In the poem "Out, Out -," what personification is in the poem, and what words indicate onomatopoeia? What is the theme?

Frost's poem is based on a true incident which is believed to have happened in April 1915; Raymond Fitzgerald, the son of Frost’s friend and neighbour, lost his hand to a buzz saw and bled so profusely that he went into shock, and died of cardiac arrest in spite of the best efforts of the doctor.  Frost’s title invites us to compare the poem’s shocking story with Macbeth’s speech on learning of his wife’s death:

The key to understanding the theme of Frost's "Out, out-" lies in the intertextual reference to Shakespeare's "Macbeth" Act V Sc.5, where Macbeth soliloquizes bitterly on the futility of life after he learns of the death of his wife:

Out, out, brief candle!
Life's but a walking shadow, a poor player,
That struts and frets his hour upon the stage,
And then is heard no more. It is a tale
Told by an idiot, full of sound and fury,
Signifying nothing.

Frost's poem ironically comments on the death of a small boy who dies tragically at such a young age because of an accident when he was sawing wood.  His life is compared to a "brief candle."

When the boy's sister announces that it's supper time, the boy is distracted and even before he realizes it the saw has cut off his hand:

His sister stood beside them in her apron
To tell them "Supper." At the word, the saw,
As if to prove saws knew what supper meant,
Leaped out at the boy's hand, or seemed to leap—

Frost has anthropomorphized the inanimate object 'saw' by giving it human attributes - 'knew' and 'leaped.' the word 'buzz-saw' itself is an example of onomatopoeia - the buzzing sound of the machine saw.

The last two lines contain the message or moral which Frost wants to convey to his readers. Frost's message is that anything can happen at any time. There is no absolute safety or security for human life. The next minute is not ours and we may be alive one minute and dead the very next minute. The only thing that we can do is to go on with our lives. Just because the small boy died it does not mean that all the others will die in a similar fashion. The death of the small boy cannot be an excuse for inaction. So, the others continue with their work and lives even after the death of the boy:

No one believed. They listened at his heart. Little--less--nothing!--and that ended it. No more to build on there. And they, since they Were not the one dead, turned to their affairs.