Shaphak (H8210) means to pour out, to shed, to pour forth. It is used of pouring out water, blood, or the soul before God. The pouring out of blood carries covenantal and sacrificial weight; the pouring out of the soul in prayer is a posture of total surrender.
The shedding of blood (shophek dam) in Genesis 9:6 establishes the sanctity of human life made in God's image. Hannah 'poured out her soul' before the LORD (1 Samuel 1:15) — an act of radical transparency in prayer. Most profoundly, the New Covenant is inaugurated by the poured-out blood of Christ (Luke 22:20), fulfilling every sacrificial type.