Parenteral nutrition (PN) provides calories and necessary fatty acids to individuals who are unable to acquire enough nourishment orally or enterally. The Institute for Safe Drug Practices (ISMP) classifies parenteral nutrition (PN) as a medication requiring a high level of vigilance because to its significant potential for adverse effects. Filtration during preparation or administration of parenteral solutions, such as PN, is an essential method for minimizing adverse effects. Nevertheless, filtering suggestions have evolved over time and diverged across professional associations and manufacturers, resulting in a variety of practical ways. The American Society for Parenteral and Enteral Nutrition (ASPEN) published a filtering PN solution recommendations paper in 2020. In addition, in 2021, the Infusion Nurses Society (INS) revised its Standards of Practice. This article will examine significant topics pertaining to the filtering of PN solutions and provide a summary of these two publications, which reflect the most recent suggestions for the filtering of PN solutions.
Safety Concerns Regarding Particles and Pathogens in Parenteral Nutrition
Included among the universal safety concerns for all parenteral solutions are exposure to particles and pathogens. Due to their content and the intricacy of their production, parenteral feeding solutions have a significant probability of harboring both particulate matter and microorganisms. Solutions combining lipids and dextrose may stimulate bacterial and fungal development, and the use of numerous components can raise the risk of pathogen contamination and the introduction of foreign particles.
The likelihood of an unfavorable response is related to the number of particles of parenteral solution that reach the patient. Particles may enter a PN product in a variety of ways, including medication incompatibility-related precipitation, glass from ampules, rubber from bottle or vial stoppers, plastic from infusion sets, and contamination from the environment or employees. Local consequences such as vein irritation, phlebitis, and capillary blockage to more severe end-organ effects such as venous thromboembolism, particle deposition in the lungs, and rhabdomyolysis are among the short-term safety issues associated with particle exposure.
Long-term risks of particle exposure include lung talcosis and renal diseases resulting from particle accumulation in the kidney (eg, granulomatous glomerulonephritis, interstitial nephritis). The risk of these occurrences may be small with short-term PN administration, but PN is often administered in greater volumes and for longer periods than other solutions, which may raise the risk.
Although animal research and observational studies on intravenous drug users indicate that particles in parenteral solutions may be harmful, clear proof of damage from unfiltered PN solutions is sparse.
These concerns are supported by 5,8 cases of respiratory distress and abrupt mortality after exposure to the amino acid composition of a PN solution and subsequent deposition of calcium-phosphate crystals in the lungs. Filtration during administration might decrease patient exposure to particles and microorganisms, hence lowering the risk of adverse effects. Nonetheless, many practitioners may see the evidence as inadequate to warrant the frequent filtration of PN solutions. A study done by ISMP in 2012 revealed that just 58% of firms have policies geared at minimizing PN-related damage. In another study done in 2017, 20.6%, 7.2%, and 15.5% of respondents reported not filtering total nutritional admixtures (TNA, admixtures including dextrose, amino acids, and lipids), dextrose/amino acid admixtures, and lipid infusions in adults.
Recommendations for Parenteral Nutrition Filtration: A Brief History
Prior to the 1990s, the employment of in-line filters for PN management was the subject of much controversy. Some research supported the use of in-line filters for all PN products, whilst other writers advocated for the use of other infection control techniques. After two fatalities and at least two incidents of respiratory distress linked to calcium phosphate precipitate in unfiltered TNA, the Food and Drug Administration (FDA) issued a safety advisory in 1994. The FDA proposed the use of a 1.2 micron air-eliminating filter for lipid-containing goods and a 0.22 micron air-eliminating filter for lipid-free products after analyzing these instances and talking with ASPEN. In 1998, ASPEN produced a PN guideline that recommended the use of a 1.2 micron filter for all PN products, a 0.2 micron or 1.2 micron filter for dextrose/amino acid admixtures, and a 1.2 to 5 micron filter for TNA. 13 In contrast to the aforementioned standards, the Centers for Disease Control and Prevention’s 2002 guideline on avoiding bloodstream infections advised against the regular use of in-line filters in favor of the more cost-effective method of filtering PN solutions in the pharmacy. The ASPEN standards were revised in 2014 to propose air-eliminating filters with a pore size of 1.2 microns for lipid-containing PN solutions and 0.22 microns for lipid-free PN solutions.
The 2016 INS Standards of Practice included filtration recommendations comparable with the 2014 ASPEN standards, but also encouraged providers to adhere to the manufacturer’s instructions on the filtering needs for each product.
ISMP may also provide suggestions for filtering. ISMP issued a safety warning in 2016 on the updated labeling for ILE (intravenous lipid emulsion) infusions used alone or in combination. 4 The safety caution stressed that 1.2 micron filters should be used for ILE infusions, whereas 0.22 micron filters should not be utilized. At the time of the warning, manufacturers’ filtration recommendations were variable; however, all ILE package inserts in the United States now suggest a 1.2 micron in-line filter whether ILE is given alone or as part of an admixture.
Current Parenteral Nutrition Filtration Recommendations
The 2020 ASPEN advice proposes a 1.2 micron filter for all PN solutions to minimize misunderstanding caused by the use of filters with varying pore sizes in various situations. 4 The 2021 INS guidelines suggest a 0.2 micron filter for PN without lipids and a 1.2 micron filter for PN with lipids. The 2021 INS Guidelines additionally propose that all PN filters be replaced according to the manufacturer’s recommendations, which is normally every 24 hours, and that filters for specialized ILE infusions be changed every 12 hours. There is a substantial amount of agreement between the 2021 INS guidelines and the 2020 ASPEN recommendations, but there are also a number of notable discrepancies, which are shown in Table 1 below.
Recommendations Additional for Parenteral Nutrition Administration
Both ASPEN and INS include additional suggestions for enhancing the safety of PN solutions, including as correct techniques for filter priming, insertion, and replacement, as well as counseling for specific clinical conditions (see Table 2).
Considerations Unique to Pediatric Patients
PN is regularly administered to critically sick neonates and older children, although the 2017 ASPEN guideline on nutrition in critically ill children makes no reference of PN filtration. In the lack of pediatric-specific filtration guidelines for PN solutions, some doctors may utilize global filtration recommendations to this group. Other practitioners may choose to follow European guidelines, which include using a 1.2 to 1.5 micron filter with lipid-containing PN infusions and a 0.22 micron filter with lipid-free PN solutions. 19 TNA, dextrose/amino acid admixtures, and lipid infusions were not filtered in 18.6%, 1.7%, and 9.0% of children, respectively, according to a study done in 2017. 10 If a filter is used in youngsters, some experts advise keeping it below the level of the patient’s heart to minimize accidental bolus dosage and hemodynamic changes that may occur when the filter is raised and lowered.
Numerous parameters associated with pediatric PN usage suggest the possible advantage of filtration. It is believed that neonates and other children have a greater risk of PN-associated adverse effects, owing in part to their smaller blood volume and narrower blood arteries, which make it more difficult to dilute potentially incompatible dietary components and/or drugs. Mixed evidence supports the benefits of filtration in children, according to 3,21 studies. Some research have shown that the use of in-line filters reduces the incidence of systemic inflammatory response syndrome, respiratory function, renal dysfunction, and overall consequences, whereas another study did not demonstrate a benefit in reducing sepsis. None of these research were centered on PN, and the majority are older, limiting their applicability to contemporary practice.
Using an in-line filter during parenteral solution administration is a common method for minimizing exposure to particulate matter and pathogens, but shifting and contradictory guidelines for PN solutions have hampered the implementation of a consistent methodology. Recent guidelines from ASPEN and INS advocate employing a 1.2 micron filter for all PN solutions (especially those containing lipids), whereas INS recommends using a 0.2 micron filter for non-lipid-containing solutions. Clinicians are strongly encouraged to adhere to current best practices for the administration of sterile solutions, especially PN solutions.