Why effective oxygen delivery in critical illness must be considered beyond hemoglobin concentration, arterial saturation and macrocirculatory parameters.
The review describes how severe, dysregulated acute inflammation can compromise tissue oxygenation through vascular mechanisms operating at both the macrocirculatory and microcirculatory levels. Increased vascular permeability and edema can increase the distance over which oxygen must diffuse, while altered perfusion, coagulation and endothelial dysfunction can further restrict effective oxygen delivery to tissues.
In severe inflammation, sepsis and shock, the oxygen-delivery problem can extend beyond a single number such as hemoglobin concentration, SpO₂ or blood pressure. The clinically relevant endpoint is the ability of oxygen to reach cells and support tissue metabolism.
Oxygen carriage → blood flow → microcirculation → diffusion → tissue oxygen availability.
This broader pathway is central to the scientific framework of Precision Oxygenation Therapeutics: evaluating oxygen support according to functional tissue oxygen delivery rather than relying on one systemic surrogate alone.
This publication does not evaluate BHOC or an HBOC product directly. Its importance for the BHOC evidence framework is pathophysiological: it defines conditions in which conventional oxygen transport can be limited by endothelial dysfunction, impaired microcirculation, edema and abnormal perfusion.
The review also places nitric oxide, endothelial function and vascular tone inside the tissue-oxygenation problem. In severe inflammatory states, NO biology is complex: systemic vasodilation, endothelial dysfunction and microvascular regulation can occur simultaneously.
For next-generation HBOC and BHOC development, this supports a more complete evaluation than asking only whether cell-free hemoglobin scavenges nitric oxide or produces vasoconstriction. The more functional question is the net effect on microvascular perfusion, oxygen unloading and tissue oxygen delivery.
Read: Nitric Oxide Scavenging, HBOC Vasoconstriction & Tissue Oxygenation →
This review supports the pathophysiological rationale for a Precision Oxygenation Therapeutics approach: moving from a macrocirculation-only view toward assessment of oxygen delivery at the tissue level.
In critical conditions, the limitation may extend beyond hemoglobin concentration or arterial oxygen saturation. RBC-dependent oxygen transport, endothelial dysfunction, impaired microcirculation, edema, vascular stasis and increased diffusion distance can all restrict effective tissue oxygenation.
This page forms part of the broader BHOC scientific evidence platform. Related literature is indexed under both BHOC and legacy HBOC terminology, including research associated with HBOC-201 / Hemopure, Oxyglobin and historical Biopure programs. Product-specific evidence and claims remain separated from the pathophysiological rationale described in this review.