《黄帝内经·素问·三部九候论》
若七诊出现、其脉候有败坏现象的，这是死征，死的时候，必发呃逆等证候。
若有七诊之病，其脉候亦败者死矣，必发哕噫。
If the Seven Examinations appear and the pulse images are damaged, this is a sign of death. At the time of death, one will definitely develop symptoms such as hiccups.