The administration of intravenous fat emulsions (IVFE) is an essential component of parenteral nutrition (PN) regimes for pediatric and adult patients. IVFEs are formulated to provide essential fatty acids and a dense source of calories to help reduce the volume required for PN. The majority of IVFE’s available are made up of long-chain triglycerides (LCT) including soybean oil (omega-6), olive oil (omega-9), fish oil (omega-3) and medium-chain triglycerides (MCT). Undiluted, these IVFEs can be given separately from the PN admixtures or added to the PN for an “all-in-one” (AIO) admixture.

Whether administering AIOs or IVFEs, both methods are prone to precipitation, meaning that large particulates (e.g., enlarged lipid droplets) have the potential to enter the body, leading to patient injury. Special populations such as the critically ill, neonatal and pediatric patients are at a higher risk due to their co-morbidities and size, and serious injuries up to and including death can occur.

Filtering emulsions and AIO mixes

Practices regarding filtering these lipid emulsions or AIO mixes have historically varied. In recent years, consensus on the use of a 1.2-micron filter for IVFE has grown, with organizations such as A.S.P.E.N (American Society of Parenteral and Enteral Nutrition) and INS4 (Intravenous Nursing Society) promoting their use to reduce the potential for patient harm that may occur due to infusion of particulate, precipitates and air emboli. Despite these recommendations, end user post-market surveillance data and published literature cite reports of patient side occlusion alarms and clogged filters when a 1.2-micron filter is used.

Occlusion alarms and clogged filters

Lipid emulsions contain particles that can range from about 0.1 micron to 1 micron, however, and some can pass through a 1.2 micron filter. Conversely, newer lipid emulsions have larger lipid globules (greater than 5 microns) which can pose the greatest patient risk since particles of this size can lodge in pulmonary capillaries and cause complications if filters are not utilized.

Filters can also become clogged due to the size of the lipid globules, which can result in an interruption in the infusion. As the filter is “doing its job” of trapping particulate matter before it is infused to the patient, the pressure upstream of the filter may increase over time due to the filter retaining particulate matter, and in the case of IVFE, large amounts of enlarged lipid droplets. Filter blockage may result in a patient-side occlusion alarm, as higher pressures exist upstream of the filter vs downstream. In these cases, the clinician is needed to respond to the audible/visual infusion pump alarm and investigate the root cause of the occlusion.

Investigating possible causes

Pharmacy has an important role to fully investigate possible causes of a clogged filter, including a review of the PN formulation to determine if incompatibility issues and/or particulate matter formation may be the cause and identify actions to prevent further occurrences. All clinicians should be aware that an occluded filter may be a sign of compatibility problems with the PN solution and that filters should be replaced, but never removed, in order to ensure patient safety. Close adherence to the drug manufacturer’s, associations, official regulatory bodies and filter manufacturer on filter usage and filter change policies are recommended for optimal filter performance and patient safety.

Read the White Paper

To learn more about clinical practice challenges, pharmacy troubleshooting and techniques to trouble-shoot patient side occlusion alarms when filtering PN/IVFE, read the full white paper, Filtering out the Facts: Recommendations to Optimize Performance of In-Line Filters for Parenteral Nutrition and Intravenous Fat Emulsion Infusions.

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