The aim of this study is to measure the efficacy of local anesthetics (LA) administered into the intra-peritoneal cavity compared to placebo. Our hypothesis is that the injection of local LAs intra-peritoneally would reduce post-operative pain and the inflammatory process caused by the massive release of cytokines during extensive cytoreductive surgery. The study is a controlled, parallel group, double blind, prospective, randomized and performed at Sahlgrenska University Hospital in Goteborg, Sweden . Twenty mL of ropivacaine or saline would be injected every hour by an automatic pump via the intra-peritoneal catheter into the abdomen according to group randomization in order to double blind patients and all personnel involved in the study.