Low Systemic Oxygen Delivery and BP and Risk of Progression of Early AKI

Abstract

Background and objectives: The optimal hemodynamic management of patients with early AKI is unknown. This study aimed to investigate the association between hemodynamic parameters in early AKI and progression to severe AKI and hospital mortality.

Design, setting, participants, & measurements: This study retrospectively analyzed the data of all patients admitted to the adult intensive care unit in a tertiary care center between July 2007 and June 2009 and identified those with stage 1 AKI (AKI I) per the AKI Network classification. In patients in whom hemodynamic monitoring was performed within 12 hours of AKI I, hemodynamic parameters in the first 12 hours of AKI I and on the day of AKI III (if AKI III developed) or 72 hours after AKI I (if AKI III did not develop) were recorded. Risk factors for AKI III and mortality were identified using univariate and multivariate logistic regression analyses.

Results: Among 790 patients with AKI I, 210 (median age 70 years; 138 men) had hemodynamic monitoring within 12 hours of AKI I; 85 patients (41.5%) progressed to AKI III and 91 (43%) died in the hospital. AKI progressors had a significantly higher Sequential Organ Failure Assessment score (8.0 versus 9.6; P<0.001), lower indexed systemic oxygen delivery (DO2I) (median 325 versus 405 ml/min per m(2); P<0.001), higher central venous pressure (16 versus 13; P=0.02), and lower mean arterial blood pressure (MAP) (median 71 versus 74 mmHg; P=0.01) in the first 12 hours of AKI I compared with nonprogressors. Multivariate analysis confirmed that raised lactate, central venous pressure, and Sequential Organ Failure Assessment score as well as mechanical ventilation were independently associated with progression to AKI III; higher DO2I and MAP were independently associated with a lower risk of AKI III but not survival. The associations were independent of sepsis, heart disease, recent cardiac surgery, or chronic hypertension.

Conclusions: Higher DO2I and MAP in early AKI were independently associated with a lower risk of progression.

Keywords: ARF; hypotension; kidney failure; mortality risk.

Copyright © 2015 by the American Society of Nephrology.

Figures

Figure 1.

Flow of patients. AKI I, stage 1 AKI; AKI II, stage 2 AKI; AKI III, stage 3 AKI; ICU, intensive care unit.

Figure 2.

Association between MAP and risk of progression to AKI III. The figure demonstrates odds ratios and 95% confidence intervals per multivariate analysis (reference: MAP category = 60–64.9 mmHg). Number indicates the number of patients included per category. AKI III, stage 3 AKI; MAP, mean arterial pressure in first 12 hours after diagnosis of AKI I (in mmHg).

Figure 3.

Association between DO2I and risk of progression to AKI III. The figure demonstrates odds ratios and 95% confidence intervals per multivariate analysis (reference: DO2I category = 300–399 ml/min per m2). Number indicates the number of patients included per category. AKI III, stage 3 AKI; DO2I, indexed systemic oxygen delivery (in ml/min per m2).