Background

Heterogeneity of microvascular blood flow leading to tissue hypoxia is a common finding in patients with septic shock. It may be related to suboptimal systemic perfusion pressure and lead to organ failure. Mapping of skin microcirculatory oxygen saturation and relative hemoglobin concentration using hyperspectral imaging allows to identify heterogeneity of perfusion and perform targeted measurement of oxygenation. We hypothesized that increasing mean arterial pressure would result in improved oxygenation in areas of the skin with most microvascular blood pooling.

Methods

We included adult patients admitted to the intensive care unit within the previous 24 h with sepsis and receiving a noradrenaline infusion. Skin oxygen saturation was measured using hyperspectral imaging-based method at baseline and after the increase in mean arterial pressure by 20 mm Hg by titration of noradrenaline doses. The primary outcome was an increase in skin oxygen saturation depending upon disease severity.

Results

We studied 30 patients with septic shock. Median skin oxygen saturation changed from 26.0 (24.5–27.0) % at baseline to 30.0 (29.0–31.0) % after increase in mean arterial pressure (p = 0.04). After adjustment for baseline saturation, patients with higher SOFA scores achieved higher oxygen saturation after the intervention (r² = 0.21; p = 0.02). Skin oxygen saturation measured at higher pressure was found to be marginally predictive of mortality (OR: 1.10; 95% CI 1.00–1.23; p = 0.053).

Conclusions

Improvement of microcirculatory oxygenation can be achieved with an increase in mean arterial pressure in most patients. Response to study intervention is proportional to disease severity.

中文翻译：

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平均动脉压升高对需要升压药的脓毒症患者皮肤微循环氧合的影响：一项干预研究。

背景

导致组织缺氧的微血管血流的异质性是败血性休克患者的常见发现。它可能与最佳的全身灌注压力有关，并导致器官衰竭。使用高光谱成像对皮肤微循环血氧饱和度和相对血红蛋白浓度进行映射，可以识别灌注的异质性并进行有针对性的氧合作用测量。我们假设，随着大多数微血管血库的积累，平均动脉压的升高将导致皮肤区域的氧合改善。

方法

我们纳入了过去24小时内进入重症监护病房并患有败血症并接受去甲肾上腺素输注的成年患者。在基线时和通过测定去甲肾上腺素剂量使平均动脉压升高20 mm Hg之后，使用基于高光谱成像的方法测量皮肤氧饱和度。主要结果是皮肤氧饱和度的升高，取决于疾病的严重程度。

结果

我们研究了30名败血性休克患者。平均动脉压增加后，中位数皮肤氧饱和度从基线的26.0（24.5–27.0）％变为30.0（29.0–31.0）％（p  = 0.04）。调整基线饱和度后，干预后SOFA评分较高的患者达到了较高的氧饱和度（r ²  = 0.21; p  = 0.02）。发现在较高压力下测得的皮肤氧饱和度仅可预测死亡率（或：1.10； 95％CI 1.00–1.23；p  = 0.053）。

结论

在大多数患者中，平均动脉压的升高可改善微循环氧合。对研究干预的反应与疾病严重程度成正比。