I'm no so sure the vortex of confusion quote by St. Augustine is something written against baptism of blood or desire, but against proposing that "casualties that which [God] has predestinated [are] not permitted to come to pass", using the sacrament of baptism and infants as an example.
From what I understand, St. Augustine was writing to someone named Victor, who put forth a doctrine (the text says dogma, but I think doctrine is meant) wherein divine providence could decree from all eternity that certain infants should receive the sacrament of baptism, but a chance event could rupture what God predestined, consequently assigning greater power to chance than God's power of predestination.
As if God were not omnipotent, nor omniscient. As if chance could override divine providence. As if the chain of events that unfold in our lives are not subject to divine providence.
If you wish to be a catholic, do not venture to believe, to say, or to teach that they whom the Lord has predestinated for [the sacrament of] baptism can be snatched away from his predestination, or die before that has been accomplished in them which the Almighty has predestined.
There is in such a dogma more power than I can tell assigned to chances in opposition to the power of God, by the occurrence of which casualties that which He has predestinated is not permitted to come to pass. It is hardly necessary to spend time or earnest words in cautioning the man who takes up with this error against the absolute vortex of confusion into which it will absorb him [. . .]
It also appears St. Augustine put forth baptism of blood in chapter 17 of the second book of On the Soul and its Origin
. Which is one chapter before the vortex of confusion quote.
St. Augustine:On the Soul and its Origin (Book I)https://www.newadvent.org/fathers/15081.htm
Chapter 11.— Martyrdom for Christ Supplies the Place of Baptism.
The Faith of the Thief Who Was Crucified Along with Christ Taken as Martyrdom and Hence for Baptism.
Accordingly, the thief, who was no follower of the Lord previous to the cross, but His confessor upon the cross, from whose case a presumption is sometimes taken, or attempted, against the sacrament of baptism, is reckoned by St. Cyprian among the martyrs who are baptized in their own blood, as happens to many unbaptized persons in times of hot persecution. For to the fact that he confessed the crucified Lord so much weight is attributed and so much availing value assigned by Him who knows how to weigh and value such evidence, as if he had been crucified for the Lord. Then, indeed, his faith on the cross flourished when that of the disciples failed, and that without recovery if it had not bloomed again by the resurrection of Him before the terror of whose death it had drooped. They despaired of Him when dying — he hoped when joined with Him in dying; they fled from the author of life — he prayed to his companion in punishment; they grieved as for the death of a man — he believed that after death He was to be a king; they forsook the sponsor of their salvation — he honoured the companion of His cross. There was discovered in him the full measure of a martyr, who then believed in Christ when they fell away who were destined to be martyrs. All this, indeed, was manifest to the eyes of the Lord, who at once bestowed so great felicity on one who, though not baptized, was yet washed clean in the blood, as it were, of martyrdom. On the Soul and its Origin (Book II)https://www.newadvent.org/fathers/15082.htm
Chapter 17.— Disobedient Compassion and Compassionate Disobedience Reprobated. Martyrdom in Lieu of Baptism.
[. . .]On the Soul and its Origin (Book III)https://www.newadvent.org/fathers/15083.htm
Truth, by the mouth of Itself incarnate, proclaims as if in a voice of thunder: Unless a man be born again of water and of the Spirit, he cannot enter into the kingdom of God. John 3:5 And in order to except martyrs from this sentence, to whose lot it has fallen to be slain for the name of Christ before being washed in the baptism of Christ, He says in another passage, He that loses his life for my sake shall find it. Matthew 10:39 And so far from promising the abolition of original sin to any one who has not been regenerated in the laver of Christian faith, the apostle exclaims, By the offense of one, judgment came upon all men to condemnation. Romans 5:18 And as a counterbalance against this condemnation, the Lord exhibits the help of His salvation alone, saying, He that believes, and is baptized, shall be saved; but he that believes not shall be damned. Mark 16:16.
[. . .]
Chapter 12 [IX.]— His Sixth Error. (See Above in Book I. 10-12 [IX., X.], and in Book II. 13, 14 [IX., X.].)
If you wish to be a catholic, refrain from believing, or saying, or teaching that infants which are forestalled by death before they are baptized may yet attain to forgiveness of their original sins. For the examples by which you are misled — that of the thief who confessed the Lord upon the cross, or that of Dinocrates the brother of St. Perpetua — contribute no help to you in defense of this erroneous opinion. As for the thief, although in God's judgment he might be reckoned among those who are purified by the confession of martyrdom, yet you cannot tell whether he was not baptized. For, to say nothing of the opinion that he might have been sprinkled with the water which gushed at the same time with the blood out of the Lord's side, John 19:34 as he hung on the cross next to Him, and thus have been washed with a baptism of the most sacred kind, what if he had been baptized in prison, as in after times some under persecution were enabled privately to obtain? Or what if he had been baptized previous to his imprisonment? If, indeed, he had been, the remission of his sins which he would have received in that case from God would not have protected him from the sentence of public law, so far as appertained to the death of the body. What if, being already baptized, he had committed the crime and incurred the punishment of robbery and lawlessness, but yet received, by virtue of repentance added to his baptism, forgiveness of the sins which, though baptized, he had committed? For beyond doubt his faith and piety appeared to the Lord clearly in his heart, as they do to us in his words.
If, indeed, we were to conclude that all those who have quitted life without a record of their baptism died unbaptized, we should calumniate the very apostles themselves; for we are ignorant when they were, any of them, baptized, except the Apostle Paul. Acts 9:18 If, however, we could regard as an evidence that they were really baptized the circuмstance of the Lord's saying to St. Peter, He that is washed needs not save to wash his feet, John 13:10 what are we to think of the others, of whom we do not read even so much as this — Barnabas, Timothy, Titus, Silas, Philemon, the very evangelists Mark and Luke, and innumerable others, about whose baptism God forbid that we should entertain any doubt, although we read no record of it? As for Dinocrates, he was a child of seven years of age; and as children who are baptized so old as that can now recite the creed and answer for themselves in the usual examination, I know not why he may not be supposed after his baptism to have been recalled by his unbelieving father to the sacrilege and profanity of heathen worship, and for this reason to have been condemned to the pains from which he was liberated at his sister's intercession. For in the account of him you have never read, either that he was never a Christian, or died a catechumen. But for the matter of that, the account itself that we have of him does not occur in that canon of Holy Scripture whence in all questions of this kind our proofs ought always to be drawn.
Chapter 13 [X]— His Seventh Error. (See Above in Book II. 13 [IX.].)
If you wish to be a catholic, do not venture to believe, to say, or to teach that they whom the Lord has predestinated for baptism can be snatched away from his predestination, or die before that has been accomplished in them which the Almighty has predestined. There is in such a dogma more power than I can tell assigned to chances in opposition to the power of God, by the occurrence of which casualties that which He has predestinated is not permitted to come to pass. It is hardly necessary to spend time or earnest words in cautioning the man who takes up with this error against the absolute vortex of confusion into which it will absorb him, when I shall sufficiently meet the case if I briefly warn the prudent man who is ready to receive correction against the threatening mischief. Now these are your words: We say that some such method as this must be had recourse to in the case of infants who, being predestinated for baptism, are yet, by the failing of this life, hurried away before they are born again in Christ. Is it then really true that any who have been predestinated to baptism are forestalled before they come to it by the failing of this life? And could God predestinate anything which He either in His foreknowledge saw would not come to pass, or in ignorance knew not that it could not come to pass, either to the frustration of His purpose or the discredit of His foreknowledge? You see how many weighty remarks might be made on this subject; but I am restrained by the fact of having treated on it a little while ago, so that I content myself with this brief and passing admonition.