Rationale: There are no prospective observational studies exploring the relationship between relative hypotension and adverse kidney-related outcomes among critically ill patients with shock.Objectives: To investigate the magnitude of relative hypotension during vasopressor support among critically ill patients with shock and to determine whether such relative hypotension is associated with new significant acute kidney injury (AKI) or major adverse kidney events (MAKE) within 14 days of vasopressor initiation.Methods: At seven multidisciplinary ICUs, 302 patients, aged ≥40 years and requiring ≥4 hours of vasopressor support for nonhemorrhagic shock, were prospectively enrolled. We assessed the time-weighted average of the mean perfusion pressure (MPP) deficit (i.e., the percentage difference between patients' preillness basal MPP and achieved MPP) during vasopressor support and the percentage of time points with an MPP deficit > 20% as key exposure variables. New significant AKI was defined as an AKI-stage increase of two or more (Kidney Disease: Improving Global Outcome creatinine-based criteria).Measurements and Main Results: The median MPP deficit was 19% (interquartile range, 13-25), and 54% (interquartile range, 19-82) of time points were spent with an MPP deficit > 20%. Seventy-three (24%) patients developed new significant AKI; 86 (29%) patients developed MAKE. For every percentage increase in the time-weighted average MPP deficit, multivariable-adjusted odds of developing new significant AKI and MAKE increased by 5.6% (95% confidence interval, 2.2-9.1; P = 0.001) and 5.9% (95% confidence interval, 2.2-9.8; P = 0.002), respectively. Likewise, for every one-unit increase in the percentage of time points with an MPP deficit > 20%, multivariable-adjusted odds of developing new significant AKI and MAKE increased by 1.2% (0.3-2.2; P = 0.008) and 1.4% (0.4-2.4; P = 0.004), respectively.Conclusions: Vasopressor-treated patients with shock are often exposed to a significant degree and duration of relative hypotension, which is associated with new-onset, adverse kidney-related outcomes.Study registered with Australian New Zealand Clinical Trial Registry (ACTRN 12613001368729).
Keywords: acute kidney injury; blood pressure deficit; intensive care; relative hypotension; shock.