Relationships between Blood Transfusion, Severity of Injury and Outcome of Severely Injured Patients Admitted to a Trauma Intensive Care Unit in Nigeria: An Observational Study

Abstract

Background: Anaemia is common in critically ill trauma patients admitted into the Intensive Care Unit. The aetiology of the anaemia in trauma patients is often multi-factorial, usually resulting from the trauma event, from subsequent interventions and from complications that may arise such as severe sepsis and multiple organ failure. Treatment of anaemia in severely injured patients admitted into the Intensive Care Unit often necessitates blood transfusion. Presently, there is a dearth of quality studies on blood transfusion and outcome among trauma patients especially in Nigeria. This article is aimed at evaluating the association between red blood cell transfusion and severity of injury in adult patients admitted to a trauma ICU. Methods: Prospective observational study without intervention on transfusion pattern in adult patients admitted to the trauma ICU of a dedicated trauma Hospital in Nigeria between the periods October 1, 2010 and September 30, 2011. Results: One hundred and fifty eight (158) patients (30.4%) out of the 664 patients admitted into the trauma ICU during the period of observation received a total of 447 units of blood. The mean age of patients that were transfused was 34.7 ±11.2 years, a mean injury severity score (ISS) of 24.1 ± 9.9, and an average frequency of transfusions of 3.5 ± 2.0 units. The mean pre-transfusion [Hb] for all patients was 66.5 g/L ± 10 g/L. The need to receive blood transfusion was significantly correlated to the Injury Severity Score (rho = 0.29, p < 0.001) but not with Simplified Acute Physiology II Score (p >0.05). Blood transfusion was significantly associated with longer stay in the ICU (4.5 ± 4.0) days versus (3.5 ±2.8) days, P < 0.0001) and longer hospital stay (21.9 ± 17.5) days versus (8.6 ±7.2 days) for transfused and non-transfused patients respectively. This relationship increases with the number of blood transfused (p< 0 0.0001). Also the risk of developing some complications in patients with severe injury admitted into the ICU increases with transfusion, OR (CI) of having a complication between the patients that received transfusion and those that were not transfused was 20.808 (12.6951 -  34.1062), {(z stat.) = 12.040, p <0.0001} Whereas there was association between blood transfusion and higher mortality (4 versus 2) respectively, this association was not statistically significant (p> 0.05) for the patients that received blood transfusion and those that did not. Conclusions: Anaemia often requiring RBC transfusion is common in patients admitted to the trauma ICU, and the anaemia increases progressively during the course of ICU admission. Older patients and patients with higher severity of injury have higher tendency to receive blood transfusion in the trauma ICU. Despite that blood transfusion can be life-saving; it is associated with identifiable adverse consequences which is dose dependent.