Sodium bicarbonate versus THAM in ICU patients with mild metabolic acidosis.
BACKGROUND
Sodium bicarbonate is despite its side effects, considered the standard alkali therapy in metabolic acidosis. THAM is an alternative alkalizing agent; however, there are limited data on the use of THAM in metabolic acidosis. The aim of this study was to compare the efficacy and adverse effects of a single dose of sodium bicarbonate and THAM in intensive care unit (ICU) patients with mild metabolic acidosis.


METHODS
18 adult ICU patients with mild metabolic acidosis (serum bicarbonate < 20 mmol/L) were randomized to a single dose of either sodium bicarbonate or THAM, administered over a 1-hour period, and titrated to buffer the excess of acid load.


RESULTS
Sodium bicarbonate and THAM had equivalent alkalinizing effect during the infusion period. This was still present 4 hours after start of infusion of sodium bicarbonate, and until 3 hours after start of infusion of THAM. Serum potassium levels decreased after sodium bicarbonate infusion, and remained unchanged after THAM. After sodium bicarbonate, sodium increased, and after THAM, serum sodium decreased.


CONCLUSIONS
Sodium bicarbonate and THAM had a similar alkalinizing effect in patients with mild metabolic acidosis; however, the effect of sodium bicarbonate was longer lasting. Sodium bicarbonate did decrease serum potassium, and THAM did not; THAM is therefore not recommended in patient with hyperkalemia. As sodium bicarbonate leads to an increase of serum sodium and THAM to a decrease, THAM may be the alkalinizing agent of choice in patients with hypernatremia. Similarly, because sodium bicarbonate increases PaCO2 and THAM may even decrease PaCO2, sodium bicarbonate is contraindicated and THAM preferred in patients with mixed acidosis with high PaCO2 levels.
Hoste
Eric A
EA
Intensive Care Unit, Ghent University Hospital, Gent, Belgium. erik.hoste@UGent.be
Colpaert
Kirsten
K
Vanholder
Raymond C
RC
Lameire
Norbert H
NH
De Waele
Jan J
JJ
Blot
Stijn I
SI
Colardyn
Francis A
FA
D000138:Acidosis / Q000097:blood / Q000188:drug therapy*; D001784:Blood Gas Analysis; D002021:Buffers; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007262:Infusions, Intravenous; D007297:Inpatients; D007362:Intensive Care Units; D007773:Lactates / Q000097:blood; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood; D012720:Severity of Illness Index; D012964:Sodium / Q000097:blood; D017693:Sodium Bicarbonate / Q000008:administration & dosage / Q000627:therapeutic use*; D016896:Treatment Outcome; D014325:Tromethamine / Q000008:administration & dosage / Q000627:therapeutic use*
D002021:Buffers; D007773:Lactates; D014325:Tromethamine; D017693:Sodium Bicarbonate; D012964:Sodium; D011188:Potassium