Introduction: Dynamic predictors of fluid responsiveness have shown good performance in mechanically ventilated patients at tidal volumes (Vt) > 8 mL kg ⁻¹ . Nevertheless, most critically ill conditions demand lower Vt. We sought to evaluate the operative performance of several predictors of fluid responsiveness at Vt ≤ 8 mL kg ⁻¹ by using meta-regression and subgroup analyses. Methods: A sensitive search was conducted in the Embase and MEDLINE databases. We searched for studies prospectively assessing the operative performance of pulse pressure variation (PPV), stroke volume variation (SVV), end-expiratory occlusion test (EEOT), passive leg raising (PLR), inferior vena cava respiratory variability (Δ-IVC), mini-fluid challenge (m-FC), and tidal volume challenge (VtC), to predict fluid responsiveness in adult patients mechanically ventilated at Vt ≤ 8 ml kg ⁻¹ , without respiratory effort and arrhythmias, published between 1999 and 2020. Operative performance was assessed using hierarchical and bivariate analyses, while subgroup analysis was used to evaluate variations in their operative performance and sources of heterogeneity. A sensitivity analysis based on the methodological quality of the studies included (QUADAS-2) was also performed. Results: A total of 33 studies involving 1,352 patients were included for analysis. Areas under the curve (AUC) values for predictors of fluid responsiveness were: for PPV = 0.82, Δ-IVC = 0.86, SVV = 0.90, m-FC = 0.84, PLR = 0.84, EEOT = 0.92, and VtC = 0.92. According to subgroup analyses, variations in methods to measure cardiac output and in turn, to classify patients as responders or non-responders significantly influence the performance of PPV and SVV ( p < 0.05). Operative performance of PPV was also significantly affected by the compliance of the respiratory system ( p = 0.05), while type of patient ( p < 0.01) and thresholds used to determine responsiveness significantly affected the predictability of SVV ( p = 0.05). Similarly, volume of fluids infused to determine variation in cardiac output, significantly affected the performance of SVV ( p = 0.01) and PLR ( p < 0.01). Sensitivity analysis showed no variations in operative performance of PPV ( p = 0.39), SVV ( p = 0.23) and EEOT ( p = 0.15). Conclusion: Most predictors of fluid responsiveness reliably predict the response of cardiac output to volume expansion in adult patients mechanically ventilated at tidal volumes ≤ 8 ml kg ⁻¹ . Nevertheless, technical and clinical variables might clearly influence on their operative performance

Introduction: Prediction of fluid responsiveness in acutely ill patients might be influenced by a number of clinical and technical factors. We aim to identify variables potentially modifying the operative performance of fluid responsiveness predictors commonly used in clinical practice. Methods: A sensitive strategy was conducted in the Medline and Embase databases to search for prospective studies assessing the operative performance of pulse pressure variation, stroke volume variation, passive leg raising (PLR), end-expiratory occlusion test (EEOT), mini-fluid challenge, and tidal volume challenge to predict fluid responsiveness in critically ill and acutely ill surgical patients published between January 1999 and February 2023. Adjusted diagnostic odds ratios (DORs) were calculated by subgroup analyses (inverse variance method) and meta-regression (test of moderators). Variables potentially modifying the operative performance of such predictor tests were classified as technical and clinical. Results: A total of 149 studies were included in the analysis. The volume used during fluid loading, the method used to assess variations in macrovascular flow (cardiac output, stroke volume, aortic blood flow, volume‒time integral, etc.) in response to PLR/EEOT, and the apneic time selected during the EEOT were identified as technical variables modifying the operative performance of such fluid responsiveness predictor tests (p < 0.05 for all adjusted vs. unadjusted DORs). In addition, the operative performance of fluid responsiveness predictors was also influenced by clinical variables such as the positive end-expiratory pressure (in the case of EEOT) and the dose of norepinephrine used during the fluid responsiveness assessment for PLR and EEOT (for all adjusted vs. unadjusted DORs). Conclusion: Prediction of fluid responsiveness in critically and acutely ill patients is strongly influenced by a number of technical and clinical aspects. Such factors should be considered for individual intervention decisions.

Management with intravenous fluids can improve cardiac output in some surgical patients. Management with static preload indicators, such as central venous pressure and pulmonary artery occlusion pressure, has not demonstrated a suitable relationship with changes in the cardiac output induced by intravenous fluid therapy. Dynamic indicators, such as the variability of arterial pulse pressure or stroke volume variation, have demonstrated a suitable relationship. Since improvement in cardiac output does not guarantee an adequate perfusion pressure, in patients with hypotension, it is also necessary to know whether arterial pressure will also increase with intravenous fluid therapy. In this regard, the functional assessment of arterial load by dynamic arterial elastance could help to determine which patients will improve not only their cardiac output but also their mean arterial pressure.

Introduction: Pulse pressure variation (PPV) has been shown to be useful to predict fluid responsiveness in patients ventilated at tidal volume (Vt) >8 mL kg⁻¹. Nevertheless, most conditions in critical care force to use lower Vt. Thus, we sought to evaluate the operative performance of PPV when a Vt ⩽8 mL kg⁻¹ is used during mechanical ventilation support. Methods: We searched PubMed and Embase databases for articles evaluating the operative performance of PPV as a predictor of fluid responsiveness in critical care and perioperative adult patients ventilated with tidal volume ⩽8 mL kg⁻¹ without respiratory effort and arrhythmias, between January 1990 and January 2019. We included cohort and cross-sectional studies. Two authors performed an Independently selection using predefined terms of search. The fitted data of sensitivity, specificity, and area under the curve (AUC) were assessed by bivariate and hierarchical analyses. Results: We retrieved 19 trials with a total of 777 patients and a total of 935 fluid challenges. The fitted sensitivity of PPV to predict fluid responsiveness during mechanical ventilation at Vt ⩽8 mL kg⁻¹ was 0.65 (95% confidence interval [CI]: 0.57-0.73), the specificity was 0.79 (95% CI: 0.73-0.84), and the AUC was 0.75. The diagnostic odds ratio was 5.5 (95% CI: 3.08-10.01, P < .001) by the random-effects model. Conclusions: Pulse pressure variation shows a fair operative performance as a predictor of fluid responsiveness in critical care and perioperative patients ventilated with a tidal volume ⩽8 mL kg⁻¹ without respiratory effort and arrhythmias.

Introduction: Amidst the routine utilization of protocolized sedation in ventilated ICU patients, existing management guidelines exhibit a lack of unanimous recommendations for its widespread adoption. This study endeavors to comprehensively assess the effectiveness and safety of protocolized sedation in critically ill ventilated patients. Objective: The primary objective of this study was to systematically review and conduct a meta-analysis of clinical trials comparing protocolized sedation with standard management in critically ill ventilated patients. Key outcomes under scrutiny include ICU and hospital mortality, ventilation days, duration of ICU stay, and incidents of self-extubation. The evaluation incorporates the Risk of Bias 2 (RoB2) tool to assess the quality of included studies. Data analysis utilizes a random-effects model for relative risk (RR) and mean differences. Subgroup analysis categorizes sedation protocols into algorithmic or daily interruption, addressing potential heterogeneity. Additionally, a GRADE evaluation is performed to ascertain the overall certainty of the evidence. Results: From an initial pool of 1504 records, 10 studies met the inclusion criteria. Protocolized sedation demonstrated a reduced RR for mortality (RR: 0.80, 95% CI 0.68–0.93, p < 0.01, I² = 0%) and a decrease in ventilation days (mean difference: − 1.12, 95% CI − 2.11 to − 0.14, p = 0.03, I² = 84%). Furthermore, there was a notable reduction in ICU stay (mean difference: − 2.24, 95% CI − 3.59 to − 0.89, p < 0.01, I² = 81%). However, incidents of self-extubation did not exhibit a significant difference (RR: 1.20, 95% CI 0.49–2.94, p = 0.69, I² = 35%). Subgroup analyses effectively eliminated heterogeneity (I² = 0%), and the GRADE evaluation yielded moderate results for mortality, ventilation days, and ICU duration. Conclusion: Protocolized sedation, whether implemented algorithmically or through daily interruption, emerges as a safe and effective approach when compared to standard management in ventilated ICU patients. The findings from this study contribute valuable insights to inform evidence-based practices in sedation management for this critical patient population.

Dynamic arterial elastance (Eadyn) has been investigated for its ability to predict hypotension during the weaning of vasopressors. Our study focused on assessing Eadyn’s performance in the context of critically ill adult patients admitted to the intensive care unit, regardless of diagnosis. Our study was conducted in accordance with the Preferred Reported Items for Systematic Reviews and Meta-Analysis checklist. The protocol was registered in PROSPERO (CRD42023421462) on May 26, 2023. We included prospective observational studies from the MEDLINE and Embase databases through May 2023. Five studies involving 183 patients were included in the quantitative analysis. We extracted data related to patient clinical characteristics, and information about Eadyn measurement methods, results, and norepinephrine dose. Most patients (76%) were diagnosed with septic shock, while the remaining patients required norepinephrine for other reasons. The average pressure responsiveness rate was 36.20%. The synthesized results yielded an area under the curve of 0.85, with a sensitivity of 0.87 (95% CI 0.74–0.93), specificity of 0.76 (95% CI 0.68–0.83), and diagnostic odds ratio of 19.07 (95% CI 8.47–42.92). Subgroup analyses indicated no variations in the Eadyn based on norepinephrine dosage, the Eadyn measurement device, or the Eadyn diagnostic cutoff to predict cessation of vasopressor support. Eadyn, evaluated through subgroup analyses, demonstrated good predictive ability for the discontinuation of vasopressor support in critically ill patients.