Beyond macrocirculatory targets: a multimodal framework for microcirculatory and organ perfusion monitoring in sepsis

Microcirculatory dysfunction may persist despite restoration of conventional macrocirculatory targets in sepsis, reflecting loss of hemodynamic coherence. This review synthesizes current microcirculatory monitoring approaches according to the physiological information they provide and examines how complementary modalities may be integrated to characterize persistent or regional tissue hypoperfusion.

A narrative review of PubMed-indexed literature was conducted, with emphasis on bedside peripheral perfusion assessment, tissue oxygenation and superficial perfusion imaging, direct microvascular visualization, and organ- or tissue-specific monitoring. Recent studies were prioritized together with landmark methodological and validation studies. Available techniques interrogate distinct but overlapping components of the circulation. Bedside peripheral measures provide rapid information on skin reperfusion and vascular tone; spectroscopic and optical techniques characterize tissue oxygenation, reactivity, and spatial perfusion heterogeneity; direct microvascular imaging enables assessment of microvascular density and flow; and organ-specific approaches provide information on renal, cerebral, or retinal perfusion and oxygenation. Discordance between these domains may persist despite improvement in blood pressure or cardiac output, supporting serial multimodal rather than single-variable interpretation. However, substantial heterogeneity in acquisition protocols, measurement sites, devices, analytical methods, and proposed thresholds limits comparability and clinical implementation.

Microcirculatory monitoring should currently be viewed as a complementary framework for identifying persistent or heterogeneous tissue hypoperfusion beyond conventional macrocirculatory targets. Its integration into individualized resuscitation remains promising but requires standardized methodology, external validation, and prospective interventional evidence before any single modality or multimodal strategy can be adopted as a validated resuscitation endpoint.