Intensive Care Medicine

, Volume 33, Issue 8, pp 1329–1336 | Cite as

Variability in outcome and resource use in intensive care units

  • Hans U. RothenEmail author
  • Kay Stricker
  • Johanna Einfalt
  • Peter Bauer
  • Philip G. H. Metnitz
  • Rui P. Moreno
  • Jukka Takala



To examine variability in outcome and resource use between ICUs. Secondary aims: to assess whether outcome and resource use are related to ICU structure and process, to explore factors associated with efficient resource use.

Design and setting

Cohort study, based on the SAPS 3 database in 275 ICUs worldwide.


16,560 adults.

Measurements and results

Outcome was defined by standardized mortality rate (SMR). Standardized resource use (SRU) was calculated based on length of stay in the ICU, adjusted for severity of acute illness. Each unit was assigned to one of four groups: “most efficient” (SMR and SRU < median); “least efficient” (SMR, SRU > median); “overachieving” (low SMR, high SRU), “underachieving” (high SMR, low SRU). Univariate analysis and stepwise logistic regression were used to test for factors separating “most” from “least efficient” units. Overall median SMR was 1.00 (IQR 0.77–1.28) and SRU 1.07 (0.76–1.58). There were 91 “most efficient”, 91 “least efficient”, 47 “overachieving”, and 46 “underachieving” ICUs. Number of physicians, of full-time specialists, and of nurses per bed, clinical rounds, availability of physicians, presence of emergency department, and geographical region were significant in univariate analysis. In multivariate analysis only interprofessional rounds, emergency department, and geographical region entered the model as significant.


Despite considerable variability in outcome and resource use only few factors of ICU structure and process were associated with efficient use of ICU. This suggests that other confounding factors play an important role.


Intensive care unit Severity of illness Resource use ICU mortality Health services research Quality assessment 



We are grateful to all staff of participating ICUs who made this project possible. We express special thanks to Jeannie Wurz, Medical Writer/Editor, Department of Intensive Care Medicine, University Hospital Berne, Switzerland, for editing the manuscript and to Barbara Jordan, Department of Medical Statistics, University of Vienna, Vienna, Austria for support in statistical analyses.

Supplementary material


  1. 1.
    Bion JF, Heffner JE (2004) Challenges in the care of the acutely ill. Lancet 363:970–977PubMedCrossRefGoogle Scholar
  2. 2.
    Lassnigg A, Hiesmayr MJ, Bauer P, Haisjackl M (2002) Effect of centre-, patient- and procedure-related factors on intensive care resource utilisation after cardiac surgery. Intensive Care Med 28:1453–1461PubMedCrossRefGoogle Scholar
  3. 3.
    Niskanen MM, Takala J (2001) Use of resources and postoperative outcome. Eur J Surg 167:643–649PubMedCrossRefGoogle Scholar
  4. 4.
    Pollack MM, Patel KM (2002) Need for shift in focus in research into quality of intensive care. Lancet 359:95–96PubMedCrossRefGoogle Scholar
  5. 5.
    Suter PM (2005) Some ICUs save more lives than others: we need to know why! Intensive Care Med 31:1301–1302PubMedCrossRefGoogle Scholar
  6. 6.
    Amaravadi RK, Dimick JB, Pronovost PJ, Lipsett PA (2000) ICU nurse-to-patient ratio is associated with complications and resource use after esophagectomy. Intensive Care Med 26:1857–1862PubMedCrossRefGoogle Scholar
  7. 7.
    Pronovost PJ, Dang D, Dorman T, Lipsett PA, Garrett E, Jenckes M, Bass EB (2001) Intensive care unit nurse staffing and the risk for complications after abdominal aortic surgery. Eff Clin Pract 4:199–206PubMedGoogle Scholar
  8. 8.
    Metnitz PG, Lang T, Vesely H, Valentin A, Le Gall JR (2000) Ratios of observed to expected mortality are affected by differences in case mix and quality of care. Intensive Care Med 26:1466–1472PubMedCrossRefGoogle Scholar
  9. 9.
    Tucker J (2002) Patient volume, staffing, and workload in relation to risk-adjusted outcomes in a random stratified sample of UK neonatal intensive care units: a prospective evaluation. Lancet 359:99–107PubMedCrossRefGoogle Scholar
  10. 10.
    Iapichino G, Gattinoni L, Radrizzani D, Simini B, Bertolini G, Ferla L, Mistraletti G, Porta F, Miranda DR (2004) Volume of activity and occupancy rate in intensive care units. Association with mortality. Intensive Care Med 30:290–297PubMedCrossRefGoogle Scholar
  11. 11.
    Kahn JM, Goss CH, Heagerty PJ, Kramer AA, O'Brien CR, Rubenfeld GD (2006) Hospital volume and the outcomes of mechanical ventilation. N Engl J Med 355:41–50PubMedCrossRefGoogle Scholar
  12. 12.
    Glance LG, Li Y, Osler TM, Dick A, Mukamel DB (2006) Impact of patient volume on the mortality rate of adult intensive care unit patients. Crit Care Med 34:1925–1934PubMedCrossRefGoogle Scholar
  13. 13.
    Metnitz PG, Moreno RP, Almeida E, Jordan B, Bauer P, Campos RA, Iapichino G, Edbrooke D, Capuzzo M, Le Gall JR (2005) SAPS 3—from evaluation of the patient to evaluation of the intensive care unit. I. Objectives, methods and cohort description. Intensive Care Med 31:1336–1344PubMedCrossRefGoogle Scholar
  14. 14.
    Moreno RP, Metnitz PG, Almeida E, Jordan B, Bauer P, Campos RA, Iapichino G, Edbrooke D, Capuzzo M, Le Gall JR (2005) SAPS 3—from evaluation of the patient to evaluation of the intensive care unit. II. Development of a prognostic model for hospital mortality at ICU admission. Intensive Care Med 31:1345–1355PubMedCrossRefGoogle Scholar
  15. 15.
    Rothen HU, Stricker KH, Einfalt J, Metnitz PG, Moreno RP, Takala J (2006) Variability in outcome and resource use in ICU's. Intensive Care Med 32(Suppl 1):S138Google Scholar
  16. 16.
    Rapoport J, Teres D, Lemeshow S, Gehlbach S (1994) A method for assessing the clinical performance and cost-effectiveness of intensive care units: a multicenter inception cohort study. Crit Care Med 22:1385–1391PubMedCrossRefGoogle Scholar
  17. 17.
    Katz MH (2003) Multivariable analysis: a primer for readers of medical research. Ann Intern Med 138:644–650PubMedGoogle Scholar
  18. 18.
    Garland A (2005) Improving the ICU. I. Chest 127:2151–2164PubMedCrossRefGoogle Scholar
  19. 19.
    Sirio CA, Shepardson LB, Rotondi AJ, Cooper GS, Angus DC, Harper DL, Rosenthal GE (1999) Community-wide assessment of intensive care outcomes using a physiologically based prognostic measure: implications for critical care delivery from Cleveland Health Quality Choice. Chest 115:793–801PubMedCrossRefGoogle Scholar
  20. 20.
    Kaboli PJ, Barnett MJ, Fuehrer SM, Rosenthal GE (2001) Length of stay as a source of bias in comparing performance in VA and private sector facilities: lessons learned from a regional evaluation of intensive care outcomes. Med Care 39:1014–1024PubMedCrossRefGoogle Scholar
  21. 21.
    Jegers M, Edbrooke DL, Hibbert CL, Chalfin DB, Burchardi H (2002) Definitions and methods of cost assessment: an intensivist's guide. Intensive Care Med 28:680–685PubMedCrossRefGoogle Scholar
  22. 22.
    Negrini D, Sheppard L, Mills GH, Jacobs P, Rapoport J, Bourne RS, Guidet B, Csomos A, Prien T, Anderson G, Edbrooke DL (2006) International Programme for Resource Use in Critical Care (IPOC)—a methodology and initial results of cost and provision in four European countries. Acta Anaesthesiol Scand 50:72–79PubMedCrossRefGoogle Scholar
  23. 23.
    Pronovost PJ, Needham DM, Waters H, Birkmeyer CM, Calinawan JR, Birkmeyer JD, Dorman T (2006) Intensive care unit physician staffing: financial modelling of the Leapfrog standard. Crit Care Med 34(Suppl 3):S18–S24PubMedCrossRefGoogle Scholar
  24. 24.
    Clermont G, Angus DC, Linde-Zwirble WT, Lave JR, Pinsky MR (1998) Measuring resource use in the ICU with computerized therapeutic intervention scoring system-based data. Chest 113:434–442PubMedGoogle Scholar
  25. 25.
    Stricker K, Rothen HU, Takala J (2003) Resource use in the ICU: short- vs. long-term patients. Acta Anaesthesiol Scand 47:508–515PubMedCrossRefGoogle Scholar
  26. 26.
    Angus DC, Linde-Zwirble WT, Sirio CA, Rotondi AJ, Chelluri L, Newbold RC 3rd, Lave JR, Pinsky MR (1996) The effect of managed care on ICU length of stay: implications for medicare. JAMA 276:1075–1082PubMedCrossRefGoogle Scholar
  27. 27.
    Rapoport J, Teres D, Zhao Y, Lemeshow S (2003) Length of stay data as a guide to hospital economic performance for ICU patients. Med Care 41:386–397PubMedCrossRefGoogle Scholar
  28. 28.
    Iapichino G, Radrizzani D, Bertolini G, Ferla L, Pasetti G, Pezzi A, Porta F, Miranda DR (2001) Daily classification of the level of care. A method to describe clinical course of illness, use of resources and quality of intensive care assistance. Intensive Care Med 27:131–136PubMedCrossRefGoogle Scholar
  29. 29.
    Rosenthal GE, Harper DL, Quinn LM, Cooper GS (1997) Severity-adjusted mortality and length of stay in teaching and nonteaching hospitals. Results of a regional study. JAMA 278:485–490PubMedCrossRefGoogle Scholar
  30. 30.
    Render ML, Kim HM, Deddens J, Sivaganesin S, Welsh DE, Bickel K, Freyberg R, Timmons S, Johnston J, Connors AF Jr, Wagner D, Hofer TP (2005) Variation in outcomes in Veterans Affairs intensive care units with a computerized severity measure. Crit Care Med 33:930–939PubMedCrossRefGoogle Scholar
  31. 31.
    Zimmerman JE, Kramer AA, McNair DS, Malila FM, Shaffer VL (2006) Intensive care unit length of stay: benchmarking based on Acute Physiology and Chronic Health Evaluation (APACHE) IV. Crit Care Med 34:2517–2529PubMedCrossRefGoogle Scholar
  32. 32.
    Thorens JB, Kaelin RM, Jolliet P, Chevrolet JC (1995) Influence of the quality of nursing on the duration of weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease. Crit Care Med 23:1807–1815PubMedCrossRefGoogle Scholar
  33. 33.
    Pronovost PJ, Angus DC, Dorman T, Robinson KA, Dremsizov TT, Young TL (2002) Physician staffing patterns and clinical outcomes in critically ill patients: a systematic review. JAMA 288:2151–2162PubMedCrossRefGoogle Scholar
  34. 34.
    Dara SI, Afessa B (2005) Intensivist-to-bed ratio: association with outcomes in the medical ICU. Chest 128:567–572PubMedCrossRefGoogle Scholar
  35. 35.
    Durairaj L, Torner JC, Chrischilles EA, Vaughan Sarrazin MS, Yankey J, Rosenthal GE (2005) Hospital volume-outcome relationships among medical admissions to ICUs. Chest 128:1682–1689PubMedCrossRefGoogle Scholar
  36. 36.
    Carson SS, Stocking C, Podsadecki T, Christenson J, Pohlman A, MacRae S, Jordan J, Humphrey H, Siegler M, Hall J (1996) Effects of organizational change in the medical intensive care unit of a teaching hospital: a comparison of ‘open’ and ‘closed’ formats. JAMA 276:322–328PubMedCrossRefGoogle Scholar
  37. 37.
    Baggs JG, Schmitt MH, Mushlin AI, Mitchell PH, Eldredge DH, Oakes D, Hutson AD (1999) Association between nurse-physician collaboration and patient outcomes in three intensive care units. Crit Care Med 27:1991–1998PubMedCrossRefGoogle Scholar
  38. 38.
    Barrett H, Bion JF (2005) An international survey of training in adult intensive care medicine. Intensive Care Med 31:553–561PubMedCrossRefGoogle Scholar
  39. 39.
    Thomas JW, Hofer TP (1999) Accuracy of risk-adjusted mortality rate as a measure of hospital quality of care. Med Care 37:83–92PubMedCrossRefGoogle Scholar
  40. 40.
    Pronovost PJ, Nolan T, Zeger S, Miller M, Rubin H (2004) How can clinicians measure safety and quality in acute care? Lancet 363:1061–1067PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Hans U. Rothen
    • 1
    Email author
  • Kay Stricker
    • 2
  • Johanna Einfalt
    • 3
  • Peter Bauer
    • 3
  • Philip G. H. Metnitz
    • 4
  • Rui P. Moreno
    • 5
  • Jukka Takala
    • 1
  1. 1.Department of Intensive Care MedicineUniversity HospitalBerneSwitzerland
  2. 2.Department of Anesthesiology and Department of Intensive Care MedicineUniversity HospitalBerneSwitzerland
  3. 3.Department of Medical StatisticsUniversity of ViennaViennaAustria
  4. 4.Department of Anesthesiology and General Intensive CareUniversity Hospital of ViennaViennaAustria
  5. 5.Unidade de Cuidados Intensivos PolivalenteHospital de St. António dos Capuchos, Centro Hospitalar de Lisboa (Zona Central)LisbonPortugal

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