayrovitz H N, Smith J
Nova Southeastern University, College of Medical Sciences, Department of Physiology, Fort Lauderdale, FL 33328, USA.
Microcirculation. 1998;5(2-3):227-33.
Sustained heel pressure during surgery and during acute and long-term care residence can cause heel blood flow deprivation sufficient to cause pressure ulcers. Because little is known about the amount and distribution of heel blood perfusion changes under these conditions, the aim of this study was to characterize the main features of these changes.
Heel blood perfusion by laser Doppler imaging (LDI, 40 x 40 mm scans) was measured in 11 vascularly normal persons before (10 minutes), during heel loading (40 minutes) and after off-loading (20 minutes). Loading was done with subjects supine and one heel on a transparent plate through which LDI data were obtained during loading. Analyses were on progressively increasing areas around the central compression site using 10 x 10, 20 x 20, 30 x 30, and 40 x 40 mm assay areas at each of multiple time points during the 70-minute test.
(1) Heel perfusion is rapidly and significantly reduced on loading (P < 0.01) with the greatest reduction within the central heel area; (2) perfusion remains uniformly depressed throughout the loading interval; (3) off-loading is associated with a rapid onset, specially heterogeneous hyperemia which exceeds baseline (P < 0.01) for 10 minutes.
The present seminal findings may serve as a guide to develop sorely needed microvascular tests to help classify heel breakdown risk on a patient-by-patient basis.
手术期间以及急性和长期护理期间持续的足跟压力可导致足跟血流供应不足，足以引发压疮。由于在这些情况下，对于足跟血液灌注变化的量和分布了解甚少，本研究的目的是描述这些变化的主要特征。
对11名血管正常的受试者在足跟加载前（10分钟）、加载期间（40分钟）和卸载后（20分钟），通过激光多普勒成像（LDI，40×40mm扫描）测量足跟血液灌注。加载时受试者仰卧，一只足跟放在透明板上，在加载过程中通过该透明板获取LDI数据。在70分钟的测试过程中的多个时间点，使用10×10、20×20、30×30和40×40mm的检测区域，对中心受压部位周围逐渐增大的区域进行分析。
（1）加载时足跟灌注迅速且显著降低（P<0.01），足跟中心区域降低最为明显；（2）在整个加载期间，灌注持续均匀降低；（3）卸载与快速出现的、特别不均匀的充血有关，这种充血超过基线水平（P<0.01）达10分钟。
目前的重要发现可作为开发急需的微血管检测方法的指南，以帮助逐例评估足跟破溃风险。
