Early transfer to a high-volume ICU (upgrading) reduces mortality

Introduction

The outcome of ICU treatment is improved in high-volume compared with low-volume ICUs [1]. It is unclear whether transfer of patients from a low-volume to a high-volume ICU (upgrading) improves outcome and whether early transfer is beneficial.

Methods

In a retrospective cohort study the timing of upgrading was determined and related to mortality. Included were all upgraded patients transported to our level 3 ICU between 2002 and 2008. The APACHE II score was determined in the first 24 hours after admission to the high-volume ICU. Odds ratios, the Mann–Whitney test and multiple regression were performed.

Results

Three hundred and eighty-five patients were included with a mean age of 62 years (SD = 14.8) and mean APACHE II score of 22.5 (SD = 8.4). The median time to transfer was 1 day (IQR = 4). Patients transported immediately after stabilisation to the high-volume ICU (ICU length of stay (LOS) before transfer = 0) had a mortality rate of 9% (Figure 1). Mortality in patients with ICU LOS before transport > 0 was 25% (P < 0.001). In a multiple regression analysis a higher APACHE II score was associated with increased mortality (OR = 1.1, 95% CI = 1.0 to 1.2), as was APACHE II predicted mortality. Immediate transfer was associated with a decrease in ICU mortality (OR = 0.38; 95% CI = 0.18 to 0.80) and hospital mortality (OR = 0.51; 95% CI = 0.27 to 0.95). In patients with upgrading as the explicit reason for transport the findings were the same (OR = 0.15; 95% CI = 0.03 to 0.71).

Figure 1

(abstract P480)

Conclusion

In this retrospective cohort study patients who were immediately transferred from a low-volume to a high-volume level 3 ICU had a lower mortality compared with patients with delayed transfer, which was independent of the APACHE score.