Does plasma transfusion portend pulmonary dysfunction? A tale of two ratios

Area of Science:

• Trauma resuscitation
• Critical care medicine
• Hemorrhagic shock management

Background:

• Massive transfusion (MT) protocols aim to improve outcomes but raise concerns about transfusion-associated lung injury.
• The relationship between the ratio of plasma to packed red blood cells (PRBCs) and pulmonary dysfunction after MT is not well understood.
• Evaluating the impact of plasma/PRBC ratio on the PaO2-to-FIO2 (P/F) ratio in trauma patients undergoing MT is crucial.

Purpose of the Study:

• To investigate the association between the plasma-to-PRBC ratio and the P/F ratio in trauma patients receiving massive transfusions.
• To identify factors influencing pulmonary dysfunction (defined by P/F ratio) following massive hemorrhage resuscitation.

Main Methods:

• A prospective prognostic study involving 199 trauma patients who received MT (≥10 units PRBCs) over 5.5 years.
• Exclusion of patients deceased within 48 hours of arrival.
• Acute lung injury (ALI) and ARDS defined by P/F ratio <300 and <200 at 48 hours, respectively; stepwise multiple regression analysis used to identify determinants of P/F ratio.

Main Results:

• 80% of patients developed ALI, and 53% developed ARDS, both associated with increased mortality.
• Paradoxically, patients with higher P/F ratios received more plasma and had higher plasma-to-PRBC ratios.
• Stepwise regression identified patient age and chest injury severity (AIS score) as independent predictors of P/F ratio, not the plasma/PRBC ratio.

Conclusions:

• Pulmonary dysfunction is common in MT survivors and linked to higher mortality.
• The plasma-to-PRBC ratio during hemorrhage control did not significantly impact the subsequent P/F ratio.
• Unmodifiable patient factors like age and thoracic injury severity are the primary determinants of pulmonary function post-MT.