Authors: John H. Ferguson, Maurice M. Otterstetter, Nicholas JK Tranchida, James DeFoe
Objective: Severe metabolic acidosis often occurs in the setting of septic shock and hemodynamic collapse. Acid buffering agents such as sodium bicarbonate are often used to improve acidosis, although the hemodynamic benefit of improving the serum pH is uncertain and has been evaluated only in a few small clinical studies.
Design: A retrospective cohort of patients with vasopressor-dependent septic shock who were treated with sodium bicarbonate.
Setting: A single-center mixed medical-cardiac-surgical intensive care unit.
Patients and participants: 21 patients with vasopressor-dependent septic shock who were treated with sodium bicarbonate. Patients with vasopressor-dependent septic shock who were not treated with sodium bicarbonate served as a matched control group.
Interventions: The primary endpoint was the change in norepinephrine equivalent (NEEq) dose at 24 and 48 hours after initiation of sodium bicarbonate when compared to non-sodium bicarbonate treated patients. Secondary outcomes included: hospital mortality, the impact of hypocalcemia on vasopressor requirements, and the impact of hypercapnia on vasopressor requirements in sodium bicarbonate treated patients.
Measurements and results: Patients with vasopressor-dependent septic shock who were not treated with sodium bicarbonate had no difference in the decline of vasopressor requirements than those administered sodium bicarbonate at 24 hours (0.09 μg/kg/min; 95% CI, [-0.23, 0.05], p=0.19) and at 48 hours (0.04 μg/kg/min; 95% CI [-0.11, 0.18], p=0.60). In patients with pH≤7.15, there was no difference in the change in NEEq dose between sodium bicarbonate treated or non-bicarbonate treated patients at 24 hours (0.05 μg/kg/min, 95% CI, [-0.09, 0.11], p=0.69) or at 48 hours (0.19 μg/kg/min, 95% CI, [-0.52, 0.14], p=0.17).
Conclusions: Administration of sodium bicarbonate did not improve vasopressor requirements at 24 or 48 hours, even in patients with a pH less than 7.15. Mortality and vasopressor needs are high in patients with pH less than 7.15 and unaffected by sodium bicarbonate administration.