Hypotension prediction index guided goal-directed therapy to reduce postoperative acute kidney injury during major abdominal surgery: study protocol for a multicenter randomized controlled clinical trial.

BACKGROUND: Acute kidney injury (AKI) is a significant postoperative complication associated with increased mortality and hospital costs. Hemodynamic strategies, such as goal-directed therapy, might reduce AKI risk. Predicting and proactively managing intraoperative hypotension may be helpful. This trial aims to investigate if a preemptive hemodynamic strategy guided by the hypotension prediction index (HPI) can decrease the incidence of moderate-to-severe AKI within 30 days following major elective abdominal surgery. METHODS: This is an open-label, controlled, multicenter, randomized clinical trial that involves daily patient follow-up until hospital discharge. Inclusion criteria are patients aged over 65 and/or categorized as ASA III or IV physical status, undergoing major elective abdominal surgery (general, urological, or gynecological procedures) via laparoscopic or open approach under general or combined anesthesia. INTERVENTION: In the intervention group, hemodynamic management will be based on the HPI and the advanced functional hemodynamic variables provided by the Hemosphere platform and the AcumenIQ® sensor (Edwards Lifesciences). The primary outcome is the incidence of moderate-to-severe AKI within 7 days post-surgery. Secondary outcomes include postoperative complications and 30-day mortality. DISCUSSION: This study explores the potential of HPI-guided hemodynamic management in reducing AKI after major elective abdominal surgery, with implications for postoperative outcomes and patient care. TRIAL REGISTRATION: ClinicalTrials.gov NCT05569265. Registered on October 6, 2022.

UNVEILING THE SIGNIFICANCE OF DYNAMIC ARTERIAL ELASTANCE: AN INSIGHTFUL APPROACH TO ASSESSING ARTERIAL LOAD IN AN ENDOTOXIN SHOCK MODEL.

ABSTRACT: Background: The aim of this study was to investigate the relationship between dynamic arterial elastance (EaDyn) and the pulsatile and steady components of arterial load in an endotoxin shock model using a two-element Windkessel model and to describe the behavior of EaDyn in this model. Methods : Ten female Yorkshire pigs were administered lipopolysaccharide intravenously to induce endotoxin shock, while three female pigs served as the control group. Measurements of EaDyn (ratio between pulse pressure variation and stroke volume variation), effective arterial elastance, arterial compliance (Cart), and systemic vascular resistance were taken every 30 min in the endotoxin group until shock was induced. In the control group, these variables were measured every 30 min for 3 h. Subsequently, a fluid load was administered to both groups, and measurements were repeated every 30 min. After 1 hour of shock induction, the endotoxin group was divided into two subgroups: one receiving norepinephrine (END-NE) and the other not receiving it (END-F). Results: EaDyn showed an association with Cart, while pulse pressure variation was connected to both pulsatile and steady components, and stroke volume variation was solely associated with steady components. In addition, EaDyn exhibited higher values in the END groups than in the control group when shock was achieved. Furthermore, after the administration of norepinephrine, EaDyn displayed higher values in END-F than in END-NE. Conclusions: The EaDyn variable helps identify changes in the pulsatile component of arterial load, providing valuable guidance for management strategies aimed at improving cardiac performance.

Mini fluid chAllenge aNd End-expiratory occlusion test to assess flUid responsiVEness in the opeRating room (MANEUVER study): A multicentre cohort study.

BACKGROUND: The fluid challenge response in surgical patients can be predicted by functional haemodynamic tests. Two tests, the mini-fluid challenge (mini-FC) and end-expiratory occlusion test (EEOT), have been assessed in a few small single-centre studies with conflicting results. In general, functional haemodynamic tests have not performed reliably in predicting fluid responsiveness in patients undergoing laparotomy. OBJECTIVE: This trial is designed to address and compare the reliability of the EEOT and the mini-FC in predicting fluid responsiveness during laparotomy. DESIGN: Prospective, multicentre study. SETTING: Three university hospitals in Italy. PATIENTS: A total of 103 adults patients scheduled for elective laparotomy with invasive arterial monitoring. INTERVENTIONS: The study protocol evaluated the changes in the stroke volume index (SVI) 20 s (EEOT20) and 30 s (EEOT30) after an expiratory hold and after a mini-FC of 100 ml over 1 min. Fluid responsiveness required an increase in SVI at least 10% following 4 ml kg-1 of Ringer's solution fluid challenge infused over 10 min. MAIN OUTCOME MEASUREMENTS: Haemodynamic data, including SVI, were obtained from pulse contour analysis. The area under the receiver operating characteristic curves of the tests were compared with assess fluid responsiveness. RESULTS: Fluid challenge administration induced an increase in SVI at least 10% in 51.5% of patients. The rate of fluid responsiveness was comparable among the three participant centres (P = 0.10). The area under the receiver operating characteristic curves (95% CI) of the changes in SVI after mini-FC was 0.95 (0.88 to 0.98), sensitivity 98.0% (89.5 to 99.6) and specificity 86.8% (75.1 to 93.4) for a cut-off value of 4% of increase in SVI. This was higher than the SVI changes after EEOT20, 0.67 (0.57 to 0.76) and after EEOT30, 0.73 (0.63 to 0.81). CONCLUSION: In patients undergoing laparotomy the mini-FC reliably predicted fluid responsiveness with high-sensitivity and specificity. The EEOT showed poor discriminative value and cannot be recommended for assessment of fluid responsiveness in this surgical setting. TRIAL REGISTRATION: NCT03808753.

Multivariable haemodynamic approach to predict the fluid challenge response: A multicentre cohort study.

BACKGROUND: Beat-to-beat stroke volume (SV) results from the interplay between left ventricular function and arterial load. Fluid challenge induces time-dependent responses in cardiac performance and peripheral vascular and capillary characteristics. OBJECTIVE: To assess whether analysis of the determinants of the haemodynamic response during fluid challenge can predict the final response at 10 and 30 min. DESIGN: Observational multicentric cohort study. SETTING: Three university ICUs. PATIENTS: 85 ICU patients with acute circulatory failure diagnosed within the first 48 h of admission. INTERVENTION(S): The fluid challenge consisted of 500 ml of Ringer's solution infused over 10 min. A SV index increase at least 10% indicated fluid responsiveness. MAIN OUTCOME MEASURES: The SV, pulse pressure variation (PPV), arterial elastance, the systolic-dicrotic pressure difference (SAP-Pdic) and cardiac cycle efficiency (CCE) were measured at baseline, 1, 2, 3, 4, 5, 10, 15 and 30 min after the start of the fluid challenge. All haemodynamic data were submitted to a univariable logistic regression model and a multivariable analysis was then performed using the significant variables given by univariable analysis. RESULTS: The multivariable model including baseline PPV, and the changes of arterial elastance at 1 min and of the CCE and SAP-Pdic at 5 min when compared with their baseline values, correctly classified 80.5% of responders and 90.7% of nonresponders at 10 min. For the response 30 min after starting the fluid challenge, the model, including the changes of PPV, CCE, SAP-Pdic at 5 min and of arterial elastance at 10 min compared with their baseline values, correctly identified 93.3% of responders and 91.4% of nonresponders. CONCLUSION: In a selection of mixed ICU patients, a statistical model based on a multivariable analysis of the changes of PPV, CCE, arterial elastance and SAP-Pdic, with respect to baseline values, reliably predicts both the early and the late response to a standardised fluid challenge. TRIAL REGISTRATION: ACTRN12617000076370.