Defining Fluid Responsiveness: A Guide to Patient-Tailored Volume Titration

Optimising fluid requirements after initial resuscitation: A pilot study evaluating mini-fluid challenge and passive leg raising test in patients with predicted severe acute pancreatitis

BACKGROUND

The goals and approaches to fluid therapy vary through different stages of resuscitation. This pilot study was designed to test the safety and feasibility of a fluid therapy protocol for the second or optimisation stage of resuscitation in patients with predicted severe acute pancreatitis (SAP).

METHODS

Spontaneously breathing patients with predicted SAP were admitted after initial resuscitation and studied over a 24-h period in a tertiary hospital ward. Objective clinical assessment (OCA; heart rate, mean arterial pressure, urine output, and haematocrit) was done at 0, 4, 8, 12, 18-20, and 24 h. All patients had mini-fluid challenge (MFC; 250 ml intravenous normal saline within 10 min) at 0 h and repeated at 4 and 8 h if OCA score ≥2. Patients who were fluid responsive (>10% change in stroke volume after MFC) received 5-10 ml/kg/h, otherwise 1-3 ml/kg/h until the next time point. Passive leg raising test (PLRT) was done at each time point and compared with OCA for assessing volume status and predicting fluid responsiveness.

RESULTS

This fluid therapy protocol based on OCA, MFC, and PLRT and designed for the second stage of resuscitation was safe and feasible in spontaneously breathing predicted SAP patients. The PLRT was superior to OCA (at 0 and 8 h) for predicting fluid responsiveness and guiding fluid therapy.

CONCLUSIONS

This pilot study found that a protocol for intravenous fluid therapy specifically for the second stage of resuscitation in patients with predicted SAP was safe, feasible, and warrants further investigation.

Shock Management Without Formal Fluid Responsiveness Assessment: A Retrospective Analysis of Fluid Responsiveness and Its Outcomes

BACKGROUND

In order to quantify fluid administration and evaluate the clinical consequences of conservative fluid management without hemodynamic monitoring in undifferentiated shock, we analyzed previously collected data from a study of carotid Doppler monitoring as a predictor of fluid responsiveness (FR).

METHODS

This study was a retrospective analysis of data collected from a single tertiary academic center from a previous study. Seventy-four patients were included for post-hoc analysis, and 52 of them were identified as fluid responsive (cardiac output increase > 10% with passive leg raise) according to NICOMTM bioreactance monitoring (Cheetah Medical, Newton Center, MA, USA). Treating teams provided standard of care conservative fluid resuscitation but were blinded to independently performed FR testing results. Outcomes were compared between fluid responsive and fluid non-responsive patients. Primary outcome measures were volume fluids administered and net fluid balance 24- and 72-hour post-FR assessment. Secondary outcome measures included change in vasopressor requirements, mean peak lactate levels, length of hospital/intensive care unit stay, acute respiratory failure, hemodialysis requirement, and durations of vasopressors and mechanical ventilation.

RESULTS

Mean fluids administered within 72 hours were similar between fluid non-responsive and fluid responsive patients (139 mL/kg [95% confidence interval [CI]: 102.00-175.00] vs. 136 mL/kg [95% CI: 113.00-158.00], p = 0.92, respectively). We observed an insignificant trend toward higher 28-day mortality among fluid non-responsive patients (36% vs. 19%, p = 0.14). Volume of fluids administered significantly correlated with adverse outcomes such as increased hemodialysis requirements (32 patients, 43%), (odds ratio [OR] = 1.7200, p = 0.0018). Subgroup analysis suggested administering ≥ 30 mL/kg fluids to fluid responsive patients had a trend toward increased mortality (25% vs. 0%, p = 0.09) and a significant increase in hemodialysis (55% vs. 17%, p = 0.024).

CONCLUSIONS

Without formal FR assessment, similar amounts of total fluids were administered in both fluid responsive and non-responsive patients. As greater volumes of intravenous fluids administered were associated with adverse outcomes, we suggest that dedicated FR assessment may be a beneficial utility in early shock resuscitation.

Terms, Definitions, Nomenclature, and Routes of Fluid Administration

Fluid therapy is administered to veterinary patients in order to improve hemodynamics, replace deficits, and maintain hydration. The gradual expansion of medical knowledge and research in this field has led to a proliferation of terms related to fluid products, fluid delivery and body fluid distribution. Consistency in the use of terminology enables precise and effective communication in clinical and research settings. This article provides an alphabetical glossary of important terms and common definitions in the human and veterinary literature. It also summarizes the common routes of fluid administration in small and large animal species.

Albumin Use After Cardiac Surgery

Objectives

To investigate the effect of albumin exposure in ICU after cardiac surgery on hospital mortality, complications, and costs.

Design

A retrospective, single-center cohort study with economic evaluation.

Setting

Cardiothoracic ICU in Australia.

Patients

Adult patients admitted to the ICU after cardiac surgery.

Interventions

None.

Measurements and Main Results

Comparison of outcomes and costs in ICU after cardiac surgery based on 4% human albumin exposure. During the study period, 3,656 patients underwent cardiac surgery. After exclusions, 2,594 patients were suitable for analysis. One-thousand two-hundred sixty-four (48.7%) were exposed to albumin and 19 (1.4%) of those died. The adjusted hospital mortality of albumin exposure compared with no albumin was not significant (odds ratio, 1.24; 95% CI, 0.56-2.79; p = 0.6). More patients exposed to albumin returned to the operating theater for bleeding and/or tamponade (6.1% vs 2.1%; odds ratio, 2.84; 95% CI, 1.81-4.45; p < 0.01) and received packed red cell transfusions (p < 0.001). ICU and hospital lengths of stay were prolonged in those exposed to albumin (mean difference, 18 hr; 95% CI, 10.3-25.6; p < 0.001 and 87.5 hr; 95% CI, 40.5-134.6; p < 0.001). Costs (U.S. dollar) were higher in patients exposed to albumin, compared with those with no albumin exposure (mean difference in ICU costs, $2,728; 95% CI, $1,566-3,890 and mean difference in hospital costs, $5,427; 95% CI, $3,294-7,560).

Conclusions

There is no increased mortality in patients who are exposed to albumin after cardiac surgery. The patients exposed to albumin had higher illness severity, suffered more complications, and incurred higher healthcare costs. A randomized controlled trial is required to determine whether albumin use is effective and safe in this setting.

Accuracy of Passive Leg Raising Test in Prediction of Fluid Responsiveness in Children

Aim

To assess the accuracy of the passive leg raising (PLR) test to anticipate fluid responsiveness in critically ill children under age of 5 years.

Materials and methods

A prospective observational study was conducted, in a university hospital pediatric intensive care unit from June 1, 2017, to January 30, 2018. Hemodynamic parameters including stroke volume using bedside transthoracic echocardiography were assessed at baseline I (45° semi-recumbent position), after PLR, at baseline II, and following fluid challenge. Changes in the stroke volume (delta SV) and in the cardiac index (CI) were recorded after PLR and fluid challenge.

Findings

Delta SV of 10% after PLR was an excellent discriminator of the fluid responsiveness with an area under ROC (AUC) of 0.81 (95% CI 0.68-0.9) with a sensitivity of 65.38% and a specificity of 100%. The change in CI of 8.7% after PLR was a significant discriminator of fluid responsiveness with an AUC of 0.7 (95% CI 0.56-0.81) with 57.78% sensitivity and 91.67% specificity.

Conclusion

Passive leg raising can identify nonresponders among seriously ill children under the age of 5 years but it cannot identify all responders with certainty.

Clinical significance

Passive leg raising is reliable test in under 5 year-old-children if performed appropriately using bedside echocardiography for the measurement of its transient effect.

How to cite this article

El-Nawawy AA, Farghaly PM, Hassouna HM, Accuracy of Passive Leg Raising Test in Prediction of Fluid Responsiveness in Children. Int J Clin Pediatr Dent 2020;24(5):344-349.

Assessing Fluid Resuscitation in Adults with Sepsis Who Are Not Mechanically Ventilated: a Systematic Review of Diagnostic Test Accuracy Studies

BACKGROUND

Fluid resuscitation is a widely used intervention that is mandated in the management of sepsis. While its use can be life-saving, its overuse is associated with harm. Despite this, the best means of assessing a need for fluid resuscitation in an acute medical setting is unclear.

OBJECTIVE

To assess studies of diagnostic tests that identify the need for fluid resuscitation in adults with sepsis, as defined by the presence of fluid responsiveness.

DESIGN

Protocol registration was performed in advance (PROSPERO:CRD42017048651). Research database searches were performed alongside additional searches to identify grey literature. Diagnostic test accuracy studies that assessed any fluid assessment tool were identified independently by two authors, before data extraction and quality assessments were performed.

PARTICIPANTS

Adults with sepsis, without intensive care organ support, who would be appropriate for admission to an acute medical unit.

KEY RESULTS

Of the 26,841 articles that were screened, 14 studies were identified for inclusion, involving a combined total of 594 patients. Five categories of index test were identified: inferior vena cava collapsibility index (IVCCI), haemodynamic change with passive leg raise, haemodynamic change with respiration, haemodynamic change with intravenous fluid administration, and static assessment tools. Due to the high level of clinical heterogeneity affecting all aspects of study design, quantitative analysis was not feasible. There was a lack of consensus on reference tests to determine fluid responsiveness.

CONCLUSION

While fluid resuscitation is considered a key part of the management of sepsis, evidence to support fluid assessment in awake adults is lacking. This review has highlighted a number of research recommendations that should be addressed as a matter of urgency if patient harm is to be avoided.

Diastolic Function and Peripheral Venous Pressure as Indices for Fluid Responsiveness in Cardiac Surgical Patients

OBJECTIVE

Identifying fluid responsiveness is critical to optimizing perfusion while preventing fluid overload. An experimental study of hypovolemic shock resuscitation showed the importance of ventricular compliance and peripheral venous pressure (PVP) on fluid responsiveness. The authors tested the hypothesis that reduced ventricular compliance measured using transesophageal echocardiography results in decreased fluid responsiveness after a fluid bolus.

DESIGN

Prospective observational study.

SETTING

Two-center, university hospital study.

PARTICIPANTS

The study comprised 29 patients undergoing elective coronary revascularization.

INTERVENTION

Albumin 5%, 7 mL/kg, was infused over 10 minutes to characterize fluid responders (>15% increase in stroke volume) from nonresponders.

MEASUREMENTS AND MAIN RESULTS

Invasive hemodynamics and the ratio of mitral inflow velocity (E-wave)/annular relaxation (e'), or E/e' ratio, were measured using transesophageal echocardiography to assess left ventricular (LV) compliance at baseline and after albumin infusion. Fifteen patients were classified as responders and 14 as nonresponders. The E/e' ratio in responders was 7.4 ± 1.9 at baseline and 7.1 ± 1.8 after bolus. In contrast, E/e' was significantly higher in nonresponders at baseline (10.7 ± 4.6; p = 0.04) and further increased after bolus (12.6 ± 5.5; p = 0.002). PVP was significantly greater in the nonresponders at baseline (14 ± 4 mmHg v 11 ± 3 mmHg; p = 0.02) and increased in both groups after albumin infusion. Fluid responsiveness was tested using the area under the receiver operating characteristic curve and was 0.74 for the E/e' ratio (95% confidence interval 0.55-0.93; p = 0.029) and 0.72 for the PVP (95% confidence interval 0.52-0.92; p = 0.058).

CONCLUSION

Fluid responders had normal LV compliance and lower PVP at baseline. In contrast, nonresponders had reduced LV compliance, which worsened after fluid bolus. E/e,' more than PVP, may be a useful clinical index to predict fluid responsiveness.

What is the evidence base for fluid resuscitation in acute medicine?

Intravenous fluids are commonly prescribed but uncertainty remains about how to assess when fluids are required and how much to give, particularly in our multimorbid, polymedicated and ageing population. Furthermore, studies have noted that fluid resuscitation can be harmful even if clinical evidence of hypervolaemia is not present. Two recent guidelines have acknowledged a limited evidence base to guide fluid assessment. A recommended means to assess hypovolaemia includes assessment of fluid responsiveness. Fluid responsiveness is a rise in stroke volume following an increase in preload, achieved using a fluid challenge or a passive leg raise. However, the means of defining fluid responsiveness and its ability to identify patients who would benefit from fluid resuscitation is currently unclear. This review discusses the current guidelines about, and the evidence base for the provision of, intravenous fluids in the acutely unwell medical patient. It highlights how little evidence is available to guide medical practice.

Changes in blood volume indicators and dynamic indicators measured with transpulmonary ultrasound velocity during blood depletion and repletion in a neonatal swine model

BACKGROUND

Dynamic indicators such as pulse pressure and stroke volume variations can be measured to track changes in preload during hemorrhage, and evaluate fluid therapy. However, these dynamic indicators require mechanical ventilation, and might be affected by cardiac dysrhythmias and changes in vascular tone. Blood volume indicators may offer alternatives for assessing changes in volume status.

AIMS

The aims of this study were to measure changes in blood volume indicators and dynamic indicators during removal of blood in two stages and subsequent blood replacement in anesthetized, mechanically ventilated, neonatal pigs.

METHODS

In eight anesthetized, mechanically ventilated piglets (5-6 weeks old), cardiac index, stroke volume index, total end-diastolic volume, central blood volume, active circulating volume, pulse pressure variation, and stroke volume variation were measured during blood removal in two stages (15 mL kg^-1 each stage) and blood replacement (30 mL kg^-1 ). Values after each intervention were measured for each parameter.

RESULTS

All indicators differed from baseline after removal of 15 mL kg^-1 of blood, except for stroke volume variation. Differences between both stages of hemorrhage were only observed for indexed stroke volume, total end-diastolic volume, central blood volume, and pulse pressure variation.

CONCLUSION

Total end-diastolic volume and central blood volume changed during blood depletion and repletion, and differed between stages of hemorrhage. These indicators might be useful for assessing volume status instead of, or in addition to cardiac index and dynamic indicators.

Passive Leg-Raising and Prediction of Fluid Responsiveness: Systematic Review

Fluid boluses are often administered with the aim of improving tissue hypoperfusion in shock. However, only approximately 50% of patients respond to fluid administration with a clinically significant increase in stroke volume. Fluid overload can exacerbate pulmonary edema, precipitate respiratory failure, and prolong mechanical ventilation. Therefore, it is important to predict which hemodynamically unstable patients will increase their stroke volume in response to fluid administration, thereby avoiding deleterious effects. Passive leg-raising (lowering the head and upper torso from a 45° angle to lying supine [flat] while simultaneously raising the legs to a 45° angle) is a transient, reversible autotransfusion that simulates a fluid bolus and is performed to predict a response to fluid administration. The article reviews the accuracy, physiological effects, and factors affecting the response to passive-leg raising to predict fluid responsiveness in critically ill patients.

Fluid resuscitation practices in cardiac surgery patients in the USA: a survey of health care providers

Background

Fluid resuscitation during cardiac surgery is common with significant variability in clinical practice. Our goal was to investigate current practice patterns of fluid volume expansion in patients undergoing cardiac surgeries in the USA.

Methods

We conducted a cross-sectional online survey of 124 cardiothoracic surgeons, cardiovascular anesthesiologists, and perfusionists. Survey questions were designed to assess clinical decision-making patterns of intravenous (IV) fluid utilization in cardiovascular surgery for five types of patients who need volume expansion: (1) patients undergoing cardiopulmonary bypass (CPB) without bleeding, (2) patients undergoing CPB with bleeding, (3) patients undergoing acute normovolemic hemodilution (ANH), (4) patients requiring extracorporeal membrane oxygenation (ECMO) or use of a ventricular assist device (VAD), and (5) patients undergoing either off-pump coronary artery bypass graft (OPCABG) surgery or transcatheter aortic valve replacement (TAVR). First-choice fluid used in fluid boluses for these five patient types was requested. Descriptive statistics were performed using Kruskal-Wallis test and follow-up tests, including t tests, to evaluate differences among respondent groups.

Results

The most commonly preferred indicators of volume status were blood pressure, urine output, cardiac output, central venous pressure, and heart rate. The first choice of fluid for patients needing volume expansion during CPB without bleeding was crystalloids, whereas 5% albumin was the most preferred first choice of fluid for bleeding patients. For volume expansion during ECMO or VAD, the respondents were equally likely to prefer 5% albumin or crystalloids as a first choice of IV fluid, with 5% albumin being the most frequently used adjunct fluid to crystalloids. Surgeons, as a group, more often chose starches as an adjunct fluid to crystalloids for patients needing volume expansion during CPB without bleeding. Surgeons were also more likely to use 25% albumin as an adjunct fluid than were anesthesiologists. While most perfusionists reported using crystalloids to prime the CPB circuit, one third preferred a mixture of 25% albumin and crystalloids. Less interstitial edema and more sustained volume expansion were considered the most important colloid traits in volume expansion.

Conclusions

Fluid utilization practice patterns in the USA varied depending on patient characteristics and clinical specialties of health care professionals.

Electronic supplementary material

The online version of this article (10.1186/s13741-017-0071-6) contains supplementary material, which is available to authorized users.

Peripheral Venous Pressure as an Indicator of Preload Responsiveness During Volume Resuscitation from Hemorrhage

BACKGROUND

Fluid resuscitation of hypovolemia presumes that peripheral venous pressure (PVP) increases more than right atrial pressure (RAP), so the net pressure gradient for venous return (PVP-RAP) rises. However, the heart and peripheral venous system function under different compliances that could affect their respective pressures during fluid infusion. In a porcine model of hemorrhage resuscitation, we examined whether RAP increases more than PVP, thereby reducing the venous return pressure gradient and blood flow.

METHODS

Anesthetized pigs (n = 8) were bled to a mean arterial blood pressure of 40 mm Hg and resuscitated with stored blood and albumin for pulmonary artery occlusion pressures (PAOPs) of 5, 10, 15, and 20 mm Hg. Venous pressures, inferior vena cava blood flow (ultrasonic flowprobe), and left ventricular diastolic compliance (Doppler echocardiography) were measured. Stroke volume variability was calculated.

RESULTS

With volume resuscitation, the slope of RAP exceeded PVP (P ≤ 0.0001) when PAOP is 10 to 20 mm Hg, causing the pressure gradient for venous return to progressively decrease. Inferior vena cava blood flow did not further increase after PAOP > 10 mm Hg. The E/e' ratio increased (P = 0.001) during resuscitation indicating reduced diastolic compliance. A significant curvilinear relationship was found between PVP and stroke volume variability (R = 0.62; P < 0.001), where fluid responders had PVP < 15 mm Hg.

CONCLUSIONS

Fluid resuscitation above a PAOP 10 mm Hg reduces myocardial compliance and reduces the venous return pressure gradient. The hemodynamic response to fluid resuscitation becomes limited by diastolic properties of the heart. PVP measurement during hemorrhage resuscitation may predict fluid responsiveness and nonresponsiveness.

The haemodynamic dilemma in emergency care: Is fluid responsiveness the answer? A systematic review

BACKGROUND

Fluid therapy is a common and crucial treatment in the emergency department (ED). While fluid responsiveness seems to be a promising method to titrate fluid therapy, the evidence for its value in ED is unclear. We aim to synthesise the existing literature investigating fluid responsiveness in ED.

METHODS

MEDLINE, Embase and the Cochrane library were searched for relevant peer-reviewed studies published from 1946 to present.

RESULTS

A total of 249 publications were retrieved of which 22 studies underwent full-text review and eight relevant studies were identified. Only 3 studies addressed clinical outcomes - including 2 randomised controlled trials and one feasibility study. Five articles evaluated the diagnostic accuracy of fluid responsiveness techniques in ED. Due to marked heterogeneity, it was not possible to combine results in a meta-analysis.

CONCLUSION

High quality, adequately powered outcome studies are still lacking, so the place of fluid responsiveness in ED remains undefined. Future studies should have standardisation of patient groups, the target response and the underpinning theoretic concept of fluid responsiveness. The value of a fluid responsiveness based fluid resuscitation protocol needs to be established in a clinical trial.

Ventilator-induced central venous pressure variation can predict fluid responsiveness in post-operative cardiac surgery patients

BACKGROUND

Ventilator-induced dynamic hemodynamic parameters such as stroke volume variation (SVV) and pulse pressure variation (PPV) have been shown to predict fluid responsiveness in contrast to static hemodynamic parameters such as central venous pressure (CVP). We hypothesized that the ventilator-induced central venous pressure variation (CVPV) could predict fluid responsiveness.

METHODS

Twenty-two elective cardiac surgery patients were studied post-operatively on the intensive care unit during mechanical ventilation with tidal volumes of 6-8 ml/kg without spontaneous breathing efforts or cardiac arrhythmia. Before and after administration of 500mL hydroxyethyl starch, SVV and PPV were measured using pulse contour analysis by modified Modelflow^® , while CVP was obtained from a central venous catheter positioned in the superior vena cava. CVPV was calculated as 100 × (CVP_max -CVP_min )/[(CVP_max + CVP_min) /2].

RESULTS

Nineteen patients (86%) were fluid responders defined as an increase in cardiac output of ≥ 15% after fluid administration. CVPV decreased upon fluid loading in responders, but not in non-responders. Baseline CVP values showed no correlation with a change in cardiac output in contrast to baseline SVV (r = 0.60, P = 0.003), PPV (r = 0.58, P = 0.005), and CVPV (r = 0.63, P = 0.002). Baseline values of SVV > 9% and PPV > 8% could predict fluid responsiveness with a sensitivity of 89% and 95%, respectively, both with a specificity of 100%. Baseline CVPV could identify all fluid responders and non-responders correctly at a cut-off value of 12%. There was no difference between the area under the receiver operating characteristic curves of SVV, PPV, and CVPV.

CONCLUSION

The use of ventilator-induced CVPV could predict fluid responsiveness similar to SVV and PPV in post-operative cardiac surgery patients.

Fluid resuscitation practice patterns in intensive care units of the USA: a cross-sectional survey of critical care physicians

BACKGROUND

Fluid resuscitation is a cornerstone of intensive care treatment, yet there is a lack of agreement on how various types of fluids should be used in critically ill patients with different disease states. Therefore, our goal was to investigate the practice patterns of fluid utilization for resuscitation of adult patients in intensive care units (ICUs) within the USA.

METHODS

We conducted a cross-sectional online survey of 502 physicians practicing in medical and surgical ICUs. Survey questions were designed to assess clinical decision-making processes for 3 types of patients who need volume expansion: (1) not bleeding and not septic, (2) bleeding but not septic, (3) requiring resuscitation for sepsis. First-choice fluid used in fluid boluses for these 3 patient types was requested from the respondents. Descriptive statistics were performed using a Kruskal-Wallis test to evaluate differences among the physician groups. Follow-up tests, including t tests, were conducted to evaluate differences between ICU types, hospital settings, and bolus volume.

RESULTS

Fluid resuscitation varied with respect to preferences for the factors to determine volume status and preferences for fluid types. The 3 most frequently preferred volume indicators were blood pressure, urine output, and central venous pressure. Regardless of the patient type, the most preferred fluid type was crystalloid, followed by 5 % albumin and then 6 % hydroxyethyl starches (HES) 450/0.70 and 6 % HES 600/0.75. Surprisingly, up to 10 % of physicians still chose HES as the first choice of fluid for resuscitation in sepsis. The clinical specialty and the practice setting of the treating physicians also influenced fluid choices.

CONCLUSIONS

Practice patterns of fluid resuscitation varied in the USA, depending on patient characteristics, clinical specialties, and practice settings of the treating physicians.

Assessment of volume status and fluid responsiveness in the emergency department: a systematic approach

When treating acutely ill patients in the emergency department (ED), the successful management of a variety of medical conditions, such as sepsis, acute kidney injury, and pancreatitis, is highly dependent on the correct assessment and optimization of a patient's intravascular volume status. Therefore, it is crucial that the ED physician knows and uses available means to assess intravascular volume status to adequately guide fluid therapy. This review focuses on techniques for volume status assessment that are available in the ED including basic clinical and laboratory findings, apparatus-based tests such as sonography and chest x-ray, and functional tests to evaluate fluid responsiveness. Furthermore, we provide an outlook on promising innovative, noninvasive technologies that might be used for advanced hemodynamic monitoring in the ED.