Influence of parenteral nutrition on postoperative recovery in an experimental model of peritonitis

Background and aims: There seems to be no clear-cut indications for routine TPN support after major elective surgery. The present study was designed to investigate whether TPN could improve the results of standard surgical care for acute peritonitis (laparotomy plus antibiotics). Animals and methods: Peritonitis was induced in 48 New Zealand rabbits (day -2). On day 0, appendectomy and peritoneal lavage were performed, ceftriaxone (250 mg, i.m./24 h.) was started and animals were randomly assigned to receive regular fluids (RF), glucose-based TPN (G-TPN) or isocaloric fat-based TPN (F-TPN) for 6 days. Main outcome measures: Balance studies (days 1–3), s-albumin, thyroid hormones and urinary catecholamines were determined at various points of the experiment. At postmortem, wound infection, residual intra-abdominal infection and laparotomy wound breaking strength were recorded. Results: Peritonitis produced a fall in weight, s-albumin and T3. At day 6, weight-loss was more pronounced in RF than in G-TPN or F-TPN (−7 vs 1.5 vs −1.2%;P=0.0001) but s-albumin and T3 concentrations were similar. Diuresis (377 vs 268 vs 269 mL/3 days;P=0.01) was higher and water balance lower (373 vs 511 vs 480 mL/3 days;P=0.01) in Group RF. Although the differences were not statistically significant (P<0.2), persistent infection and wound breaking strength were slightly worse in the pooled TPN groups compared with the RF group (19 vs 6% and 542 vs 701 g, respectively). Conclusions: TPN failed to improve relevant biochemical markers and clinical outcome after laparotomy for peritonitis.