Therapeutic intervention scoring system (TISS)--a method for measuring workload and calculating costs in the ICU

The Therapeutic Intervention Scoring System (TISS) is an easily applicable method for measurement of workload in the intensive care unit (ICU). In the present study a modified TISS-scoring (mTISS) was performed daily during 1988-1989 on 2693 patients in a general ICU. Of these, 900 could be classified as 'true' ICU-patients (ICU-stay > or = 24 h or TISS > or = 20 points), whereas the rest were postoperative. In ICU-patients the average length of stay was 4.5 +/- 8.9 days and the average workload 114 +/- 218 mTISS-points. The workload was not significantly related to age or type of admission (scheduled vs unscheduled). Hospital non-survivors (13.6%) showed a significantly increased mean total mTISS-score (239 +/- 364, P < 0.001). Critically ill (TISS Class IV) patients (14% of the sample), with an average workload of 437 +/- 401 mTISS-points, consumed 53% of the total resources. Patients categorized (ICD-9) to respiratory and infectious diseases showed the greatest average workload (207 +/- 315 and 208 +/- 355 mTISS-points, respectively). A workload-index was also developed relating the actual workload to the ICU personnel. The cost of each mTISS-point was calculated. In conclusion, the present study showed that mTISS is a valuable tool when evaluating resource utilization in the ICU. Together with the proposed workload-index and calculation of costs, mTISS could be used for ICU management control.