Massive Haemorrhage Product Ratio Calculator
Massive Haemorrhage Product Ratio Calculator
How many units of plasma and of platelets accompany a given number of red cell units at 1:1:1 or 1:1:2 — with the PROPPR notation spelt out, because the ratio is written plasma first and the 2 is red cells.
Massive Haemorrhage Product Ratio
Red cell units × ratio6 red cell units at 1:1:1
Formula — and what the notation means
At 1:1:2 — plasma units = platelet units = red cell units ÷ 2
Plasma and platelet unit counts are equal in both ratios, so one number sizes both
Six whole-blood-derived platelet units ≈ one adult therapeutic dose ≈ one apheresis unit
- which number is the red cells
- in PROPPR the notation runs plasma : platelets : red cells, so the 2 in 1:1:2 is RED CELLS. Read the other way round, 1:1:2 would mean twice as many platelets — the opposite prescription to the one the trial studied
- platelet units, not platelet doses
- PROPPR counted a pool of five or six whole-blood-derived platelet units as equivalent to one apheresis unit, and each container’s platelet dose counted as six units in the ratio. Six ratio-units is therefore one adult therapeutic dose, and ordering six adult doses instead delivers about six times the platelets intended
- plasma equals platelets
- in both arms the plasma and platelet unit counts are identical, which is why a single headline figure covers both. The arms differ only in how many red cells accompany them
- when the ratio stops applying
- as soon as a fibrinogen, a platelet count and ideally a viscoelastic trace are available. From then on the ratio is a worse guide than the results, and fibrinogen in particular is not adequately replaced by plasma
Worked example
6 red cell units at 1:1:1
At 1:1:1 the notation is plasma : platelets : red cells, so 6 red cell units are matched by 6 units of plasma and 6 units of platelets
Six platelet units is one adult therapeutic dose — a pool of five or six whole-blood-derived units, or one apheresis unit
Asking for 6 adult platelet doses instead of 6 platelet units would deliver roughly six times the platelets intended
At 1:1:2 the same 6 red cell units are matched by 3.0 units of plasma and 3 platelet units — half an adult platelet dose
Both PROPPR arms gave platelets first, then alternated red cells and plasma, so the plasma is not held back to the end of the pack
The two PROPPR arms, and what the trial found
| 1:1:1 (intervention) | 1:1:2 (control) | |
|---|---|---|
| Contents of one container | 6 units plasma, 1 platelet dose (a pool counted as 6 units), 6 units red cells | Alternating containers: 3 units plasma and 6 units red cells, then 3 units plasma, 1 platelet dose and 6 units red cells |
| Order of administration | Platelets first, then alternating red cells and plasma | Platelets first where present, then alternating red cells and plasma |
| 24-hour mortality | 12.7% | 17.0% — not a significant difference (P = 0.12) |
| 30-day mortality | 22.4% | 26.1% — not a significant difference (P = 0.26) |
| Achieved haemostasis | 86% | 78% — significantly better with 1:1:1 (P = 0.006) |
| Death from exsanguination at 24 hours | 9.2% | 14.6% — significantly fewer with 1:1:1 (P = 0.03) |
What replaces the ratio once results are back
| Target | Threshold | Product |
|---|---|---|
| Fibrinogen | Maintain above 1.5 g/L; above 2.0 g/L in obstetric haemorrhage | Cryoprecipitate or fibrinogen concentrate. Plasma does not replace fibrinogen adequately |
| Platelet count | Maintain above 50 × 10⁹/L; above 100 × 10⁹/L with multiple or central nervous system trauma | Platelets |
| PT and APTT ratio | Keep below 1.5 | Plasma |
| Ionised calcium | Keep above 1.0 mmol/L | Calcium chloride or gluconate — citrate in the components chelates calcium |
| Antifibrinolysis | Within 3 hours of injury | Tranexamic acid, which does not depend on any laboratory result |
A ratio for the first ten minutes, and results for everything after
Ratio-driven resuscitation exists to solve a timing problem. In the first minutes of a major haemorrhage nobody has a fibrinogen, a platelet count or a viscoelastic trace, and waiting for them means transfusing red cells alone into a patient who is already coagulopathic. Shipping plasma and platelets alongside the red cells in a fixed proportion removes that decision from the moment when it cannot be made well. The two proportions actually studied head to head are 1:1:1 and 1:1:2, in PROPPR.
The notation is read wrongly often enough to be worth spelling out. In PROPPR it runs plasma : platelets : red cells, so the 2 in 1:1:2 is red cells — half as much plasma and half as many platelet units for each red cell unit. Reversed, 1:1:2 would mean twice as many platelets, which is the opposite prescription. The second trap is the platelet unit: the trial counted a pool of five or six whole-blood-derived units as one apheresis unit and as six units in the ratio, so six ratio-units is one adult therapeutic dose. A request for six adult platelet doses where six platelet units were meant delivers roughly six times the platelets intended.
What PROPPR found is worth stating precisely, because it is frequently rounded up or down. The 1:1:1 arm did not significantly reduce mortality at 24 hours (12.7% against 17.0%) or at 30 days (22.4% against 26.1%). It did significantly increase the proportion achieving haemostasis (86% against 78%) and significantly reduce death from exsanguination within 24 hours (9.2% against 14.6%). So 1:1:1 is not proven to save lives overall and is better at stopping the bleeding — which is a reasonable basis for using it in the opening phase without overstating the case.
The ratio should then get out of the way. Once a Clauss fibrinogen, a platelet count and ideally a viscoelastic trace are available, goal-directed replacement is the better guide: fibrinogen above 1.5 g/L and above 2.0 g/L in obstetric haemorrhage, platelets above 50 × 10⁹/L and above 100 with multiple or central nervous system trauma, PT and APTT ratios under 1.5. Fibrinogen is the reason this matters — it falls first and plasma is a dilute source of it, so a patient resuscitated strictly by ratio can be hypofibrinogenaemic while the ratio looks immaculate. None of it substitutes for tranexamic acid, calcium, warming and stopping the bleeding. Every dose here supports a clinician’s prescription rather than replacing it, and blood products are given against a clinical indication, not against a number.
Frequently asked questions
What does 1:1:2 mean in a massive transfusion protocol?
In PROPPR the notation runs plasma : platelets : red cells, so 1:1:2 means one unit of plasma and one platelet unit for every two red cell units. The 2 is red cells, not platelets — read the other way round the ratio would double the platelets instead of halving them.
What did the PROPPR trial show?
No significant mortality difference between 1:1:1 and 1:1:2 at 24 hours (12.7% against 17.0%) or 30 days (22.4% against 26.1%), but significantly more patients achieved haemostasis with 1:1:1 (86% against 78%) and significantly fewer died of exsanguination within 24 hours (9.2% against 14.6%).
How many platelet units is one adult dose?
About six. PROPPR counted a pool of five or six whole-blood-derived platelet units as equivalent to one apheresis unit and as six units in the ratio, so six ratio-units is one adult therapeutic dose. Ordering six adult doses instead of six units gives roughly six times too many platelets.
When should ratio-driven transfusion give way to goal-directed therapy?
As soon as a Clauss fibrinogen, a platelet count and ideally a viscoelastic trace are available. From that point the results are a better guide than the assumed ratio, particularly for fibrinogen, which falls first and is not adequately replaced by plasma.
How much plasma and platelets go with 6 units of red cells?
At 1:1:1, six units of plasma and six platelet units — the latter being one adult therapeutic dose. At 1:1:2, three units of plasma and three platelet units, which is half an adult platelet dose. Plasma and platelet unit counts are equal in both ratios.
Related calculators
References
- Holcomb JB, Tilley BC, Baraniuk S, et al. Transfusion of plasma, platelets, and red blood cells in a 1:1:1 vs a 1:1:2 ratio and mortality in patients with severe trauma: the PROPPR randomized clinical trial. JAMA. 2015;313(5):471–482.
- Hunt BJ, Allard S, Keeling D, et al. A practical guideline for the haematological management of major haemorrhage. Br J Haematol. 2015;170(6):788–803.
- Rossaint R, Afshari A, Bouillon B, et al. The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition. Crit Care. 2023;27(1):80.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.