Trends in Severity of Illness on ICU Admission and Mortality among the Elderly

Background: There is an increase in admission rate for elderly patients to the ICU. Mortality rates are lower when more liberal ICU admission threshold are compared to more restrictive threshold. We sought to describe the temporal trends in elderly admissions and outcomes in a tertiary hospital before and after the addition of an 8-bed medical ICU. Methods: We conducted a retrospective analysis of a comprehensive longitudinal ICU database, from a large tertiary medical center, examining trends in patients’ characteristics, severity of illness, intensity of care and mortality rates over the years 2001–2008. The study population consisted of elderly patients and the primary endpoints were 28 day and one year mortality from ICU admission. Results: Between the years 2001 and 2008, 7,265 elderly patients had 8,916 admissions to ICU. The rate of admission to the ICU increased by 5.6% per year. After an eight bed MICU was added, the severity of disease on ICU admission dropped significantly and crude mortality rates decreased thereafter. Adjusting for severity of disease on presentation, there was a decreased mortality at 28- days but no improvement in one- year survival rates for elderly patient admitted to the ICU over the years of observation. Hospital mortality rates have been unchanged from 2001 through 2008. Conclusion: In a high capacity ICU bed hospital, there was a temporal decrease in severity of disease on ICU admission, more so after the addition of additional medical ICU beds. While crude mortality rates decreased over the study period, adjusted one-year survival in ICU survivors did not change with the addition of ICU beds. These findings suggest that outcome in critically ill elderly patients may not be influenced by ICU admission. Adding additional ICU beds to deal with the increasing age of the population may therefore not be effective

Trends in Severity of Illness on ICU Admission and Mortality among the Elderly

Background: There is an increase in admission rate for elderly patients to the ICU. Mortality rates are lower when more liberal ICU admission threshold are compared to more restrictive threshold. We sought to describe the temporal trends in elderly admissions and outcomes in a tertiary hospital before and after the addition of an 8-bed medical ICU. Methods: We conducted a retrospective analysis of a comprehensive longitudinal ICU database, from a large tertiary medical center, examining trends in patients’ characteristics, severity of illness, intensity of care and mortality rates over the years 2001–2008. The study population consisted of elderly patients and the primary endpoints were 28 day and one year mortality from ICU admission. Results: Between the years 2001 and 2008, 7,265 elderly patients had 8,916 admissions to ICU. The rate of admission to the ICU increased by 5.6% per year. After an eight bed MICU was added, the severity of disease on ICU admission dropped significantly and crude mortality rates decreased thereafter. Adjusting for severity of disease on presentation, there was a decreased mortality at 28- days but no improvement in one- year survival rates for elderly patient admitted to the ICU over the years of observation. Hospital mortality rates have been unchanged from 2001 through 2008. Conclusion: In a high capacity ICU bed hospital, there was a temporal decrease in severity of disease on ICU admission, more so after the addition of additional medical ICU beds. While crude mortality rates decreased over the study period, adjusted one-year survival in ICU survivors did not change with the addition of ICU beds. These findings suggest that outcome in critically ill elderly patients may not be influenced by ICU admission. Adding additional ICU beds to deal with the increasing age of the population may therefore not be effective

On the significance of high spatial resolution to capture all relevant scales in the turbulent flow over periodic hills

Due to the complex nature of turbulence, the simulation of turbulent flows is still challenging and numerical models have to be further improved. For the validation of these numerical flow simulation methods reliable experimental data is essential as the simulation can only be more precise than the validation data but never be more accurate. However, for the correct numerical prediction of flows, the accuracy is the essential quantity. A typical test case is the flow over periodic hills. The numerical prediction is difficult, since flow separation and reattachment are not fixed in space and time due to the smooth geometry [10, 2]. Furthermore, the separated and fully three-dimensional flow from the previous hill impinges on the next hill, which will result in very complex turbulent flow features as shown in Fig. 1 on the left side. With the increasing computer performance available, it becomes possible to examine larger Reynolds numbers with DNS and LES. Typical grid sizes are in the order of several (3-10) Kolmogorov length scales h for LES and approach h for DNS [1]. The resolution of currently available measurements is in the order of 30 h (Re = 8,000) and above which is not sufficient to resolve the large gradients in the shear layer at the hill crest for instance. Even more severe, the contribution of the small eddies is averaged over a region associated with the measurement resolution. Thus an important part of the turbulent energy cannot be measured at all and is lost for the validation of turbulence models. Since these models are supposed to simulate the contribution of these small eddies it is of inherent interest to increase the resolution in the experiment. The aim of the current measurement campaign was therefore to increase the spatial resolution in order to study the resolution effect systematically and to provide an additional data set for the validation of numerical tools

Cox Regression Models for 1-Year Survival of ICU Patients.

<p>Landmark analysis of 28 day survivors, n = 5317.</p><p>SOFA, sequential organ failure assessment; DNR, do not resuscitate; ICU, intensive care unit; COPD, chronic obstructive pulmonary disease; CHF, congestive heart failure; DM, Diabetes Melitus; CRF, chronic renal failure.</p

One-year mortality in 28 days survivors of first admission (5,317 subjects) presented by LOcally wEighted Scatterplot Smoothing (LOESS) curves.

<p>One-year mortality in 28 days survivors of first admission (5,317 subjects) presented by LOcally wEighted Scatterplot Smoothing (LOESS) curves.</p

Proportion of patients within each age subgroup out of total ICU admissions presented by LOcally wEighted Scatterplot Smoothing (LOESS) curves.

<p>N = 8,916.</p

Logistic Regression Models of 28 days Survival of ICU Patients.

<p>First admissions (n = 7265).</p><p>SOFA, sequential organ failure assessment; DNR, do not resuscitate; COPD, chronic obstructive pulmonary disease; CHF, congestive heart failure; DM, Diabetes Melitus; CRF, chronic renal failure.</p

Severity of disease on admission presented by LOcally wEighted Scatterplot Smoothing (LOESS) curves.

<p>N = 8,916.</p

Clinical outcomes (n = 7265).

<p>LOS length of stay; ICU intensive care unit.</p