IMMUNE-RESPONSE - EFFECTS OF OPERATIVE STRESS IN A PEDIATRIC MODEL

Purpose: The purpose of this study is to delineate the effect of diffe rent operative procedures on the cell-mediated immune response in a pe diatric animal model using the delayed type hypersensitivity (DTH) ski n test. Methods: Sprague Dawley rats (1 week old) were sensitized agai nst keyhole limpet hemocyanin (KLH). Animals were challenged 2 weeks l ater by an intradermal injection of KLH (0.3 mg) in sterile saline. Ra ts with positive DTH skin reactions at 24 and 48 hours after challenge (baseline) were divided randomly into five groups (n = 10 each): grou p I, unmanipulated control; group II, anesthesia; group III, anesthesi a and midline extraperitoneal incision; Group IV, anesthesia and lapar oscopy (pneumoperitoneum with carbon dioxide); Group V, anesthesia and midline laparotomy. Before each procedure (day 0) and on postoperativ e days 3 and 6, animals were again challenged intradermally with KLH ( 0.3 mg). DTH skin reaction was evaluated 24 and 48 hours later. Result s: A statistically significant difference (P < .05) in DTH skin reacti on at 24 and 48 hours was observed between postoperative days 1 to 5 i n the extraperitoneal and laparotomy groups with respect to baseline a nd the control group. Statistically significant differences were found in postoperative days 1, 4, and 5 between laparoscopy and laparotomy. The laparoscopy group showed a statistically significant decrease in DTH skin induration on postoperative day 2 when compared with the cont rol group. At postoperative day 7 and 8 there was no statistical diffe rence in DTH skin response comparing baseline values or between groups . Conclusions: These results suggest that in a pediatric animal model, abdominal surgical procedures accompanied by extensive tissue dissect ion produce a cellular immunosuppression, lasting up to 7 days, which is not observed in less invasive procedures. Observations concerning l esser immunosuppressive effects of laparoscopy when compared with lapa rotomy in adult models, as previously described by our laboratory, wer e also found in this pediatric model. Copyright (C) 1998 by W.B. Saund ers Company.