Anaesthesia carries risks. It is difficult to judge the risk accurately, especially when it is presented as a statistic. A 2006 paper by Rupert Pearse and colleagues based on 4.1 million surgical procedures showed that the risk of death is about 0.44% for elective surgery and 5.4% for emergency surgery. For a healthy patient the risk is low. Second to death, awareness during surgery is a fear of many people undergoing surgery. There are other risks involved such as equipment failure, human error, and deliberately low dosage. Side effects of anaesthetic include nausea, vomiting, sore throat, shivering, headache, chest infection, confusion, itching, sleep disturbance, and bodily aches.