Gary Cyril S, Iskandarova Aygul, Abadeer Andrew I, Yohe Gabriel J, Giladi Aviram M
The Curtis National Hand Center, MedStar Union Memorial Hospital, Baltimore, MD; Department of Plastic Surgery, MedStar Georgetown University Hospital, Washington, DC.
The Curtis National Hand Center, MedStar Union Memorial Hospital, Baltimore, MD.
J Hand Surg Am. 2025 Feb;50(2):236.e1-236.e8. doi: 10.1016/j.jhsa.2023.06.012. Epub 2023 Jul 26.
Diagnosing acute tissue ischemia is challenging, particularly in patients with higher skin melanin content. We investigated whether near-infrared spectroscopy (NIRS) is effective and consistent in detecting upper extremity ischemia across various skin phenotypes.
Volunteers underwent tourniquet-induced upper extremity ischemia. Skin color was evaluated by the Fitzpatrick scale (FP, range: I-VI) and the Von Luschan scale (vL, range: 1-36). A NIRS probe was placed on one finger. The tourniquet was inflated to 250 mmHg and perfusion was restricted for 7 minutes, followed by a 10-minute monitored reperfusion period. The percent tissue oxygenation (StO) was recorded.
A total of 55 volunteers were enrolled (22 self-identified as Caucasian, 21 African American, 7 Asian, 2 Latinx, and 2 Biracial). Average starting and ending StO for the cohort was 72.2% and 45.9%, respectively. However, there was variability based on skin melanin content. Increasing vL correlated with lower starting StO, smaller StO decrease, and shorter time to reach ischemic steady state. High skin melanin (FP scale IV-VI) was associated with significantly lower starting StO (-7.1%) and shorter time to reach ischemic steady state (-0.3 mins). African Americans had lower starting StO (-8.6%) and 7.8% lesser total StO decrease than other groups.
NIRS can rapidly detect acute onset tissue ischemia in the upper extremity. However, given the lower starting StO and smaller total StO decrease after tourniquet-induced ischemia for patients with higher skin melanin, using NIRS for clinical detection of acute ischemia may be more challenging in these patients. These inconsistencies may limit use of NIRS clinically for spot identification of ischemia.
Although NIRS has utility in tracking tissue oxygenation, variable performance with different skin melanin content raises concerns as to whether different cutoff/threshold levels are needed for different groups, and whether NIRS is reliable for spot checks in acute events.
诊断急性组织缺血具有挑战性，尤其是在皮肤黑色素含量较高的患者中。我们研究了近红外光谱（NIRS）在检测不同皮肤表型的上肢缺血方面是否有效且具有一致性。
志愿者接受止血带诱导的上肢缺血。通过菲茨帕特里克量表（FP，范围：I - VI）和冯·卢尚量表（vL，范围：1 - 36）评估皮肤颜色。将一个NIRS探头放置在一根手指上。将止血带充气至250 mmHg并限制灌注7分钟，随后进行10分钟的监测再灌注期。记录组织氧合百分比（StO）。
共招募了55名志愿者（22名自我认定为白种人，21名非裔美国人，7名亚洲人，2名拉丁裔和2名混血儿）。该队列的平均起始和结束StO分别为72.2%和45.9%。然而，基于皮肤黑色素含量存在差异。vL增加与起始StO降低、StO降低幅度较小以及达到缺血稳态的时间较短相关。高皮肤黑色素（FP量表IV - VI）与显著更低的起始StO（-7.1%）和更短的达到缺血稳态时间（-0.3分钟）相关。非裔美国人的起始StO较低（-8.6%），且总StO降低幅度比其他组小7.8%。
NIRS可快速检测上肢急性发作的组织缺血。然而，鉴于皮肤黑色素含量较高的患者在止血带诱导缺血后起始StO较低且总StO降低幅度较小，在这些患者中使用NIRS进行急性缺血的临床检测可能更具挑战性。这些不一致性可能会限制NIRS在临床上用于缺血的现场识别。
尽管NIRS在跟踪组织氧合方面有用，但不同皮肤黑色素含量下的性能差异引发了对于不同群体是否需要不同的临界值/阈值水平以及NIRS在急性事件的现场检查中是否可靠的担忧。
