Risk factors associated with acute kidney injury in patients who underwent cardiac surgery : a retrospective review

Abstract

Background: Acute kidney injury occurs in one out of ten cardiac surgery patients. Cardiac surgery-associated acute kidney injury not only increases patients’ mortality rate but the length of stay in intensive care unit and hospital. Cardiac surgery patients’ long- term risk for chronic kidney disease and heart failure increases with the incidence of acute kidney injury. Various preoperative, intraoperative and postoperative risk factors are associated with the development of cardiac surgery-associated acute kidney injury. Aim: The aim of the study was to identify the risk factors associated with acute kidney injury in patients who underwent cardiac surgery. The identified risk factors were categorized into modifiable, partially modifiable and non-modifiable risks. The frequency of acute kidney injury among cardiac surgery patients was also assessed. Research design: The researcher chose a quantitative correlational retrospective design and conducted a retrospective chart review to assess the risk factors associated with AKI in patients that had undergone cardiac surgery. Methods: Non-probability purposive sampling was used to select the records of patients that underwent cardiac surgery between January 2014 and December 2018. Data collection was done using a self-developed audit tool. Descriptive and inferential statistics were used for data analysis. Significance: The study enabled the researcher to identify and categorize the risk factors into modifiable, partially modifiable and non-modifiable categories. Early recognition and mitigation of risk factors could prevent patients from developing cardiac surgery- associated acute kidney injury. Research findings: The study found a 22.7% frequency of CSA-AKI. Anaemia, hypoalbuminemia, hyperglycaemia, use of N-acetylcysteine and fluid overload were identified as modifiable risk factors. Bicarbonate level <22mmol/L, use of diuretics, use of antibiotics, longer duration of surgery, fresh frozen plasma use >500ml on the day of surgery, red blood cell transfusion >1L on the day of surgery and prolonged use of mechanical ventilation were partially modifiable risk factors. No non-modifiable risk factors were identified. Keywords: Cardiac surgery-associated acute kidney injury; risk factors; modifiable, partially modifiable and non-modifiable.