Commentary: "Infusion Line contamination in Preterm Neonates

Jean-charles PICAUD^1,2*Stephane Hays²Cédric Dananché^1,2

• ¹Université Claude Bernard Lyon 1, Lyon, France
• ²Hospices Civils de Lyon, Lyon, Rhône-Alpes, France

In the ChronoBIOline study a bacterial contamination was detected in 22.2% of 108 infusion sets with 28 different designs, and the conclusion was that multiline systems were at high risk of contamination (1). Nevertheless, several concerns prevent firm conclusions to be made.The first methodological concern is the intermediate outcome, as colonization of the catheter is not always associated with bloodstream infection (2,3). In the ChronoBIOline study, the authors collected lines when they were changed or removed, independently of the presence of an infection. As data about infections was not collected, and as noted by the authors, the results preclude the inference that colonized catheters will lead to an infection (1). Moreover, published studies investigating the association between contamination of infusion sets and infection in neonatal intensive care units (NICU) remains poor and report conflicting results (2,3); furthermore, after implementation of a multiline multilumen infusion set in a tertiary care neonatal unit in 2020 we found a drastic reduction in the rate of central venous line-associated bloodstream infection (CLABSI; -88%) (4).Minor and major contamination. The second concern is the definition of major contamination (≥50 colony-forming units, CFU) (1), which is not supported by any reference reporting that the risk of infection is significant above this. Methodologically, the use of this threshold should have been justified, for example by an additional risk of infection if infusion lines are colonized above this number. Accordingly, data about the risk related to major contamination cannot be interpreted.Micro-organism recovery. Infusion sets were removed and sent to the coordinating center, which might be a source of contamination and information about the time needed to transfer sets was not reported (1). The method used for sample processing was derived from a procedure originally used to detect microbial biofilm in flexible endoscope channels (5), but the authors did not validate this for all types of infusion sets tested; notably no multiline multilumen system was tested, although the authors deliver a key message concerning these systems (1).Identified micro-organisms. The micro-organisms identified in contaminated infusion lines seem to reflect cutaneous or common environmental flora. In France, coagulase-negative Staphylococcus spp. represent the vast majority of microorganisms identified in cases of CLABSI (4,6). In the ChronoBIOline study the authors reported that nearly half of infusion lines (10/24, 41.7%) were contaminated with 10 different species of non-cereus Bacillus (1), a well-known environmental microorganism (7,8). Most contamination (15/24, 62.5%) appears to be ≤5 CFUs of cutaneous or environmental flora, suggesting a contamination that could originate from manipulations of infusion sets at removal, transport, or sampling for microorganism recovery (1).Heterogeneity of the infusion systems analyzed. Infusion sets were collected in only about 20% of French NICUs without specific selection, which does not ensure representativeness of systems used nationally. In addition, the sets were 10-180 cm in length, with 1 to 6 "parts", with or without filters, open or closed, and single or multiline. As a consequence, only a very small number of each system was analyzed, which does not allow reliable comparisons.Furthermore, there was even heterogeneity among the 21 "multiline" systems, as 18 were Edelvaiss ® and 3 other systems. However, the former stands out from the others because it is a closed multiline multilumen system which is fully assembled by the manufacturer prior to sterilization and end-user packaging (4,9,10). Other systems are open systems, assembled at the bedside from several components sourced from one or multiple manufacturers. Edelvaiss ® , which was part of the infusion line tested, is a new infusion system composed of 8 lumens within the same tube to reduce physical incompatibility and drug delivery disturbances during simultaneous administration of drugs in neonates (8). As it is a closed system it requires fewer manipulations (fewer connections / disconnections, purging system), and the long line allows this to be done remotely from the patient; both preserve the infant's autonomic stability and sleep, as well as help to reduce the risk of CLABSI (4). Although the ChronoBIOline study provides useful data, a follow-up study using standardized infusion set systems is needed for more precise comparisons.As the duration of use of infusion system is considered as a risk factor of bacterial contamination, it is recommended that the infusion set is removed before 7 days (11,12). This was based on five studies, none of which included neonates and reported only the use of legacy infusion sets that are open systems composed of a single lumen with multiple stopcocks and connectors (13); the Edelvaiss ® system, however, was specifically designed for neonates and is certified for use up to 21 days. Furthermore, although there is a significant difference in the frequency of contamination over time, stratified according to whether the set was a multi-or single-line system a significant difference was found only during the first four days (1).Although the ChronoBIOline study provides valuable insights into contamination risks, its design (i.e. observational, descriptive and based on an intermediate outcome) is not adequate to assess the effectiveness and safety of multiline multilumen infusion lines. The authors present raw results of infusion set colonization, but a center effect might exist (as noted in the paper), as participating NICUs use different infusion sets and different infection prevention measures (1). Furthermore, the adherence to these measures, which is a major risk factor of CLABSI, might vary according to the NICU (14). Finally, the implementation of a multi-infusion device requires a strict training program for nurses, with regular assessment of practices (4). The absence of these data (1) limits the interpretation of the results. The authors interpret their findings as "Overall, our data suggest that the use of the multiline systems could promote CLABSIs in preterm neonates"; they conclude that their results support current guidelines i.e. "simpler infusion lines" and maximum duration of 7 days (1), but neither the study design nor the data analysis support this conclusion. Harmonized outcome definitions and more robust designs are needed. In addition, clinical benefits conferred by the use of multiline multilumen devices in preterm infants, including drug administration and monitoring, must be considered in their evaluation. Further well-designed, prospective randomized studies are needed in order to address the aim of the ChronoBIOline study.