Evaluation Of Fluid Responsiveness Research Articles

The role of point-of-care ultrasound to assess fluid responsiveness and fluid tolerance in the intensive care unit

Fluid accumulation is epidemiologically associated with adverse outcomes in various clinical contexts. Assessing fluid responsiveness identifies conditions where intravenous fluids can increase cardiac output, improve organ blood supply during hypoperfusion and prevent the administration of ineffective fluids with deleterious effects. Point-of-care ultrasound (POCUS) enables fluid administration guided by fluid responsiveness, serving as one of the few non-invasive technological aids widely accessible both within and outside the intensive care unit. In this review, we focus on how POCUS can complement the evaluation of fluid responsiveness and fluid tolerance. The topics include a review of POCUS techniques to estimate the change in cardiac output following preload modifying manoeuvers, evaluation of thoracic fluid tolerance through lung ultrasound, and evaluation of systemic fluid tolerance through venous Doppler and the venous excess ultrasound (VExUS) assessment.

Evaluation of fluid responsiveness using liver compression in dogs with experimentally induced hypovolemia.

To investigate whether liver compression (LC) could increase stroke volume (SV) by more than 15% in healthy, anesthetized dogs with hypovolemia and suggest LC as a novel method to evaluate fluid responsiveness. 6 healthy Beagles. This prospective, nonrandomized experimental study was conducted from November 2023 to February 2024. The dogs were anesthetized with isoflurane and mechanically ventilated under neuromuscular blockade. After instrumentation, the dogs underwent the following 4 experimental stages in a sequential, nonrandomized manner: stage 1, baseline; stage 2, 30% withdrawal of circulating blood volume; stage 3, 50% infusion of the collected blood; and stage 4, the remaining 50% infusion of the collected blood. At each stage, SV via pulmonary artery thermodilution and hemodynamic variables were measured before, during, and after the LC. In stage 2, LC significantly increased mean SV by 30%, from 6.9 to 9 mL/beat. Simultaneously, LC significantly increased mean arterial pressure by 11 mm Hg and mean central venous pressure by 2 mm Hg, while pulse pressure variation significantly decreased from 28% to 22%. In stages 1, 3, and 4, LC did not significantly change mean SV, mean arterial pressure, and pulse pressure variation; however, mean central venous pressure significantly increased during stage 3. This study demonstrates that LC at 22 mm Hg for 1 minute could increase SV more than 15% in anesthetized, hypovolemic dogs and LC could be used as a novel method to evaluate fluid responsiveness.

Prediction of fluid responsiveness in spontaneously breathing patients with hemodynamic stability: a prospective repeated-measures study

Evaluating fluid responsiveness with dynamic parameters is recommended for fluid management. However, in hemodynamically stable patients who are breathing spontaneously, accurately measuring stroke volume variation via echocardiography and passive leg raising is challenging due to subtle SV changes. This study aimed to identify normal SV changes in healthy volunteers and evaluate the precision of hemodynamic parameters in screening mild hypovolemia in patients. This prospective, repeated-measures, cross-sectional study screened 269 subjects via echocardiography. Initially, 45 healthy volunteers underwent a fluid challenge test, the outcomes of which served as criteria to screen 215 ICU patients. Among these patients, 53 underwent additional fluid challenge testing. Hemodynamic parameters, including medians of maximum velocity time integrals (VTImaxs), peak velocity of VTImax (PV), internal jugular vein diameters (IJVD), and area (IJVA) were repeatedly measured first at a 60° upper body elevation (UBE), second in a supine position, third at UBE, fourth in a supine position, and lastly in a supine position after fluid loading. The hemodynamic responses to the position changes were compared between 83 fluid non-responders and 15 fluid responders. Fluid responsiveness was defined as fluid-induced medians’ change of VTImaxs (fluid-induced median VTImax change) ≥ 10%. None of the healthy volunteers showed the mean value of repeatedly measured medians of VTImaxs ≥ 7%, following either UBE position (UBE-induced median VTImax change) or fluid loading (fluid-induced median VTImax change). UBE-induced median VTImax and PV changes were significantly correlated with fluid responsiveness (p < 0.001, AUC 0.959; p < 0.001, AUC 0.804). The significant correlations were demonstrated via multivariable analysis using binary logistic regression (p = 0.001, OR 90.1) and the correlation coefficient (R2 = 0.793) using linear regression analysis. UBE-induced median VTImax changes (≥ 11.8% and 7.98%) predicted fluid-induced median VTImax changes ≥ 10% and 7% (AUC 0.959 and 0.939). The collapsibility and variation of IJVD and IJVA showed no significant correlation. An increase in the mean value of medians of repeatedly measured VTImaxs transitioning from an UBE to a supine position, effectively screened mild hypovolemia and demonstrated a significant correlation with fluid responsiveness in spontaneously breathing patients maintaining hemodynamic stability.

Nurse-Driven Fluid Responsiveness Evaluation in Patients With Septic Shock: A Quality Improvement Initiative.

Fluid responsiveness should be assessed in patients with septic shock because only 50% of patients are fluid responsive. Dynamic measures of fluid responsiveness, like pulse pressure variation measured after a passive leg raise maneuver, are recommended to guide fluid administration in patients with sepsis after initial fluid resuscitation. The purpose of the project was to evaluate outcomes after implementing a nurse-driven fluid responsiveness evaluation using passive leg raise and pulse pressure variation measurement in patients with septic shock. The project included 30 adult patients with septic shock in a 24-bed medical-surgical intensive care unit at a community hospital. A new nursing process was initiated for bedside fluid responsiveness evaluation (pulse pressure variation measurement after passive leg raise). Staff members received in-person individual training sessions. Preintervention and 20-week postintervention patient outcomes data were collected to estimate the project's impact on incidence of fluid overload and acute kidney injury, duration of mechanical ventilation, and intensive care unit length of stay. Preintervention and postintervention staff satisfaction surveys assessed nurses' perception of the project's value. Before intervention, 24 of 37 patients (65%) met criteria of fluid overload. The project resulted in a 28% decrease in the incidence of fluid overload. Staff satisfaction surveys revealed a significant increase in nurses' feelings of empowerment to positively affect patient outcomes; all nurses agreed that the new process was efficient. The results indicate that the project had a positive impact on patient outcomes and nurse autonomy.

Comparing the Non-Invasive Cardiometry with Ultrasound Guided Inferior Vena Cava Collapsibility for Evaluation of Fluid Responsiveness in Septic Patient, Randomized Clinical Triall

Comparing the Non-Invasive Cardiometry with Ultrasound Guided Inferior Vena Cava Collapsibility for Evaluation of Fluid Responsiveness in Septic Patient, Randomized Clinical Triall

Rethinking Fluid Responsiveness during Septic Shock: Ameliorate Accuracy of Noninvasive Cardiac Output Measurements through Evaluation of Arterial Biomechanical Properties.

Beat-to-beat estimates of cardiac output from the direct measure of peripheral arterial blood pressure rely on the assumption that changes in the waveform morphology are related to changes in blood flow and vasomotor tone. However, in septic shock patients, profound changes in vascular tone occur that are not uniform across the entire arterial bed. In such cases, cardiac output estimates might be inaccurate, leading to unreliable evaluation of fluid responsiveness. Pulse wave velocity is the gold-standard method for assessing different arterial biomechanical properties. Such methods might be able to guide, personalize and optimize the management of septic patients.

Assessing Fluid Responsiveness Using Noninvasive Hemodynamic Monitoring in Pediatric Shock: A Review

AbstractNoninvasive hemodynamic monitoring devices have been introduced to better quantify fluid responsiveness in pediatric shock; however, current evidence for their use is inconsistent. This review aims to examine available noninvasive hemodynamic monitoring techniques for assessing fluid responsiveness in children with shock. A comprehensive literature search was conducted using PubMed and Google Scholar, examining published studies until December 31, 2022. Articles were identified using initial keywords: [noninvasive] AND [fluid responsiveness]. Inclusion criteria included age 0 to 18, use of noninvasive techniques, and the emergency department (ED) or pediatric intensive care unit (PICU) settings. Abstracts, review papers, articles investigating intraoperative monitoring, and non-English studies were excluded. The methodological index for nonrandomized studies (MINORS) score was used to assess impact of study bias and all study components were aligned with Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Our review yielded 1,353 articles, 17 of which met our inclusion criteria, consisting of 618 patients. All were prospective observational studies performed in the ED (n = 3) and PICU (n = 14). Etiologies of shock were disclosed in 13/17 papers and consisted of patients in septic shock (38%), cardiogenic shock (29%), and hypovolemic shock (23%). Noninvasive hemodynamic monitors included transthoracic echocardiography (TTE) (n = 10), ultrasonic cardiac output monitor (USCOM) (n = 1), inferior vena cava ultrasonography (n = 2), noninvasive cardiac output monitoring (NICOM)/electrical cardiometry (n = 5), and &gt;2 modalities (n = 1). To evaluate fluid responsiveness, most commonly examined parameters included stroke volume variation (n = 6), cardiac index (CI) (n = 6), aortic blood flow peak velocity (∆V peak) (n = 3), and change in stroke volume index (n = 3). CI increase &gt;10% predicted fluid responsiveness by TTE in all ages; however, when using NICOM, this increase was only predictive in children &gt;5 years old. Additionally, ∆SV of 10 to 13% using TTE and USCOM was deemed predictive, while no studies concluded distensibility index by transabdominal ultrasound to be significantly predictive. Few articles explore implications of noninvasive hemodynamic monitors in evaluating fluid responsiveness in pediatric shock, especially in the ED setting. Consensus about their utility remains unclear, reiterating the need for further investigations of efficacy, accuracy, and applicability of these techniques.

Evaluation of a Nurse-Driven Fluid Management Protocol to Improve Outcomes in Critically Ill Patients.

This article reports results of a nurse-driven fluid management protocol in a medical-surgical intensive care unit (ICU). Use of static measures such as central venous pressure monitoring, heart rate, blood pressure, and urine output is poor predictors of fluid responsiveness and can result in inappropriate fluid administration. Indiscriminate administration of fluid can result in prolonged mechanical ventilation time, increased vasopressor requirements, increased length of stay, and greater costs. Use of dynamic preload parameters such as stroke volume variation (SVV), pulse pressure variation, or changes in stroke volume with a passive leg raise has been shown to be more accurate predictors of fluid responsiveness. Improved patient outcomes including decreased length of hospital stay, reduction in kidney injury, decreased mechanical ventilation time and requirements, and reduced vasopressor requirements have been demonstrated by using dynamic preload parameters. ICU nurses were educated on cardiac output and dynamic preload parameters and a nurse-driven fluid replacement protocol was established. Knowledge scores, confidence scores, and patient outcomes were measured pre- and post-implementation. The results indicated that there was no change in knowledge scores between pre- and postimplementation groups (mean = 80%). There was a statistically significant increase in nurse confidence in using SVV (P = .003); however, this change is not clinically significant. There was no statistically significant difference in other confidence categories. The study indicated that ICU nurses were resistant to adoption of a nurse-driven fluid management protocol. While anesthesia clinicians are familiar with technologies to evaluate fluid responsiveness in the perioperative setting, the new technology posed challenges to ICU confidence. This project demonstrates that traditional methods of nursing education did not provide the support needed for implementation of a novel approach to fluid management, and that there is a need for further improvement in educational strategies.

Usefulness of the velocity–time integral of the left ventricular outflow tract variability index to predict fluid responsiveness in patients undergoing cardiac surgery

BackgroundHaemodynamic monitoring of patients after cardiac surgery using echocardiographic evaluation of fluid responsiveness is both challenging and increasingly popular. We evaluated fluid responsiveness in the first hours after surgery by determining the variability of the velocity–time integral of the left ventricular outflow tract (VTI-LVOT).MethodsWe conducted a cross-sectional study of 50 consecutive adult patients who underwent cardiac surgery and in whom it was possible to obtain VTI-LVOT measurements. We then determined the variability and correlations with our pulse pressure variation (PPV) measurements to predict fluid responsiveness.ResultsA strong positive correlation was seen between the VTI-LVOT variability index absolute values and PPV for predicting fluid responsiveness in the first hours after cardiac surgery. We also found that the VTI-LVOT variability index has high specificity and a high positive likelihood ratio compared with the gold standard using a cut-off point of ≥ 12%.ConclusionsThe VTI-LVOT variability index is a valuable tool for determining fluid responsiveness during the first 6 postoperative hours in patients undergoing cardiac surgery.

Contemporary perspectives on perioperative fluid therapy.

The primary purpose of perioperative IV fluid administration is to preserve tissue perfusion by maintaining or restoring the effective circulating intravascular volume. Fluids are drugs that produce beneficial or harmful effects dependent upon their composition, osmotic potential, kinetics, and dose. Appropriate dosing requires an understanding of body fluid compartments, fluid balance, and the administered fluids' behavior in the body. Anesthetic drugs and general anesthesia produce CNS, neuroendocrine, and macro-/microvascular hemodynamic effects. These effects modulate the response to IV fluid administration and promote interstitial fluid accumulation, third-space fluid loss, and fluid overload. This narrative review discusses current knowledge regarding anesthesia-associated physiologic and IV fluid kinetic changes that influence the efficacy of IV fluid administration during the intraoperative period. A rationale for intraoperative fluid dosing that addresses intraoperative hypotension, blood loss, and practices that promote fluid overload is provided. Intraoperative IV fluid administration should be individualized and monitored by dynamic goal-directed methods that evaluate fluid responsiveness.

Integrated ultrasonographic approach to evaluate fluid responsiveness in critically ill patients

In patients with acute circulatory failure, we tested the feasibility of the evaluation of the fluid-responsiveness (FR) by a combined approach with echocardiography and lung ultrasound. We enrolled 113 consecutive patients admitted to the Emergency Department High-Dependency Unit of Careggi University-Hospital from January 2015 to June 2020. We assessed: (1) inferior vena cava collapsibility index (IVCCI); (2) the variation of aortic flow (VTIAo) during the passive leg raising test (PLR); (3) the presence of interstitial syndrome by lung ultrasound. FR was defined as an increase in the VTIAo > 10% during PLR or IVCCI ≥ 40%. FR patients were treated with fluid and those non-FR with diuretics or vasopressors. The therapeutic strategy was reassessed after 12 h. The goal was to maintain the initial strategy. Among 56 FR patients, at lung ultrasound, 15 patients showed basal interstitial syndrome and 4 all-lung involvement. One fluid bolus was given to 51 patients. Among 57 non-FR patients, 26 patients showed interstitial syndrome at lung ultrasound (basal fields in 14, all lungs in 12). We administered diuretics to 21 patients and vasopressors to 4 subjects. We had to change the initial treatment plan in 9% non-FR patients and in 12% FR patients (p = NS). In the first 12 h after the evaluation, non-FR patients received significantly less fluids compared to those FR (1119 ± 410 vs 2010 ± 1254 ml, p < 0.001). The evaluation of the FR based on echocardiography and lung ultrasound was associated with the reduction in fluid administration for non-FR patients compared with those FR.

Variation in central venous oxygen saturation to evaluate fluid responsiveness: a systematic review and meta-analysis

BackgroundSince oxygen content and oxygen consumption typically remain unchanged within a short period, variation in central venous oxygen saturation (ΔScvO2) during fluid challenge can theoretically track the changes in cardiac output (CO). We conducted this meta-analysis to systematically assess the diagnostic performance of ΔScvO2 during a fluid challenge for fluid responsiveness in mechanically ventilated patients receiving volume expansion.MethodsElectronic databases were systematically searched to identify relevant studies published before October 24, 2022. As the cutoff value of ΔScvO2 was expected to vary across the included studies, we estimated the area under the hierarchical summary receiver operating characteristic curve (AUHSROC) as the primary measure of diagnostic accuracy. The optimal threshold of ΔScvO2 and the corresponding 95% confidential interval (CI) were also estimated.ResultsThis meta-analysis included 5 observational studies comprising 240 participants, of whom 133 (55%) were fluid responders. Overall, the ΔScvO2 during the fluid challenge exhibited excellent performance for defining fluid responsiveness in mechanically ventilated patients receiving volume expansion, with an AUHSROC of 0.86 (95% CI 0.83–0.89), a pooled sensitivity of 0.78 (95% CI 0.69–0.85), a pooled specificity of 0.84 (95% CI 0.72–0.91), and a pooled diagnostic odds ratio of 17.7 (95% CI 5.9–53.2). The distribution of the cutoff values was nearly conically symmetrical and concentered between 3 and 5%; the mean and median cutoff values were 4% (95% CI 3–5%) and 4% (95% CI not estimable), respectively.ConclusionsIn mechanically ventilated patients receiving volume expansion, the ΔScvO2 during the fluid challenge is a reliable indicator of fluid responsiveness.Clinical trial registration PROSPERO, https://www.crd.york.ac.uk/prospero/, registry number: CRD42022370192.

Evaluation of fluid responsiveness with dynamic superior vena cava collapsibility index in mechanically ventilated patients

BackgroundThis study aimed to evaluate the predictive accuracy of the superior vena cava collapsibility index measured by transesophageal echocardiography and compare the index with stroke volume variation measured by FloTrac™/Vigileo™ in mechanically ventilated patients.MethodsIn the prospective study, a total of 60 patients were enrolled for elective general surgery under mechanical ventilation, where all patients received 10 ml/kg of Ringer’s lactate. Five kinds of related data were recorded before and after the fluid challenge, including the superior vena cava collapsibility index (SVC-CI), the ratio of E/e’, cardiac index (CI), stroke volume variation (SVV), and central venous pressure (CVP). Based on the collected data after the fluid challenge, we classified the patients as responders (FR group) if their CI increased by at least 15% and the rest were non-responders (NR).ResultsTwenty-five of 52 (48%) of the patients were responders, and 27 were non-responders (52%). The SVC-CI was higher in the responders (41.90 ± 11.48 vs 28.92 ± 9.05%, P < 0.01). SVC-CI was significantly correlated with △CI FloTrac (r = 0.568, P < 0.01). The area under the ROC curve (AUROC) of SVC-CI was 0.838 (95% CI 0.728 ~ 0.947, P < 0.01) with the optimal cutoff value of 39.4% (sensitivity 64%, specificity 92.6%). And there was no significant difference in E/e’ between the two groups (P > 0.05). The best cutoff value for SVV was 12.5% (sensitivity 40%, specificity 89%) with the AUROC of 0.68 (95% CI 0.53 ~ 0.826, P < 0.05).ConclusionsThe SVC-CI and SVV can predict fluid responsiveness effectively in mechanically ventilated patients. And SVC-CI is superior in predicting fluid responsiveness compared with SVV. The E/e’ ratio and CVP cannot predict FR effectively.Trial registrationChinese clinical trial registry (ChiCTR2000034940).

Effects of tidal volume challenge on the reliability of plethysmography variability index in hepatobiliary and pancreatic surgeries: a prospective interventional study

BackgroundThe plethysmography variability index (PVI) is a non-invasive, real-time, and automated parameter for evaluating fluid responsiveness, but it does not reliably predict fluid responsiveness during low tidal volume (VT) ventilation. We hypothesized that in a ‘tidal volume challenge’ with a transient increase in tidal volume from 6 to 8 ml Kg− 1, the changes in PVI could predict fluid responsiveness reliably.MethodWe performed a prospective interventional study in adult patients undergoing hepatobiliary or pancreatic tumor resections and receiving controlled low VT ventilation. The values for PVI, perfusion index, stroke volume variation, and stroke volume index (SVI) were recorded at baseline VT of 6 ml Kg− 1, 1 min after the VT challenge (8 ml Kg− 1), 1 min after VT 6 ml Kg− 1 reduced back again, and then 5 min after crystalloid fluid bolus 6 ml kg− 1 (actual body weight) administered over 10 min. The fluid responders were identified by SVI rise ≥ 10% after the fluid bolus.ResultsThe area under the receiver operating characteristic curve for PVI value change (ΔPVI6–8) after increasing VT from 6 to 8 ml Kg− 1 was 0.86 (95% confidence interval, 0.76–0.96), P < 0.001, 95% sensitivity, 68% specificity, and with best cut-off value of absolute change (ΔPVI6–8) = 2.5%.ConclusionIn hepatobiliary and pancreatic surgeries, tidal volume challenge improves the reliability of PVI for predicting fluid responsiveness and changes in PVI values obtained after tidal volume challenge are comparable to the changes in SVI.

Volumetric evaluation of fluid responsiveness using a modified passive leg raise maneuver during experimental induction and correction of hypovolemia in anesthetized dogs

ObjectiveTo demonstrate if modified passive leg raise (PLRM) maneuver can be used for volumetric evaluation of fluid responsiveness (FR) by inducing cardiac output (CO) changes during experimental induction and correction of hypovolemia in healthy anesthetized dogs. The effects of PLRM on plethysmographic variability index (PVI) and pulse pressure variation (PPV) were also investigated. Study designProspective, crossover study. AnimalsA total of six healthy anesthetized Beagle dogs. MethodsDogs were anesthetized with propofol and isoflurane. They were mechanically ventilated under neuromuscular blockade, and normothermia was maintained. After instrumentation, all dogs were subjected to four stages: 1, baseline; 2, removal of 27 mL kg–1 circulating blood volume; 3, after blood re-transfusion; and 4, after 20 mL kg–1 hetastarch infusion over 20 minutes. A 10 minute stabilization period was allowed after induction of each stage and before data collection. At each stage, CO via pulmonary artery thermodilution, PVI, PPV and cardiopulmonary variables were measured before, during and after the PLRM maneuver. Stages were sequential, not randomized. Statistical analysis included repeated measures anova and Tukey’s post hoc test, considering p < 0.05 as significant. ResultsDuring stage 2, PLRM at a 30° angle significantly increased CO (mean ± standard deviation, 1.0 ± 0.1 to 1.3 ± 0.1 L minute–1; p < 0.001), with a simultaneous significant reduction in PVI (38 ± 4% to 21 ± 4%; p < 0.001) and PPV (27 ± 2% to 18 ± 2%; p < 0.001). The PLRM did not affect CO, PPV and PVI during stages 1, 3 and 4. Conclusions and clinical relevanceIn anesthetized dogs, PLRM at a 30° angle successfully detected FR during hypovolemia, and identified fluid nonresponsiveness during normovolemia and hypervolemia. Also, in hypovolemic dogs, significant decreases in PVI and PPV occurred in response to PLRM maneuver.

Esophageal Doppler-derived indices and arterial load variables provide useful hemodynamic information during assessment of fluid responsiveness in anesthetized dogs undergoing acute changes in blood volume.

To investigate the relationship between invasively measured stroke volume (SV) and (1) esophageal Doppler-derived indices such as stroke distance (StrokeD), flow time corrected (FTc), stroke distance variation (SDV), and peak velocity variation (PVV); and (2) arterial load (AL) variables during evaluation of fluid responsiveness (FR) in anesthetized dogs undergoing sudden hemodynamic shifts in blood volume. 6 healthy male dogs. Dogs were anesthetized with isoflurane, ventilated mechanically, and instrumented to undergo sequential, nonrandomized experimental stages. The dogs transitioned from normovolemia (NORMO-BL) to hypovolemia (30% blood loss; HYPO-30), followed by autologous blood transfusion, and then to hypervolemia (colloid bolus). During each stage, SV was quantified using pulmonary artery thermodilution and its relationship with StrokeD, FTc, SDV, and PVV; and AL variables such as effective arterial elastance (Ea), dynamic arterial elastance (Eadyn), and total arterial compliance (Ca) were established. As SV decreased significantly during HYPO-30 compared to NORMO-BL, there was a significant (P < .001) decrease in StrokeD, FTc, and Ca, with simultaneous increases in SDV, PVV, Ea, and Eadyn. Upon restoration of blood volume, these values stabilized closer to NORMO-BL. A significant (P < .001) correlation was observed between SV and StrokeD, FTc, Ea, Eadyn, and Ca. Minimally invasive StrokeD, FTc, SDV, and PVV act as SV surrogates and help assess FR during different blood volume stages in healthy dogs. During hypovolemia-induced hypotension, Ea, Eadyn, and Ca may be able to guide therapeutic decisions favoring improvement in blood pressure and SV.

Dynamic parameters for fluid responsiveness in mechanically ventilated children: A systematic review.

Fluid administration is the initial step of treatment of unstable pediatric patients. Evaluation of fluid responsiveness is crucial in mechanically ventilated children to avoid fluid overload, which increases mortality. We aim to review and compare the diagnostic performance of dynamically hemodynamic parameters for predicting fluid responsiveness in mechanically ventilated children. A systematic review was performed using four electronic databases, including PubMed, EMBASE, Scopus, and Central, for published articles from 1 January 2010 to 31 December 2020. Studies were included if they described diagnostic performance of dynamic parameters after fluid challenge was performed in mechanically ventilated children. Pediatric intensive and cardiac intensive care unit, and operative room. Children aged 1 month to 18 years old who were under mechanical ventilation and required an intravenous fluid challenge. Twenty-seven studies were included in the systematic review, which included 1,005 participants and 1,138 fluid challenges. Respiratory variation in aortic peak velocity was reliable among dynamic parameters for predicting fluid responsiveness in mechanically ventilated children. All studies of respiratory variation in aortic peak velocity showed that the area under the receiver operating characteristic curve ranged from 0.71 to 1.00, and the cutoff value for determining fluid responsiveness ranged from 7% to 20%. Dynamic parameters based on arterial blood pressure (pulse pressure variation and stroke volume variation) were also used in children undergoing congenital heart surgery. The plethysmography variability index was used in children undergoing neurological and general surgery, including the pediatric intensive care patients. The respiratory variation in aortic peak velocity exhibited a promising diagnostic performance across all populations in predicting fluid responsiveness in mechanically ventilated children. High sensitivity is advantageous in non-cardiac surgical patients and the pediatric intensive care unit because early fluid resuscitation improves survival in these patients. Furthermore, high specificity is beneficial in congenital heart surgery because fluid overload is particularly detrimental in this group of patients. https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=206400.

Changes in carotid corrected flow time in guiding fluid resuscitation in septic patients

Introduction Accurate estimation of intravascular volume status is important in the resuscitation of patients in ICUs. Although intensive fluid therapy in patients with life-threatening volume depletion can prevent death and end-organ damage, volume overload is known to result in increased mortality, morbidity, and duration of hospital stay. Ultrasonography has become a common diagnostic choice in assessment of fluid status in septic patients. This method is noninvasive, easy to learn, and provides real-time assessment at the patient’s bedside. Various ultrasound modalities have been developed to provide accurate and minimally invasive assessment of volume status. In this regard, one of the most promising methods is the evaluation of the blood flow velocity waveform in the descending thoracic aorta via a nonimaging Doppler probe. This modality is based on calculating the systolic flow time with cycle time correction [corrected flow time (FTc)]. FTc is known to be directly associated with volume status. FTc measurement in carotid artery is a completely noninvasive and much more feasible approach. Aim To compare the use of ultrasonography in the measurement of the changes in carotid FTc with echocardiography in the assessment of changes in heart dynamics to assess changes in volume status before and after passive leg raising (PLR) in septic patients. Patients and methods A total of 40 septic patients, including 18 (45.5%) patients as fluid responders and 22 (54.5%) patients as nonfluid responders, were included. Increased FTc by 7 ms, as well as 10% increase in stroke volume was considered to be fluid responsive. Results Our study results showed that 45.5% (n=18) of study population were fluid responders. The PLR test could assess fluid responsiveness with a specificity of 100% and sensitivity of 95% at a cutoff of 10.6% change in CO to predict fluid responsiveness. The study showed a statistically significant moderate positive correlation between CCA FTc and the percent of change in CO measured by echocardiography. An agreement analysis was formed. We concluded that there was a strong relation between change in carotid corrected blood flow and change in COP before and after PLR, with P value less than 0.001. Therefore, we can use this parameter to predict fluid responsiveness after PLR. Conclusions Carotid artery blood flow is a promising noninvasive and easy-to-perform tool for the evaluation of fluid responsiveness in critically ill septic patients. The PLR maneuver has demonstrated excellent performance for predicting fluid responsiveness. It is simple to perform but requires a reliable system of carotid corrected blood flow (COP) monitoring able to quantify the short-term changes.

Agreement between subcostal and transhepatic longitudinal imaging of the inferior vena cava for the evaluation of fluid responsiveness: A systematic review.

Assessment of fluid-responsiveness is a key aspect of daily management in critically ill patients. Non-invasive evaluation of the variation of inferior vena cava (IVC) diameter during ventilation may provide useful information. However, a standard sagittal IVC visualization from the subcostal (SC) region is not always feasible. An alternative method to visualize the IVC is a coronal trans-hepatic (TH) approach. We performed a systematic search to explore the interchangeability of IVC evaluation with SC and TH views. We searched Medline and EMBASE to identify prospective studies. We did not consider the relationship between axial and sagittal visualization of the IVC. We included seven studies reporting data on IVC evaluation with both SC and TH IVC views. Four studies were conducted on spontaneously breathing patients/volunteers, two on fully mechanically ventilated patients, and one in a mixed population, with large heterogeneity regarding the analyses reported. Limits of agreement between SC and TH were large. Concordance of the IVC collapsibility/distensibility indices are not interchangeable between SC and TH view. Correlation between diameters measured with SC and TH approach and intra/inter-observer correlation produced variable results. An overview of the included studies suggests that longitudinal TH and SC assessment of IVC size and respiratory variation are not interchangeable. New studies with accurate data reporting and appropriate statistical analysis are needed to define proper cut-offs for fluid responsiveness when using TH approach for IVC visualization.

Perioperative fluid management in children: an updated review

Background: Perioperative fluid management in children has been a major topic for debate. Objectives: Our aim is to review the current evidence on perioperative fluid management in children including: type of fluid, administration rates, preoperative fluid intake and monitoring techniques. Design: Narrative review. Method: Following the PRISMA-S guidelines we performed a search (2010-March 2022) in databases Medline (through PubMed) and Cochrane Library. 4297 citations were found and screened by two independent researchers. After screening, 64 articles were withheld for our review. Results: The perioperative administration of isotonic fluids is safer than hypotonic solutions, concerning the development of hyponatremia. A balanced isotonic solution with 1-2,5% glucose should be used as perioperative maintenance IV fluid in children (1 month to 18 years). Colloids can be used in children when inadequate effect in volume correction is achieved with crystalloids. The preferred synthetic colloid for children is a third generation HES in a balanced solution. To date, most clinicians use the “4-2-1 rule” for calculating fluid rate. This may not be the optimal fluid rate, as little research has been done. Preoperative fasting for clear fluids should be limited to 1 hour, children should even be encouraged to drink up until 1 hour before induction. Respiratory variation of aortic blood flow peak velocity (ΔVpeak) with echocardiography is currently the most reliable technique for evaluating fluid responsiveness in children.