Acute Kidney Injury and Hemodilution During Cardiopulmonary Bypass: A Changing Scenario.
BACKGROUND
Severe hemodilution during cardiopulmonary bypass (CPB) is a risk factor for acute kidney injury (AKI) after heart operations. Many improvements to CPB technology have been proposed during the past decade to limit the hemodilution-related AKI risk. The present study is a retrospective analysis of the relationship between hemodilution during CPB and AKI in cardiac operations in the setting of different interventions applied over 14 years.


METHODS
We retrospectively analyzed 16,790 consecutive patients undergoing heart operations from 2000 to 2013. Various risk factors for AKI were collected and analyzed, together with a number of interventions as possible modifiers of the relationship between a nadir hematocrit (HCT) value during CPB and AKI.


RESULTS
The relationship between the nadir HCT value during CPB and AKI was confirmed in a multivariable analysis, with the relative risk of AKI increasing by 7% per percentage point of decrease of the nadir HCT value during CPB. The relative risk of AKI decreased by 8% per year of observation (p = 0.001) despite a significantly increased risk of AKI (p = 0.001). A sensitivity analysis based on differences before and after different interventions demonstrated a beneficial effect of the application of goal-directed perfusion (aimed at preserving oxygen delivery during CPB), with a reduction in the AKI rate from 5.8% to 3.1% (p = 0.001). A policy restricting angiographic examination on the day of operation was also useful (reduction of AKI rate from 4.8% to 3.7%; p = 0.029).


CONCLUSIONS
A bundle of interventions mainly aimed at limiting the renal impact of hemodilution during CPB is effective in reducing the AKI rate.
Departments of Cardiothoracic and Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy. Electronic address: cardioanestesia@virgilio.it.
Marco
M
Ranucci
Departments of Cardiothoracic and Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy.
Tommaso
T
Aloisio
Departments of Cardiothoracic and Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy.
Giovanni
G
Carboni
Departments of Cardiothoracic and Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy.
Andrea
A
Ballotta
Departments of Cardiothoracic and Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy.
Valeria
V
Pistuddi
Department of Cardiac Surgery, IRCCS Policlinico San Donato, Milan, Italy.
Lorenzo
L
Menicanti
Department of Cardiac Surgery, IRCCS Policlinico San Donato, Milan, Italy.
Alessandro
A
Frigiola
D058186:Acute Kidney Injury / Q000209:etiology*; D000368:Aged; D002315:Cardiopulmonary Bypass; D015331:Cohort Studies; D006438:Hemodilution / Q000009:adverse effects*; D006801:Humans; D007431:Intraoperative Complications / Q000209:etiology*; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors