Last month, the discussion for this blog was about feeding tube measurement and placement. This month, the discussion will focus on evidence and opinion around frequency of feeding tube changes.
Studies have focused on colonization of feeding tubes related to feeding regimen and dwell time.1, 2 The Hurrell study’s intent was to identify any association with feeding regimen i.e. formula vs breast milk. They found colonization occurred in all feeding tubes, even those from babies who were not fed through the tube. The organisms were different but still present. Two of the organisms caused infections in the NICUs. These two organisms accounted for 51% of all organisms and were Klebsiella and Serratia. The Mehall study cultured tubes after 7 days and found all but one tube was colonized with various organisms, including Klebsiella. Based on these studies, some institutions have shortened the dwell time of the feeding tube to no more than 7 days. However, the Mehall study did not document that there were no organisms prior to 7 days, just that they were present at 7 days. In an adult study, the colonization of the feeding tube was traced to the gut vs the feeding solution.3 This group documented retrograde travel of the organisms into the feeding tube. Mehall et al showed this as well but also found organisms that are not present in the gastrointestinal tract, suggesting contamination from another source. This was posited to be from healthcare workers or the environment and not from the feeding solution itself.
When considering timing of tube changes, unrelated to the infectious issues are issues related to materials of which the tube is made. For many years, there have been recommendations that PVC tubes should not be left in place for “too long.” For some units, this means changing the tube at least every 24 hours while for others, it means changing the tube every 3 days. This is usually based on manufacturer’s recommendation. The only data that exists to guide this practice are case reports of intestinal/esophageal puncture by the stiff tube. Over the last several years, though, the use of PVC tubes has decreased as many contained the chemical DEHP, something that was recommended to be avoided in male infants, at least and linked to infertility (www.FDA.gov). Therefore, with the adoption of tubes made of softer materials or PVC softened with a different plasticizer that are less likely to cause trauma to the tissues, longer periods between changing of the tube came into practice. These softer tubes are also thought to be more comfortable for the infant as well. Silicone tubes are often left in place for up to 30 days, based on manufacturer recommendation. This is based on the safety of the tube materials in contact with the body, not on any infectious data.
Furthermore, the practice in adults is to flush the tube to remove formula and not allow it to linger in the tube at body temperature which would provide a nice warm environment for bacteria to grow. The purpose of this flush is as much to prevent obstruction of the feeding tube as to remove the environment for bacterial growth. This practice is being adopted more in neonates but when the tubes are flushed, they may be flushed with air or water. The amount of the flush is very small even when proportions are considered with the adult population as there is concern about administering too much water to the infant. This begs the question about how well the tube is cleared, even when “flushed”? In addition, neonates are often fed continuously, not allowing for flushing of the tube and constant movement of formula or EBM through the tube. This constant movement may decrease the bacterial growth but this has not been studied specifically.
Berthelot et al 2001 reported on an infectious outbreak in France. This included digestive tract colonization of Klebsiella oxytoca in 24 infants. One of these infants died and others were clinically ill.4 Ultimately, the colonization and cross-contamination was eradicated with the implementation and enforcement of hand hygiene and use of gloves when handling feeding tubes. Gastmeier et al reported a summary of www.outbreak-database.com regarding outbreaks in NICUs.5 They identified klebsiella as the most frequent organism involved in reported neonatal outbreaks (Keep in mind that this represents a fraction of all outbreaks, in all likelihood.) Most of the neonatal outbreaks were not able to be traced to any specific source in most cases while adult outbreaks often were. Therefore, the attention to detail and perhaps moving toward a safer practice without a lot of evidence is warranted in this population. At least, there seems to be sufficient evidence to support changing feeding tubes at least every 7 days, using clean gloves for handling feeding tubes and maintaining the feeding tube as a closed system as much as possible.
1. Hurrell E, Kucerova E, Loughlin M, Caubilla-Barron J, Hilton A, Armstrong R, et al. Neonatal enteral feeding tubes as loci for colonization by members of the Enterobacteriaceae. BMC Infectious Diseases. 2009; 9:146.
2. Mehall JR, Kite CA, Saltzman DA, Wallett T, Jackson RJ, Smith SD. Prospective study of the incidence and complications of bacterial contamination of enteral feeding in neonates. Journal of Pediatric Surgery. 2002; 37(8):1177-1182.
3. Mathus-Vliegen EMH, Brediu MWJ, Binnekade JM. Analysis of sites of bacterial contamination in an enteral feeding system. Journal of Prenteral and Enteral Nutrition. 2006;30(6):519-525.
4. Berthelot P, Grattard F, Patural H, Ros A, Jelassi-Saoudin H, Pozzetto B, et al. Nosocomial colonization of premature babies with Kelbsiella Oxytoca: Probable role of enteral feeding procedure in transmission and control of the outbreak with the use of gloves. Infection Control and Hospital Epidemiology. 2001;22:148-151.
5. Gastmeier P, Loui A, Stamm-Balderjahn S, Hansen S, Zuschneid I, Sohr D, et al. Outbreaks in neonatal intensive care units—they are not like others. American Journal of Infection Control. 2007; 35:172-176.