Length of Stay in the Intensive Care Unit during Index Admission for Left Ventricular Assist Device and Total Artificial Heart Insertion is a Risk Factor for Infection

Abstract

Purpose Each admission to the intensive care unit (ICU) carries a risk of infection, with worldwide prevalence of infections in ICU patients estimated to be as high as 51.4%. For patients with left ventricular assist devices (LVAD), and total artificial hearts (TAH), blood stream infection (BSI) can lead to death and other long-term sequelae. The aim was to determine whether length of stay (LOS) in ICU post insertion of mechanical circulatory support (MCS) is an important seeding time that predisposes to infection despite aggressive pre-operative antibiotic prophylaxis. To determine whether return to ICU during the index admission increases the risk of infection or whether index ICU admission effects outcome. Methods This is a retrospective single center study of patients with a LVAD or TAH inserted between February 2003 and December 2016. Patients were included if they had available data for index ICU admission. Subsequent return to ICU during the same hospital admission was recorded as well as overall ICU LOS. To determine the significance of the index ICU admission, total ICU LOS minus first ICU admission LOS was reviewed. Results A total of 171 (LVAD 147, BIVAD 13, TAH 7) patients were included. Patients were well matched at baseline for age, sex and INTERMACS score. Median ICU LOS in days for admission 1 post LVAD insertion in the BSI-free group was 7 (IQR 4-15) compared with 10 (IQR 5.25-26.5) in the BSI group (p =0.02). Overall ICU LOS for all ICU admissions during the total hospital admission post MCS insertion was 9 (IQR 6-21) in the BSI-free group compared with 13.5 (IQR 8-33.5) days in the BSI group (p=0.01). Total ICU LOS minus first admission LOS was 7 (IQR 3-13.5) in the BSI-free group compared with 8 (IQR 3-22) days (p= NS). ICU LOS was also important in patients developing multiple organism BSIs, with median ICU LOS in days for admission 1 post LVAD being 7 (IQR 4-18) in the BSI free group and 14 (IQR 9-34) in the multiple organism BSI group (p =0.03). Similarly total LOS was significant (p=0.01) but total LOS minus first admission was not between the two groups. Conclusion Post-operative ICU LOS after MCS insertion is an important risk factor for developing BSI, and is also a risk factor for multiple organism BSIs. This data suggests that patients should be moved to a dedicated cardiac ward at the earliest opportunity from the ICU.