Does SOFA and TISS scores correlate in long term ICU patients?

Introduction

SOFA score is a useful tool for monitoring of organ function in ICU patients [1]. TISS score is used for measuring of workload in intensive care [2]. We studied if there is any link between SOFA and TISS scores in long term ICU patients (i.e. patients staying in the ICU >3 days).

Materials and methods

Daily SOFA and TISS scores of ICU patients admitted between July and November 1998 who stayed in the ICU >3 days were retrieved from data collection system. An experienced ICU doctor has collected SOFA scores into this system daily. Pooled scores for the whole group, for ICU survivals (S) and nonsurvivals (NS) separately and the scores on the first day of ICU stay were analysed.

Results

Sixty-two patients (i.e. 42% out of total admissions; age 60.0 ± 14.7 years) fulfilled the inclusion criteria and stayed in the ICU for the mean of 11.9 ± 10.8 days). ICU mortality was 30.6% (19 patients). Significant correlation was found for pooled SOFA and TISS scores (r² = 0.52, P < 0.0001) and it was more pronounced in survivals (S) than in nonsurvivals (NS) (r²=0.52, P < 0.0001 and r ²=0.19, P < 0.000l, respectively). Significant link between the two scores was already present on the first day of ICU stay (r ²=0.54, P < 0.0001).

Conclusion

In long term ICU patients a significant correlation is present between organ failures (scored by SOFA) and workload (measured by TISS). This link is already present on the day of admission and later on is more pronounced in survivals possibly because in NS the care is more often witheld or withdrawn.