Blood pressure variability during pediatric cardiac surgery is associated with acute kidney injury

Relationship between intraoperative blood pressure variability and postoperative acute kidney injury in pediatric cardiac surgery

BACKGROUND

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a notably common complication in pediatrics, with an incidence rate ranging from 15 to 64%. This rate is significantly higher than that observed in adults. Currently, there is a lack of substantial evidence regarding the association between intraoperative blood pressure variability (BPV) during cardiac surgery with cardiopulmonary bypass (CPB) and the development of AKI in pediatric patients.

METHODS

This retrospective observational study encompassed children aged 0-7 years undergoing cardiac surgery with CPB. Intraoperative BPV was calculated using coefficients of variation (CVs) and the area under the curve (AUC). Univariate and multivariate analyses were employed to identify risk factors associated with CSA-AKI.

RESULTS

Among 570 patients (median age 1 year) reviewed, 36.1% developed CSA-AKI (68.9% risk stage, 22.8% injury stage, and 8.3% failure stage). After adjusting for other variables, male gender (OR = 2.044, 95% CI 1.297-3.222, P = 0.002), congenital heart surgery risk assessment grade (RACHS-1) classification ≥ 3 (OR = 0.510, 95% CI 0.307-0.846, P = 0.009), longer CPB time (OR = 1.022, 95% CI 1.007-1.037, P = 0.004) and higher peak value of intraoperative vasoactive inotropic score (VIS) (OR = 1.072, 95% CI 1.026-1.119, P = 0.002) were identified as independent risk factors for CSA-AKI. ± 30% AUCm was different in univariate analysis (P = 0.014), however, not statistically different in multifactor analysis (P = 0.610).

CONCLUSION

Greater BPV, specifically MAP variations exceeding 30% AUC during CPB, may be a potential risk factor for CSA-AKI in pediatric patients. Further large sample clinical studies are warranted to analyze the correlation between BPV and CSA-AKI.

A rule-based clinical decision support system for detection of acute kidney injury after pediatric cardiac surgery

BACKGROUND

Acute kidney injury (AKI) is common in children with congenital heart disease following open-heart surgery with cardiopulmonary bypass (CPB). Early AKI detection in critically ill children requires clinician expertise to compile various data from different sources within a stressful and time-sensitive environment. However, as electronic health records provide data in a machine-readable format, this process could be supported by computerized systems. Therefore, we developed a time-aware, rule-based clinical decision support system (CDSS) to detect, stage, and track temporal AKI progression in children.

METHODS

We integrated retrospective clinical routine data from n = 290 randomly selected cases (n = 263 patients, aged 0-17 years) who underwent cardiac surgery with CPB into a dataset. We adapted Kidney Disease: Improving Global Outcome (KDIGO) criteria, including serum creatinine, urine output, and estimated glomerular filtration rate, and translated them into computable rules for the CDSS. As a reference standard, patients were manually assessed by blinded clinical experts.

RESULTS

The AKI incidence, according to the reference standard, was n = 146 cases for stage 1, n = 58 for stage 2, and n = 20 for stage 3. The CDSS achieved sensitivities of 92.2 % (95 % CI: 86.8-95.5 %) for AKI stage 1, 88.1 % (95 % CI: 77.2-94.2 %) for stage 2, and 95 % (95 % CI: 70.5-99.3 %) for stage 3. The specificities were 97.0 % (95 % CI: 94.4-98.4 %), 98.5 % (95 % CI: 96.5-99.4 %), and 99.3 % (95 % CI: 97.3-99.8 %), respectively.

CONCLUSIONS

We demonstrated that a CDSS is able to perform a complex AKI detection and staging process, including 11 criteria across three stages. For accurate automated AKI detection, standardized machine-readable data of high data quality are required. CDSS with high diagnostic accuracy, like presented, can support clinical management and be used for surveillance and quality management. The prototypical use for surveillance and further studies, such as the development of prediction models, should demonstrate the system's benefits in the future.

Oxygen Delivery During Cardiopulmonary Bypass in Pediatric Patients With Congenital Heart Disease: Association With Postoperative Acute Kidney Injury

OBJECTIVE

This study was designed to investigate the distribution of nadir oxygen delivery (DO2), mean DO2, and area under ideal DO2 (AUiDO2) among categorized age groups of pediatric patients and their associations with postoperative cardiac surgery-associated (CSA) acute kidney injury (AKI) and clinical outcomes.

DESIGN

Retrospective cohort study.

SETTING

A tertiary teaching hospital.

PARTICIPANTS

Patients aged <15 years with congenital heart disease who underwent cardiac surgery between May 2018 and May 2022.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Nadir DO2, mean DO2, and AUiDO2 were defined as the lowest DO2, average DO2, and dose of decrement combining the intensity and duration of DO2 less than the calculated ideal DO2, respectively. The primary outcome was CSA-AKI occurrence within 48 hours postoperatively. Secondary outcomes included maximum serum lactate levels (Lacmax) for the first 24 hours after pediatric cardiac intensive care unit admission. Of 479 patients, 147 (30.7%) developed AKI. Nadir DO2 and AUiDO2 were not significantly different between patients with CSA-AKI and those without CSA-AKI (p = 0.115 and p = 0.12, respectively). However, the mean DO2 was significantly higher in patients with CSA-AKI (p = 0.025). After adjusting for potential confounders, no significant differences were observed in the odds for CSA-AKI based on increments in nadir DO2, mean DO2, or AUiDO2. In contrast, nadir DO2 and mean DO2 were significantly associated with Lacmax in both univariate and multivariable regression analyses.

CONCLUSION

DO2-related values during cardiopulmonary bypass were not associated with CSA-AKI in pediatric patients with congenital heart disease. However, nadir DO2 and mean DO2 were significantly associated with postoperative serum lactate levels.

Development and Validation of a Nomogram for Predicting Acute Kidney Injury in Pediatric Patients Undergoing Cardiac Surgery

Acute kidney injury (AKI) is a common complication after cardiac surgery and associated with adverse outcomes. The purpose of this study is to construct a nomogram to predict the probability of postoperative AKI in pediatric patients undergoing cardiac surgery. We conducted a single-center retrospective cohort study of 1137 children having cardiac surgery under cardiopulmonary bypass. We randomly divided the included patients into development and validation cohorts at a ratio of 7:3. The least absolute shrinkage and selection operator regression model was used for feature selection. We constructed a multivariable logistic regression model to select predictors and develop a nomogram to predict AKI risk. Discrimination, calibration and clinical benefit of the final prediction model were evaluated in the development and validation cohorts. A simple nomogram was developed to predict risk of postoperative AKI using six predictors including age at operation, cyanosis, CPB duration longer than 120 min, cross-clamp time, baseline albumin and baseline creatinine levels. The area under the receiver operator characteristic curve of the nomogram was 0.739 (95% CI 0.693-0.786) and 0.755 (95% CI 0.694-0.816) for the development and validation cohort, respectively. The calibration curve showed a good correlation between predicted and observed risk of postoperative AKI. Decision curve analysis presented great clinical benefit of the nomogram. This novel nomogram for predicting AKI after pediatric cardiac surgery showed good discrimination, calibration and clinical practicability.

Hypertension, Blood Pressure Variability, and Acute Kidney Injury in Hospitalized Children

Background Although hypertensive blood pressure measurements are common in hospitalized children, the degree of inpatient hypertension and blood pressure variability (BPV) associated with end organ complications like acute kidney injury (AKI) is unknown. Methods and Results All analyses are based on a retrospective cohort of children aged 1 to 17 years with ≥2 creatinine measurements during admission from 2014 to 2018. We used time-updated Cox models to evaluate the association between BPV and hypertension with AKI. Time-varying BPV and hypertension were based on blood pressure in the preceding 72 hours. For the analysis of hypertension and AKI, we excluded patients on vasopressors to ensure comparison between hypertensive and normotensive patients. During 5425 pediatric encounters, 258 430 blood pressure measurements were recorded (median [interquartile range] 22 [11-47] readings per encounter). Among all measurements, 32.7% were ≥95th percentile and 18.9% were ≥99th percentile for age, sex, and height. AKI occurred in 389 (7.2%) encounters. We observed a U-shaped relationship between mean blood pressure and incident AKI. BPV was associated with AKI, with the largest effect sizes in the systolic and mean arterial pressure variability measures. Multiple hypertension thresholds were associated with AKI after controlling for confounders. In an additional multivariable model adjusted for BPV, the association between hypertension and AKI was attenuated but remained significant for hypertension defined as three stage 2 measurements in 1 day (hazard ratio, 1.43 [95% CI, 1.01-2.01]). Conclusions Hypertension and BPV are associated with AKI in hospitalized children. Future studies are needed to determine how pharmacologic and nonpharmacologic interventions modify AKI risk in pediatric inpatients with hypertension.