Skip to main content
SpringerLink
Log in

Patient volume affects outcome in critically ill patients

Patienten-Volumen beeinflusst den Outcome kritisch kranker Patienten

  • Original Article
  • Published:
Wiener klinische Wochenschrift Aims and scope Submit manuscript

Zusammenfassung

KONTEXT: Ein positiver Zusammenhang zwischen Patientenvolumen und Outcome wurde bereits für eine ganze Reihe von klinischen Prozeduren demonstriert, für die Intensivmedizin gibt es allerdings nur sehr spärliche Daten. ZIEL: Den Zusammenhang zwischen Patientenvolumen und Outcome in einer großen Kohorte kritisch kranker Patienten zu untersuchen. DESIGN: Prospektive, multizentrische Kohortenstudie. SETTING: 40 österreichische Intensivstationen (IBS). PATIENTEN: 83.259 von Jänner 1998 bis Dezember 2005 konsekutiv aufgenommene Patienten. MESSUNGEN UND ERGEBNISSE: Die Strukturqualität der IBS wurde mittels Fragebogen evaluiert und mit dem prospektiv erfassten Patientendaten gematcht. Aus diesen Daten wurden mehrere Volumen-Indizes berechnet: Patienten-Turnover, Belagsdichte, Arbeitsbelastung des Pflegepersonals und die diagnostische Variabilität. RESULTATE: Die Univariate Analyse zeigte, dass etliche Volums-Indizes mit dem Outcome der Patienten assoziiert waren: mehr Patienten pro Jahr pro Intensivbett und mehr Patienten welche in der gleichen Diagnosekategorie aufgenommen wurden, senkten significant das Risiko im Spital zu versterben. In Kontrast dazu führten weniger Pflegepersonal pro Patient als auch mehr Aufnahmsdiagnosen zu einer Erhöhung des Risikos. Die Multivariate Analyse bestätigte diese Resultate. Die Beziehung zwischen der Anzahl an Patienten welche in der gleichen Diagnosekategorie behandelt wurden und der Mortalität zeigte keine lineare, sondern eine U-förmige Beziehung, mit steigender Mortalität an beiden Enden. SCHLUSS: Unsere Resultate deuten sehr deutlich auf eine Beziehung zwischen Patientenvolumen und Outcome hin. Neben der Anzahl der Patienten spielt dabei auch die diagnostische Variabilität eine Rolle. Der Zusammenhang zwischen Patientenvolumen und Outcome scheint jedoch komplex zu sein und wird offensichtlich auch von anderen Variablen wie dem Arbeitsaufwand mit beeinflusst.

Summary

CONTEXT: A positive relationship between patient volume and outcome has been demonstrated for a variety of clinical conditions and procedures, but the evidence is sparse for critically ill patients. OBJECTIVE: To evaluate the relationship between patient volume and outcome in a large cohort of critically ill patients. DESIGN: Prospective multicenter cohort study, January 1998 through December 2005. SETTING: 40 intensive care units in Austria. PATIENTS: A total of 83,259 consecutively admitted patients. MAIN OUTCOME MEASURES: Structural quality of participating ICUs was evaluated using a questionnaire and merged with the prospectively collected data. Volume related indices were then calculated, representing patient turnover, occupancy rate, nursing workload and diagnostic variability. RESULTS: Univariate analysis revealed that several volume variables were associated with outcome: more patients treated per year per bed in the intensive care unit and more patients treated in the same diagnostic category reduced the risk of dying in the hospital (odds ratios, 0.967 and 0.991 for each additional 10 patients treated, respectively). In contrast, an increase in the patient-to-nurse ratio and an increase in the number of diagnostic categories were associated with increased mortality rates. Multivariate analysis confirmed these results. The relationship between the number of patients treated in the same diagnostic category and their outcomes showed not a linear but a U shape, with increasing mortality rates below and above a certain patient volume. CONCLUSIONS: Our results provide evidence for a relationship between patient volume and outcome in critically ill patients. Besides the total number of patients, diagnostic variability plays an important role. The relationship between volume and outcome seems, however, to be complex and to be influenced by other variables, such as workload of nursing staff.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

References

  • Halm EA, Lee C, Chassin MR (2002) Is volume related to outcome in health care? A systematic review and methodologic critique of the literature. Ann Intern Med 137: 511–520

    Article  PubMed  Google Scholar 

  • Nathens AB, Jurkovich GJ, Maier RV, et al (2001) Relationship between trauma center volume and outcomes. JAMA 285: 1164–1171

    Article  CAS  PubMed  Google Scholar 

  • Durairaj L, Torner JC, Chrischilles EA, et al (2005) Hospital volume-outcome relationships among medical admissions to ICUs. Chest 128: 1682–1689

    Article  PubMed  Google Scholar 

  • Kahn JM, Goss CH, Heagerty PJ, et al (2006) Hospital volume and the outcomes of mechanical ventilation. N Engl J Med 355: 41–50

    Article  CAS  PubMed  Google Scholar 

  • Clark DE, DeLorenzo MA, Lucas FL, Cushing BM (2007) Initial presentation of older injured patients to high-volume hospitals is not associated with lower 30-day mortality in Medicare data. Crit Care Med 35: 1829–1836

    Article  PubMed  Google Scholar 

  • Needham DM, Bronskill SE, Rothwell DM, et al (2006) Hospital volume and mortality for mechanical ventilation of medical and surgical patients: a population-based analysis using administrative data. Crit Care Med 34: 2349–2354

    Article  PubMed  Google Scholar 

  • Metnitz PhGH, Vesely H, Valentin A, et al (1999) Evaluation of an interdisciplinary data set for national ICU assessment. Crit Care Med 27: 1486–1491

    Article  CAS  PubMed  Google Scholar 

  • Metnitz PhGH, Steltzer H, Popow C, et al (1997) Definition and evaluation of a documentation standard for intensive care medicine: the ASDI pilot project. Wien Klin Wochenschr 109: 132–138

    CAS  PubMed  Google Scholar 

  • Le Gall JR, Lemeshow St, Saulnier F (1993) A new simplified acute physiology score (SAPS II) based on a European/North American multicenter study. JAMA 270: 2957–2963

    Article  CAS  PubMed  Google Scholar 

  • Le Gall JR, Klar J, Lemeshow S, et al (1996) The logistic organ dysfunction system. A new way to assess organ dysfunction in the intensive care unit. JAMA 276: 802–810

    Article  CAS  PubMed  Google Scholar 

  • Miranda DR, De Rijk A, Schaufeli W (1996) Simplified therapeutic interventions scoring system: The TISS-28 items – results from a multicenter study. Crit Care Med 4: 64–73

    Article  Google Scholar 

  • Moreno R, Miranda DR (1998) Nursing staff in intensive care in Europe. The mismatch between planning and practice. Chest 113: 752–758

    Article  CAS  PubMed  Google Scholar 

  • Ridley S, Rowan K (1997) Be wary of occupancy figures. Health Trends. 29: 100–105

    Google Scholar 

  • Hosmer DW, Lemeshow S (1995) Confidence interval estimates of an index of quality performance based on logistic regression models. Stat Med 14: 2161–2172

    Article  CAS  PubMed  Google Scholar 

  • The Acute Respiratory Distress Syndrome Network (2000) Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. N Engl J Med 342: 1301–1308

    Article  Google Scholar 

  • Shorr AF, Micek ST, Jackson WL Jr, Kollef MH (2007) Economic implications of an evidence-based sepsis protocol: can we improve outcomes and lower costs? Crit Care Med 35: 1257–1262

    Article  PubMed  Google Scholar 

  • Bull SV, Douglas IS, Foster M, Albert RK (2007) Mandatory protocol for treating adult patients with diabetic ketoacidosis decreases intensive care unit and hospital lengths of stay: results of a nonrandomized trial. Crit Care Med 35: 41–46

    Article  PubMed  Google Scholar 

  • Valentin A, Capuzzo M, Guidet B, Moreno RP, Dolanski L, Metnitz PhGH (2006) Patient safety in intensive care: results from the multinational Sentinel Events Evaluation (SEE) study. Intensive Care Med 32: 1591–1598

    Article  PubMed  Google Scholar 

  • 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: 1857–1862

    Article  CAS  PubMed  Google Scholar 

  • Pronovost PJ, Jenckes MW, Dorman T, et al (1999) Organizational characteristics of intensive care units related to outcomes of abdominal aortic surgery. JAMA 281: 1310–1317

    Article  CAS  PubMed  Google Scholar 

  • Pronovost PJ, Dang D, Dorman T, et al (2001) Intensive care unit nurse staffing and the risk for complications after abdominal aortic surgery. Eff Clin Pract 4: 199–206

    CAS  PubMed  Google Scholar 

  • Dimick JB, Swoboda S, Pronovost PJ, Lipsett PA (2001) Effect of nurse-to-patient ratio in the intensive care unit on pulmonary complications and resource use after hepatectomy. Am J Crit Care 10: 376–382

    CAS  PubMed  Google Scholar 

  • Tucker J; for the UK Neonatal Staffing Study Group (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: 99–107

    Article  PubMed  Google Scholar 

  • Metnitz PhGH, Kopp A, Jordan B, Lang Th (2004) More interventions do not necessarily improve outcome in critically ill patients. Intensive Care Med 30: 1586–1593

    Article  PubMed  Google Scholar 

  • Metnitz PhGH, Moreno RP, Almeida E, et al; on behalf of the SAPS 3 Investigators (2005) SAPS 3 – from evaluation of the patient to evaluation of the intensive care unit. Part 1: Objectives, methods and cohort description. Intensive Care Med 31: 1336–1344

    Article  PubMed  PubMed Central  Google Scholar 

  • Moreno RP, Metnitz PhGH, Almeida E, et al; on behalf of the SAPS 3 Investigators (2005) SAPS 3 – from evaluation of the patient to evaluation of the intensive care unit. Part 2: Development of a prognostic model for hospital mortality at ICU admission. Intensive Care Med 31: 1345–1355

    Article  PubMed  PubMed Central  Google Scholar 

  • Angus DC, Shorr AF, White A, Dremsizov TT, Schmitz RJ, Kelley MA; for the Committee on Manpower for Pulmonary and Critical Care Societies (COMPACCS) (2006) Critical care delivery in the United States: distribution of services and compliance with Leapfrog recommendations. Crit Care Med 34: 1016–1024

    Article  PubMed  Google Scholar 

  • Brilli RJ, Spevetz A, Branson RD, et al; for the American College of Critical Care Medicine Task Force on Models of Critical Care Delivery (2001) The American College of Critical Care Medicine guidelines for the definition of an intensivist and the practice of critical care medicine. Critical care delivery in the intensive care unit: defining clinical roles and the best practice model. Crit Care Med 29: 2007–2019

    Article  CAS  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Medical Statistics, Medical University of Vienna, Vienna, Austria

    Barbara Metnitz & Peter Bauer

  2. Department of Anesthesiology and General Intensive Care, Medical University of Vienna, Vienna, Austria

    Philipp G.H. Metnitz

  3. Department Internal Medicine, KH Rudolfstiftung, Vienna, Austria

    Andreas Valentin

Authors
  1. Barbara Metnitz
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Philipp G.H. Metnitz
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Peter Bauer
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Andreas Valentin
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Philipp G.H. Metnitz.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Metnitz, B., Metnitz, P., Bauer, P. et al. Patient volume affects outcome in critically ill patients. Wien Klin Wochenschr 121, 34–40 (2009). https://doi.org/10.1007/s00508-008-1019-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00508-008-1019-0

Keywords

Search

Navigation