ACUTE KIDNEY INJURY IN INFANTS POST CARDIAC SURGERY - INCIDENCE , RISK FACTORS AND OUTCOME

Introduction:

Acute kidney injury ( AKI ) is a frequent and serious complication after open heart surgery, particularly among infants.

Once , considered to be self-limited consequence of illness or surgery without direct impacts on patient outcomes,  AKI in hospitalized children is now recognized to be  associated with greater  resource utilization, morbidity and hospital mortality . This shift of  paradigm warrants efforts to improve detection, management and secondary prevention of permanent sequelae.

The incidence of acute kidney injury following cardiac surgery (CS - AKI ) in pediatric patients varies between 15 and 64%, depending on the various definitions used for AKI and complexities of surgery . The purpose of this study is to present our experience with AKI post-cardiac surgery with emphasis on implicating  factors and outcomes .

Methods:

Objective: We evaluated the incidence of AKI using the KDIGO criteria in 140 infants undergoing cardiac surgeries between 2021 and 2023. 

Design: A prospective observational study.

Setting: A 10-bed cardiothoracic ICU.

Patients: One hundred and forty infants admitted to the cardiothoracic ICU following cardiopulmonary bypass ( CPB)  surgery.

Methods: Data collected included age, gender, weight, length , type of heart disease, prior cardiac surgeries, RACHS-1 category,  pre- and post-operative creatinine levels (mg/dl) and urine output (ml/kg/hr) , Hemogram , liver function tests . Duration of cardiopulmonary bypass (CPB) and aortic cross clamp time (ACC) time (minutes), need of renal replacement therapy , were also noted.

Statistical analysis - Demographic data and study variables  expressed as mean ± SD. Patients with AKI were compared with those without kidney injury using the standard statistical tests. Multiple logistic regression analyses to compute odds ratios were analyzed to find the independent predictors of AKI.

Clinical outcomes – Length of ICU and hospital stay , discharge , death were observed .   

Results:

Study included 140 infants, with male preponderance (76%). As per KDIGO criteria, 47 (33%) developed AKI. Stage 1 AKI observed in 55.8 %, stage 2 in 29 % and stage 3 in 14 .2 % of those developing AKI.  

Infants who had CS AKI were younger ( (6.1 months  v/s 4.5 months) , had lesser weight on admission ( 4.3 kilograms v/s 5.4 kilograms ) , had cyanotic heart disease , had complex heart conditions ( higher RACHS score ) , had longer CPB time ( 78 v/s 60 min ) , longer ACC time ( 57 v/s 38 min ) , had more events of re intubation ( 11 v/s 6 ) and re exploration ( 9 v/s 1). 

In this study, after adjusting for possible confounding variables by multivariate logistic regression,  3 independent risk factors for onset of AKI were found: cyanotic heart disease  OR  2.525 ( 95 % CI  1.06-5.00)  ,  longer cardio pulmonary bypass time  (>90 min) OR  3.775  ( 95 % CI 1.54- 9.25) and prolonged ventilation ( more than 48 hours ) OR 6.01 with 95 % CI 1.98 – 14.21.

Seven infants with AKI required renal replacement therapy (RRT), out of which 4 (2.9%) died. A total of 91.5 % of infants with AKI recovered. 

 Figure 1 - Stages of AKI (KDIGO) 

 Figure 2- Cardio pulmonary bypass time and development of AKI 

Figure 3- Simple Box plot of age ( in months ) and Development of AKI       

Figure 4 - Type of heart disease and development of AKI among study subjects

Conclusions:

Using the KDIGO criteria, the incidence of AKI in infants  following cardiac surgery was 33%. Children with cyanotic cardiac disease,  younger age , and longer duration of cardiopulmonary bypass (CPB) were more prone to develop AKI.

CS - AKI  is one of the very significant issues in pediatric cardiac intensive care due to its noteworthy impact on both the early postoperative period and long-term outcomes. Infants with AKI had longer ICU stay , higher chances of prolonged ventilation and greater in hospital mortality .

These results will provide more scientific data to nephrology community and thus might help improve the clinical care protocols prior to cardiac surgery to minimize the disease burden of CS-AKI in smaller children

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.