TPN‐Induced Sympathetic Activation Is Related to Diet, Bacterial Translocation, and an Intravenous Line HELTON WS, ROCKWELL M, GARCIA RM, ET AL: Arch Surg 130:209–214, 1995

Total parenteral nutrition (TPN) has been associated with impaired immune response, breakdown in gut mucosal integrity, and the development of hepatic toxicity. Diet alone, however, may not account for increases in bacterial translocation (BT) and mucosal permeability. 1,2 There is increasing recognition of the role of neural innervation of visceral organs such as the gut and the potential mediating effects of parenteral nutrition. Catecholamines, including epinephrine and norepinephrine, may be further inhibitory to immune function. 3 Male Sprague‐Dawley rats were randomized to one of four groups: sham operation and food feeding (C); IV line, saline, and food feeding (S); IV TPN (T); or IV line and oral TPN (O). Urine was collected for catecholamine determination. On day 7, animals were killed, and mesenteric lymph nodes were cultured to assess BT. Food‐fed animals (C) gained significantly more weight than either groups T or O despite isocaloric feeds. Animals with IV lines (S, T, and O) manifest BT at a rate of 40% to 50%, whereas animals with no lines had sterile lymph nodes. Both groups T and O had higher levels of catecholamine secretion; the presence of a central line alone minimally increased catecholamine levels. Data were pooled to examine specific factors. The provision of TPN, whether via oral or IV routes significantly increased both norepinephrine and epinephrine secretion. When catecholamine secretion was correlated with BT, a twofold increase in norepinephrine output was noted in those animals with BT (126 ± 23 vs 64 ± 14 pmol/μmol creatinine, p <.05).