how is accidental premature burrial prevented in Islam?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

To be on the safe side, one should not hasten to decide that a person has died or bury him before making sure of his death. Death occurs when the soul leaves the body. There are signs with which it can be identified. Shaykh Bakr Abu Zayd said in his book Fiqh An-Nawaazil: “According to Jurists, signs of death are as follows:

Umm Salamah narrated that the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said: “When the soul is taken, the eyes follow it.” Staring with a fixed gaze is a clear sign that the soul was taken and that it left the body.

Jurists mentioned the signs and manifestations that indicate the death of somebody. The signs they have mentioned are:

1- Breathing stops.

2- Feet become relaxed, not erect.

3- Palms separate.

4- Nose becomes inclined to one side.

5- Skin of the face expands.

6- Cheeks sink.

7- Testicles shrink to above while their skin becomes loose.

8- The body gets cold.  

It can be noted that such signs are proofs and manifestations that can be realized through seeing and feeling, and all people know them.” [End quote] 

Then, he draws attention to what An-Nawawi stated in Rawdhat At-Taalibeen, quoting Ar-Raafi‘i as saying: “If there is a doubt that he has no illness and there is a possibility that he has a stroke or that signs of panic or the like appeared on him, then his burial should be delayed till certainty is attained through change of smell or the like.” [End quote]

Also, certainty can be better achieved through medical devices.

Allaah Knows best.