Can the Sequential Organ Failure Assessment (SOFA) Score Predict Mortality of the Patients Receiving Extracorporeal Life Support?
Pranya Sakiyalak MD, FACS*, Pawana Chanawangsa MD*
Affiliation : * Division of Cardiothoracic Surgery, Department of Surgery, Siriraj Hospital, Faculty of Medicine, Mahidol University, Bangkok, Thailand
Objective : To assess the applicability of the Sequential Organ Failure Assessment (SOFA) score to the patients who underwent
extracorporeal life support (ECLS).
Material and Method: This study retrospectively reviewed the medical records of all 97 critically ill patients who underwent
ECLS between January 2006 and December 2014. Demographics, comorbidities, primary diagnoses, ECLS days, length of
hospital stay, presence of prior cardiac arrest and intra-aortic balloon pump, mode and indication of ECLS, clinical and
laboratory data, and outcome of each patient were collected. The SOFA scores of each patient were calculated.
Results : The overall survival rate was 19.6%. The most common indication was postcardiotomy cardiogenic shock (26%).
The SOFA score when utilized to assess the patients on the first day of ECLS treatment could not predict either removal of the
ECLS or survival of the patient (mean SOFA scores of the ECLS-survivor group vs. the non-survivor group were 12.75+2.44
and 13.66+2.83; p = 0.144 and mean SOFA scores of the hospital-survivor group vs. the non-survivor group were
12.94+2.41 and 13.49+2.81; p = 0.455). However, among the ECLS survivors, the SOFA score assessed after ECLS
removal could predict hospital survival as the SOFA scores of the survivor group vs. non-survivor group were 9.89+3.78
and 14.40+2.95; p = 0.003). When analyzed by the receiver-operating characteristic (ROC) curve, the area under the curve
(AUC) of the SOFA score obtained on one day after ECLS removal was 0.832 (95% confidence interval [CI]: 0.676 to 0.987,
p = 0.004). However, the appropriate cutoff point of the SOFA score to predict a patient’s survival cannot be accurately
determined because of downward bulge in the middle of the ROC curve, which represents the range of the SOFA scores of
10.50 to 15.50.
Conclusion : The SOFA score can be a useful tool to predict the survival of a patient after ECLS removal. The lower the SOFA
score, the higher the chance of a patient’s survival. However, it cannot predict the success of removal of the ECLS or survival
while the patient is on ECLS, partly because of physiologic changes in various systems after ECLS insertion.
Keywords : Sequential Organ Failure Assessment score, SOFA score, Extracorporeal life support, ECLS
