Retrospective observational analysis of the infective risk of arterial lines in a general ICU

Introduction

This study aims to describe the infective morbidity of arterial line catheters in a general ICU.

Methods

All ICU admissions for the year 2012 were listed on the WardWatcher database. All cases in which arterial line tip samples returned any growth were reviewed in conjunction with the medical, nursing and daily chart recordings. Data were collected on the organisms grown and antimicrobial sensitivities. A qualitative decision of clinical relevance was established based on necessitated change in patient management, signs of local site infection or evidence of bacteraemia with the same organism.

Results

During 2012 there were 416 ICU admissions, representing a total of 2,440 ITU-days and 1,994 arterial line-days. A total of 48 arterial line tips suspected of being infected were sent for culture. Thirty-seven arterial lines returned no growth (77.08%). Seven cultures grew organisms likely to be contaminants (14.58%). Four cultures grew significant organisms (yield of 8.33%). There were two cases with documented clinical signs of catheter-related local infection (CRLI) at the arterial line puncture site. In one case of CRLI the primary source of infection was felt to be remote from the arterial line. The second represented a local infection with organisms that are typically skin commensals. Of the four cultures likely to represent invasive pathogens, three had clinical suspicion that the primary source was a site remote from the arterial line. In two of these cases this was confirmed by growing the same organism at an alternative site more likely to be the source of infection.

Conclusion

These results suggest that CRLI rates for arterial lines are low at 1.003 per 1,000 arterial line-days. However, there is a significant bacterial colonisation rate of the arterial lines sampled. Three arterial lines (6.25%) grew organisms that could represent an important potential source of ongoing bacteraemia. There is evidence to suggest that the risk of infection and colonisation of arterial lines may be similar to that of central lines [1]. Further prospective work is needed to assess the impact of catheter care bundles on colonisation and infection rates of arterial lines in the ICU.