What is the best process to transition from continuous parenteral infusion to cyclic parenteral nutrition based on published studies as well as national guidelines such as ASPEN and ESPEN? How fast should be patients be transitioned and are there protocols available to support identifying patients who can transition faster and what monitoring should be implemented?

Comment by InpharmD Researcher

A thorough literature search did not reveal any clinical studies or societal guidance which denote the most optimal process in transitioning from continuous to cyclic parenteral nutrition (PN). Guidance primarily addresses tapering down strategies for cyclic PN, though some regimens may allow for gradual tapering up to a maximum rate over a period of about two hours; however, there is a lack of clinical evidence to support this practice. There is a similar lack of guidance for monitoring requirements and ways to identify patients that may benefit from transitioning to cyclic PN, though more cautious monitoring may be necessary in patients who are below 3 years of age, have low glycogen stores, abnormal fluid status, or receiving long-acting insulin or insulin drips.

Background

Guidance from the American Society for Parenteral and Enteral Nutrition (ASPEN) and the European Society for Clinical Nutrition and Metabolism (ESPEN) focus on tapering down strategies for cyclic parenteral nutrition (PN); however, no specific recommendations could be found regarding transitioning to cyclic PN from continuous PN. In general, a cautious approach to cyclic infusion is recommended if there are concerns of adverse events (e.g., hyperglycemia, edema, or fluid intolerance). Similarly, one 2011 review article notes a risk of increasing blood glucose concentration when initiating cyclic PN, which may predispose patients to hyperglycemia. Notably, direct comparisons between abrupt and gradual initiation of cyclic PN have not been performed. Some regimens allow for a gradual increase to the maximum rate over a certain time period, typically up to 2 hours. In general, cyclic PN infusion may be considered in stable inpatients; patients who are receiving daytime acute care therapy or transferring to rehabilitation services/facilities; ambulatory patients whose movement is hindered by infusion equipment; and patients who are expected to receive long-term PN at home. Prudent monitoring may be necessary in pediatric patients <3 years of age; patients with low glycogen stores (e.g., neonates, severe malnourishment); abnormal fluid status (e.g., congestive heart failure); or patients who are receiving insulin drips or long-acting insulin. Cyclic PN should be avoided in patients with hemodynamic instability, who are critically ill, or who are mechanically ventilated. [1], [2], [3]

Though not specific to transitioning from continuous to cyclic PN, a 2003 article presents a mathematical method of calculating cyclic PN flow rates for patients. The authors were motivated due to a flaw in a widely-used mathematical model (Faubion method) which only delivers the correct volume at the exact cycle time of 17.5 hours. In this proposed model, a basal flow rate is determined and administered for the first and last hour. The basal flow rate multiplied by 2 will flow on the second and penultimate hour. Then the basal flow rate multiplied by 4 will be administered for the rest of the cycle. The Faubion method also allowed for an initial ramping rate based on one-half and one-quarter of the calculated peak flow rate; however, neither method cites clinical evidence which denotes the safety of gradually increasing the flow rate. [4]

References: [1] Ayers P, Adams S, Boullata J, et al. A.S.P.E.N. parenteral nutrition safety consensus recommendations. JPEN J Parenter Enteral Nutr. 2014;38(3):296-333. doi:10.1177/0148607113511992
[2] Pironi L, Boeykens K, Bozzetti F, et al. ESPEN practical guideline: Home parenteral nutrition. Clin Nutr. 2023;42(3):411-430. doi:10.1016/j.clnu.2022.12.003
[3] Parrish CR, Cober MP, Stout S. Cyclic Parenteral Nutrition Infusion: Considerations for the Clinician. Pract Gastroenterol. 2011;XXXV(7):11.
[4] Longhurst C, Naumovski L, Garcia-Careaga M, Kerner J. A practical guideline for calculating parenteral nutrition cycles. Nutr Clin Pract. 2003;18(6):517-520. doi:10.1177/0115426503018006517