Ultrasonographic measurement of the respiratory variation in the inferior vena cava diameter is predictive of fluid responsiveness in critically ill patients: systematic review and meta-analysis

The role of point-of-care ultrasound to monitor response of fluid replacement therapy in pregnancy

Fluid management in obstetrical care is crucial because of the complex physiological conditions of pregnancy, which complicate clinical manifestations and fluid balance management. This expert review examined the use of point-of-care ultrasound to evaluate and monitor the response to fluid therapy in pregnant patients. Pregnancy induces substantial physiological changes, including increased cardiac output and glomerular filtration rate, decreased systemic vascular resistance, and decreased plasma oncotic pressure. Conditions, such as preeclampsia, further complicate fluid management because of decreased intravascular volume and increased capillary permeability. Traditional methods for assessing fluid volume status, such as physical examination and invasive monitoring, are often unreliable or inappropriate. Point-of-care ultrasound provides a noninvasive, rapid, and reliable means to assess fluid responsiveness, which is essential for managing fluid therapy in pregnant patients. This review details the various point-of-care ultrasound modalities used to measure dynamic changes in fluid status, focusing on the evaluation of the inferior vena cava, lung ultrasound, and left ventricular outflow tract. Inferior vena cava ultrasound in spontaneously breathing patients determines diameter variability, predicts fluid responsiveness, and is feasible even late in pregnancy. Lung ultrasound is crucial for detecting early signs of pulmonary edema before clinical symptoms arise and is more accurate than traditional radiography. The left ventricular outflow tract velocity time integral assesses stroke volume response to fluid challenges, providing a quantifiable measure of cardiac function, which is particularly beneficial in critical care settings where rapid and accurate fluid management is essential. This expert review synthesizes current evidence and practice guidelines, suggesting the integration of point-of-care ultrasound as a fundamental aspect of fluid management in obstetrics. It calls for ongoing research to enhance techniques and validate their use in broader clinical settings, aiming to improve outcomes for pregnant patients and their babies by preventing complications associated with both under- and overresuscitation.

Efficacy of the inferior vena cava collapsibility index in predicting anaesthesia-induced hypotension in elderly patients undergoing hip arthroplasty

The inferior vena cava collapsibility index (IVCCI) has been used to predict fluid responsiveness. This study aimed to evaluate the accuracy of the perioperative IVCCI to predict postinduction hypotension (PIH) under general anaesthesia (GA) combined with lumbar plexus sacral plexus block (LSPB) in elderly patients undergoing hip arthroplasty. A total of forty patients aged over 65 years were recruited for this prospective observational study. The diameters of the inferior vena cava (IVC), common iliac vein (CIV) and IVCCI were measured at baseline and 15 min post-LSPB. PIH was defined as a systolic blood pressure less than 90 mmHg or a ≥ 30% drop from baseline; patients were divided into hypotensive and nonhypotensive groups. The primary objective of this study was to evaluate the ability of the IVCCI to predict PIH via receiver operating characteristic (ROC) analysis. The secondary objective was to observe the change in CIV diameter. Eighteen patients (45%) developed PIH during GA. No statistically significant differences in baseline or post-LSPB IVCCI were detected between hypotensive and nonhypotensive patients (p > 0.05), whereas a significant expansion of the CIV (0.83 cm to 1.10 cm) was observed 15 min post-LSPB in all patients (p < 0.0001). According to the ROC curve analysis, the IVCCI cannot accurately predict severe PIH: the area under the ROC curve for the IVCCI was 0.54 (95% confidence interval: 0.35-0.72, P = 0.69). Thus, the IVCCI is not an effective predictor of PIH during GA combined with LSPB in elderly patients undergoing hip arthroplasty. Additionally, significant expansion of the CIV was observed 15 min after LSPB, indicating sympathetic blockade of the unilateral lower extremity.

Mistaken Identity: Misidentification of Other Vascular Structures as the Inferior Vena Cava and How to Avoid It

While point-of-care ultrasound (POCUS) of the inferior vena cava (IVC) is broadly perceived as having value in intravascular volume status assessment, this has not been borne out in large-scale meta-analyses containing heterogenous populations of acutely ill patients. While the limitations of IVC POCUS could be largely due to the complexity of the relationship between IVC appearance and volume status, another confounder not widely appreciated is the ease with which the aorta or right hepatic vein (RHV) can be mistaken for the IVC. While misidentification of the aorta as the IVC has been recognized elsewhere, misidentification of the RHV for the IVC has not and, in our experience, occurs frequently, even in the hands of experienced sonographers. We demonstrate how these errors occur and provide guidance on how to systematically avoid them.

Stroke volume variation induced by lung recruitment maneuver to predict fluid responsiveness in patients receiving mechanical ventilation: A systematic review and meta-analysis

STUDY OBJECTIVE

The aim of this study was to evaluate the accuracy of lung recruitment maneuver induced stroke volume variation (ΔSVLRM) in predicting fluid responsiveness in mechanically ventilated adult patients by systematic review and meta-analysis.

METHODS

A comprehensive electronic search of relevant literature was conducted in PubMed, Web of Science, Cochrane Library, Ovid Medline, Embase and Chinese databases (including China National Knowledge Infrastructure, Wanfang and VIP databases). Review Manager 5.4, Meta-DiSc 1.4 and STATA 16.0 were selected for data analysis, and QUADAS-2 tool was used for quality assessment. Data from selected studies were pooled to obtain sensitivity, specificity, diagnostic likelihood ratio (DLR) of positive and negative, diagnostic odds ratio (DOR), and summary receiver operating characteristic curve.

RESULTS

A total of 6 studies with 256 patients were enrolled through March 2024. The risk of bias and applicability concerns for each included study were low, and there was no significant publication bias. There was moderate to substantial heterogeneity for the non-threshold effect, but not for the threshold effect. The combined sensitivity and specificity were 0.84 (95% CI, 0.77-0.90) and 0.79 (95% CI, 0.70-0.86), respectively. The DOR and the area under the curve (AUC) were 22.15 (95%CI, 7.62-64.34) and 0.90 (95% CI, 0.87-0.92), respectively. The positive and negative predictive values of DLR were 4.53 (95% CI, 2.50-8.18) and 0.19 (95% CI, 0.11-0.35), respectively. Fagan's nomogram showed that with a pre-test probability of 52%, the post-test probability reached 83% and 17% for the positive and negative tests, respectively.

CONCLUSIONS

Based on the currently available evidence, ΔSVLRM has a good diagnostic value for predicting the fluid responsiveness in adult patients undergoing mechanical ventilation. Given the heterogeneity and limitations of the published data, further studies with large sample sizes and different clinical settings are needed to confirm the diagnostic value of ΔSVLRM in predicting fluid responsiveness. PROSPERO registration number: CRD42023490598.

Inferior vena cava ultrasound to predict hypotension after general anesthesia induction: a systematic review and meta-analysis of observational studies

PURPOSE

Hypotension after induction of general anesthesia is common and is associated with significant adverse events. Identification of patients at high risk can inform the use of preoperative mitigation strategies. We conducted a systematic review and meta-analysis to assess the diagnostic accuracy of the inferior vena cava collapsibility index (IVC-CI) and maximal diameter (dIVCmax) in predicting postinduction hypotension and to identify their predictive performance across different threshold ranges.

METHODS

We searched MEDLINE, PubMed®, and Embase from inception to March 2023 for prospective observational studies exploring the performance of IVC-CI and dIVCmax in predicting postinduction hypotension in adults presenting for elective surgery under general anesthesia. We excluded studies reporting on IVC parameters predicting postinduction hypotension in the obstetric patient population or exclusively in patients with obesity. Trials screening and data extraction were conducted independently. We performed meta-analyses to identify the performance of IVC parameters in predicting postinduction hypotension, followed by subgroup analyses that sought the IVC-CI range with the highest hierarchical summary receiver-operating characteristic area under the curve (HSROC-AUC). We used a bivariate random effects model to calculate summary estimates. We evaluated study quality using Newcastle-Ottawa scores and certainty of evidence using the GRADE framework.

RESULTS

We included 14 studies involving 1,166 patients. Pooled sensitivity and specificity of the IVC-CI to predict postinduction hypotension was 0.68 (95% confidence interval [CI], 0.55 to 0.79; coverage probability, 0.91) and 0.78 (95% CI, 0.69 to 0.85; coverage probability, 0.9), respectively, with an HSROC-AUC of 0.80 (95% CI, 0.68 to 0.85, high quality of evidence). An IVC-CI threshold range of 40-45% had an HSROC-AUC of 0.86 (95% CI, 0.69 to 0.93, high quality of evidence).

CONCLUSIONS

Preoperative IVC-CI is a strong predictor of postinduction hypotension. We recommend that future studies use an IVC-CI threshold of 40-45% (low certainty of evidence). Future studies are needed to establish whether ultrasound-guided preoperative optimization improves outcomes in high-risk patients.

STUDY REGISTRATION

PROSPERO ( CRD42022316140 ); first submitted 10 March 2022.

[Treatment of Burn Shock - The First 24 hours and Beyond]

Acute phase and resuscitation after burn trauma are challenging even for specialised burn centres due to the individual onset and differences compared with other forms of shock. The guidelines of the German Society of Burn Medicine (DGV) cover the scientific basis of modern burn treatment. Nevertheless, uncertainty remains regarding the detailed practical handling. This expert consensus focuses on best practices for the treatment of patients with major burns in specialised burn centres and by clinical first responders. The short version of this expert consensus can be downloaded at: https://verbrennungsmedizin.de/files/dgv_files/pdf/positionspapier/Pos%20Therapie%20des%20Verbrennungsschock%20AK%20Intensivmedizin%202023.pdf.

THE ACCURACY OF INFERIOR VENA CAVA DISTENSIBILITY THROUGH THE TRANSHEPATIC APPROACH TO PREDICT FLUID RESPONSIVENESS IN PATIENTS WITH SEPTIC SHOCK AFTER EMERGENCY LAPAROTOMY

ABSTRACT

Background: We aimed to evaluate the ability of inferior vena cava (IVC) distensibility using the transhepatic approach to predict fluid responsiveness in mechanically ventilated patients with septic shock after emergency laparotomy. Methods: This prospective observational study included mechanically ventilated paralyzed adult who had septic shock after emergency laparotomy. The IVC dimensions were measured through the transhepatic and subxiphoid approaches. The fluid responsiveness was confirmed with >15% increase in cardiac output after 500 mL of fluid bolus. The outcomes were the ability of transhepatic (primary outcome) and subxiphoid approach to predict fluid responders using the area under the receiver operating characteristics curve analysis. The gray zone for the two approaches was calculated. Results: Data from 51 patients were analyzed, and the number of fluid responders was 30 of 52 (58%). The transhepatic approach was feasible in all patients, whereas the subxiphoid approach was only feasible in 42 patients. The area under the receiver operating characteristics curve (95% confidence interval) for the transhepatic IVC distensibility was 0.88 (0.76-0.95), and it was comparable with that of the subxiphoid approach (0.81 [0.66-0.92], P = 0.417). The gray zone for the transhepatic IVC distensibility was 17% to 35% including 24 of 51 patients (47%), whereas the gray zone for the subxiphoid IVC distensibility was 13% to 34% including 18 of 42 patients (43%). Conclusion: In conclusion, the transhepatic approach for evaluation of IVC distensibility showed good accuracy in predicting fluid responsiveness in patients with septic shock after emergency laparotomy. The transhepatic approach showed the same accuracy as the subxiphoid approach with the advantage of being feasible in larger number of patients.

The 2023 Core Content of advanced emergency medicine ultrasonography

In February 2023, the American Board of Emergency Medicine (ABEM) approved modifications to the Advanced Emergency Medicine Ultrasonography (AEMUS) Core Content, which defines the areas of knowledge considered essential for the practice of AEMUS. This manuscript serves as a revision of the AEMUS Core Content originally published in 2014. The revision of the Core Content for AEMUS training aims to establish standardized education and qualifications necessary for AEMUS fellowship program leadership, clinical application, administration, quality improvement, and research. The Core Content provides the organizational framework and serves as the basis for the development of content for the Focused Practice Examination (FPE) administered by ABEM. AEMUS fellowship directors may reference the Core Content when designing AEMUS fellowship curricula to help prepare graduates for the autonomous practice of AEMUS and the FPE. In this article, an updated revision of the previously published AEMUS Core Content is detailed, and the entire development of the Core Content is presented.

Monitoring Macro- and Microcirculation in the Critically Ill: A Narrative Review

Circulatory shock is a common and important diagnosis in the critical care environment. Hemodynamic monitoring is quintessential in the management of shock. The currently used hemodynamic monitoring devices not only measure cardiac output but also provide data related to the prediction of fluid responsiveness, extravascular lung water, and also pulmonary vascular permeability. Additionally, these devices are minimally invasive and associated with fewer complications. The area of hemodynamic monitoring is progressively evolving with a trend toward the use of minimally invasive devices in this area. The critical care physician should be well-versed with current hemodynamic monitoring limitations and stay updated with the upcoming advances in this field so that optimal therapy can be delivered to patients in circulatory shock.

Efficacy of inferior vena cava collapsibility index and caval aorta index in predicting the incidence of hypotension after spinal anaesthesia- A prospective, blinded, observational study

Background and Aim

Spinal anaesthesia-induced hypotension (SAIH) is a frequent side effect of spinal anaesthesia. SAIH is usually observed in patients with hypovolemia. Ultrasonography has evolved as a non-invasive tool for volume status assessment.

Methods

This prospective, blinded, observational study was conducted on 75 adult patients who required spinal anaesthesia after receiving ethical approval and registering the study. Ultrasonographic evaluation of the aorta and the inferior vena cava (IVC) was done preoperatively, and the IVC collapsibility index (IVCCI) and caval aorta index were calculated. The incidence of SAIH was recorded. The strength of the association between different parameters and SAIH was calculated. To find out the value of the optimal cut-off for the prediction of SAIH, receiver operating characteristic (ROC) analysis for various ultrasound parameters was done. The bidirectional stepwise selection was utilised for multivariate analysis to choose the single best predictor.

Results

SAIH was observed in 36 patients. Among demographic parameters, age, female gender, and height showed a medium correlation. Among ultrasonographic measurements, minimum IVC internal diameter (IVC_min) and IVCCI showed a strong association with SAIH. The best parameter regarding area under the ROC curve (AUC) and diagnostic accuracy was IVCCI (0.828 and 85%, respectively). On multivariate analysis, age (95% CI [1.01, 1.12], P = 0.024) and IVCCI (95% CI [1.05, 1.18], P < 0.001) were significant independent predictors. At a cut-off point of ≥43.5%, IVCCI accurately predicted SAIH (sensitivity 81% and specificity 90%).

Conclusion

Preoperative ultrasonographic assessment of IVC to evaluate its collapsibility index is a convenient, cost-effective, and reproducible tool for predicting SAIH.

Perioperative Fluid Management and Volume Assessment

Fluid therapy is an integral component of perioperative care and helps maintain or restore effective circulating blood volume. The principal goal of fluid management is to optimize cardiac preload, maximize stroke volume, and maintain adequate organ perfusion. Accurate assessment of volume status and volume responsiveness is necessary for appropriate and judicious utilization of fluid therapy. To accomplish this, static and dynamic indicators of fluid responsiveness have been widely studied. This review discusses the overarching goals of perioperative fluid management, reviews the physiology and parameters used to assess fluid responsiveness, and provides evidence-based recommendations on intraoperative fluid management.

Renal arterial resistive index, monocyte chemotactic protein 1 and neutrophil gelatinase-associated lipocalin, for predicting acute kidney injury in critically ill cancer patients

PURPOSE

We evaluated the renal arterial resistive index (RRI), urine monocyte chemotactic protein 1 (uMCP-1), and urine neutrophil gelatinase-associated lipocalin (uNGAL) to predict acute kidney injury (AKI) in critically ill cancer patients.

METHODS

In this prospective study, we included patients without AKI. We compared the area under the curve (AUC) of RRI, uMCP-1, and uNGAL to predict any stage of AKI and stage-3 AKI with the DeLong method, and we established cutoff points with the Youden index.

RESULTS

We included 64 patients, and 43 (67.2%) developed AKI. The AUC to predict AKI were: 0.714 (95% CI 0.587-0.820) for the RRI, 0.656 (95% CI 0.526-0.770) for uMCP-1, and 0.677 (95% CI 0.549-0.789) for uNGAL. The AUC to predict stage-3 AKI were: 0.740 (95% CI 0.615-0.842) for the RRI, 0.757 (95% CI 0.633-0.855) for uMCP-1, and 0.817 (95% CI 0.701-0.903) for uNGAL, without statistical differences among them. For stage 3 AKI prediction, the sensitivity and specificity were: 56.3% and 87.5% for a RRI > 0.705; 70% and 79.2% for an uMCP-1 > 2169 ng/mL; and 87.5% and 70.8% for a uNGAL > 200 ng/mL. The RRI was significantly correlated to age (r = 0.280), estimated glomerular filtration rate (r = - 0.259), mean arterial pressure (r = - 0.357), and serum lactate (r = 0.276).

CONCLUSION

The RRI, uMCP-1, and uNGAL have a similar ability to predict AKI. The RRI is more specific, while urine biomarkers are more sensitive to predict stage 3 AKI. The RRI correlates with hemodynamic variables. The novel uMCP-1 could be a useful biomarker that needs to be extensively studied.

Fluid responsiveness assessment using inferior vena cava collapsibility among spontaneously breathing patients: Systematic review and meta-analysis

OBJECTIVE

To synthesize the evidence about diagnostic accuracy of inferior vena cava collapsibility (IVCc) in prediction of fluid responsiveness among spontaneously breathing patients.

DESIGN

Systematic review of diagnostic accuracy studies.

SETTING

Intensive care units or emergency departments.

PATIENTS AND PARTICIPANTS

spontaneously breathing patients with indication for fluid bolus administration.

INTERVENTIONS

A search was conducted in MEDLINE and EMBASE. We included studies assessing IVCc accuracy for fluid responsiveness assessment with a standard method for cardiac output measure as index test.

MAIN VARIABLES OF INTEREST

General information (year, setting, cutoffs, standard method), sensitivity, specificity, and area under the receiving operator characteristics curve (AUROC). Risk of bias was assessed with QUADAS 2 tool. We obtained the pooled sensitivity, specificity and summary ROC curve, with estimated confidence intervals from a bivariate model. We also calculated positive and negative likelihood ratios and developed a Fagon nomogram.

RESULTS

Eight studies were included with 497 patients. Overall, the studies presented a high risk of bias. IVCc sensitivity was 63% (95% CI - 46-78%) and specificity 83% (95% CI - 76-87%). Despite moderate accuracy of IVCc (SROC 0.83, 95% CI - 0.80-0.86), post-test probability of being fluid responsive based on a 50% pre-test probability led to considerable misclassification.

CONCLUSIONS

IVCc had moderate accuracy for fluid responsiveness assessment in spontaneously breathing patients and should not be used in isolation for this purpose.

Pre-anesthesia ultrasound monitoring of subclavian vein diameter changes induced by modified passive leg raising can predict the occurrence of hypotension after general anesthesia: a prospective observational study

BACKGROUND

Perioperative hypotension increases postoperative complication rates and prolongs postoperative recovery time. Whether Passive Leg Raising test (PLR) and Subclavian Vein Diameter (DSCV) can effectively predict post-anesthesia hypotension remains to be tested. This study aimed to identify specific predictors of General Anesthesia (GA)induced hypotension by measuring DSCV in the supine versus PLR position.

METHODS

A total of 110 patients who underwent elective gynecological laparoscopic surgery under general anesthesia, were enrolled in this study. Before anesthesia, DSCV and theCollapsibility Index of DSCV(DSCV-CI) were measured by ultrasound, and the difference in maximal values of DSCV between supine and PLR positions was calculated, expressed as ΔDSCV. Hypotension was defined as Mean Blood Pressure (MBP) below 60mmhg or more than 30% below the baseline. Patients were divided into two groups according to the presence (Group H) or absence (Group N) of postanesthesia hypotension. The area under the receiver operating characteristic curve (ROC) and logistic regression analyses were used to evaluate the predictability of DSCV and other parameters for predicting preincision hypotension.

RESULTS

Three patients were excluded due to unclear ultrasound scans, resulting in a total of 107 patients studied. Twenty-seven (25.2%) patients experienced hypotension. Area under the ROC curve of ΔDSCV was 0.75 (P < 0.001) with 95% confidence interval (0.63-0.87), while DSCV and DSCV-CI were less than 0.7. The odds ratio (OR)of ΔDSCV was 1.18 (P < 0.001, 95%CI 1.09-1.27) for predicting the development of hypotension. ΔDSCV is predictive of hypotension following induction of general anesthesia.

CONCLUSIONS

ΔDSCV has predictive value for hypotension after general anesthesia.

TRIAL REGISTRATION

The trial was registered in the Chinese Clinical Trial Registry on 04/10/2021.

Ultrasonographically derived caudal vena cava parameters acquired in a standing position and lateral recumbency in healthy, lightly sedated cats: a pilot study

OBJECTIVES

The aim of this study was to determine the feasibility of ultrasonographically measuring the caudal vena cava (CVC) at the subxiphoid view of healthy, lightly sedated cats in a standing position and lateral recumbency.

METHODS

This was a prospective, observational, experimental single-centre study. Twenty healthy research-purposed cats were enrolled. Two trained operators scanned each cat in two positions - standing and lateral recumbency - in a randomised order. CVC diameter was measured at the narrowest diameter during inspiration and at the widest diameter during expiration, at two anatomical locations along the CVC - where the CVC crosses the diaphragm (base) and 2 mm caudal to the diaphragm. The CVC collapsibility index (CVC-CI) was calculated for each site. Normalcy was assessed with a Shapiro-Wilk test. A one-way ANOVA with post-hoc Tukey's test was used to compare inspiratory with expiratory values within and between groups. A paired t-test compared the CVC-CI between groups (P ⩽0.05 indicated statistical significance). Spearman's correlation and Bland-Altman analysis assessed inter-operator variability.

RESULTS

All ultrasonographic data passed normalcy and were reported as mean ± SD. When compared with each other, inspiratory and expiratory values were statistically different for position, location and operator (all P <0.0001). There was no statistically significant difference between lateral recumbency or standing position for inspiratory, expiratory and CVC-CI values. Inter-operator variability was substantial, with operator 2 consistently obtaining smaller measurements than operator 1. The mean CVC-CI in lateral recumbency at the base was 24% for operator 1 and 37% for operator 2. For the same site in standing position, CVC-CI was 27% and 41% for operators 1 and 2, respectively.

CONCLUSIONS AND RELEVANCE

This pilot study demonstrates that it is possible to ultrasonographically measure the CVC diameter in both lateral recumbency and a standing position in healthy, lightly sedated cats. However, measurements obtained are operator dependent with variability between individuals. Further studies are needed to determine if ultrasonographic CVC assessment will prove helpful in estimating intravascular volume status in cats.

Monitoring patients with acute dyspnea with serial point-of-care ultrasound of the inferior vena cava (IVC) and the lungs (LUS): a systematic review

PURPOSE

The primary aim was to investigate if treatment guided by serial ultrasound of the inferior vena cava-collapsibility index (IVC-CI) and B-lines on lung ultrasound (LUS) could reduce mortality, readmissions, and length of stay (LOS) in acutely dyspneic patients admitted to a hospital, compared to standard monitoring. The secondary aim was to determine how the changes of B-lines and IVC-CI are correlated to vitals and symptoms.

METHODS

A systematic search was conducted on PubMed, Embase, Cochrane, Google Scholar, Web of Science, Scopus, OpenGrey, ProQuest, and databases for ongoing trials. The risk of bias was assessed according to study design.

RESULTS

Of the 8258 studies identified, 50 were selected for full-text screening, and 24 studies were chosen for data extraction (19 pre-post-, two non-randomized controlled-, two randomized controlled-, and one retrospective cohort study), covering 2040 patients. Most studies were single-center and had small study populations with only heart failure patients. The risk of bias was high. No studies evaluated how the difference between two ultrasound measurements correlated with the primary outcomes. Seven studies reported that a decline in either B-lines or IVC size, or an increased IVC-CI reduced mortality, readmissions, and LOS when correlated to a single ultrasound measurement. All studies showed changes in the IVC-CI and B-lines, but these were not related to vitals or symptoms.

CONCLUSION

B-lines and IVC-CI are dynamic variables that change over time and with treatment. A single ultrasound measurement can influence prognostic outcomes, but it remains uncertain if repeated scans can have the same impact.

Response Guided Slow Infusion of Albumin, Vasoconstrictors and Furosemide Improves Ascites Mobilization and Survival in Acute on Chronic Liver Failure: A Proof-of-Concept Study

Background and Aims

Acute-on-chronic liver failure (ACLF) with increasing organ failure is associated with poor outcomes. Severely deranged systemic hemodynamics and decreased effective arterial blood volume contribute to tissue damage and organ failure. Response-guided therapy with albumin, vasoconstrictors, and furosemide may help overcome effective hypovolemia, improve diuresis and impact survival.

Methods

In the observation cohort, 230 patients with ACLF (CANONIC criteria) with ascites (≥Grade II) and ACLF ≥Grade I were enrolled. A total of 136 patients (GROUP I) received response-guided (urine sodium >80mmol/day) slow albumin-furosemide infusion ± terlipressin (SAFI ± T), while 94 patients (GROUP II) received standard medical therapy. Twenty-eight-day survival, ascites mobilization (nil or grade 1), and adverse events were noted. In another mechanistic cohort (n = 40), laboratory evidences for improvement in various pathophysiological alterations; gut permeability, endotoxemia, cytokine storm, neutrophil dysfunction, and hemodynamic alterations following SAFI ± T/Noradrenaline (NAdr) were evaluated.

Results

Age, gender, CLIF-C-ACLF, SOFA and MELD scores, ACLF grades and urine sodium were not different between the two groups in the observation cohort. Ascites was mobilized in 102/136 in GROUP I (SAFI ± T) and 23/94 in GROUP II (p < 0.05). Twenty-eight-day survival was significantly higher in GROUP I = 103/136 (75.7%) vs GROUP II = 50/94 (53.2%), (P = <0.001). All those who were unable to reach urine sodium >80 mmol/day died. Four patients in GROUP I developed scrotal gangrene. In the mechanistic cohort, 72% of patients survived with significant improvement in gut permeability, endotoxemia, serum cytokines, neutrophil dysfunction, and hemodynamic alterations.

Conclusion

Ascitic fluid mobilization by response-guided SAFI ± T/NAdr therapy improves survival by improving splanchnic and systemic hemodynamics, decreasing gut congestion, gut permeability, and endotoxemia, improving neutrophil functions, and reducing pro-inflammatory cytokines in circulation.

Correlation of Ultrasound-Based Hydration Assessment Measures with CVP and Clinical Hydration Status among Children Admitted to the PICU: A Prospective Observational Study

Purpose This article assesses the correlation of respiratory variation in inferior vena cava (IVC) with central venous pressure (CVP) in children. Secondary objective was to evaluate IVC variability with clinical hydration status.

Methods IVC variability was assessed at the subcostal (SC) and right lateral (RL) region, and collapsibility index (CI) (spontaneously breathing) and distensibility index (DI) (positive pressure) and IVC/aortic ratio were calculated. Partial correlations were calculated between CI/DI with CVP adjusting for body mass index and age. Sensitivity of CI and DI to predict clinical dehydration was calculated using receiver operating characteristic curves.

Results A total of 145 ultrasounds were performed on 72 patients (41% positive pressure). Only RL CI in spontaneously breathing patients strongly correlated with CVP (r = –0.65, p < 0.001). A moderate correlation was observed between CI and DI from SC and RL regions (r's = 0.38 and 0.47). Among spontaneously breathing patients, a significant difference was observed in the SC CI based on hydration status. For patients on positive pressure, IVC/aortic ratio had a significant difference. SC CI had the highest area under the curve (0.82) to detect dehydration with 80% sensitivity/87% specificity for a cutoff of 40%.

Conclusion SC CI is the most reliable measure to assess the hydration status of spontaneously breathing children, while the IVC/aortic ratio performs well for patients under positive pressure. RL CI has strong negative correlation with CVP in spontaneously breathing patients.

Comparison of superior and inferior vena cava diameter variation measured with transthoracic echocardiography to predict fluid responsiveness in mechanically ventilated patients after abdominal surgery

Background

The volume status of patients after major abdominal surgery constantly varies owing to postoperative diverse issues comprising fluid loss or capillary leakage secondary to systemic inflammatory reaction syndrome, et.al, the precise fluid responsiveness assessment is crucial for those patients. The purpose of this study is to validate the transthoracic ultrasonographic measurement of superior and inferior vena cava variation in predicting fluid responsiveness of mechanically ventilated patients after surgery.

Methods

A total of 70 patients undergoing the scheduled major abdominal surgeries in the anesthesia ICU ward were included. The superior vena cava (SVC) collapsibility index (SVCCI), the inferior vena cava distensibility index (dIVC), SVC variation over the cardiac cycle (SVCV), and cardiac output (CO) were measured by transthoracic ultrasonography were recorded before and after fluid challenge test of 5 ml/kg crystalloid within 15 min. The responders were defined as a 15% or more increment in CO.

Results

Thirty patients (42.9%) responded to fluid challenge, while the remnant forty patients (57.1%) did not. The areas under the ROC curve (AUC) of SVCCI, dIVC and SVCV were 0.885 (95% CI, 0.786–0.949; P < 0.0001) and 0.727 (95% CI, 0.608–0.827; P < 0.001) and 0.751 (95% CI, 0.633–0.847; P < 0.0001), respectively. AUC_dIVC and AUC_SVCV were significantly lower when compared with AUC_SVCCI (P < 0.05). The optimal cutoff values were 19% for SVCCI, 14% for dIVC, and 15% for SVCV. The gray zone for SVCCI was 20%-25% and included 15.7% of patients, while 7%-27% for dIVC including 62.9% of patients and 9%-21% for SVCV including 50% of patients.

Conclusion

Superior vena cava-related parameters measured by transthoracic ultrasound are reliable indices to predict fluid responsiveness. The accuracy of SVCCI in mechanically ventilated patients after abdominal surgery is better than that of dIVC and SVCV.

Trial registration

ChiCTR-INR-17013093. The initial registration date was 24/10/2017.

Correlation Between Ultrasound-Measured Diameter and Blood Flow Velocity of the Internal Jugular Veins with the Preoperative Blood Volume in Elderly Patients

The study aimed to explore the correlation of the diameter and blood flow velocity of the internal jugular vein with the preoperative blood volume in elderly patients and to providence for rapid evaluation of preoperative blood volume with ultrasound in elderly patients. Thirty patients over 65 years old were recruited in the study. Patient’s central venous pressure (CVP) was recorded before anesthesia. The maximum diameter (Dmax) and the minimum diameter (Dmin) of the left internal jugular vein were measured by M type ultrasound and the respiratory variation index (RVI), defined as (Dmax − Dmin) / Dmax × 100%, was calculated. The maximum blood flow velocity (BVmax) and the minimum blood flow velocity (BVmin) were measured by Doppler ultrasound, and the blood flow variation index (BVI), defined as (BVmax − BVmin) / BVmax × 100%, was calculated. Then, each of the patients was given with 5 ml/kg crystalloid solution, and the relevant data were measured again and compared to that before infusion. The correlation between each measurement index and CVP, and their efficiency in predicting CVP > 6 mmHg were statistically evaluated. No matter before or after infusion, Dmax, Dmin, BVmax, and BVmin were positively correlated with CVP (Correlation is significant at the 0.01 level (2-tailed)); and RVI was negatively correlated with CVP (Correlation is significant at the 0.01 level (2-tailed)); however, BVI is negatively correlated with the CVP with no statistically significant difference. Through the analysis of ROC curve, Dmax, Dmin, RVI, BVmax, and BVmin could be used to predict the CVP > 6 mmHg in these patients, and the best index was BVmax; BVI diagnosis was not effective. Ultrasonic measurements of internal jugular vein diameter, respiratory variability, and blood flow velocity were correlated with preoperative CVP in elderly patients, indicating that these indexes could potentially be used to evaluate the preoperative blood volume in elderly patients.

Preoperative assessment of inferior vena cava collapsibility index by ultrasound is not a reliable predictor of post-spinal anesthesia hypotension

BACKGROUND

Post-spinal anesthesia hypotension is of common occurrence, and it hampers tissue perfusion. Several preoperative factors determine patient susceptibility to hypotension. This study aimed to assess the effectiveness of the Inferior Vena Cava Collapsibility Index (IVCCI) for predicting intraoperative hypotension.

METHODS

One hundred twenty-nine adult patients who were scheduled for elective surgical procedures after administration of spinal (intrathecal) anesthesia were included in the study. Ultrasound evaluation of the Inferior Vena Cava (IVC) was done in the preoperative area, and the patients were shifted to the Operating Room (OR) for spinal anesthesia. An independent observer recorded the change in blood pressure after spinal anesthesia inside the OR.

RESULTS

Twenty-five patients developed hypotension (19.37%). Baseline systolic blood pressure and mean blood pressures were statistically higher in those patients who developed hypotension (p = 0.001). The logistic regression analysis for IVCCI and the incidence of hypotension showed r² of 0.025. Receiver Operating Characteristic (ROC) curve analysis demonstrated the Area Under the Curve (AUC) of 0.467 (95% Confidence Interval, 0.338 to 0.597; p = 0.615).

CONCLUSIONS

Preoperative evaluation of IVCCI is not a good predictor for the occurrence of hypotension after spinal anesthesia.

Hospital at home for acute medical illness: The 21st century acute medical unit for a changing population

Recent trends across Europe show a year-on-year increase in the number of patients with acute medical illnesses presenting to hospitals, yet there are no plans for a substantial expansion in acute hospital infrastructure or staffing to address demand. Strategies to meet increasing demand need to consider the fact that there is limited capacity in acute hospitals and focus on new care models in both hospital and community settings. Increasing the efficiency of acute hospital provision by reducing the length of stay entails supporting acute ambulatory care, where patients receive daily acute care interventions but do not stay overnight in the hospitals. This approach may entail daily transfer between home and an acute setting for ongoing treatment, which is unsuitable for some patients living with frailty. Acute hospital at home (HaH) is a care model which, thanks to advances in point of care diagnostic capability, can provide a credible model of acute medical assessment and treatment without the need for hospital transfer. Investment and training to support scaling up of HaH are key strategic aims for integrated healthcare systems.

Inferior Vena Cava Collapsibility Index Can Predict Hypotension and Guide Fluid Management After Spinal Anesthesia

Purpose

We hypothesized that inferior vena cava collapsibility index (IVCCI)-guided fluid management would reduce the incidence of postspinal anesthesia hypotension in patients undergoing non-cardiovascular, non-obstetric surgery.

Methods

A receiver operating characteristic (ROC) curve was used to determine the diagnostic value of IVCCI for predicting hypotension after induction of spinal anesthesia and calculate the cut-off value. Based on the cut-off variation value, the following prospective randomized controlled trial aimed to compare the incidence of postspinal anesthesia hypotension between the IVCCI-guided fluid administration group and the standard fluid administration group. Secondary outcomes included the rate of vasoactive drug administration, the amount of fluid administered, and the incidence of nausea and vomiting.

Results

ROC curve analysis revealed that IVCCI had a sensitivity of 83.9%, a specificity of 76.3%, and a positive predictive value of 84% for predicting postspinal anesthesia hypotension at a cut-off point of >42%. The area under the curve (AUC) was 0.834 (95% confidence interval: 0.740–0.904). According to the cut-off variation value of 42%, the IVCCI-guided group exhibited a lower incidence of hypotension than the standard group [9 (15.3%) vs. 20 (31.7%), P = 0.032]. Total fluid administered was lower in the IVCCI-guided group than in the standard group [330 (0–560) mL vs. 345 (285–670) mL, P = 0.030].

Conclusions

Prespinal ultrasound scanning of the IVCCI provides a reliable predictor of hypotension following spinal anesthesia at a cut-off point of >42%. IVCCI-guided fluid management before spinal anesthesia can reduce the incidence of hypotension following spinal anesthesia.

Approach to echocardiography in ARDS patients in the prone position: A systematic review

Echocardiography is commonly utilized in patients with acute respiratory distress syndrome (ARDS) for assessment of cardiac function, volume status, and the potential development of acute cor pulmonale. In severe ARDS, prone positioning is frequently used, which imposes technical challenges during transthoracic echocardiography (TTE) image acquisition. Moreover, prone positioning can affect cardiopulmonary function in ways that are reflected on the echocardiographic findings in this position. Historically, a transesophageal approach was recommended when a patient is prone, with few studies reporting utility of TTE in this setting. However, recent publications have begun to address this knowledge gap. This review explores recent literature addressing the use of TTE in prone patients with ARDS, with a special focus on the cardiopulmonary effects of proning and potential solutions to the technical difficulties that arise in this position.

Predictive Value of the Respiratory Variation in Inferior Vena Cava Diameter for Ventilated Children With Septic Shock

OBJECTIVES

This study aimed to investigate the predictive utility of respiratory variations of inferior vena cava diameters on fluid responsiveness in children with septic shock.

DESIGN

A prospective observational single-center study.

SETTING

A pediatric intensive care unit in a tertiary hospital in China.

PARTICIPANTS

Patients with sepsis shock who require invasive mechanical ventilation were recruited between 1 December 2017 and 1 November 2021.

INTERVENTIONS AND MEASUREMENTS

Volume expansion (VE) was induced by a 30-min infusion of 20 ml/kg of normal saline. Hemodynamics indexes were obtained through bedside transthoracic echocardiography (TTE) measurement and calculation.

RESULTS

A total of 86 patients were enrolled in this study, among them, 45 patients (52.3%) were considered to be non-responders (NR), with an increase in stroke volume variation (SVV) <15% after VE. Multivariate logistic analysis showed that ΔIVC (adjusted OR = 1.615, 95% CI 1.092-2.215, p = 0.012) was the significant predictor associated with the fluid responsiveness. The area under the ROC of ΔIVC was 0.922 (95% CI: 0.829-1.000, p < 0.01), and the cutoff value of ΔIVC used to predict fluid responsiveness was 28.5%, with a sensitivity and specificity of 95.4 and 68.5%, respectively.

CONCLUSIONS

The ΔIVC was found to have a potential value in predicting fluid responsiveness in mechanically ventilated children with septic shock.

Inferior vena cava diameter and collapsibility index as a marker of fluid status in regular hemodialysis patients

Background

Patients with renal failure suffer from fluid overload which is a risk factor for mortality and morbidity. Therefore, fluid status assessment in patients on regular hemodialysis is very important. Dry weight assessment by clinical parameters is not always reliable. We evaluate the role of inferior vena cava ultrasound in estimating fluid overload in regular hemodialysis patients.

Results

A total of 45 persons, 30 end-stage renal disease patients on regular hemodialysis in group A (18 men and 12 women) and 15 healthy persons in group B (10 men and 5 women), were included in the study. The patients in group A ages ranged from 29 to 70 years with a mean of 48.38 ± 12.70 years and in group B ages ranged from 25 to 55 years with a mean of 34.93 ± 8.26. By clinical methods, the mean dry weight was 68.37 kg (68.37 ± 10.42). After HD mean, IVCe decreased from 2.01 ± 0.29 to 1.79 ± 0.22 cm (P < 0.001) similarly, mean IVCi decreased from 0.99 ± 0.48 to 0.64 ± 0.39 cm (P < 0.001). Changes in IVCD were significantly correlated with alterations in body weight following dialysis (P < 0.001). The IVC-CI increased significantly after dialysis (P < 0.001). IVCD and its IVC-CI reflected alterations in fluid status (P < 0.001). Considering the clinical parameters of fluid status, following HD mean, heart rate increased from 81.80 ± 5.15 beats per minute to 89.87 ± 6.42, (P < 0.001), systolic blood pressure decreased from 130 ± 18.43 mmHg to 113.33 ± 15.27 (P < 0.001), and diastolic blood pressure decreased from 80.17 ± 10.12 mmHg to 71.50 ± 9.29 (P < 0.001).

Conclusion

It was found a significant correlation between IVCD and IVC-CI with ultrafiltration of hemodialysis. Thus, IVC ultrasound can be used in dry weight assessment in ESRD patients on regular HD by measurement of IVCD and IVC-CI before and after hemodialysis.

Ten answers to key questions for fluid management in intensive care

This review focuses on fluid management of critically ill patients. The topic is addressed based on 10 single questions with simplified answers that provide clinicians with the basic information needed at the point of care in treating patients in the Intensive Care Unit. The review has didactic purposes and may serve both as an update on fluid management and as an introduction to the subject for novices in critical care. There is an urgent need to increase awareness regarding the potential risks associated with fluid overload. Clinicians should be mindful not only of the indications for administering fluid loads and of the type of fluids administered, but also of the importance to set safety limits. Lastly, it is important to implement proactive strategies seeking to establish negative fluid balance as soon as the clinical conditions are considered to be stable and the risk of deterioration is low.

[Focus ultrasound for cardiology practice. Russian consensus document]

This document is a consensus document of Russian Specialists in Heart Failure, Russian Society of Cardiology, Russian Association of Specialists in Ultrasound Diagnostics in Medicine and Russian Society for the Prevention of Noncommunicable Diseases. In the document a definition of focus ultrasound is stated and discussed when it can be used in cardiology practice in Russian Federation.

Point-of-care ultrasound in a pandemic: Practical guidance in COVID-19 units

The coronavirus disease 2019 (COVID-19) pandemic has stretched our healthcare system to the brink, highlighting the importance of efficient resource utilization without compromising healthcare provider safety. While advanced imaging is a great resource for diagnostic purposes, the risk of contamination and infection transmission is high and requires extensive logistical planning for intrahospital patient transport, healthcare provider safety, and post-imaging decontamination. This dilemma has necessitated the transition to more bedside imaging. More so than ever, during the current pandemic, the clinical utility and importance of point-of-care ultrasound (POCUS) cannot be overstressed. It allows for safe and efficient beside procedural guidance and provides front line providers with valuable diagnostic information that can be acted upon in real-time for immediate clinical decision-making. The authors have been routinely using POCUS for the management of COVID-19 patients both in the emergency department and in intensive care units turned into “COVID-units.” In this article, we review the nuances of using POCUS in a pandemic situation and maximizing diagnostic output from this bedside technology. Additionally, we review various methods and diagnostic uses of POCUS which can replace conventional imaging and bridge current literature and common clinical practices in critically ill patients. We discuss practical guidance and pertinent review of the literature for the most relevant procedural and diagnostic guidance of respiratory illness, hemodynamic decompensation, renal failure, and gastrointestinal disorders experienced by many patients admitted to COVID-units.

Point-of-care ultrasound assessment of the inferior vena cava distensibility index in mechanically ventilated children in the operating room

Background and aim

Point-of-care ultrasound imaging of the inferior vena cava distensibility index is a potential indicator for determining fluid overload and dehydration in the mechanically ventilated patients. Data on inferior vena cava distensibility index and inferior vena cava distensibility variability are limited in mechanically ventilated pediatric patients. That is why our aim in this study was to measure inferior vena cava distensibility index and to obtain mean values in pediatric patients, ventilated in the operating room before the ambulatory surgical procedure started.

Materials and methods

This crosssectional study was performed between February 2019 and February 2020. Ultrasonographic measurements were performed in a total of 125 children.

Results

In a period of 13 months, the measurements were performed in a total of 125 children, of which 120 (62.5% male) met the criteria and were included in the study. Overall inferior vena cava distensibility index (%): mean ± SD: 6.8 ± 4.0, median (min–max): 5.7 (1.4–19.6), IQR: 3.8–8.7. Overall inferior vena cava distensibility variability (%): mean ± SD: 6.5 ± 3.7, median (min–max): 5.5 (1.4–17.8), IQR: 3.7–8.4.

Conclusion

Our study is the largest series of children in the literature in which inferior vena cava distensibility index measurements were investigated.

Respiratory variability of inferior vena cava at different mechanical ventilator settings

BACKGROUND

Assessment of the respiratory changes of the inferior vena cava (IVC) diameter have been investigated as a reliable tool to estimate the volume status in mechanically ventilated and spontaneously breathing patients. Our purpose was to compare the echocardiographic measurements the IVC diameter, stroke volume and cardiac output in different positive pressure ventilation parameters.

METHODS

This prospective clinical study with crossover design was conducted in the Intensive Care Unit (ICU). Twenty-five sedated, paralyzed, intubated, and mechanically ventilated patients with volume control mode (CMV) in the ICU due to respiratory failure were included in the study. Positive End-Expiratory Pressure (PEEP) and Tidal Volume (TV) were changed in each patient consecutively (Group A: TV 6 ml/kg, PEEP 5 cmH20, B: TV 6, PEEP 8, C: TV 8, PEEP 5, D: TV 8, PEEP 8) and the changes in vital parameters, central venous pressure (CVP) and ultrasonographic changes in IVC and cardiac parameters were measured. All measures were compared between groups by robust repeated measures ANOVA with trimmed mean.

RESULTS

The respiratory changes of the IVC diameter and echocardiographic parameters showed no significant difference in separate mechanical ventilator settings. Significant difference was found in peak and plateau pressure values among groups (p < 0.05).

CONCLUSION

The results of our study suggest that IVC related parameters are not affected with different ventilatory settings. Further studies are needed to confirm the reliability of these parameters as a predictor of fluid assessment.

A History of Fluid Management-From "One Size Fits All" to an Individualized Fluid Therapy in Burn Resuscitation

Fluid management is a cornerstone in the treatment of burns and, thus, many different formulas were tested for their ability to match the fluid requirements for an adequate resuscitation. Thereof, the Parkland-Baxter formula, first introduced in 1968, is still widely used since then. Though using nearly the same formula to start off, the definition of normovolemia and how to determine the volume status of burn patients has changed dramatically over years. In first instance, the invention of the transpulmonary thermodilution (TTD) enabled an early goal directed fluid therapy with acceptable invasiveness. Furthermore, the introduction of point of care ultrasound (POCUS) has triggered more individualized schemes of fluid therapy. This article explores the historical developments in the field of burn resuscitation, presenting different options to determine the fluid requirements without missing the red flags for hyper- or hypovolemia. Furthermore, the increasing rate of co-morbidities in burn patients calls for a more sophisticated fluid management adjusting the fluid therapy to the actual necessities very closely. Therefore, formulas might be used as a starting point, but further fluid therapy should be adjusted to the actual need of every single patient. Taking the developments in the field of individualized therapies in intensive care in general into account, fluid management in burn resuscitation will also be individualized in the near future.

Role of Inferior Vena Cava Parameters as Predictors of Fluid Responsiveness in Pediatric Septic Shock: A Prospective Study

Fluid resuscitation is the initial therapy for septic shock worldwide. Prediction of fluid responsiveness is essential for optimizing fluid administration. Only few pediatric studies have evaluated the role of inferior vena cava (IVC) as a reliable predictor of fluid responsiveness. The aim of this study was to evaluate the role of IVC parameters as predictors of fluid responsiveness in children (under the age of 5 years) having septic shock at different times from admission. A prospective observational study included 51 children having septic shock. It was conducted in the nine-bedded pediatric intensive care unit of a university hospital from January 1, 2018, to the August 31, 2018. Echocardiography was used to assess minimal and maximal IVC diameters and its distensibility index with simultaneous assessment of stroke volume (SV), at 1, 6, and 24 hours from admission. The decision to give fluid in these children was thereby based on the presence of at least one sign of inadequate tissue perfusion. SV was reassessed directly after administration of a fluid bolus of 10 mL/kg over 10 minutes. Fluid responsiveness was considered adequate when there was ≥ 10% increase in SV after fluid bolus. Minimal IVC diameter indexed to body surface area and its distensibility index can be predictors of fluid responsiveness at all times: 1 hour (area under curve [AUC] = 0.88; 95% confidence interval [CI] = 0.77–0.96), 6 hours (AUC = 0.86; 95% CI = 0.67–0.97), and 24 hours (AUC = 0.77; 95% CI = 0.6–0.95). IVC distensibility index can also predict fluid responsiveness at 1 hour (AUC= 0.87; 95% CI = 0.74–0.95), 6 hours (AUC = 0.86; 95% CI = 0.73–0.94), and 24 hours (AUC = 1; 95% CI = 0.77–1). The cutoff points of each parameter differed from time to time (contradicts with previous statement that says it is predictor at all times). The maximum IVC diameter could not predict fluid responsiveness at any time from admission. Minimal IVC diameter and its distensibility index were feasible noninvasive surrogates of fluid responsiveness in pediatric septic shock at different times from admission.

Randomized Controlled Trial of Ultrasound-guided Fluid Resuscitation of Sepsis-Induced Hypoperfusion and Septic Shock

Introduction

The ultrasound measurement of inferior vena cava (IVC) diameter change during respiratory phase to guide fluid resuscitation in shock patients is widely performed, but the benefit on reducing the mortality of sepsis patients is questionable. The study objective was to evaluate the 30-day mortality rate of patients with sepsis-induced tissue hypoperfusion (SITH) and septic shock (SS) treated with ultrasound-guided fluid management (UGFM) using ultrasonographic change of the IVC diameter during respiration compared with those treated with the usual-care strategy.

Methods

This was a randomized controlled trial conducted in an urban, university-affiliated tertiary-care hospital. Adult patients with SITH/SS were randomized to receive treatment with UGFM using respiratory change of the IVC (UGFM strategy) or with the usual-care strategy during the first six hours after emergency department (ED) arrival. We compared the 30-day mortality rate and other clinical outcomes between the two groups.

Results

A total of 202 patients were enrolled, 101 in each group (UGFM vs usual-care strategy) for intention-to-treat analysis. There was no significant difference in 30-day overall mortality between the two groups (18.8% and 19.8% in the usual-care and UGFM strategy, respectively; p > 0.05 by log rank test). Neither was there a difference in six-hour lactate clearance, a change in the sequential organ failure assessment score, or length of hospital stay. However, the cumulative fluid amount given in 24 hours was significantly lower in the UGFM arm.

Conclusion

In our ED setting, the use of respiratory change of IVC diameter determined by point-of-care ultrasound to guide initial fluid resuscitation in SITH/SS ED patients did not improve the 30-day survival probability or other clinical parameters compared to the usual-care strategy. However, the IVC ultrasound-guided resuscitation was associated with less amount of fluid used.

Predictors of fluid responsiveness in critically ill patients mechanically ventilated at low tidal volumes: systematic review and meta-analysis

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

Use of inferior venacaval collapsibility index in spinal anesthesia during orthopedic surgeries

Background:

Volume deficit is one of the predictors of hypotension. Inferior venacaval collapsibility index (IVCCI) can detect volume deficit and aids volume resuscitation in patients of intensive care unit.

Aims:

The primary aim was to compare the incidence of postspinal anesthesia hypotension (PSAH) in IVCCI measured and nonmeasured groups. The secondary aim was to determine IVCCI association with PSAH within IVCCI measured group in spite of fluid bolus.

Settings and Designs:

This was a prospective, randomized, controlled, single-blinded study.

Methodology:

One hundred patients posted for orthopedic surgery under spinal anesthesia (SA) were randomly divided as IVCCI measured (CI) and non-IVCCI measured (NCI) groups before SA. If IVCCI was more than 40% fluid bolus was given. Intraoperative hemodynamics was monitored. PSAH managed with fluids and vasopressors which were noted. Data collected were analyzed with unpaired t-test, Z-test, logistic regression test, and Pearson's correlation.

Results:

PSAH incidence was 18% in group (CI) whereas 38% in group (NCI), and the difference was statistically significant. Vasopressors given were higher in group NCI. Perioperative fluids were more in group CI, but the intraoperative fluids were more in group NCI. There was no statistically significant association between PSAH after fluid preloading and IVCCI within the IVCCI measured group.

Conclusion:

Prespinal anesthesia evaluation of IVCCI to optimize fluid therapy can reduce the incidence of PSAH in orthopedic surgeries and the vasopressor requirement, and hence, the association of IVCCI of more than 40% with PSAH.

Ten answers to key questions for fluid management in intensive care

This review focuses on fluid management of critically ill patients. The topic is addressed based on 10 single questions with simplified answers that provide clinicians with the basic information needed at the point of care in treating patients in the Intensive Care Unit. The review has didactic purposes and may serve both as an update on fluid management and as an introduction to the subject for novices in critical care. There is an urgent need to increase awareness regarding the potential risks associated with fluid overload. Clinicians should be mindful not only of the indications for administering fluid loads and of the type of fluids administered, but also of the importance to set safety limits. Lastly, it is important to implement proactive strategies seeking to establish negative fluid balance as soon as the clinical conditions are considered to be stable and the risk of deterioration is low.

Multi-directional Assessment of Respiratory and Cardiac Pulsatility of the Inferior Vena Cava From Ultrasound Imaging in Short Axis

The pulsatility of the inferior vena cava (IVC) reflects the volume status of patients. It can be investigated by ultrasounds (US), offering an important non-invasive tool supporting fluid management. However, the method has limitations attributable to many confounding factors, e.g., related to IVC movements and non-regular shapes. Short- or long-axis views have been used, both having advantages and limitations in counteracting such confounding factors, depending on the specific condition. The aim of this study is to investigate IVC pulsatility in the different directions on the transverse plane and to assess its variability. Moreover, different components of this pulsatility (induced by either respiratory or cardiac activity) are investigated. The method is tested on 10 healthy patients, with large variations across them of IVC section (mean diameters in the range 1 cm to 3 cm), shape and pulsatility (average caval index [CI] ranging from approximately 20% to 70%). The average coefficient of variation of the CI estimated on 10 different directions was 13% (21% and 20% for the respiratory and cardiac components, respectively), with a range that was approximately 50% of the mean CI across different directions (approximately the same for the 2 different components). The minimum and maximum CI were found close to the directions of maximum and minimum IVC diameter, respectively. The investigation of IVC dynamics in the entire cross-section is crucial to obtain a more repeatable and reliable characterization of IVC pulsatility. The calculation of a CI based on the "equivalent" diameter (proportional to the square root of the IVC cross-sectional area) is encouraged.

The Relation Between Common Carotid Artery Diameter and Central Venous Pressure for Assessment of Intravascular Fluid Status after Major Surgeries; an Observational Study

Objectives

The current study aimed to find the relation between the changes in the common carotid artery (CCA) diameter and the central venous pressure (CVP) in response to a fluid challenge in spontaneously breathing adult patients.

Methods

This study included 65 adult patients aged 20 - 60 years who were admitted to the surgical ICU. The CCA diameter and CVP were measured before and after fluid challenge, and the percentage of increase in the CCA diameter and CVP were calculated. The correlation was assessed between changes in the CVP and CCA diameter.

Results

The CCA diameter before fluid administration had a significant strong positive correlation to the CVP (r = 0.8, P value < 0.001); the increase in the CCA diameter after fluid administration had a significant moderate positive correlation with the increase in the CVP (r = 0.4, P value < 0.001). The percentage of increase in CCA diameters was positively correlated to the percentage of increase in CVP (r = 0.589, P value = 0.001) following fluid administration. However, the Receiver Operating Characteristic (ROC) analysis was an invalid test (area under curve 0.513, P value = 0.885).

Conclusions

After major surgeries, the change in the CCA diameter was positively correlated with the change in the CVP values in response to fluid administration in the spontaneously breathing adult patients, but the cut-off limit cannot be reached.

Assessment of end-tidal carbon dioxide and vena cava collapsibility in volume responsiveness in spontaneously breathing patients

BACKGROUND

The benefit of end-tidal carbon dioxide (ETCO2) and inferior vena cava collapsibility index (IVCCI) in predicting fluid responsiveness in mechanically ventilated patients has been demonstrated. However, the data on spontaneously breathing patients is controversial. This study aims to investigate the accuracy of variations in the ETCO2 (∆ETCO2) and IVCCI (∆IVCCI) gradient in predicting volume responsiveness in spontaneously breathing patients with hypovolemia.

METHODS

This was a prospective observational study conducted in an academic emergency department (ED). Spontaneously breathing patients who required fluid resuscitation due to hypovolemia were included in the study. Cardiac output (CO), IVCCI and ETCO2 were measured before and after the passive leg raise (PRL). A change in the CO of ≥15% after the PLR were considered volume responsive. The difference in the ∆ETCO2 and ∆IVCCI were compared between the volume responsive and nonresponsive groups.

RESULTS

A total of 31 patients were included in the study, of whom 15 patients were volume responsive. The difference in the ∆ETCO2 was 4 mm Hg in the volume responsive and 2 mm Hg in the nonresponsive group (p = 0.02). There was no significant difference in ∆IVCCI between the groups. A moderate correlation was detected between the difference in ∆ETCO2 and CO (0.585; p = 0.001).

CONCLUSION

∆ETCO2 can be an alternative method in predicting volume responsiveness in spontaneously breathing patients with hypovolemia.

Automated Volume Status Assessment Using Inferior Vena Cava Pulsatility

Assessment of volume status is important to correctly plan the treatment of patients admitted and managed by cardiology, emergency and internal medicine departments. Non-invasive assessment of volume status by echography of the inferior vena cava (IVC) is a promising possibility, but its clinical use is limited by poor reproducibility of current standard procedures. We have developed new algorithms to extract reliable information from non-invasive IVC monitoring by ultrasound (US) imaging. Both long and short axis US B-mode video-clips were taken from 50 patients, in either hypo-, eu-, or hyper-volemic conditions. The video-clips were processed to extract static and dynamic indexes characterizing the IVC behaviour. Different binary tree models (BTM) were developed to identify patient conditions on the basis of those indexes. The best classifier was a BTM using IVC pulsatility indexes as input features. Its accuracy (78.0% when tested with a leave-one-out approach) is superior to that achieved using indexes measured by the standard clinical method from M-mode US recordings. These results were obtained with patients in conditions of normal respiratory function and cardiac rhythm. Further studies are necessary to extend this approach to patients with more complex cardio-respiratory conditions.

Role of ultrasonographic inferior venacaval assessment in averting spinal anaesthesia-induced hypotension for hernia and hydrocele surgeries-A prospective randomised controlled study

Background and Aims:

Hypotension is one of the most common side effects of spinal anaesthesia and preoperative volume status is one of the predictive variables for developing spinal-induced hypotension (SIH). Inferior venacaval ultrasound (IVCUS) is effective to assess fluid responsiveness in critical care patients. The aim of this study was to evaluate the IVCUS-guided volume optimisation prior to spinal anaesthesia to prevent SIH and requirement of vasopressors.

Methods:

Eighty patients undergoing inguinal hernia/hydrocele surgeries under spinal anaesthesia were randomised into group A consisting of an IVCUS-guided volume optimisation before spinal anaesthesia and group B with no IVCUS assessment. Unpaired t-test and Z test were used for statistical analysis. Pearson's correlation coefficient was used to find correlation. The primary outcome was relative risk reduction in the incidence of SIH between the groups. Secondary outcomes were the need for vasopressor drugs, the total volume of fluids required throughout procedure, and correlation between IVC collapsibility index (IVCCI) versus prespinal fluids, IVCCI versus baseline mean arterial pressure (MAP).

Results:

The relative risk reduction in the incidence of SIH was lower in group A compared to group B which was 40% (P = 0.002 CI = 95%). The SIH in group A was 20% and group B was 50%. There was decreased requirement of vasopressors in group A compared to group B. Total IV fluids given was more in group A. There was a positive correlation between IVCCI and pre-spinal fluids.

Conclusion:

IVCUS assessment reduces the SIH as well as requirement of vasopressor for hernia and hydrocele surgeries.