A new model to predict acute kidney injury after cardiac surgery in patients with renal insufficiency

A systematic review of cardiac surgery clinical prediction models that include intra-operative variables

BACKGROUND

Most cardiac surgery clinical prediction models (CPMs) are developed using pre-operative variables to predict post-operative outcomes. Some CPMs are developed with intra-operative variables, but none are widely used. The objective of this systematic review was to identify CPMs with intra-operative variables that predict short-term outcomes following adult cardiac surgery.

METHODS

Ovid MEDLINE and EMBASE databases were searched from inception to December 2022, for studies developing a CPM with at least one intra-operative variable. Data were extracted using a critical appraisal framework and bias assessment tool. Model performance was analysed using discrimination and calibration measures.

RESULTS

A total of 24 models were identified. Frequent predicted outcomes were acute kidney injury (9/24 studies) and peri-operative mortality (6/24 studies). Frequent pre-operative variables were age (18/24 studies) and creatinine/eGFR (18/24 studies). Common intra-operative variables were cardiopulmonary bypass time (16/24 studies) and transfusion (13/24 studies). Model discrimination was acceptable for all internally validated models (AUC 0.69-0.91). Calibration was poor (15/24 studies) or unreported (8/24 studies). Most CPMs were at a high or indeterminate risk of bias (23/24 models). The added value of intra-operative variables was assessed in six studies with statistically significantly improved discrimination demonstrated in two.

CONCLUSION

Weak reporting and methodological limitations may restrict wider applicability and adoption of existing CPMs that include intra-operative variables. There is some evidence that CPM discrimination is improved with the addition of intra-operative variables. Further work is required to understand the role of intra-operative CPMs in the management of cardiac surgery patients.

Meaning and Management of Perioperative Oliguria

Perioperative oliguria is an alarm signal. The initial assessment includes closer patient monitoring, evaluation of volemic status, risk-benefit of fluid challenge or furosemide stress test, and investigation of possible perioperative complications.

Effect of timing of enteral nutrition initiation on poor prognosis in patients after cardiopulmonary bypass: A prospective observational study

OBJECTIVES

Current guidelines recommend that enteral nutrition (EN) be implemented as early as possible in patients after cardiopulmonary bypass (CPB), but the optimal time to initiate EN remains controversial. Therefore, the aim of this study was to investigate the effect of timing of EN initiation on poor prognosis in patients after CPB.

METHODS

This was a prospective observational study with patients who underwent CPB in a tertiary hospital from September 1, 2021, to January 31, 2022. The patients were divided into three groups according to the timing of EN initiation: <24 h, 24 to 48 h, and >48 h. Unconditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals to identify independent risk factors for poor prognosis.

RESULTS

The study included 579 patients, of whom 255 patients had EN initiated at <24 h (44%), 226 at 24 to 48 h (39%), and at >48 h (17%). With EN <24 h as a reference, multivariate logistic analysis showed that EN 24 to 48 h (OR, 1.854, P = 0.008) and EN >48 h (OR, 7.486, P <0.001) were independent risk factors for poor prognosis after CPB. Age (OR, 1.032, P = 0.001), emergency surgery (OR, 10.051; P <0.001), surgical time (OR, 1.006; P <0.001), and sequential organ failure assessment score (OR, 1.269; P = 0.001) also increased the risk for poor prognosis after CPB.

CONCLUSIONS

Compared with early EN <24 h, EN 24 to 48 h and EN >48 h increased the risk for poor prognosis in patients after CPB.

Diagnosis, pathophysiology and preventive strategies for cardiac surgery-associated acute kidney injury: a narrative review

Acute kidney injury (AKI) is a common and serious complication of cardiac surgery and is associated with increased mortality and morbidity, accompanied by a substantial economic burden. The pathogenesis of cardiac surgery-associated acute kidney injury (CSA-AKI) is multifactorial and complex, with a variety of pathophysiological theories. In addition to the existing diagnostic criteria, the exploration and validation of biomarkers is the focus of research in the field of CSA-AKI diagnosis. Prevention remains the key to the management of CSA-AKI, and common strategies include maintenance of renal perfusion, individualized blood pressure targets, balanced fluid management, goal-directed oxygen delivery, and avoidance of nephrotoxins. This article reviews the pathogenesis, definition and diagnosis, and pharmacological and nonpharmacological prevention strategies of AKI in cardiac surgical patients.