Please help! what is the exact mechanism of paralytic ileus seen post-operatively?

Post-op ileus: Whenever the intestines are handled in surgery, the normal motion can decrease. Each short piece of bowel squeezes and pushes the food inside along the bowel. After surgery, the pushing is not coordinated, and the fluid in the bowel can back up. All narcotic pain medication slows the bowel down as well. Your surgeon may not want to let you eat - you will be more likely to throw up.