PHBTC 2026 · Evidence analysis · Prehospital EMS

Prehospital Blood Transfusion: Physiology First, Oxygen Delivery and Why Every Minute Matters

This paper is important for BHOC for three simple reasons. In the field, decisions are made from the patient's physiology, not by waiting for Hb or hematocrit. The paper explicitly says that early transfusion restores oxygen delivery before critical ischemia. And the evidence it reviews shows that delay is associated with higher mortality.

1. Physiology firstShock, hypoperfusion and the condition of the patient drive the prehospital decision.

2. Oxygen delivery is a goalThe paper explicitly places restoration of oxygen delivery before critical ischemia inside the purpose of early transfusion.

3. Time mattersThe framework cites rising mortality with delays in transfusion or early resuscitation.

Why this matters for BHOC

This paper does not study BHOC and it does not prove BHOC efficacy. Its value is different. It defines the problem any prehospital oxygen-delivery therapeutic would have to solve.

Recognize shock quickly → act quickly → restore the functions needed before critical ischemia develops.

For BHOC, the relevant question is therefore not simply whether a product increases a laboratory hemoglobin number. The question is whether an oxygen-delivery therapeutic can help restore effective physiology early enough to matter when donor blood is delayed, unavailable or difficult to deploy.

1. The decision is made from the patient, not from waiting for Hb/Hct

The PHBTC framework sets prehospital inclusion criteria around signs of hemorrhagic shock and hypoperfusion. For adults these include:

SBP below 90 mmHg or a weak radial pulse
HR above 100 bpm despite initial intervention
Shock Index above 1.0
altered mental status
delayed capillary refill
ETCO₂ below 25 mmHg
paramedic assessment based on physical presentation, history and scene details

Hemoglobin and hematocrit are not listed as the primary triggers for prehospital transfusion.

Important: the paper does not say Hb or hematocrit are useless, and it does not say they directly measure tissue oxygenation. It does something more practical: it does not use them as the main field decision or as the main immediate response metric.

In the field the immediate question is simpler:

Is this patient in hemorrhagic shock now? Is perfusion failing? Do we need to act now?

2. Oxygen delivery is explicitly one of the physiological goals

The paper states that prehospital transfusion is most impactful when combined with immediate hemorrhage control because it:

“restores oxygen delivery and corrects coagulopathy before critical ischemia occurs.”

That sentence matters. Blood has many functions, and hemorrhage control and coagulation remain essential. But the paper directly identifies restoration of oxygen delivery before critical ischemia as one of the reasons for early transfusion.

Hemorrhage → shock and hypoperfusion → impaired oxygen delivery → critical ischemia

3. They do not directly measure oxygen delivery in the field

The framework says oxygen delivery should be restored, but its immediate clinical assessment is based mainly on the patient's physiology and outcome. It does not require direct measurement of tissue oxygen delivery, tissue PO₂, oxygen extraction, microcirculatory oxygenation or oxygen unloading from hemoglobin.

This is not a weakness. This is emergency medicine. The purpose is not to run a physiology experiment at the roadside. The purpose is to see whether the patient is deteriorating or improving.

Hb/Hct are also not the principal immediate success metrics in this framework.

4. What do they use as immediate and later metrics?

<15 minTarget median time from patient contact to transfusion.

>0.2Target reduction in Shock Index after transfusion.

24 h / 30 dMortality and survival are part of the clinical outcome framework.

The framework also follows vital signs, transfusion reactions, hospital blood-product utilization, ED disposition, ICU and hospital length of stay, Injury Severity Score and Abbreviated Injury Scale.

So the logic is clear:

Field trigger = signs of shock. Immediate response = physiology. Final outcome = survival and downstream clinical results.

5. Time matters

The paper brings together several studies showing the same direction: delay in transfusion or early resuscitation is associated with higher mortality.

+27%Increase in the odds of death associated with each 10-minute delay in an earlier transfusion study cited by PHBTC.

+2% / minIncrease in the odds of 24-hour and 30-day mortality for each minute of delayed early resuscitative intervention in the Deeb et al. analysis.

OR 1.11 / minAdjusted increase in mortality odds for each minute of delayed blood administration in the “Every Minute Matters” penetrating-trauma study.

These are different studies, with different populations and designs. The numbers should not be mixed into one universal biological rule.

But the common message is difficult to miss: every minute matters.

What this paper really shows

1. When to act: based on signs of hemorrhagic shock and hypoperfusion.

2. What they are trying to restore: among other functions, oxygen delivery before critical ischemia.

3. How they judge the early response: improvement in patient physiology, especially Shock Index and vital signs.

4. What ultimately matters: survival and clinical outcome.

This is why the distinction between a laboratory number and a physiological result matters. In prehospital care, the clinical problem is not simply “low hemoglobin.” The problem is a patient in hemorrhagic shock who is losing perfusion and oxygen delivery while the clock is running.

BHOC research question

For Precision Oxygen Therapeutics, the question that follows is straightforward:

Can an independently deployable oxygen-delivery therapeutic help restore effective physiology early enough to matter when donor blood is delayed, unavailable or difficult to deploy?

This is a research question, not a clinical claim.

Evidence analysis
Archil Jaliashvili
BHOC Therapeutics · 11 Sep 2026

Primary source

O’Byrne H, Krohmer J, Schaefer R, et al. 2026. Prehospital Blood Transfusion Coalition: framework for EMS Blood Program Coordinator responsibilities. Trauma Surgery & Acute Care Open. 11(3):e002134. DOI ↗ · BMJ full text ↗ · PubMed ↗

Timing studies cited in the framework

Deeb AP, et al. 2023. Time to early resuscitative intervention association with mortality in trauma patients at risk for hemorrhage. J Trauma Acute Care Surg. 94(4):504-512. PubMed ↗

Duchesne J, et al. 2024. Every minute matters: Improving outcomes for penetrating trauma through prehospital advanced resuscitative care. J Trauma Acute Care Surg. 97(5):710-715. PubMed ↗

Explore the Prehospital EMS application context →

← Return to BHOC Science

Evidence qualification: O’Byrne et al. is a PHBTC operational and clinical framework for prehospital blood transfusion programs. It does not evaluate BHOC, HBOC-201, Hemopure, Oxyglobin or another investigational oxygen carrier. The BHOC section above is an interpretation of the clinical problem and a research question, not evidence of product efficacy or safety.