I'm a nursing student and also was confused about the difference between potential complications (PC) and collaborative problems. From what I can understand potential complications is encompassed in collaborative problems. Per my text book, "Collaborative problems are potential or actual complications of disease or treatment that nurses treat with other health care providers, most frequently physicians". So for care plans collaborative problems should include not only potential problems but also existing actual problems. So you were right, they are essentially the same. Hope this is helpful for future confused students.