Near-Infrared-Based Cerebral Oximetry for Prediction of Severe Acute Kidney Injury in Critically Ill Children After Cardiac Surgery

Cerebral oximetry in high-risk surgical patients: where are we?

PURPOSE OF REVIEW

This review aims to summarize the latest evidence on the role of near-infrared spectroscopy (NIRS) in monitoring cerebral oxygenation in high-risk surgical patients, including both cardiac and noncardiac surgeries, and to present a new algorithm for its application.

RECENT FINDINGS

NIRS effectively measures brain oxygen saturation noninvasively, proving valuable in cardiac surgeries to reduce neurological complications, though its impact on nonneurological outcomes is less clear. In noncardiac surgeries, NIRS can help prevent complications like postoperative cognitive dysfunction, particularly in high-risk and major surgeries. Studies highlight the variability of cerebral oxygenation impacts based on surgical positions, with mixed results in positions like the beach chair and sitting positions. A structured algorithm for managing cerebral desaturation has been proposed to optimize outcomes by addressing multiple factors contributing to blood oxygen content and delivery.

SUMMARY

Despite its limitations, including spatial resolution and interindividual variability, NIRS is a useful tool for intraoperative cerebral monitoring. Further studies are needed to confirm its broader applicability in noncardiac surgeries, but current evidence supports its role in reducing postoperative complications especially in cardiac surgeries.

Acute Effects of Aminophylline Effects on Hemodynamic Parameters and Fluid Balance in Pediatric Cardiac Intensive Care Patients: Machine Learning Insights Using High Fidelity Data

Fluid overload is associated with increased morbidity and mortality after pediatric cardiac surgery. Management of fluid overload can be difficult and conventional tools may increase the risk of acute kidney injury. This study aimed to study the effects of aminophylline on fluid balance, urine output, blood urea nitrogen, and serum creatinine. Pediatric cardiac surgical patients who received aminophylline between September 2022 and December 2023 were identified. Data for various clinical parameters before and after an aminophylline dose were collected. Paired univariable analyses and a random forest classifier were conducted to help characterize the effects of aminophylline. A total of 169 aminophylline administrations in 72 unique patients were included in the final analyses. Fluid balance decreased by 115% in the 24 h after aminophylline administration compared to the 24 h preceding. Urine output peaked at 2 h after administration and increased 100% from baseline. Heart rate increased by 5% after administration and peaked between 2 and 4 h after. In pediatric patients after cardiac surgery, a 5 mg/kg dose of aminophylline is safe and is associated with a reduction in fluid balance and increase in urine output without significantly changing blood urea nitrogen or serum creatinine levels.

Regional Cerebral Oxygen Saturation and Estimated Oxygen Extraction Ratio as Predictive Markers of Major Adverse Events in Infants with Congenital Heart Disease

Regional cerebral oxygen saturation (ScO2) determined by near-infrared spectroscopy, monitoring both arterial and venous blood oxygenation of the brain, could reflect the balance between oxygen delivery and consumption. The aim of this study was to determine the predictabilities of ScO2 and estimated oxygen extraction ratio (eO2ER) with outcomes in infants with congenital heart disease (CHD). This study was a two-center, retrospective study of patients at 12 months of age or younger with CHD who underwent cardiac surgery. The primary outcome was a composite of one or more major adverse events (MAEs) after surgery: death from any cause, circulatory collapse that needed cardiopulmonary resuscitation, and requirement for extracorporeal membrane oxygenation. Based on the assumptions of arterial to venous blood ratio, eO2ER was calculated. A total of 647 cases were included in this study. MAEs occurred in 16 patients (2.5%). There were significant differences in post-bypass ScO2 [46.61 (40.90, 52.05) vs. 58.52 (51.52, 66.08), p < 0.001] and post-bypass eO2ER [0.66 (0.60, 0.78) vs. 0.52 (0.43, 0.61), p < 0.001] between patients with MAEs and patients without MAEs. Area under the receiver operating curve (AUROC) of post-bypass ScO2 was 0.818 (95% confidence interval: 0.747-0.889), AUROC of post-bypass eO2ER was 0.783 (0.697-0.870) and AUROC of post-bypass maximum serum lactate level was 0.635 (0.525-0.746). Both ScO2 and eO2ER, especially after weaning off bypass, are acceptable predictive markers for predicting MAEs after cardiac surgery in infants.(227 words).

Fluid Overload and AKI After the Norwood Operation: The Correlation and Characterization of Routine Clinical Markers

The purpose of this study was to determine the correlation of different methods of assessing fluid overload and determine which metrics are associated with development of acute kidney injury (AKI) in the period immediately following Norwood palliation. This was a retrospective single-center study of Norwood patients from January 2011 through January 2021. AKI was defined using the Kidney Disease Improving Global Outcomes (KDIGO). Patients were separated into two groups: those with AKI and those without. A logistic regression analysis was conducted with AKI at any point in the study period as the dependent variable and clinical and laboratory data as independent variables. Analysis was conducted as a stepwise regression. The coefficients from the logistic regression were then used to develop a cumulative AKI risk score. Spearman correlations were conducted to analyze the correlation of fluid markers. 116 patients were included, and 49 (42.4%) developed AKI. The duration of open chest, duration of mechanical ventilation, need for dialysis, need for extracorporeal membrane oxygenation, and inpatient mortality were associated with AKI (p ≤ 0.05). Stepwise logistic regression demonstrated the following significant independent associations AKI: age at Norwood in days (p < 0.01), blood urea nitrogen (p < 0.01), central venous pressure (p = 0.04), and renal oxygen extraction ratio (p < 0.01). The area under the receiver operating characteristic curve for the logistic regression was 0.74. The fluid markers had weak R-value. Urea, central venous pressure, and renal oxygen extraction ratio are associated with AKI after the Norwood operation. Common clinical metrics used to assess fluid overload are poorly correlated with each other for postoperative Norwood patients.

Is there an association of near-infrared spectroscopy with low cardiac output and adverse outcomes in single-ventricle patients after stage 1 palliation?

Objective

Our primary objective study was to evaluate the association between near-infrared spectroscopy (NIRS) and low cardiac output (LCO) in patients with single-ventricle physiology after stage 1 palliation.

Methods

In this retrospective study, infants ≤6 months of age with single-ventricle physiology who underwent stage 1 palliation were included. Cerebral and renal NIRS values at various time intervals after surgery were compared between patients with low and normal cardiac output. LCO within the first 48 after surgery was defined as per the pediatric cardiac critical care consortium database. NIRS values were also compared with other adverse outcomes such as cardiac arrest, need for extracorporeal membrane oxygenation and mortality. The receiver operative characteristic curve was generated to determine an optimal cut-off NIRS value for detecting LCO.

Results

Ninety-one patients with median (Interquartile range) age of 10 days (6-26) and weight of 3.3 kg (3-3.5) were included in the study. Cerebral NIRS at 1 h (41.2 vs. 49.5; P = 0.002), 6 h (44 vs. 52.2; P = 0.001), and 12 h (51.8 vs. 56; P = 0.025) was significantly lower in the grouP with LCO compared to no LCO. Cerebral NIRS at 6 h was independently associated with LCO (P = 0.018), and cerebral NIRS at 6 h ≤57% had 91% sensitivity and 72% specificity to detect LCO.

Conclusions

Cerebral NIRS ≤57% at 6 h after surgery detected LCO after stage 1 palliation in single-ventricle patients. Cerebral or renal NIRS was not associated with adverse outcomes and therefore, may not be useful in predicting adverse outcomes in this population.

Postoperative Cerebral Oxygen Saturation in Children After Congenital Cardiac Surgery and Long-Term Total Intelligence Quotient: A Prospective Observational Study

OBJECTIVES

During the early postoperative period, children with congenital heart disease can suffer from inadequate cerebral perfusion, with possible long-term neurocognitive consequences. Cerebral tissue oxygen saturation can be monitored noninvasively with near-infrared spectroscopy. In this prospective study, we hypothesized that reduced cerebral tissue oxygen saturation and increased intensity and duration of desaturation (defined as cerebral tissue oxygen saturation < 65%) during the early postoperative period, independently increase the probability of reduced total intelligence quotient, 2 years after admission to a PICU.

DESIGN

Single-center, prospective study, performed between 2012 and 2015.

SETTING

The PICU of the University Hospitals Leuven, Belgium.

PATIENTS

The study included pediatric patients after surgery for congenital heart disease admitted to the PICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Postoperative cerebral perfusion was characterized with the mean cerebral tissue oxygen saturation and dose of desaturation of the first 12 and 24 hours of cerebral tissue oxygen saturation monitoring. The independent association of postoperative mean cerebral tissue oxygen saturation and dose of desaturation with total intelligence quotient at 2-year follow-up was evaluated with a Bayesian linear regression model adjusted for known confounders. According to a noninformative prior, reduced mean cerebral tissue oxygen saturation during the first 12 hours of monitoring results in a loss of intelligence quotient points at 2 years, with a 90% probability (posterior β estimates [80% credible interval], 0.23 [0.04-0.41]). Similarly, increased dose of cerebral tissue oxygen saturation desaturation would result in a loss of intelligence quotient points at 2 years with a 90% probability (posterior β estimates [80% credible interval], -0.009 [-0.016 to -0.001]).

CONCLUSIONS

Increased dose of cerebral tissue oxygen saturation desaturation and reduced mean cerebral tissue oxygen saturation during the early postoperative period independently increase the probability of having a lower total intelligence quotient, 2 years after PICU admission.

Cerebral Tissue Regional Oxygen Saturation as a Valuable Monitoring Parameter in Pediatric Patients Undergoing Extracorporeal Membrane Oxygenation

Objective: Brain function monitoring technology for extracorporeal membrane oxygenation (ECMO) support has been developing quite slowly. Our objective was to explore the data distribution, variation trend, and variability of cerebral tissue regional oxygen saturation (CrSO₂) in pediatric patients undergoing ECMO. Methods: Eight patients who received venoarterial ECMO (V-A ECMO) were included in our study. All of them accepted continuous CrSO₂ monitoring by near-infrared spectroscopy (NIRS) within 12 h of ECMO initiation until ECMO wean. Differences in the CrSO₂ distribution characteristic, the variation trend of daily CrSO₂, and the variability of CrSO₂ for the first 5 days following ECMO initiation were compared between survivors and non-survivors according to pediatric intensive care unit (PICU) mortality. Results: The percentage of time of CrSO₂ <60% against the whole monitoring time was significantly lower in survivors in both hemispheres {right: 4.34% [interquartile range (IQR) = 0.39-8.55%] vs. 47.45% [IQR = 36.03-64.52%], p = 0.036; left: 0.40% [IQR = 0.01-1.15%] vs. 30.9% [IQR = 26.92-49.62%], p = 0.036}. Survivors had significantly higher CrSO₂ on the first 4 days. Root mean of successive squared differences (RMSSD), the variability variable of CrSO₂, was significantly lower in survivors (right: 3.29 ± 0.79 vs. 6.16 ± 0.67, p = 0.002; left: 3.56 ± 1.20 vs. 6.04 ± 1.44, p = 0.039). Conclusion: Lower CrSO₂, CrSO₂ <60% over a longer period of time, and higher fluctuation of CrSO₂ are likely associated with PICU mortality in pediatric patients undergoing V-A ECMO. Clinical Trial Registry: URL: http://www.chictr.org.cn/showproj.aspx?proj=46639, trial registry number: ChiCTR1900028021.