Mean perfusion pressure deficit during the initial management of shock-an observational cohort study

Purpose: It is unclear if blood pressure targets for patients with shock should be adjusted to pre-morbid levels. We aimed to investigate mean deficit between the achieved mean perfusion pressure (MPP) in vasopressor-treated patients and their estimated basal (resting) MPP, and assess whether MPP deficit has any association with subsequent acute kidney injury (AKI). Materials and Methods: Fifty-one consecutive, non-trauma patients, aged >= 40 years, with >= 2 organ dysfunction and requiring vasopressor >= 4 hours were observed at an academic intensive care unit. Mean MPP deficit [=%(basal MPP - achieved MPP)/basal MPP] and % time spent with >20% MPP deficit were assessed during initial 72 vasopressor hours (T0-T72) for each patient. Results: Achieved MPP was unrelated to basal MPP (P=.99). Mean MPP deficit was 18%(95% CI 15-21). Patients spent 48% (95% CI 39-57) time with >20% MPP deficit. Despite similar risk scores at T0, subsequent AKI (>= 2 RIFLE class increase from T0) occurred more frequently in patients with higher (>median) MPP deficit compared to patients with lower MPP deficit (56% vs 28%; P=.045). Incidence of subsequent AKI was also higher among patients who spent greater% time with >20% MPP deficit (P=.04). Conclusions: Achieved blood pressure during vasopressor therapy had no relationship to the pre-morbid basal level. This resulted in significant and varying degree of relative hypotension (MPP deficit), which could be a modifiable risk factor for AKI in patients with shock. (C) 2013 Elsevier Inc. All rights reserved.