ESSENTIAL FATTY-ACID DEFICIENCY AND HOME TOTAL PARENTERAL-NUTRITION PATIENTS

The requirements for essential fatty acids in patients on home parente ral nutrition are not well described. We therefore studied the needs o f 12 patients receiving parenteral nutrition for at least 4 mo (range: 4 mo-17.3 yr; mean 7.0 +/- 5.2 yr). Prior to the study, each patient had been receiving intravenous lipids either weekly or biweekly and ha d a triene to tetraene ratio (TTR) on plasma phospholipids performed a t least annually. A TTR greater than or equal to 0.2 was considered di agnostic for essential fatty acid deficiency (EFAD). The purpose of th is study was to determine the required intravenous lipid supplementati on in patients on home total parenteral nutrition (HTPN). Patients wit h an initial TTR of < 0.2 had their intravenous lipid stopped and chan ges in their serum phospholipid fatty acids were followed every 3-4 wk . Nine of 12 patients had TTRs > 0.2 at some point in the study. Phase I consisted of patients who at initiation of the study had normal TTR s and were taken off lipid supplementation until their TTR became abno rmal. Phases II, III, IV, and V consisted of lipid delivered in total nutrient admixtures in biweekly doses of 0.6, 1.2, 1.8, and 2.4 g of f at/kg bodyweight, respectively. Eight patients normalized their TTRs o n the biweekly lipid regimens. one patient expired before his ratio no rmalized; and three patients could not be made deficient in essential fatty acids after 26 or more wk of fat-free parenteral nutrition. Most patients required 1.2 to 2.4 g of lipid/kg bodyweight/biweekly to cor rect serologic EFAD. The clinical background, as well as the length of small bowel remaining, did not seem to identify those patients who re quired lipid supplementation nor the final dose of lipid needed to nor malize their TTRs.