Resource use and outcome in critically ill patients with hematological malignancy: a retrospective cohort study

Merz, Schär Pascale, Bühlmann Michael, Takala Jukka, Rothen

Description

The paucity of data on resource use in critically ill patients with hematological malignancy and on these patients' perceived poor outcome can lead to uncertainty over the extent to which intensive care treatment is appropriate. The aim of the present study was to assess the amount of intensive care resources needed for, and the effect of treatment of, hemato-oncological patients in the intensive care unit (ICU) in comparison with a nononcological patient population with a similar degree of organ dysfunction. Methods A retrospective cohort study of 101 ICU admissions of 84 consecutive hemato-oncological patients and 3,808 ICU admissions of 3,478 nononcological patients over a period of 4 years was performed. Results As assessed by Therapeutic Intervention Scoring System points, resource use was higher in hemato-oncological patients than in nononcological patients (median (interquartile range), 214 (102 to 642) versus 95 (54 to 224), P < 0.0001). Severity of disease at ICU admission was a less important predictor of ICU resource use than necessity for specific treatment modalities. Hemato-oncological patients and nononcological patients with similar admission Simplified Acute Physiology Score scores had the same ICU mortality. In hemato-oncological patients, improvement of organ function within the first 48 hours of the ICU stay was the best predictor of 28-day survival. Conclusion The presence of a hemato-oncological disease per se is associated with higher ICU resource use, but not with increased mortality. If withdrawal of treatment is considered, this decision should not be based on admission parameters but rather on the evolutional changes in organ dysfunctions.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2008
• Nombre de lectures: 3
• Langue: English

Extrait

Available online http://ccforum.com/content/12/3/R75
Vol 12 No 3
Open AccessResearch
Resource use and outcome in critically ill patients with
hematological malignancy: a retrospective cohort study
1 2 3 4 4Tobias M Merz , Pascale Schär , Michael Bühlmann , Jukka Takala and Hans U Rothen
1Department of Intensive Care Medicine, Royal North Shore Hospital of Sydney, University of Sydney, St Leonards, 2065 NSW, Australia
2Department of Internal Medicine, Inselspital, Bern University Hospital and University of Bern, 3010 Bern, Switzerland
3Department of Medical Oncology, Inselspital, Bern University Hospital and University of Bern, 3010 Bern, Switzerland
4Department of Intensive Care Medicine, Inselspital, Bern University Hospital and University of Bern, 3010 Bern, Switzerland
Corresponding author: Tobias M Merz, [e-mail]
Received: 27 Dec 2007 Revisions requested: 2 Feb 2008 Revisions received: 8 Apr 2008 Accepted: 6 Jun 2008 Published: 6 Jun 2008
Critical Care 2008, 12:R75 (doi:10.1186/cc6921)
This article is online at: http://ccforum.com/content/12/3/R75
© 2008 Merz et al.; licensee BioMed Central Ltd.
This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Introduction The paucity of data on resource use in critically ill patients than in nononcological patients (median (interquartile
patients with hematological malignancy and on these patients' range), 214 (102 to 642) versus 95 (54 to 224), P < 0.0001).
perceived poor outcome can lead to uncertainty over the extent Severity of disease at ICU admission was a less important
to which intensive care treatment is appropriate. The aim of the predictor of ICU resource use than necessity for specific
present study was to assess the amount of intensive care treatment modalities. Hemato-oncological patients and
resources needed for, and the effect of treatment of, hemato- nononcological patients with similar admission Simplified Acute
oncological patients in the intensive care unit (ICU) in Physiology Score scores had the same ICU mortality. In hemato-
comparison with a nononcological patient population with a oncological patients, improvement of organ function within the
similar degree of organ dysfunction. first 48 hours of the ICU stay was the best predictor of 28-day
survival.
Methods A retrospective cohort study of 101 ICU admissions
of 84 consecutive hemato-oncological patients and 3,808 ICU
admissions of 3,478 nononcological patients over a period of 4 Conclusion The presence of a hemato-oncological disease per
years was performed. se is associated with higher ICU resource use, but not with
increased mortality. If withdrawal of treatment is considered, this
Results As assessed by Therapeutic Intervention Scoring decision should not be based on admission parameters but
System points, resource use was higher in hemato-oncological rather on the evolutional changes in organ dysfunctions.
uncertainty over the extent to which intensive care treatment isIntroduction
Patients with hematological malignancy who are admitted to appropriate in this patient group [6-8]. Decisions to admit can-
the intensive care unit (ICU) due to complications of the under- cer patients to the ICU are exceptionally complex, as the
lying malignant disease often have a prolonged stay in the ICU chances of potentially curative cancer therapy or long-term
[1] and are believed to have a less favorable prognosis [2] palliation must be weighed against the associated risk of very
than nononcological patients. In general adult ICU popula- high morbidity or mortality and thus possible futile use of more
tions, prolonged stay has been reported to be associated with and more limited resources.
a disproportionate use of resources [3]. Information on
resource use of hemato-oncological patients requiring inten- Reported ICU mortality rates of critically ill hemato-oncological
sive care is relatively scarce [4,5], however, and comparisons patients vary widely, from 10% up to 50% depending on the
with other nononcological intensive care patient groups do not studied population [9-11]. The prognostic value of various clin-
exist. The paucity of data on resource use in hemato-oncolog- ical indicators – such as age, primary disease, chronic health
ical patients and the perceived poor outcome can lead to status, cardiovascular failure, renal insufficiency, leucopenia or
95% CI = 95% confidence interval; ICU = intensive care unit; SAPS II = Simplified Acute Physiology Score II; SOFA = Sequential Organ Failure
Assessment; TISS-28 = Therapeutic Intervention Scoring System.
Page 1 of 9
(page number not for citation purposes)Critical Care Vol 12 No 3 Merz et al.
recent bacteremia [12] – is in dispute. Likewise, the value of surgery were excluded from the analysis. For comparison of
various scoring systems applied at the time of ICU admission hemato-oncological and nononcological patient survival and
to predict outcome is controversial [13,14]. Extending any pre- resource use (see below), readmissions occurring within 48
diction to individual patients remains a clinical decision for hours of discharge from the ICU were considered with the initial
which specific outcome indicators provide little help. admission, whereas readmissions beyond 48 hours were ana-
lyzed as new cases [17].
Furthermore, treatments and outcomes of various malignan-
cies have changed, suggesting that re-evaluation of indica- The ICU stay parameters for all patients were collected from the
tions and outcomes of intensive care for this patient group is ICU database. These parameters included age, sex, date of
necessary. Although a multicenter approach is considered admission to the hospital, date of each ICU admission through-
necessary to generate the number of patients needed to eval- out the hospital stay, reason for ICU admission, date of and sta-
uate any prognostic indicator, a more detailed evaluation of tus at ICU discharge, Simplified Acute Physiology Score (SAPS
resource utilization may benefit from a single-center analysis, II) [18] calculated for the first 24 hours of the ICU stay, and the
which avoids the effect of variability between different ICUs amount of Therapeutic Intervention Scoring System (TISS-28)
[15]. points [19] accumulated throughout the ICU stay. As treatment
intensity often changes markedly, even within 1 day, we calcu-
Accordingly, the primary aim of the present single-center study lated the TISS-28 score once per nursing shift (that is, every 8
was to assess the amount of resources used per patient for hours) [3,20]. Patient-related direct costs were calculated
hemato-oncological and nononcological emergency admis- based on the hospital cost accounting, and amounted to 38
sions to the ICU. A secondary aim was to explore the survival Swiss Francs per TISS-28 point.
of hemato-oncological patients depending on their pre-exist-
ing comorbidities and on the severity of acute illness on admis- The Sequential Organ Failure Assessment (SOFA) score [21]
sion and during the course of the ICU stay, and in comparison for each day of the ICU stay was collected from information in
with a nononcological patient population with a similar degree the medical records and was available only for hemato-oncolog-
of organ dysfunction. ical patients, as it is not part of the ICU database. To assess the
change during the first 48 hours of the ICU stay, the difference
between the patients' SOFA score at ICU admission and afterMaterials and methods
Setting the first 24 and 48 hours of the ICU stay was calculated. Stabi-
The Bern University Hospital, Switzerland, is a 960-bed tertiary lization of the patients' condition was defined as an unchanged
care referral hospital. The Department of Intensive Care Medi- or decreased SOFA score, and deterioration was defined as an
cine is the sole provider of intensive care for adult patients in the increased SOFA score. The use of renal replacement therapy
hospital. The department comprises 30 beds, and is operated (intermittent hemodialysis or continuous hemodiafiltration) and
as a closed unit. Care is offered for all types of surgical, trauma mechanical ventilation were also recorded.
and medical patients, except major burn injuries. Admission of
hemato-oncological patients to the ICU takes place after con- Additional data on hemato-oncological patients, collected from
sultation with the treating oncologist and a senior intensive care their medical records, included primary oncological diagnosis,
physician. Criteria for admission are largely identical for hemato- presence of neutropenia (defined as minimal absolute neu-
oncological patients and for nononcological patients [16]. We trophil count <500/ μl) and the type of anticancer treatment. The
tend to abstain from admission of a hemato-oncological patient type of hematological malignancy was categorized into high-
in the case of progressed malignancy and short expected sur- grade malignancy (acute myelogenous leukemia, acute lym-
vival time (<3 months). The Department of Medical Oncology phoblastic leukemia and high-grade non-Hodgkin's lymphoma)
includes an inpatient section with 50 beds and an outpatient and low-grade malignancy (all other types of hematologic malig-
section handling approximately 13,