Sequential organ failure assessment score as prognostic marker in critically ill patients in a tertiary care intensive care unit

Introduction: Sepsis is one of the most important causes of mortality in the intensive care setting. An effective predictor of prognosis of sepsis is required to assess morbidity and mortality of this condition. In this study, sepsis in the intensive care unit (ICU) of a tertiary care hospital was evaluated, with specifi c reference to clinical features and causative organisms. The sequential organ failure assessment (SOFA) score was calculated to assess the severity of sepsis and multi-organ failure at presentation and after 48 h. The correlation of SOFA and mean SOFA scores with outcome was studied. Materials and Methods: This was a prospective, observational, cohort study carried out in a tertiary care teaching hospital. Forty consecutive cases of septicemia were studied. Detailed history, clinical features, and SOFA score was recorded to assess the disease severity at the time of presentation and after 48 h. Inclusion of patients in the study was performed using the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) defi nition of sepsis. Two sample t-test and 95% confi dence interval (CI) for difference of mean was applied. Results: When the SOFA score was <7, the mortality was 56%. It increased to 70% when the score was 8-15 (P = 0.0989, t value: 1.69, Mean difference: 2.12, 95% CI: 0.41-4.665). Patients with SOFA score <7 after 48 h had 52% mortality and it increased to 88% when the score was 8-15. The mean SOFA score at 48 h was 6.96 in patients who died and 2.5 in those who improved (P < 0.001, t value: 4.332, mean difference: 4.39, 95% CI: 2.34-6.44). Hence, the predictive value for mortality of SOFA score was better at 48 h than at presentation. Conclusions: Sequential assessment of organ dysfunction in ICU at presentation and at 48 h is a good indicator of prognosis. Both mean and highest SOFA scores are particularly useful predictors of outcome, independent of the initial score. A high SOFA score at 48 h of presentation predicts an increased mortality rate.


INTRODUCTION
Sepsis is one of the important problems in medicine due to its complexity from pathophysiologic, clinical, and therapeutic viewpoints.Although several defi nitions have been proposed for this syndrome, in general, it can be assumed that it represents the clinical manifestation of a systemic response of the body to infection or to an infl ammatory-associated acute disease. [1,2]rtality rates as a result of sepsis are associated with a pattern characterized by progressive dysfunction or failure of non-pulmonary organ systems, including neurologic, coagulation, and renal functions over the fi rst 3 days. [3]rious scoring systems such as Glasgow scale, APACHE II and III and sequential organ failure assessment (SOFA) scoring have been validated and are being used in predicting prognosis of patients admitted in intensive care unit (ICU).In this study, sepsis in the ICU of a tertiary care hospital was evaluated, with specifi c reference to clinical features and causative organisms.The SOFA score was calculated to assess the severity of sepsis and multi-organ failure at presentation and after 48 h.These SOFA and mean SOFA scores were correlated with outcomes.Furthermore, multi-organ dysfunction was assessed with respect to organ systems involved and their correlation with mortality.assessment of organ dysfunction in patients in ICU at presentation and at 48 h, is one of the important parameters for predicting mortality. [4]

MATERIALS AND METHODS
This was a prospective study, approved by the Ethical Review Board of a tertiary care teaching hospital in western India, which waived informed consent on the basis that this was a non-interventional epidemiological study.Forty cases of septicemia (over 18 years of age) admitted for more than 24 h to the 12 bedded medical ICU were studied.A detailed history was taken and the clinical features and causative organisms were studied.In patients with organ dysfunction or going into organ dysfunction, the incidence and outcome of sepsis and organ dysfunction was evaluated.Demographic, laboratory and clinical data were collected and the SOFA score (0-24) was calculated, on admission and at 48 h of presentation [Table 1].In the calculation of the score, the worst values for each parameter in the 24 h period were used.The delta SOFA (SOFA) was calculated as the difference between the SOFA score at 48 h and the score on the day of admission to the ICU. [5]atistical software Epi Info version 3.4.3developed by Centre of Disease Control and Prevention (CDC), Atlanta, USA was used; two sample t-test and 95% confi dence interval for difference of mean were applied.Inclusion criteria were as per the ACCP/SCCM defi nition of sepsis.Sepsis was considered present if infection was highly suspected or proven and two or more of the systemic infl ammatory response syndrome criteria were met. [6,7]
The SOFA score after 48 h was <7 in 31 patients.Out of these, there were 15 (48%) survivors and 16 (52%) non-survivors.Out    of 9 patients with score between 8 and 15, there was 1 (11.2%)survivor and 8 (88%) non-survivors.Mean score of the patients who were non-survivors was 6.96; mean ± SD was 6.9583 ± 3.8653.The score in those who survived was 2.5, mean ± SD was 2.5 ± 2.5025 (P < 0.001) [Tables 4 and 5, Figure 2].Incidence of septicemia and related mortality was more common in males (65%) as compared to females (35%).Sepsis was most commonly seen in the age group of 56-65 years (37.5%).100% mortality was observed in those above 65 years.
Multi-organ dysfunction was seen in various combinations in 13 patients (32.5%) out of whom, there were nine non-survivors [Table 7].
Diabetes mellitus (DM) (22.5%) and alcoholic liver disease (17.5%) were the most common co-morbidities.Causative agents could be identifi ed in only 50% of patients.Gram-negative organisms were more prevalent, caused more severe illness and deaths as compared to gram positive organisms.Leucocytosis was seen in 90% at the time of presentation and 65% had persistent leucocytosis after 48 h.The overall mortality was 76% in patients with persistent leucocytosis at the end of 48 h.

DISCUSSION
Sepsis is the clinical manifestation of a systemic response of the body to infection or to an infl ammatory-associated acute disease. [1,2]here are many scoring systems to determine and predict prognosis of sepsis, such as Glasgow scale, SAPS II, APACHE, and SOFA.
Studies have been performed to compare merits and prognostic ability of SAPS II with SOFA and APACHE with SOFA. [4,8]In this study, The SOFA score was calculated to assess the severity of sepsis and multi-organ failure at presentation and after 48 h.Furthermore, the causative organisms and clinical features of the sepsis syndromes were evaluated.
In this study, initially, SOFA score at admission to ICU was calculated.In the group of patients in whom SOFA was <7 at admission, there were 44% survivors.In patients who had SOFA score between 8 and 15, there were 70% non-survivors.Mean SOFA score of the patients who did not survive, was 6.625 and the mean score of those who survived was 4.5 (t-test = 1.69,P = 0.0989).Minne et al. showed SOFA scores at admission had only slightly worse performance than APACHE II/III and were competitive with SAPS II models in predicting mortality in patients in the general medical and/or surgical ICU.Models with SOFA scores seem to have a comparable performance with other organ failure scores. [5]ereafter, the SOFA score at 48 h of admission was calculated.
In the group of patients having SOFA score < 7, there were 48% survivors and 52% non-survivors.In the patient group, which had scores of 8-15, there were 88% non-survivors.Mean score of the patients who did not survive was 6.96 and the score in those who survived was 2.5 (t-test = 4.33, P < 0.001), which was statistically signifi cant.
In a study by Ferreira et al., sequential assessment of organ dysfunction during the fi rst few days of ICU admission was a good indicator of prognosis.Both mean and highest SOFA scores are particularly useful predictors of outcome.Independent of the initial score, an increase in SOFA score during the fi rst 48 h in the ICU predicts a mortality rate of 50%. [5]Thus, the results of this study collaborates with the results of the above mentioned studies.
In a study by Rangel-Frausto et al., mortality fell from 62% in the early 1990s to 56% in 2000.[11][12] In this study, out of 40 patients, the mortality was 62.5% (25), which meant that 37.5% (15) patients survived.Septic shock increases the length of stay in the ICU and hospital compared with patients without sepsis, [11,12] and results in more organ dysfunction and greater use of the unit's resources.Septic shock also increases the risk of super-infections and neuromuscular complications associated with intensive care. [13]In this study, sepsis was most commonly seen in the age group of 56-65 years (37.5%);100% mortality was observed in those above 65 years.DM (22.5%) and alcoholic liver disease (17.5%) were the common co-morbidities.In a study by Annette et al., out of the overall population of patients with sepsis, those with DM were more likely to develop acute renal failure compared to those with no diabetes (13% vs. 7%, P < 0.05), and are less likely to develop acute respiratory failure (9% vs. 14%, P < 0.05).In a study by Martin et al., incidence of sepsis was disproportionately increased in elderly adults, and age was an independent predictor of mortality.Compared with younger sepsis patients, elderly non-survivors of sepsis die earlier during hospitalization. [14]Moreno et al. recently demonstrated that the initial SOFA score can be used to quantify the degree of organ dysfunction or failure present on admission and that the total maximum SOFA score can represent the cumulative organ dysfunction experienced by the patient.They also demonstrated a strong correlation of all these parameters with mortality outcome. [15]ad-to-head comparison studies between SOFA and APACHE II showed that SOFA fared better as a predictor of outcome than APACHE II. [8]

Limitations
In this study, SOFA score was calculated at the time of presentation and after 48 h.Serial, SOFA max and SOFA scores were not measured.The sample size was rather small, so these results may not be applicable to ICUs on a large scale.

CONCLUSIONS
In this study, SOFA score at 48 h of admission was a better predictor of mortality (P < 0.001) than the score at admission.Both the mean and highest SOFA scores were particularly useful predictors of outcome.Hence, sequential assessment of organ dysfunction in patients of sepsis admitted to ICU is a good indicator of prognosis.
Sequential International Journal of Medicine and Public Health | Jul-Sep 2013 | Vol 3 | Issue 3

Figure 1 :
Figure 1: Number of patients according to sequential organ failure assessment score at presentation

Figure 2 :
Figure 2: Number of patients according to sequential organ failure assessment score at 48 h

Table 1 :
SOFA score a Adrenergic agents administered for at least 1 h (doses given are in g/kg/min).FiO 2 =Fractional inspired oxygen, MAP=Mean arterial pressure, PaO 2 =Arterial oxygen tension, SOFA=Sequential organ failure assessment

Table 4 : Number of patients according to SOFA score after 48 h
Out of 24 non-sur vivors, SOFA score was higher in 15 patients (62.5%) while it uniformly decreased in all survivors.