Sodium bicarbonate lowers intracranial pressure after traumatic brain injury.
BACKGROUND
Hypertonic saline is routinely used to treat rises in intracranial pressure (ICP) post-traumatic head injury. Repeated doses often cause a hyperchloremic metabolic acidosis. We investigated the efficacy of 8.4% sodium bicarbonate as an alternative method of lowering ICP without generating a metabolic acidosis.


METHODS
We prospectively studied 10 episodes of unprovoked ICP rise in 7 patients treated with 85 ml of 8.4% sodium bicarbonate in place of our usual 100 ml 5% saline. We measured ICP and mean arterial pressure continuously for 6 h after infusion. Serum pH, pCO(2), [Na(+)], and [Cl(-)] were measured at baseline, 30 min, 60 min and then hourly for 6 h.


RESULTS
At the completion of the infusion (t = 30 min), the mean ICP fell from 28.5 mmHg (+/-2.62) to 10.33 mmHg (+/-1.89), P < 0.01. Mean ICP remained below 20 mmHg at all time points for 6 h. Mean arterial pressure was unchanged leading to an increased cerebral perfusion pressure at all time points for 6 h post-infusion. pH was elevated from 7.45 +/- 0.05 at baseline to 7.50 +/- 0.05, P < 0.01 at t = 30 min, and remained elevated. Serum [Na(+)] increased from 145.4 +/- 6.02 to 147.1 +/- 6.3 mmol/l, P < 0.01 at t = 30 min. pCO(2) did not change.


CONCLUSIONS
A single dose of 8.4% sodium bicarbonate is effective at treating rises in ICP for at least 6 h. Serum sodium was raised but without generation of a hyperchloremic metabolic acidosis.
Bourdeaux
Chris
C
Department of Anaesthesia, Frenchay Hospital, Frenchay, Bristol, BS16 1LE, UK. chrisbourdeaux@gmail.com
Brown
Jules
J
D001794:Blood Pressure / Q000187:drug effects; D001930:Brain Injuries / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology*; D002405:Catheterization, Central Venous; D002560:Cerebrovascular Circulation / Q000187:drug effects; D002712:Chlorides / Q000097:blood; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007427:Intracranial Pressure / Q000187:drug effects*; D011446:Prospective Studies; D012964:Sodium / Q000097:blood; D017693:Sodium Bicarbonate / Q000008:administration & dosage*; D013997:Time Factors
D002712:Chlorides; D017693:Sodium Bicarbonate; D012964:Sodium