Daily Anesthesiology Research Analysis
Analyzed 93 papers and selected 3 impactful papers.
Summary
Analyzed 93 papers and selected 3 impactful articles.
Selected Articles
1. A Novel Algorithm for Continuous Real-Time Cerebral Autoregulation Assessment Based on Mean Arterial Pressure and Cerebral Oxygen Saturation.
A real-time cerebral autoregulation index (CAI) derived from MAP and NIRS cerebral oxygenation accurately discriminated intact versus impaired autoregulation in 71 surgical patients (AUC 0.92) and 10 piglets (AUC 0.99). This low-latency algorithm could enable individualized, autoregulation-guided blood pressure management during surgery.
Impact: Provides a validated, implementable metric for intraoperative cerebral autoregulation using signals already available to anesthesiologists, addressing heterogeneity in LLA/ULA and complications from out-of-range MAP.
Clinical Implications: Supports personalized BP targets based on patient-specific autoregulation status using MAP + NIRS, potentially reducing cerebral hypoperfusion/hyperperfusion complications without invasive monitoring.
Key Findings
- CAI using MAP and processed NIRS Sto2 achieved AUC 0.92 (sensitivity 0.82, specificity 0.94) to detect impaired autoregulation in 71 surgical patients.
- In a piglet hypotension model (n=10), CAI achieved AUC 0.99 with high sensitivity and specificity.
- Ground truth was established from individualized CBF/CBFV versus MAP curves identifying LLA/ULA limits.
Methodological Strengths
- Multicenter prospective human dataset plus concordant animal validation.
- Objective ground truth via individualized CBF/CBFV–MAP curves and ROC-based performance assessment.
Limitations
- Autoregulation labels derived retrospectively from CBF/CBFV–MAP plots; not interventional.
- NIRS Sto2 susceptibility to extracerebral signal and probe placement; generalizability of CAI threshold needs testing.
Future Directions: Prospective interventional trials testing CAI-guided BP management on neurologic outcomes; validation across surgical types, ages, NIRS platforms, and cerebral pathologies.
BACKGROUND: Continuous and real-time assessment of cerebral autoregulation can be of important clinical value to individualize blood pressure targets in perioperative settings. There is a high interindividual variability of the lower (LLA) and upper (ULA) limits of cerebral blood flow autoregulation, and exposure to blood pressure values outside of these limits has been associated with complications. We have developed a novel algorithm for continuous real-time assessment of cerebral autoregulation based on analysis of the dynamic interactions of mean arterial pressure (MAP) and near-infrared spectroscopy cerebral oxygen saturation (Sto2) measurements. The algorithm generates an index, the cerebral autoregulation index (CAI), which characterizes the effectiveness of cerebral autoregulation on a 0 to 100 scale. The aim of this study is to validate the algorithm using data from animals and surgical patients. METHODS: MAP, cerebral Sto2, and cerebral laser-Doppler blood flow (CBF) data were collected as part of an animal study on a piglet model of controlled hypotension. Additionally, simultaneous MAP, cerebral Sto2, and transcranial Doppler cerebral blood flow velocity (CBFV) data were collected on patients in a multicenter prospective observational study during surgery. Individual plots of CBF/CBFV versus MAP were constructed retrospectively for both the animal and human data, and ground truth labels of cerebral autoregulation status were obtained by identifying on these curves the LLA and ULA values. CAI values were generated by postprocessing MAP and cerebral Sto2 data through the algorithm. Receiver operating characteristic (ROC) analysis was then conducted to assess the capability of the algorithm to discriminate impaired autoregulation, where MAP is beyond the individual LLA/ULA limits, from intact autoregulation, where MAP is between LLA and ULA. RESULTS: Seventy-one patients were enrolled in the human study, and the ROC analysis showed an area under the ROC curve (AUC) (95% confidence interval) of 0.92 (0.89-0.94), with a sensitivity and specificity of 0.82 (0.76-0.87) and 0.94 (0.92-0.96), respectively, at the CAI threshold of 45. In addition, 10 female piglets underwent a controlled hypotension protocol where MAP was lowered below the LLA. The ROC analysis showed an AUC of 0.99 (0.98-1.00), with a sensitivity and specificity of 0.95 (0.90-0.99) and 0.96 (0.94-0.98), respectively. CONCLUSIONS: The study demonstrates that the CAI algorithm, using MAP and processed Sto2 signals, is accurate in discriminating states of intact autoregulation from states of impaired autoregulation. This algorithm may allow for personalized cerebral autoregulation-oriented blood pressure management during surgery.
2. Multicenter validation of a severity index model for predicting postoperative acute kidney injury.
Using nearly 192,000 development cases and three large external cohorts, SIM-AKI achieved good discrimination and calibration for both overall and critical postoperative AKI after non-cardiac surgery and performed favorably versus existing models. Decision curve analysis indicated meaningful clinical utility.
Impact: Delivers a simple, validated perioperative AKI risk tool with broad transportability, enabling earlier risk stratification and kidney-protective strategies across diverse centers.
Clinical Implications: Supports preoperative counseling, intraoperative vigilance (hemodynamics, transfusion), and targeted postoperative surveillance for patients at elevated AKI risk.
Key Findings
- SIM-AKI, built with routinely available variables, achieved C-statistics ~0.80 for overall AKI and ~0.84 for critical AKI in development.
- External validation across three independent cohorts (n=118,047; 86,092; 3,727) preserved good discrimination and calibration.
- Decision curve analysis demonstrated net clinical benefit compared with alternative strategies.
Methodological Strengths
- Very large development cohort with three external validations and robust variable stability assessment (bootstrap).
- Comprehensive performance evaluation (C-statistic, calibration, Brier score, and decision curve analysis).
Limitations
- Observational modeling; potential unmeasured confounding and practice variability across centers.
- Outcome time window and perioperative nephrotoxin exposures are not detailed in the abstract.
Future Directions: Prospective impact analyses testing SIM-AKI–guided care pathways on AKI incidence and patient-centered outcomes; integration into EHR with real-time alerts and external validation in broader settings.
BACKGROUND: Existing models for predicting postoperative acute kidney injury (AKI) after non-cardiac surgery are often complex and insufficiently validated for broad clinical use. We developed and externally validated a simple yet accurate model for predicting both overall and critical AKI that can be readily applied in routine practice. METHODS: The severity index model for AKI (SIM-AKI) was developed using data from 191,938 patients undergoing non-cardiac surgery at a tertiary hospital and externally validated using three independent datasets from other tertiary hospitals (n = 118,047; 86,092; 3727). Variables were selected using least absolute shrinkage and selection operator regression with 10-fold cross-validation, and predictor stability was assessed using backward elimination across 100 bootstrap resamples before multinomial logistic regression modeling. Model performance was evaluated using the C-statistic for discrimination, calibration plots, Brier scores, and decision curve analysis (DCA) for clinical utility. RESULTS: The SIM-AKI model incorporated age, sex, diabetes mellitus, American Society of Anesthesiologists classification, cancer surgery, emergency status, major abdominal surgery, anemia, hypoalbuminemia, estimated glomerular filtration rate, intraoperative transfusion, and operation time. For overall AKI, C-statistics were 0.801 (95% CI 0.796-0.806) in development and 0.754, 0.742, and 0.759 in validation cohorts. For critical AKI, C-statistics were 0.838 (95% CI 0.826-0.850) in development and 0.796, 0.805, and 0.767 in validation cohorts, demonstrating good calibration and clinical benefit in DCA. The SIM-AKI compared favorably with existing AKI prediction models in discrimination. CONCLUSION: SIM-AKI may serve as a reliable perioperative tool for predicting the risk of both overall and critical postoperative AKI in patients undergoing non-cardiac surgery.
3. Effect of maternal oxygen supplementation for parturients undergoing elective cesarean delivery by high‑flow nasal oxygen compared with room air on fetal acid-base status: a randomized clinical trial.
In an RCT of 112 elective cesarean deliveries under combined spinal-epidural anesthesia, high-flow nasal oxygen reduced umbilical artery lactate and increased pH, improved PaO2, and lowered PaCO2 versus room air, without differences in Apgar scores or oxidative stress markers.
Impact: Provides randomized evidence that HFNO favorably influences fetal acid-base status during low-risk elective cesarean under neuraxial anesthesia without short-term neonatal harm.
Clinical Implications: HFNO may be considered during elective cesarean to optimize fetal oxygenation/acid-base parameters, with monitoring and titration protocols; further study in higher-risk pregnancies is warranted.
Key Findings
- HFNO reduced umbilical artery lactate (1.60 vs 1.80 mmol/L; P=0.003) and increased pH (7.32 vs 7.31; P=0.004) versus room air.
- HFNO improved umbilical artery PaO2 and reduced PaCO2 without affecting Apgar scores.
- No increase in oxidative stress markers or short-term neonatal adverse outcomes was observed.
Methodological Strengths
- Randomized clinical trial with prespecified primary and secondary neonatal acid-base endpoints.
- Pragmatic perioperative protocol applied during routine neuraxial cesarean anesthesia.
Limitations
- Single-center with modest sample size; generalizability to high-risk pregnancies is unknown.
- Short-term neonatal outcomes only; no long-term neurodevelopmental follow-up.
Future Directions: Multicenter trials in high-risk obstetric populations and protocolized HFNO titration to maternal-fetal targets; assess maternal respiratory benefits and long-term neonatal outcomes.
BACKGROUND: High-flow nasal oxygen may offer benefits for maternal during cesarean delivery. However, its effects on fetal acid-base status remain understudied. The objective of this study was to determine if high-flow nasal oxygen improves fetal acid-base outcomes compared to room air in patients undergoing elective cesarean delivery under combined spinal-epidural anesthesia. METHODS: Patients undergoing elective cesarean delivery, gestation age of at least 37 weeks, age between 18 and 45 were eligible. Participants were randomly assigned 1:1 to receive either high-flow nasal oxygen at 40 L/min with 100% oxygen or room air at 2 L/min after epidural catheter placement until delivery. The primary outcome was umbilical artery lactate level. Secondary outcomes included umbilical artery pH, partial pressure of oxygen, partial pressure of carbon dioxide, Apgar scores, and oxidative stress markers. RESULTS: Between July to December 2023, 112 completed the study protocol. The high-flow nasal oxygen group had significantly lower umbilical artery lactate levels (1.60 [1.30-1.80] mmol/L vs. 1.80 [1.50-2.30] mmol/L; P = 0.003) and higher umbilical artery pH (7.32 [7.30-7.35] vs. 7.31 [7.28-7.33]; P = 0.004). The high-flow nasal oxygen group also showed improved umbilical artery partial pressure of oxygen (17.34 ± 3.73 vs. 15.67 ± 3.36 mmHg; P = 0.022) and lower partial pressure of carbon dioxide (50.10 [46.50-53.10] vs. 52.60 [48.35-56.65] mmHg; P = 0.003). No significant differences were observed in Apgar scores, oxidative stress markers, or other short-term neonatal outcomes between groups. CONCLUSIONS: High-flow nasal oxygen during elective cesarean delivery under combined spinal epidural anesthesia appears to improve fetal acid-base status and oxygenation without increasing oxidative stress. These findings emphasize that high-flow nasal oxygen does not adversely affect feta acid-base status, supporting its safety profile in low-risk pregnancies. This safety signal provides a rationale for further studies in higher-risk maternal populations. TRIAL REGISTRATION: This study is registered at ClinicalTrials.gov with the registration ID: NCT05921955.