Impact of Ageing and Medical Practice on Belgian ICUs Outcome

Background: The rapid increase in life expectancy in Belgium (almost 6 months on 5 years) and medical practice can modify ICU patients’ characteristics.

Objective: To assess the evolution between 2004 and 2008 of Belgian ICUs of patients’ characteristics at admission and frequency of invasive device use; their impact on ICU-acquired pneumonia (PN), blood stream (BSI) and urinary tract (UTI) infection rates; on overall mortality and to provide operational advice.

Methods: Routine data collected by the national surveillance of infections in ICU settings was analyzed. The Belgian federal law encourages ICUs to collect data, for 3 consecutive months, on ICU-acquired infections and risk factors for patients admitted more than 2 days.

Results: Altogether 30 086 patients were reported. The yearly average number of patients was 6017, and of patient-days 47711.
Patients’ characteristics: Mean age increased from 63.9 to 67.2; Median SAPS II score decreased from 34.5 to 33; Mean ICU length of stay (LOS) went from 7.6 to 8.1 days; The proportion of patients using antibiotics at admission rose from 25.4 to 47.1% while those needing acute coronary care and surgery before ICU admission lessen from 17.4 to 12.0 and from 43.0 to 38.4 % respectively. The admission for medical reasons rose from 56.0 to 63.4%.
Invasive devices exposure: The proportion of patients with intubation went from 37.0 to 44.4, with central venous catheter (CVC) from 66.5 to 68.3 and with urinary catheter from 31.6 to 58.3%. The device-days per 1000 patient-days increased for intubation and urinary catheter (307.3 to 358.5 and 350.5 to 644.2) while the CVC-days decreased (890.3 to 746.5).
Infection indicators: PN indicators rose from 6.7 to 10.6 per 100 patients and from 10.7 to 16.5 per 1000 patient-days but lessen from 15.6 to 11.1 per 1000 intubation-days. BSI and UTI increased but their frequency, per device utilization-days, remained stable over time.
Overall mortality increased from 7.3 to 8.5% and LOS among ICU survivors rose from 4 to 5 days.

Conclusions: Ageing may have modified ICU admissions, process and outcome. The reduction of ICU-acquired infections per device utilization-days suggests infection control improvement. Besides ageing, the increase in antibiotic use at admission and of invasive devises may also reveal changes in medical practice, resources and staff. LOS among ICU survivors could be seen as a proxy for increasing life expectancy and quality of care.
Variations in surveillance participation may introduce a selection bias toward largest ICUs. Further studies are needed to quantify trends and to untie the effect of changes in patients’ mix and medical practice. As ICU practitioners cannot wait for them to improve practice, national surveillance systems should use supervision to improve local data and enlarge quality assurance beyond statistics. National programs should introduce case studies and audits, and promote experience exchanges amongst ICU professionals.