Acute kidney injury in postoperative shock: is hyperoncotic albumin administration an unrecognized resuscitation risk factor?

Background: The use of hyperoncotic albumin (HA) for shock resuscitation is controversial given concerns about its cost, effectiveness, and potential for nephrotoxicity. We evaluated the association between early exposure to hyperoncotic albumin (within the first 48 h of onset of shock) and acute organ dysfunction in post-surgical patients with shock.

Methods: This retrospective, cohort study included 11,512 perioperative patients with shock from 2009 to 2012. Shock was defined as requirement for vasopressors to maintain adequate mean arterial pressure and/or elevated lactate (> 2.2 mmol/L). Subsets of 3600 were selected after propensity score and exact matching on demographics, comorbidities, and treatment variables (> 30). There was a preponderance of cardiac surgery patients. Proportional odds logistic regression, multivariable logistic regression or Cox proportional hazard regression models measured association between hyperoncotic albumin and acute kidney injury (AKI), hepatic injury, ICU days, and mortality.

Results: Hyperoncotic albumin-exposed patients showed greater risk of acute kidney injury compared to controls (OR 1.10, 95% CI 1.04, 1.17. P  = 0.002), after adjusting for imbalanced co-variables. Within matched patients, 20.3%, 2.9%, and 4.4% of HA patients experienced KDIGO stages 1-3 AKI, versus 19.6%, 2.5%, and 3.0% of controls. There was no difference in hepatic injury ( OR 1.16; 98.3% CI 0.85, 1.58); ICU days, (HR 1.05; 98.3% CI 1.00, 1.11); or mortality, (OR 0.88; 98.3% CI 0.64, 1.20).

Conclusions: Early exposure to hyperoncotic albumin in postoperative shock appeared to be associated with acute kidney injury. There did not appear to be any association with hepatic injury, mortality, or ICU days. The clinical and economic implications of this finding warrant further investigation.