RENAL PROTECTION IN THE CARDIAC SURGERY PATIENT: PERI-OPERATIVE SODIUM BICARBONATE INFUSION (POSBI) OR NOT?

Background: Acute renal failure following cardiac surgery is not uncommon and carries a high level of morbidity and mortality. The aim of our study was to determine whether perioperative sodium bicarbonate infusion (POSBI) would decrease acute kidney injury in cardiac surgery patients and improve post-operative outcomes.

Methods: A retrospective analysis of 318 cardiac surgery patients from 2008-2011 was performed. Clinical parameters were compared in patients receiving POSBI versus sodium chloride. Serum creatinine levels were measured in the first five post-operative days. The primary outcome measured was the number of patients developing post-operative renal injury. Secondary outcomes included three-month mortality, intensive care unit and hospital length of stay.

Results: Patients given POSBI showed no significant differences compared to the normal saline cohort in regards to increases in serum creatinine [< 25% rise in Cr: 93% vs 94%; > 25% rise in Cr: 6% vs 6%; > 50% rise in Cr: 1% vs 1%; > 100% rise in Cr: 1% vs 0%, all with p-value > 0.99]. There were fewer patients with AKIN stage 1 renal failure receiving POSBI [8% vs 28%, p = 0.02] however there was no difference between POSBI and sodium chloride cohorts in AKIN stages 2 and 3 renal failure. Mortality, duration of hospitalization and ICU stay were not statistically significant.

Conclusions: POSBI resulted in fewer patients developing AKIN stage 1 renal failure. Despite this, there appears to be little benefit in the prevention of acute kidney injury after 48 hours or mortality reduction in cardiac surgery patients.