Why in DKA the HCO3 is low amd NH4 is high?

IN DKA you are consuming the fats and producing ketoacids ( hydroxybutyric acid and acetoacetic acid). these ketone bodies will acidify the blood–> the chemo receptors and respiratory center in the brainstem will sense this Metabolic acidosis and therefore induce hyperventilation to decrease the pp of C02 in the blood—> to bring back the physiological Ph. As you have these 2 ketonbodies some excreeted in the urine, while lots of it in the blood, the ketoacids will dissociate releasing the H+ ion, this will react (bind) with the HC03- resulting in decreased serum bicarbonate levels.

if you want to continue with this, now that you have low HC03- (it became neutral H2c03) but you have anionic Ketone bodies ( they lost the H+ and gave it to HCO3-) " the H ion also end up reducing the Cl- --> this causes the anion gape to increase following AG= Na+ – (Cl– + HCO3–) “notice the loss in HCO3, and Cl-”

also if a patient has signs and symptoms of spastic neurogenic bladder (detrusor sphincter dyssynergia) with urinary retention following spinal cord injury. Appropriate pharmacotherapy would be bethanocol or alpha blocker prazocin?