Principles of fluid management and stewardship in septic shock: it is time to consider the four D's and the four phases of fluid therapy

Early net ultrafiltration thresholds and mortality in critically ill patients with septic acute kidney injury receiving continuous renal replacement therapy

BACKGROUND

Net ultrafiltration (NUF) rates correlate with outcomes in critically ill patients on continuous renal replacement therapy (CRRT), but optimal strategies for septic acute kidney injury (AKI) are unclear. This study evaluated early NUF rates and survival in septic AKI.

METHODS

A retrospective cohort of 219 adults with septic AKI requiring CRRT at a tertiary ICU was analyzed. Early NUF (weight-adjusted fluid removal/hour during the first 48 h of CRRT) was stratified into low- (<1.22 mL/kg/h), moderate- (1.22-1.79 mL/kg/h), and high-intensity (>1.79 mL/kg/h) groups. The primary outcome was 28-day mortality. Associations were assessed using multivariable Cox regression and restricted cubic spline models, adjusted for demographics, severity scores, fluid balance, and biomarkers.

RESULTS

The high-intensity group had the highest 28-day mortality (68.5% vs. 43.8% moderate vs. 45.2% low). High-intensity NUF was independently associated with increased mortality vs. moderate (adjusted HR = 1.88, 95% CI:1.19-2.97, p = 0.007) and low-intensity groups (adjusted HR = 2.01, 95% CI:1.25-3.22, p = 0.004). Nonlinear analysis demonstrated a nonlinear relationship, with risks escalating steeply at rates above 1.79 mL/kg/h.

CONCLUSION

High-intensity NUF during early CRRT was associated with higher mortality in patients with septic AKI mortality, particularly among those with high severity of illness. Moderate NUF had lowest mortality, suggesting that intermediate NUF rates may best balance the competing risks of worsening hemodynamic instability from excess NUF and persistent volume overload from inadequate NUF. However, future trials are needed to better define the optimal approach to NUF in patients with septic AKI.

Retrospective Evaluation of Risk Factors and Outcome in Dogs With and Without Fluid Overload During Hospitalization

BACKGROUND

Risk factors for the development of fluid overload (FO) and its potential negative effects have not been investigated in dogs.

HYPOTHESIS/OBJECTIVES

Evaluate risk factors and outcomes in hospitalized dogs that received fluids IV and developed clinical signs of FO compared to those that did not.

ANIMALS

One hundred thirty-six dogs that developed FO and 109 dogs without FO.

METHODS

Retrospective observational study of hospitalized dogs. Variables were compared between dogs that developed clinical signs of FO (FO group) and dogs without FO (control group).

RESULTS

Compared to the control group, dogs in the FO group were significantly more likely to have cardiovascular disease (odds ratio [OR], 18.1; 95% confidence interval [CI], 5.4-60), protein-losing nephropathy (OR, 15.3; 95% CI, 2.0-116.8), chronic kidney disease (OR, 10; 95% CI, 3.0-33.8), and acute kidney injury (OR, 5.2; 95% CI, 2.5-10.6). The total fluid volume administered IV was not significantly different between the groups (p = 0.16). Only 6.0% of dogs with clinical signs of FO gained > 10% weight from non-dehydrated baseline and thus met the FO definition used in human medicine. Compared with the control group, dogs with FO had a significantly longer median duration of hospitalization (p < 0.001) and were less likely to survive to discharge (p < 0.001).

CONCLUSIONS AND CLINICAL IMPORTANCE

FO was more common with certain underlying diseases but not associated with total fluid volume administered IV. The definition for FO in human medicine using weight gain requires further evaluation in dogs. FO was associated with worse outcomes and longer hospitalization time.

Clinical management of sepsis-associated acute respiratory distress syndrome: current evidence and future directions

Sepsis is a life-threatening condition characterized by organ dysfunction resulting from a dysregulated host response to infection. The lungs are among the first and most significantly affected organs in sepsis. Pulmonary infections or systemic inflammatory cascades triggered by various pathogens can lead to acute and diffuse pulmonary damage, often manifesting as persistent hypoxemia. The COVID-19 pandemic has highlighted critical knowledge gaps in SA-ARDS management, necessitating paradigm reevaluation under the new global definition of ARDS. This paper analyzes the pathomechanisms and subphenotype characteristics of SA-ARDS, reviews recent advances in clinical management, such as fluid resuscitation, antimicrobial therapy, immune modulation, respiratory support, microcirculatory improvement, and traditional Chinese medicine (TCM) therapies, and addresses controversial issues and areas requiring further investigation.

Fluid management strategies in critically ill patients with ARDS: a narrative review

Hypervolemia is associated with worse outcomes in critically ill patients with acute respiratory distress syndrome (ARDS), with early positive fluid balance linked to longer intensive care unit (ICU) stays, prolonged ventilatory support, and increased mortality risk due to cardiopulmonary complications, lung edema, and extrapulmonary organ dysfunction. However, a restrictive fluid management strategy is associated with hypoperfusion and distal organ dysfunction, including acute renal failure and cognitive impairment. Indeed, fluid administration in patients with ARDS represents a challenge, as it must take into account the underlying condition, such as sepsis or acute brain injury (ABI), where optimal fluid management is a major determinant of disease outcome. In such cases, the approach to fluid administration should be individualized based on hemodynamic and clinical parameters according to the course of the disease. The strategy of "salvage, optimization, stabilization, and de-escalation" can guide fluid administration in the initial therapeutic approach, whereas negative fluid balance with the use of diuretics or renal replacement therapy (RRT) should be the goal once hemodynamic stabilization has been achieved.

Point of View: A Holistic Four-Interface Conceptual Model for Personalizing Shock Resuscitation

The resuscitation of a patient in shock is a highly complex endeavor that should go beyond normalizing mean arterial pressure and protocolized fluid loading. We propose a holistic, four-interface conceptual model of shock that we believe can benefit both clinicians at the bedside and researchers. The four circulatory interfaces whose uncoupling results in shock are as follows: the left ventricle to arterial, the arterial to capillary, the capillary to venular, and finally the right ventricle to pulmonary artery. We review the pathophysiology and clinical consequences behind the uncoupling of these interfaces, as well as how to assess them, and propose a strategy for approaching a patient in shock. Bedside assessment of shock may include these critical interfaces in order to avoid hemodynamic incoherence and to focus on microcirculatory restoration rather than simply mean arterial pressure. The purpose of this model is to serve as a mental model for learners as well as a framework for further resuscitation research that incorporates these concepts.

Relationship Between Cumulative Fluid Balance and the Degree of Venous Congestion According to VExUS Score in Critically Ill Patients in a General Intensive Care Unit

OBJECTIVES

The Venous Excess Ultrasound Score (VExUS) assesses venous congestion using point-of-care ultrasound. While validated to predict acute kidney injury, its relationship with cumulative fluid balance and clinical edema remains unclear. This study aimed to evaluate these associations 72 hours after intensive care unit (ICU) admission.

METHODS

This analytical observational cohort study included adult ICU patients with Foley catheters inserted at admission for fluid balance quantification. Patients on dialysis or with cirrhosis or abdominal hypertension were excluded. The correlation between cumulative fluid balance, edema clinical grade, and VExUS grade was analyzed. Multivariate analysis identified factors associated with significant venous congestion (VExUS grade ≥2), with statistical significance set at P < .05.

RESULTS

A total of 123 patients were included, with a mean age of 60 years (SD ±19.2); 59.3% were male. Venous congestion (VExUS grade ≥1) was observed in 36.5% of patients, despite an average cumulative fluid balance of +0.88 L. Each liter of positive cumulative fluid balance increased the risk of significant congestion (VExUS grade ≥2) by 31% (OR = 1.31; 95% CI: 1.07-1.60). The correlation between clinical edema (Godet scale) and VExUS grade was weak (Spearman rho = 0.27), and clinical edema was not associated with significant congestion (OR = 3.22; 95% CI: 0.77-13.56).

CONCLUSIONS

In ICU patients, fluid overload is an early contributor to significant venous congestion (VExUS grade ≥2) but does not correlate with clinical edema grades, highlighting the limitations of clinical edema in assessing venous congestion.

Predictive accuracy of changes in the inferior vena cava diameter for predicting fluid responsiveness in patients with sepsis: A systematic review and meta-analysis

BACKGROUND

Existing guidelines emphasize the importance of initial fluid resuscitation therapy in sepsis management. However, in previous meta-analyses, there have been inconsistencies in differentiating between spontaneously breathing and mechanically ventilated septic patients.

OBJECTIVE

To consolidate the literature on the predictive accuracy of changes in the inferior vena cava diameter (∆IVC) for fluid responsiveness in septic patients.

METHODS

The Embase, Web of Science, Cochrane Library, MEDLINE, PubMed, Wanfang, China National Knowledge Infrastructure (CNKI), Chinese Biomedical (CBM) and VIP (Weipu) databases were comprehensively searched. Statistical analyses were performed with Stata 15.0 software and Meta-DiSc 1.4.

RESULTS

Twenty-one research studies were deemed suitable for inclusion. The sensitivity and specificity of ∆ IVC were 0.84 (95% CI 0.76, 0.90) and 0.87 (95% CI 0.80, 0.91), respectively. With respect to the distensibility of the inferior vena cava (dIVC), the sensitivity was 0.79 (95% CI 0.68, 0.86), and the specificity was 0.82 (95% CI 0.73, 0.89). For collapsibility of the inferior vena cava (cIVC), the sensitivity and specificity values were 0.92 (95% CI 0.83, 0.96) and 0.93 (95% CI 0.86, 0.97), respectively.

CONCLUSION

The results indicated that ∆IVC is as a dependable marker for fluid responsiveness in sepsis patients. dIVC and cIVC also exhibited high levels of accuracy in predicting fluid responsiveness in septic patients.

SIGH35 and end-expiratory occlusion test for assessing fluid responsiveness in critically ill patients undergoing pressure support ventilation

BACKGROUND

Assessing fluid responsiveness is problematic for critically ill patients with spontaneous breathing activity, such as during Pressure Support Ventilation (PSV), since spontaneous breathing activity physiologically affects heart-lung interplay. We compared the reliability of two hemodynamic tests in predicting fluid responsiveness in this clinical setting: SIGH35, based on a ventilator-generated sigh applied at 35 cmH2O for 4 s and the end-expiratory occlusion test (EEOT).

METHODS

Prospective study conducted in a general intensive care unit (ICU) and enrolling patients in PSV showing different inspiratory effort [assessed by airway occlusion pressure (P0.1)] and requiring volume expansion (VE). Hemodynamic variables were recorded by means of the MOSTCARE® system, patient received a VE using 4 ml/kg of crystalloids over 10 min and were considered responders if a cardiac output (CO) ≥ 10% was observed. The reliability of SIGH35 and EEOT in discriminating fluid responsiveness was assessed using receiver operating characteristic (ROC) curve approach and the area (AUC) under ROC curves was compared. For the EEOT, we considered the percent changes of CO between baseline the end of the test, while for the SIGH35, the percent changes of pulse pressure (PP) between baseline and the lowest value recorded after SIGH35 application.

RESULTS

Sixty ICU patients were enrolled, and 56 patients analysed. The AUC of PP changes after SIGH35 was 0.93 (0.84-0.99) [sensitivity of 93.1% (78.0-98.7%); specificity of 91.6 (73.0-98.9%)]; best threshold - 25% PP from baseline (grey zone - 15%/35%)]; and greater than the AUC of CO changes after EEOT [0.67 (0.52-0.81); sensitivity of 72.4% (54.3-85.3%) specificity of 70.3% (73.0-98.9%)]; best threshold 4% of CO increase from baseline (grey zone - 1%/10%)]. In the subgroup having a P0.1 < 1.5 cmH2O, the AUC of SIGH35 [0.98 (0.94-0.99)] and of EEOT [0.89 (0.72-0.99] were comparable (p = 0.26).

CONCLUSIONS

In a selected ICU population undergoing PSV, SGH35 reliably predicted fluid responsiveness and performed better than the EEOT, which is, however, still reliable in the subgroup of ICU patients having a small extent of inspiratory efforts.

Improved Prediction of Fluid Responsiveness in Ventilated Patients With Low Tidal Volume: The Role of Preload Variation

OBJECTIVES

To analyze whether two levels of preload, one reduced by the application of tourniquets with sphygmomanometer cuffs and the other increased by passive leg elevation, improve the predictive capacity of pulse pressure variation (PPV) and stroke volume variation (SVV) of fluid responsiveness in patients ventilated with low tidal volume (Vt).

DESIGN

Prospective cohort study.

SETTING

ICU at the University Hospital of Cádiz (Spain).

PATIENTS

Patients diagnosed with septic shock, on controlled invasive mechanical ventilation without spontaneous breathing, with a Vt of 6 mL/kg predicted body weight and considered for an intravascular volume load due to hemodynamic instability.

INTERVENTIONS

Patient position changes: supine position and passive leg raise. Placement of pressure cuff compression at 60 mm Hg in one upper limb and the two lower limbs. Administration of 10 mL/kg of saline solution in 10 minutes.

MEASUREMENTS AND RESULTS

Twenty-eight tests were obtained. The baseline characteristics of the responders and nonresponders were similar. The baseline variables PPV and SVV had a limited ability to predict the response to fluids, with areas under the curve of 0.71 and 0.66, respectively. However, its predictive capacity increases significantly with different maneuvers, with the best prediction of the difference between the PPV value during the application of tourniquets and the PPV value in the supine position, with an area under the receiver operating characteristic curve of 0.97.

CONCLUSIONS

Lowering preload using tourniquets improves the predictive capacity of PPV and SVV for fluid responsiveness in patients ventilated with low Vt.

Current and Future Practice in the Diagnosis and Management of Sepsis and Septic Shock in Small Animals

This review will explore the current knowledge, beginning with the physiologic underpinnings and delve into the evolving scientific literature, encompassing the inextricably intertwined diagnosis and management of sepsis and septic shock in human and small animal patients. Sepsis is a significant cause of morbidity and mortality in patients, mostly for failure to recognize or treat promptly and adequately. Diagnosis is based on the individual patient, clinical context, and clinical acumen. High quality supportive care in the intensive care unit setting is patient-centered with intensive nursing, focused on physiologic systems, goal-oriented, and multi-disciplinary with a team-based approach to patient care.

Postresuscitation pleth variability index-guided hemodynamic management of out-of-hospital cardiac arrest survivors: A randomised controlled trial

Background and purpose

Hypotension and shock after return of spontaneous circulation is harmful. Goal-directed post-resuscitation care aims at maintaining adequate perfusion pressure, but evidence.on strategies to achieve this goal is limited. This study aimed to compare outcomes of pleth variability index (PVi) supported hemodynamic management during early hospital admission with those of standard hemodynamic management.

Methods and trial design

From March 2019 to August 2023, all mechanically ventilated patients adults admitted alive after a non-traumatic out-of-hospital cardiac arrest (OHCA) to the emergency department of Saint-Pierre University Hospital in Brussels, were screened for inclusion in this prospective, parallel, randomised, single-blind study. We enrolled patients with signs of tissue hypoperfusion after cardiac arrest. Patients were randomly allocated (1:1) to undergo hemodynamic treatment based on the PVi (intervention) or standard monitoring (control). Hemodynamic interventions targeted mean blood pressure above 70 mmHg, a capillary refill time below 3 s and urine output above 0.5 ml/kg/minute. The primary outcome was lactate clearance at 3 h. We hypothesized that PVi guided hemodynamic management would result in a faster lactate clearance at 3 h.

Results

96 patients underwent randomization. Due to non-consent and loss to follow-up 82 patients were included in the analysis, 39 in the intervention and 43 in the control group. The median lactate clearance 3 h after inclusion was not different between groups (57.4% [Interquartile range (IQR): 27.7-75.8%] in the control group versus 61.5% [IQR: 39.3-74.7%] in the intervention group), with a mean difference of 4.9% (95% CI, -7.5-17.2; p = 0.44) between the two groups. No side effects were observed.

Conclusion

A pleth variability index-based protocol did not significantly improve the lactate clearance compared with standard care (NCT03841708).

Potentially modifiable ventilation factors associated with outcome in neurocritical care vs. non-neurocritical care patients: Rational and protocol for a patient-level analysis of PRoVENT, PRoVENT-iMiC and ENIO (PRIME)

INTRODUCTION

Ventilator settings and ventilation variables and parameters vary between neurocritical care and non-neurocritical care patients. We aim to compare ventilation management in neurocritical care patients versus non-neurocritical care patients under invasive mechanical ventilation support, and to determine which factors related to ventilatory management have an independent association with outcome in neurocritical patients.

METHODS AND ANALYSIS

We meta-analyze harmonized individual patient data from three observational studies ('PRactice of VENTilation in critically ill patients without ARDS' [PRoVENT], 'PRactice of VENTilation in critically ill patients in Middle-income Countries' [PRoVENT-iMiC] and 'Extubation strategies and in neuro-intensive care unit patients and associations with outcomes' [ENIO]), pooled into a database named 'PRIME'. The primary endpoint is all cause ICU mortality. Secondary endpoints are key ventilator settings and ventilation variables and parameters. To identify potentially modifiable and non-modifiable factors contributing to ICU mortality, a multivariable model will be built using demographic factors, comorbidities, illness severities, and respiratory and laboratorial variables. In analyses examining the impact of ventilatory variables on outcome, we will estimate the relative risk of ICU mortality for neurocritical and non-neurocritical care patients by dividing the study population based on key ventilator variables and parameters.

ETHICS AND DISSEMINATION

This meta-analysis will address a clinically significant research question by comparing neurocritical care with non-neurocritical care patients. As this is a meta-analysis, additional ethical committee approval is not required. Findings will be disseminated to the scientific community through abstracts and original articles in peer-reviewed journals. Furthermore, the PRIME database will be made accessible for further post-hoc analyses.

REGISTRATION

PROVENT, PROVENT-iMiC and ENIO, and the pooled database PRIME are registered at clinicaltrials.gov (NCT01868321 for PRoVENT, NCT03188770 for PRoVENT-iMiC, and NCT03400904 for ENIO, and for PRIME is pending).

Point of care ultrasound for monitoring and resuscitation in patients with shock

Point-of-Care Ultrasound (POCUS), when used by experienced physicians, is a valuable diagnostic tool for the initial minutes of shock management and subsequent monitoring. It enables early diagnosis with high sensitivity (Sn) and specificity (Sp). Published protocols have advanced towards true multi-organ ultrasonographic exploration, with the RUSH (Rapid Ultrasound in Shock) protocol likely being the most well-known nowadays. Although there is no established order, cardiac evaluation, as well as vascular system assessments including intra- and extravascular volume, should be explored. Additionally, there are ultrasonographic evaluations particularly useful for diagnosing and monitoring response/tolerance to volume. Both the identification of B lines and the increase in left ventricular pressures bring us closer to a diagnosis of fluid overload in these patients. Velocity-time integral (VTI) of the left ventricle (LV) outflow tract (LVOT, LVOTVTI) or right ventricular outflow tract (RVOT, RVOTVTI) can be indicative of distributive shock if elevated, and help identifying volume responders through leg-raising manoeuvres or crystalloid bolus administration. Several index of the inferior vena cava (IVC) can also be helpful. In addition, different parameters to establish fluid responsiveness are being investigated at the carotid level. Venous congestion parameters have not yet been proven to identify volume responders but can identify patients with poor tolerance. Currently, it is essential that physicians treating critical patients use POCUS to enhance clinical outcomes.

Emergency medicine updates: Management of sepsis and septic shock

INTRODUCTION

Sepsis is a common condition associated with significant morbidity and mortality. Emergency physicians play a key role in the diagnosis and management of this condition.

OBJECTIVE

This paper evaluates key evidence-based updates concerning the management of sepsis and septic shock for the emergency clinician.

DISCUSSION

Sepsis is a life-threatening syndrome, and rapid diagnosis and management are essential. Antimicrobials should be administered as soon as possible, as delays are associated with increased mortality. Resuscitation targets include mean arterial pressure ≥ 65 mmHg, mental status, capillary refill time, lactate, and urine output. Intravenous fluid resuscitation plays an integral role in those who are fluid responsive. Balanced crystalloids and normal saline are both reasonable options for resuscitation. Early vasopressors should be initiated in those who are not fluid-responsive. Norepinephrine is the recommended first-line vasopressor, and if hypotension persists, vasopressin should be considered, followed by epinephrine. Administration of vasopressors through a peripheral 20-gauge or larger intravenous line is safe and effective. Steroids such as hydrocortisone and fludrocortisone should be considered in those with refractory septic shock.

CONCLUSION

An understanding of the recent updates in the literature concerning sepsis and septic shock can assist emergency clinicians and improve the care of these patients.

Prognostic impact of early versus delayed loop diuretic administration in sepsis: a propensity score-matched analysis using the MIMIC-IV database

Background

Fluid resuscitation is a standard intervention for patients with sepsis, however, the ideal timing for initiating fluid deresuscitation has not been well established. This study examines the prognostic impact of early versus delayed initiation of loop diuretics in patients with sepsis.

Methods

Data for this analysis were obtained from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Patients diagnosed with sepsis were categorized into two groups based on the timing of loop diuretic administration: an early group (within 48 hours of diagnosis) and a late group (after 96 hours).

Results

A total of 8,518 patients with sepsis were included in this study. Of these, 4,485 patients received loop diuretics within the first 48 hours (early group), while the remaining 4,033 patients received loop diuretics after 96 hours (late group). In the early group, 75% of patients required mechanical ventilation, which was significantly lower than the 85.6% in the late group (P<0.001). However, the early group demonstrated a significantly higher 28-day mortality rate compared to the late group (832/4,485 vs. 679/4,033, P=0.03). Cox regression analysis indicated that the early initiation of diuretics was associated with an increased 28-day mortality rate [hazard ratio (HR) =2.590, 95% confidence interval (CI): 2.325-2.884, P<0.001]. After adjusting for the proportional hazards assumption, the corrected HR was recalculated as exp[3.55-1.20 × ln(t)]. Propensity score matching (PSM) resulted in two well-matched groups of 1,882 patients each. Post-matching analysis revealed that the early group continued to exhibit significantly higher 28-day and in-hospital mortality (P<0.001) along with a significantly higher incidence of stage 3 acute kidney injury (AKI) (8.1% vs. 5.7%, P=0.004).

Conclusions

While complete adjustment for all potential confounding factors was not possible, the findings suggest that patients who received loop diuretics within 48 hours had more severe kidney injury and a significantly higher mortality rate compared to those who received later administration (after 96 hours). These findings underscore the need for careful consideration when determining the timing of loop diuretic initiation in clinical practice.

Optimising fluid therapy during venoarterial extracorporeal membrane oxygenation: current evidence and future directions

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) offers an immediate and effective mechanical cardio-circulatory support for critically ill patients with refractory cardiogenic shock or selected refractory cardiac arrest. As fluid therapy is routinely performed as a component of initial hemodynamic resuscitation of ECMO supported patients, this narrative review intends to summarize the rationale and the evidence on the fluid resuscitation strategy in terms of fluid type and dosing, the impact of fluid balance on outcomes and fluid responsiveness assessment in VA-ECMO patients. Several observational studies have shown a deleterious impact of positive fluid balance on survival and renal outcomes. With regard to the type of crystalloids, further studies are needed to evaluate the safety and efficacy of saline versus balanced solutions in terms of hemodynamic stability, renal outcomes and survival in VA-ECMO setting. The place and the impact of albumin replacement, as a second-line option, should be investigated. During VA-ECMO run, the fluid management approach could be divided into four phases: rescue or salvage, optimization, stabilization, and evacuation or de-escalation. Echocardiographic assessment of stroke volume changes following a fluid challenge or provocative tests is the most used tool in clinical practice to predict fluid responsiveness. This review underscores the need for high-quality evidence regarding the optimal fluid strategy and the choice of fluid type in ECMO supported patients. Pending specific data, fluid therapy needs to be personalized and guided by dynamic hemodynamic approach coupled to close monitoring of daily weight and fluid balance in order to provide adequate ECMO flow and tissue perfusion while avoiding harmful effects of fluid overload.

Acute Respiratory Distress Syndrome and Fluid Management: Finding the Perfect Balance

ARDS is a challenging syndrome in which the hallmark is alveolar epithelium damage, with the consequent extravasation of fluids into the interstitium and alveolar space. Patients with severe ARDS almost always require mechanical ventilation and aggressive fluid resuscitation, at least in the initial phases. The increased intrathoracic pressure during positive pressure ventilation reduces cardiac output, worsening the circulatory status of these patients even more. In this pathological context, fluid therapies serve as a means to restore intravascular volume but can simultaneously play a detrimental role, increasing the amount of liquid in the lungs and worsening gas exchange and lung mechanics. Indeed, clinical research suggests that fluid overload leads to worsening outcomes, mostly in terms of gas exchange, days of mechanical ventilation, and ICU stay duration. For these reasons, this review aims to provide basic information about ARDS pathophysiology and heart-lung interactions, the understanding of which is essential to guide fluid therapy, together with the close monitoring of hemodynamics and fluid responsiveness.

Restrictive fluid resuscitation versus liberal fluid resuscitation in patients with septic shock: comparison of outcomes

OBJECTIVE

To compare the prognosis of restrictive fluid resuscitation (RFR) versus liberal fluid resuscitation (LFR) in patients with septic shock.

METHODS

A retrospective analysis was conducted using clinical data from 82 septic shock patients treated in the Intensive Care Unit of Aviation General Hospital from January 2021 to December 2023. Patients were divided into two groups: the LFR group (n=41) and the RFR group (n=41), based on the resuscitation strategy used.

RESULTS

Both groups demonstrated significant reductions in heart rate (HR) and significant increases in mean arterial pressure (MAP) and central venous pressure (CVP) post-treatment (all P < 0.05). After treatment, the ejection fraction (EF) and cardiac index (CI) were significantly higher in the RFR group compared to the LFR group, while levels of troponin I (cTnI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were significantly lower in the RFR group (all P < 0.05). After treatment, the Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores exhibited a marked decrease in both groups, with the RFR group exhibiting greater reductions in both scales compared to the LFR group (both P < 0.05). The incidence of complications was significantly lower in the RFR group than in the LFR group (P < 0.05). Multivariable analysis identified age and fluid resuscitation modality as risk factors for complications in septic shock.

CONCLUSIONS

In patients with septic shock, RFR, compared to LFR, appears to better maintain hemodynamic stability and reduce myocardial injury. It also enhances cardiac function, mitigates organ failure, and lowers complication rates, possibly facilitating faster recovery.

Physician awareness of fluid volume administered with intravenous antibiotics: a structured interview-based study

OBJECTIVE

Fluids administered as drug diluents with intravenous (IV) medicine constitute a substantial fraction of fluids in inpatients. Whether physicians are aware of fluid volumes administered with IV antibiotics for patients with suspected infections is unclear. Moreover, whether this leads to adjustments in 24-hour fluid administration/antibiotics is unknown.

METHODS

This cross-sectional interview-based study was conducted in three emergency departments. Physicians were interviewed after prescribing around-the-clock IV antibiotics for ≥24 hours to patients with suspected infection. A structured interview guide assessed the physicians' awareness, considerations, and practices when prescribing IV antibiotics. The 24-hour antibiotic fluid volume was calculated.

RESULTS

We interviewed 100 physicians. The 24-hour fluid volume administered with IV antibiotics was 400 mL (interquartile range, 300-400 mL). Overall, 53 physicians (53%) were unaware of the fluid volume administered with IV antibiotics. Moreover, 76 (76%) did not account for the antibiotic fluid volume in the 24-hour fluid administration, and 96 (96%) indicated that they would not adjust prescribed fluids after receiving information about 24-hour antibiotic fluid volume administered for their patient. No comorbidities associated with fluid intolerance were the primary reason for not adjusting prescribed fluids/ antibiotics. Approximately 79 (79%) opted for visibility of fluid volumes administered with IV antibiotics in the medical record.

CONCLUSION

The majority of physicians were unaware of fluid volumes administered as a drug diluent with IV antibiotics. The majority chose not to make post-prescribing adjustments to their planned fluid administration; they regarded their patient as fluid tolerant. The physicians opted for visibility of fluid volumes administered as diluents during the prescribing process.

European Society of Intensive Care Medicine (ESICM) 2025 clinical practice guideline on fluid therapy in adult critically ill patients: part 2-the volume of resuscitation fluids

OBJECTIVE

This European Society of Intensive Care Medicine (ESICM) guideline provides evidence-based recommendations on the volume of early resuscitation fluid for adult critically ill patients.

METHODS

An international panel of experts developed the guideline, focusing on fluid resuscitation volume in adult critically ill patients with circulatory failure. Using the PICO format, questions were formulated, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was applied to assess evidence and formulate recommendations.

RESULTS

In adults with sepsis or septic shock, the guideline suggests administering up to 30 ml/kg of intravenous crystalloids in the initial phase, with adjustments based on clinical context and frequent reassessments (very low certainty of evidence). We suggest using an individualized approach in the optimization phase (very low certainty of evidence). No recommendation could be made for or against restrictive or liberal fluid strategies in the optimization phase (moderate certainty of no effect). For hemorrhagic shock, a restrictive fluid strategy is suggested after blunt trauma (moderate certainty) and penetrating trauma (low certainty), with fluid administration for non-traumatic hemorrhagic shock guided by hemodynamic and biochemical parameters (ungraded best practice). For circulatory failure due to left-sided cardiogenic shock, fluid resuscitation as the primary treatment is not recommended. Fluids should be administered cautiously for cardiac tamponade until definitive treatment and guided by surrogate markers of right heart congestion in acute pulmonary embolism (ungraded best practice). No recommendation could be made for circulatory failure associated with acute respiratory distress syndrome.

CONCLUSIONS

The panel made four conditional recommendations and four ungraded best practice statements. No recommendations were made for two questions. Knowledge gaps were identified, and suggestions for future research were provided.

Understanding fluid dynamics and renal perfusion in acute kidney injury management

Acute kidney injury (AKI) is associated with an increased risk of morbidity, mortality, and healthcare expenditure, posing a major challenge in clinical practice, and affecting about 50% of patients in the intensive care unit (ICU), particularly the elderly and those with pre-existing chronic comorbidities. In health, intra-renal blood flow is maintained and auto-regulated within a wide range of renal perfusion pressures (60-100 mmHg), mediated predominantly through changes in pre-glomerular vascular tone of the afferent arteriole in response to changes of the intratubular NaCl concentration, i.e. tubuloglomerular feedback. Several neurohormonal processes contribute to regulation of the renal microcirculation, including the sympathetic nervous system, vasodilators such as nitric oxide and prostaglandin E2, and vasoconstrictors such as endothelin, angiotensin II and adenosine. The most common risk factors for AKI include volume depletion, haemodynamic instability, inflammation, nephrotoxic exposure and mitochondrial dysfunction. Fluid management is an essential component of AKI prevention and management. While traditional approaches emphasize fluid resuscitation to ensure renal perfusion, recent evidence urges caution against excessive fluid administration, given AKI patients' susceptibility to volume overload. This review examines the main characteristics of AKI in ICU patients and provides guidance on fluid management, use of biomarkers, and pharmacological strategies.

Appropriateness of intravenous fluid prescriptions in hospitalised patients: a point prevalence study

BACKGROUND

Inappropriate use of intravenous (IV) fluids results in fluid overload, electrolyte disturbances, and increased costs.

AIM

To describe IV fluid prescribing and its appropriateness in hospitalised patients.

METHOD

A point prevalence study was conducted at two sites (academic and general) of a tertiary care hospital in Belgium. All inpatients (except those in the operating theatre) and all IV fluids prescribed during a 24-h period were analysed. Data collected included type, rate and volume administered. Each IV fluid was classified by indication (i.e., resuscitation/replacement, maintenance, catheter patency management, drug administration). Appropriateness was assessed using predefined criteria and validation by attending clinicians.

RESULTS

IV fluids were administered to 60% (297) of patients, with a median of 3 [IQR 0.5-6] IV fluid bags per patient and a median daily volume of 1000 ml [IQR 100-1550]. Amongst the 1162 IV fluid prescribed bags, 61.2% (712) were for drug administration, 22.1% (257) for catheter patency, 9.7% (112) for maintenance and 7.1% (82) for replacement/resuscitation. Inappropriate use was found for 56.9% (169) of patients with an IV fluid, representing a median volume of 300 ml per patient [IQR 10-500], and median costs of 4.60 € per patient [IQR 0.4-6.7].

CONCLUSION

Inappropriate IV fluid use is frequent in hospitalised patients, and results in significant costs. Optimisation strategies are needed.

Permissive strategies in intensive care units (ICUs): actual trends?

Permissive strategies in the intensive care unit (PSICU) intentionally allow certain physiological parameters to deviate from traditionally strict control limits to mitigate the risks associated with overly aggressive interventions. These strategies have emerged in response to evidence that rigid adherence to normal physiological ranges may cause harm to critically ill patients, leading to iatrogenic complications or exacerbation of underlying conditions. This review discusses several permissive strategies, including those related to hypotension, hypercapnia, hypoxemia, and lower urinary output thresholds. The key principles of these strategies require careful balancing and close monitoring to ensure that the benefits outweigh the risks for each patient. This approach emphasizes individualized care, thoughtful decision-making, and flexible application of guidelines. The use of a PSICU may help minimize the side effects of treatment while addressing the primary condition of the patient and allowing for a more holistic view of critically ill patients.

Study based on bibliometric analysis: potential research trends in fluid management for sepsis

Objective

To investigate the potential and evolving trends in fluid management for patients with sepsis, utilizing a bibliometric approach.

Methods

Scholarly articles pertaining to fluid therapy for sepsis patients were extracted from the Web of Science (WoS) database as of June 1, 2024. The R software package, "Bibliometrix," was utilized to scrutinize the primary bibliometric attributes and to construct a three-field plot to illustrate the relationships among institutions, nations, and keywords. The VOSviewer tool was employed for author analysis, keyword co-occurrence analysis, and data visualization. Additionally, CiteSpace was used to calculate citation bursts and keywords.

Results

A comprehensive retrieval from the Web of Science (WoS) database yielded a total of 2,569 publications. The majority of these articles were predominantly published by two countries, namely the United States (US) and China. Among the myriad of journals, Critical Care and Journal for Intensive Care Medicine emerged as the most prolific. In terms of institutional contribution, the University of California System stood out as the most productive. Recent analysis of keywords revealed a significant citation burst for terms such as "balanced crystalloids" and "critically ill children".

Conclusion

There is a growing focus on the connection between fluid management and the treatment of sepsis, with research in this area being at an advanced stage.

A Mini-Fluid Challenge to Predict Fluid Responsiveness in Swine

Unnecessary and excessive fluid therapy increases the risk of adverse effects such as pulmonary edema. To prevent this, a mini-fluid challenge (MFC) has been utilized to predict whether fluid therapy will improve circulatory dynamics in human intensive care medicine. The study described here investigated whether MFC is also efficacious in pigs. Thirty-two domestic pigs anesthetized and maintained under mechanical ventilation were treated with successive IV fluid administrations of 2, 1, 1, and 2 mL/kg over a 10-min period for a total dose of 6 mL/kg of Ringer lactate. The percentage increase in mean arterial pressure (MAP) at 2, 3, and 4 mL/kg of cumulative fluid administration was examined to determine whether responders could be identified that would benefit hemodynamically from higher doses of fluids. For the purposes of this study, a 10% increase or more in MAP after 6 mL/kg of fluid administration defined responders, and an increase of less than 10% in MAP was used to define nonresponders. The percentage increase in MAP at 2, 3, and 4 mL/kg fluid administration was evaluated to determine whether this could predict responder status. Eleven of the 32 animals were determined to be responders. Responder status was predicted with high accuracy by the administration of 3 mL/kg (AUC = 0.98) and was moderately predicted with administration of 2 mL/kg (AUC = 0.80), as well as pulse pressure variation (AUC = 0.75). Thus, MFC may be helpful to maintain tissue perfusion in pigs through the use of managed fluid therapy.

Volume kinetic analysis of two crystalloid fluid bolus rates in anesthetized cats

OBJECTIVE

To investigate the volume kinetic between 2 crystalloid fluid bolus rates in anesthetized cats.

DESIGN

Prospective, randomized, dose-response study.

SETTING

University laboratory.

ANIMALS

Ten convenience-sample, purpose-bred domestic shorthair and medium hair cats.

INTERVENTIONS

Intravenous 20 mL/kg balanced crystalloid fluid over 10 (G10) or 40 (G40) minutes under anesthesia in a randomized order with at least a 5-day washout period.

MEASUREMENTS AND MAIN RESULTS

Serial measurements of hemoglobin (Hb) concentration and PCV were performed up to 60 minutes after conclusion of the fluid bolus. Plasma dilution was calculated with the Hb dilution method and fitted to a 2-compartment microconstant kinetic model using nonlinear mixed-effect models. The apparent central plasma volume (Vc) was similar between the 2 groups (G10: 81.2 ± 23.8 mL/kg and G40: 78.8 ± 10.2 mL/kg). The apparent peripheral volume (Vp) of G10 (4.81E+8 ± 2.66E+8 mL/kg) was twice that of G40 (2.36E+8 ± 6.44E+7 mL/kg). The rate constant from Vc to Vp (K12) of G10 (0.057 ± 0.0196/min) was almost twice that of G40 (0.0302 ± 0.00807/min). The elimination constant of G10 (0.0113 ± 0.00672/min) was almost twice that of G40 (0.00534 ± 0.00279/min). The peak plasma expansion was similar between G10 and G40 (20.7 ± 1.9 and 19.1 ± 5.1 mL/kg). Area under the curve for plasma dilution versus time of the first 90 minutes from the beginning of the boluses was not statistically different between G10 and G40.

CONCLUSIONS

The volume expansion over time was not different likely due to the slow elimination. The plasma dilution to crystalloid bolus between subjects is varied in anesthetized cats. Clinicians should consider the slow elimination and return of crystalloid fluid from the Vp to Vc when prescribing fluid therapy in anesthetized cats.

Fluid management in the septic peri-operative patient

PURPOSE OF REVIEW

This review provides insight into recent clinical studies involving septic peri-operative patients and highlights gaps in understanding fluid management. The aim is to enhance the understanding of safe fluid resuscitation to optimize peri-operative outcomes and reduce complications.

RECENT FINDINGS

Recent research shows adverse surgical and clinical outcomes with both under- and over-hydration of peri-operative patients. The kinetic of intravenous fluids varies significantly during surgery, general anaesthesia, and sepsis with damage to endothelial glycocalyx (EG), which increases vascular permeability and interstitial oedema. Among clinical anaesthesia, neuraxial anaesthesia and sevoflurane have less effect on EG. Hypervolemia and the speed and volume of fluid infusion are also linked to EG shedding. Despite improvement in the antisepsis strategies, peri-operative sepsis is not uncommon. Fluid resuscitation is the cornerstone of sepsis management. However, overzealous fluid resuscitation is associated with increased mortality in patients with sepsis and septic shock. Personalized fluid resuscitation based on a careful assessment of intravascular volume status, dynamic haemodynamic variables and fluid tolerance appears to be a safe approach. Balanced solutions (BS) are preferred over 0.9% saline in patients with sepsis and septic shock due to a potential reduction in mortality, when exclusive BS are used and/or large volume of fluids are required for fluid resuscitation. Peri-operative goal-directed fluid therapy (GDFT) using dynamic haemodynamic variables remains an area of interest in reducing postoperative complications and can be considered for sepsis management (Supplementary Digital Content).

SUMMARY

Optimization of peri-operative fluid management is crucial for improving surgical outcomes and reducing postoperative complications in patients with sepsis. Individualized and GDFT using BS is the preferred approach for fluid resuscitation in septic peri-operative patients. Future research should evaluate the interaction between clinical anaesthesia and EG, its implications on fluid resuscitation, and the impact of GDFT in septic peri-operative patients.

Comparative Analysis of Bacteremic and Non-bacteremic Sepsis: A Retrospective Study

INTRODUCTION

Sepsis remains a prevalent critical illness encountered in emergency departments and intensive care units (ICU), with culture-negative sepsis constituting 30-60% of cases. The effect of culture type on treatment and outcomes remains unclear, and conflicting evidence exists regarding disparities between Gram-positive and Gram-negative infections.

OBJECTIVE

To further describe and compare characteristics and outcomes of culture-positive versus culture-negative sepsis.

DESIGN, SETTING AND PARTICIPANTS

This retrospective cohort study included 1375 patients admitted to the ICU of a single tertiary care hospital between 2016 and 2019 with a diagnosis of sepsis or septic shock. Patients who did not meet the screening criteria, lacked drawn or documented cultures, or had documented non-bacterial infections, were excluded.

MAIN OUTCOMES AND MEASURES

The primary outcome was disease severity and secondary outcomes included in-hospital mortality and duration of hospital and ICU stay. The principal and secondary exposure variables were blood culture status (positive vs. negative) and Gram staining (positive vs. negative), respectively.

RESULTS

Overall, 943 patients (68.5%) were culture-negative and 432 (31.5%) were culture-positive. Gram-positive bacteria were isolated from 178 patients, Gram-negative bacteria from 199 patients, and both from 55 patients. Culture-positive patients demonstrated an almost two-fold higher likelihood of requiring vasopressors (adjusted odds ratio (OR): 1.98), a higher incidence of stress-dose steroid administration (adjusted OR, 1.68), and higher resuscitative fluid administration at six and 72 hours than culture-negative patients. No significant between-group differences emerged in the ICU or hospital length of stay, or mortality. No significant variations were observed when comparing Gram-positive and Gram-negative bacteremia.

CONCLUSION

Although significant differences in illness severity existed between blood culture-negative and blood culture-positive patients with sepsis, patient-oriented secondary outcomes did not exhibit significant between-group differences. These results indicate that clinicians should not be reassured by the lack of proven bacteremia in patients with suspected sepsis, given similar outcomes.

Preload responsiveness-guided fluid removal in mechanically ventilated patients with fluid overload: A comprehensive clinical-physiological study

This study investigated fluid removal strategies for critically ill patients with fluid overload on mechanical ventilation. Traditionally, a negative fluid balance (FB) is aimed for. However, this approach can have drawbacks. Here, we compared a new approach, namely removing fluids until patients become fluid responsive (FR) to the traditional empiric negative balance approach. Twelve patients were placed in each group (n = 24). FR assessment was performed using passive leg raising (PLR). Both groups maintained stable blood pressure and heart function during fluid management. Notably, the FR group weaned from the ventilator significantly faster than negative FB group (both for a spontaneous breathing trial (14 h vs. 36 h, p = 0.031) and extubation (26 h vs. 57 h, p = 0.007); the difference in total ventilator time wasn't statistically significant (49 h vs. 62 h, p = 0.065). Additionally, FR group avoided metabolic problems like secondary alkalosis and potential hypokalemia seen in the negative FB group. FR-guided fluid-removal in fluid overloaded mechanically ventilated patients was a feasible, safe, and maybe superior strategy in facilitating weaning and disconnection from mechanical ventilation than negative FB-driven fluid removal. FR is a safe endpoint for optimizing cardiac function and preventing adverse consequences during fluid removal.

Evaluation of a Physiologic-Driven Closed-Loop Resuscitation Algorithm in an Animal Model of Hemorrhagic Shock

OBJECTIVES

Appropriate resuscitation from hemorrhagic shock is critical to restore tissue perfusion and to avoid over-resuscitation. The objective of this study was to test the ability of a closed-loop diagnosis and resuscitation algorithm called resuscitation from shock using functional hemodynamic monitoring using invasive monitoring (ReFit1) and minimally invasive monitoring (ReFit2) to identify, treat, and stabilize a porcine model of severe hemorrhagic shock.

DESIGN

We created a ReFit algorithm using dynamic hemodynamic parameters of pulse pressure variation (PPV), stroke volume variation (SVV), dynamic arterial elastance (Ea dyn = PPV/SVV), driven by mean arterial pressure (MAP), mixed venous oxygen saturation, and heart rate targets to define the need for fluids, vasopressors, and inotropes.

SETTING

University-based animal laboratory.

SUBJECTS

Twenty-seven female pigs.

INTERVENTIONS

Anesthetized, intubated, and ventilated (8 mL/kg) pigs were bled at 10 mL/min until a MAP of less than 40 mm Hg, held for 30 minutes, then resuscitated. The ReFit algorithm used the above dynamic parameters to drive computer-controlled infusion pumps to deliver blood, lactated Ringer's solution, norepinephrine, and in ReFit1 dobutamine. In four animals, after initial resuscitation from hemorrhagic shock, the ability of the ReFit1 algorithm to treat acute air embolism-induced pulmonary hypertension and right heart failure was also tested.

MAIN RESULTS

In 10 ReFit1 and 17 ReFit2 animals, the time to stabilization from shock was not dissimilar to open controlled resuscitation performed by an expert physician (52 ± 12, 50 ± 13, and 60 ± 15 min, respectively) with similar amounts of fluids and norepinephrine needed. In four ReFit1 animals after initial stabilization, the algorithm successfully resuscitated the animals after inducing an acute air embolism right heart failure, with all animals recovering stability within 30 minutes.

CONCLUSIONS

Our physiologically based functional hemodynamic monitoring-centered closed-loop resuscitation system can effectively diagnose and treat cardiovascular shock due to hemorrhage and air embolism.

Intraoperative goal-directed hemodynamic therapy through fluid administration to optimize the stroke volume: A meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the clinical impact of optimizing stroke volume (SV) through fluid administration as part of goal-directed hemodynamic therapy (GDHT) in adult patients undergoing elective major abdominal surgery.

METHODS

This systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and was registered in the PROSPERO database in January 2024. The intervention was defined as intraoperative GDHT based on the optimization or maximization of SV through fluid challenges, or by using dynamic indices of fluid responsiveness, including stroke volume variation, pulse pressure variation, and plethysmography variation index compared to usual fluid management. The primary outcome was postoperative complications. Secondary outcome variables included postoperative acute kidney injury (AKI), length of stay (LOS), intraoperative fluid administration, and 30-day mortality.

RESULTS

A total of 29 randomized controlled trials (RCTs) met the inclusion criteria. There were no significant differences in the incidence of postoperative complications (RR 0.89; 95% CI, 0.78-1.00), postoperative AKI (OR 0.97; (95% IC, 0.55-1.70), and mortality (OR 0.80; 95% CI, 0.50-1.29). GDHT was associated with a reduced LOS compared to usual care (SMD: -0.17 [-0.32; -0.03]). The subgroup in which hydroxyethyl starch was used for hemodynamic optimization was associated with fewer complications (RR 0.79; 95% CI, 0.65-0.94), whereas the subgroup of patients in whom crystalloids were used was associated with an increased risk of postoperative complications (RR 1.08; 95% CI, 1.04-1.12).

CONCLUSIONS

In adults undergoing major surgery, goal-directed hemodynamic therapy focused on fluid-based stroke volume optimization did not reduce postoperative morbidity and mortality.

International cross-sectional survey on current and updated definitions of intra-abdominal hypertension and abdominal compartment syndrome

BACKGROUND

The Abdominal Compartment Society (WSACS) established consensus definitions and recommendations for the management of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) in 2006, and they were last updated in 2013. The WSACS conducted an international survey between 2022 and 2023 to seek the agreement of healthcare practitioners (HCPs) worldwide on current and new candidate statements that may be used for future guidelines.

METHODS

A self-administered, online cross-sectional survey was conducted under the auspices of the WSACS to assess the level of agreement among HCPs over current and new candidate statements. The survey, distributed electronically worldwide, collected agreement or disagreement with statements on the measurement of intra-abdominal pressure (IAP), pathophysiology, definitions, and management of IAH/ACS. Statistical analysis assessed agreement levels, expressed in percentages, on statements among respondents, and comparisons between groups were performed according to the respondent's education status, base specialty, duration of work experience, role (intensivist vs non-intensivist) and involvement in previous guidelines. Agreement was considered to be reached when 80% or more of the respondents agreed with a particular statement.

RESULTS

A total of 1042 respondents from 102 countries, predominantly physicians (73%), of whom 48% were intensivists, participated. Only 59% of HCPs were aware of the 2013 WSACS guidelines, and 41% incorporated them into practice. Despite agreement in most statements, significant variability existed. Notably, agreement was not reached on four new candidate statements: "normal intra-abdominal pressure (IAP) is 10 mmHg in critically ill adults" (77%), "clinical assessment and estimation of IAP is inaccurate" (65.2%), "intragastric can be an alternative to the intravesical route for IAP measurement" (70.4%), and "measurement of IAP should be repeated in the resting position after measurement in a supine position" (71.9%). The survey elucidated nuances in clinical practice and highlighted areas for further education and standardization.

CONCLUSION

More than ten years after the last published guidelines, this worldwide cross-sectional survey collected feedback and evaluated the level of agreement with current recommendations and new candidate statements. This will inform the consensus process for future guideline development.

[The ROSE concept: modern fluid management in intensive care medicine]

The ROSE concept, which is the acronym of resuscitation, optimization, stabilization and evacuation, describes the phases of fluid therapy, based on the pathophysiology of septic shock. During the first two phases, aggressive fluid therapy that is guided by clinical and hemodynamic parameters is mandatory. During the stabilization phase, recovery from shock and microcirculatory injury occurs, which enables the depletion of fluid overload in the fourth and final phase. Ultimately, euvolemia needs to be regained, which reverts interstitial edema and organ dysfunction.

Fluid deresuscitation in critically ill children: comparing perspectives of intensivists and nephrologists

Introduction

Fluid accumulation, presently defined as a pathologic state of overhydration/volume overload associated with clinical impact, is common and associated with worse outcomes. At times, deresuscitation, the active removal of fluid via diuretics or ultrafiltration, is necessary. There is no consensus regarding deresuscitation in children admitted to the pediatric intensive care unit. Little is known regarding perceptions and practices among pediatric intensivists and nephrologists regarding fluid provision and deresuscitation.

Methods

Cross-sectional electronic survey of pediatric nephrologists and intensivists from academic societies in the United States designed to better understand fluid management between disciplines. A clinical vignette was used to characterize the perceptions of optimal timing and method of deresuscitation initiation at four timepoints that correspond to different stages of shock.

Results

In total, 179 respondents (140 intensivists, 39 nephrologists) completed the survey. Most 75.4% (135/179) providers believe discussing fluid balance and initiating fluid deresuscitation in pediatric intensive care unit (PICU) patients is "very important". The first clinical vignette time point (corresponding to resuscitation phase of early shock) had the most dissimilarity between intensivists and nephrologists (p = 0.01) with regards to initiation of deresuscitation. However, providers demonstrated increasing agreement in their responses to initiate deresuscitation as the clinical vignette progressed. Compared to intensivists, nephrologists were more likely to choose "dialysis or ultrafiltration" as a deresuscitation method during the optimization [10.3 vs. 2.9% (p = 0.07)], stabilization [18.0% vs. 3.6% (p < 0.01)], and evacuation [48.7% vs. 23.6% (p < 0.01)] phases of shock. Conversely, intensivists were more likely to utilize scheduled diuretics than nephrologists [47.1% vs. 28.2% (p = 0.04)] later on in the patient course.

Discussion

Most physicians believe that discussing fluid balance and deresuscitation is important. Nevertheless, when to initiate deresuscitation and how to accomplish it differed between nephrologist and intensivists. Widely understood and operationalizable definitions, further research, and eventually evidence-based guidelines are needed to help guide care.

Sublingual microcirculatory assessment on admission independently predicts the outcome of old intensive care patients suffering from shock

Shock is a life-threatening condition. This study evaluated if sublingual microcirculatory perfusion on admission is associated with 30-day mortality in older intensive care unit (ICU) shock patients. This trial prospectively recruited ICU patients (≥ 80 years old) with arterial lactate above 2 mmol/L, requiring vasopressors despite adequate fluid resuscitation, regardless of shock cause. All patients received sequential sublingual measurements on ICU admission (± 4 h) and 24 (± 4) hours later. The primary endpoint was 30-day mortality. From September 4th, 2022, to May 30th, 2023, 271 patients were screened, and 44 included. Patients were categorized based on the median percentage of perfused small vessels (sPPV) into those with impaired and sustained microcirculation. 71% of videos were of good or acceptable quality without safety issues. Patients with impaired microcirculation had significantly shorter ICU and hospital stays (p = 0.015 and p = 0.019) and higher 30-day mortality (90.0% vs. 62.5%, p = 0.036). Cox regression confirmed the independent association of impaired microcirculation with 30-day mortality (adjusted hazard ratio 3.245 (95% CI 1.178 to 8.943, p = 0.023). Measuring sublingual microcirculation in critically ill older patients with shock on ICU admission is safe, feasible, and provides independent prognostic information about outcomes.Trial registration NCT04169204.

Testing preload responsiveness by the tidal volume challenge assessed by the photoplethysmographic perfusion index

BACKGROUND

To detect preload responsiveness in patients ventilated with a tidal volume (Vt) at 6 mL/kg of predicted body weight (PBW), the Vt-challenge consists in increasing Vt from 6 to 8 mL/kg PBW and measuring the increase in pulse pressure variation (PPV). However, this requires an arterial catheter. The perfusion index (PI), which reflects the amplitude of the photoplethysmographic signal, may reflect stroke volume and its respiratory variation (pleth variability index, PVI) may estimate PPV. We assessed whether Vt-challenge-induced changes in PI or PVI could be as reliable as changes in PPV for detecting preload responsiveness defined by a PLR-induced increase in cardiac index (CI) ≥ 10%.

METHODS

In critically ill patients ventilated with Vt = 6 mL/kg PBW and no spontaneous breathing, haemodynamic (PICCO2 system) and photoplethysmographic (Masimo-SET technique, sensor placed on the finger or the forehead) data were recorded during a Vt-challenge and a PLR test.

RESULTS

Among 63 screened patients, 21 (33%) were excluded because of an unstable PI signal and/or atrial fibrillation and 42 were included. During the Vt-challenge in the 16 preload responders, CI decreased by 4.8 ± 2.8% (percent change), PPV increased by 4.4 ± 1.9% (absolute change), PIfinger decreased by 14.5 ± 10.7% (percent change), PVIfinger increased by 1.9 ± 2.6% (absolute change), PIforehead decreased by 18.7 ± 10.9 (percent change) and PVIforehead increased by 1.0 ± 2.5 (absolute change). All these changes were larger than in preload non-responders. The area under the ROC curve (AUROC) for detecting preload responsiveness was 0.97 ± 0.02 for the Vt-challenge-induced changes in CI (percent change), 0.95 ± 0.04 for the Vt-challenge-induced changes in PPV (absolute change), 0.98 ± 0.02 for Vt-challenge-induced changes in PIforehead (percent change) and 0.85 ± 0.05 for Vt-challenge-induced changes in PIfinger (percent change) (p = 0.04 vs. PIforehead). The AUROC for the Vt-challenge-induced changes in PVIforehead and PVIfinger was significantly larger than 0.50, but smaller than the AUROC for the Vt-challenge-induced changes in PPV.

CONCLUSIONS

In patients under mechanical ventilation with no spontaneous breathing and/or atrial fibrillation, changes in PI detected during Vt-challenge reliably detected preload responsiveness. The reliability was better when PI was measured on the forehead than on the fingertip. Changes in PVI during the Vt-challenge also detected preload responsiveness, but with lower accuracy.

Fluid Overload in Pediatric Acute Respiratory Distress Syndrome after Allogeneic Hematopoietic Cell Transplantation

The aim of the study is to examine the relationship between fluid overload (FO) and severity of respiratory dysfunction in children posthematopoietic cell transplantation (HCT) with pediatric acute respiratory distress syndrome (PARDS). This investigation was a secondary analysis of a multicenter retrospective cohort of children (1month to 21 years) postallogeneic HCT with PARDS receiving invasive mechanical ventilation (IMV) from 2009 to 2014. Daily FO % (FO%) and daily oxygenation index (OI) were calculated for each patient up to the first week of IMV (day 0 = intubation). Linear mixed-effect regression was employed to examine whether FO% and OI were associated on any day during the study period. In total, 158 patients were included. Severe PARDS represented 63% of the cohort and had higher mortality (78 vs. 42%, p <0.001), fewer ventilator free days at 28 (0 [IQR: 0-0] vs. 14 [IQR: 0-23], p <0.001), and 60 days (0 [IQR: 0-27] v. 45 [IQR: 0-55], p <0.001) relative to nonsevere PARDS. Increasing FO% was strongly associated with higher OI ( p <0.001). For children with 10% FO, OI was higher by nearly 5 points (adjusted β , 4.6, 95% CI: [2.9, 6.3]). In subgroup analyses, the association between FO% and OI was strongest among severe PARDS ( p <0.001) and during the first 3 days elapsed from intubation ( p <0.001). FO% was associated with lower PaO 2 /FiO 2 (adjusted β , -1.92, 95% CI: [-3.11, -0.73], p  = 0.002), but not mean airway pressure ( p  = 0.746). In a multicenter cohort of children post-HCT with PARDS, FO was independently associated with oxygenation impairment. The associations were strongest among children with severe PARDS and early in the course of IMV.

Effect of rigorous fluid management using monitoring of ECW ratio by bioelectrical impedance analysis in critically ill postoperative patients: A prospective, single-blind, randomized controlled study

BACKGROUND & AIMS

Precise assessment of postoperative volume status is important to administrate optimal fluid management. Bioelectrical impedance analysis (BIA) which measures the body composition using electric character. Extracellular water (ECW) ratio by BIA represented as the ratio of ECW to total body water (TBW) and is known to reflect the hydration status. Based on this, we aimed to determine whether aggressive fluid control using ECW ratio could improve clinical outcomes through a single blind, randomized controlled trial.

METHODS

From November 2021 to December 2022, intensive care unit (ICU) patients admitted after surgery were randomly assigned to an intervention group or a control group whether postoperative fluid management was controlled via BIA. Among patients in the intervention group, dehydrated patients received a bolus infusion with crystalloid fluid whereas diuretics were administrated to overhydrated patients until the value of ECW ratio fell within its normal setting range (0.390-0.406). Contrarily, BIA was performed once a day for the control group. Patients in the control group received traditional fluid treatment regardless of BIA results. Primary outcome was in-hospital mortality in two groups. The secondary outcomes were postoperative morbidities, 28-day mortality.

RESULTS

77 patients of the intervention group and 90 patients of the control group were finally analyzed. The in-hospital mortality (0 in intervention, 4.4% in control, p = 0.125) and 28-day mortality (1.3% in intervention, 14.4% in control, p = 0.002) showed lower incidence in the intervention group than in the control group. In multivariate analysis, the overhydrated status whose ECW ratio exceeding 0.406 [odds ratio (OR): 2.731, 95% confidence interval (CI): 1.001-7.663, p = 0.049] and high capillary leak index (CLI) value at ICU admission (OR: 1.024, 95% CI: 1.008-1.039, p = 0.002) were risk factors of postoperative morbidities. Regarding the 28-day mortality, high CLI value (OR: 1.025, 95% CI: 1.002-1.050, p = 0.037) and traditional strategy without BIA monitoring (OR: 9.903, 95% CI: 1.095-89.566, p = 0.041) were the significant predisposing factors.

CONCLUSION

Our results revealed the rigorous fluid treatment with volume control based on ECW ratio by BIA failed to achieve significant improvement in in-hospital mortality, but it could reduce 28-day mortality of ICU patients. Monitoring of ECW ratio may help establish optimal fluid treatment strategies for postoperative ICU patients who are susceptible to fluid imbalances with fluid overload.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT06097923, retrospectively registered on October 16, 2023, https://clinicaltrials.gov/study/NCT06097923?term=NCT06097923&rank=1.

Fluid boluses and infusions in the early phase of resuscitation from septic shock and sepsis-induced hypotension: a retrospective report and outcome analysis from a tertiary hospital

BACKGROUND

Fluid administration is the first line treatment in intensive care unit (ICU) patients with sepsis and septic shock. While fluid boluses administration can be titrated by predicting preload dependency, the amount of other forms of fluids may be more complex to be evaluated. We conducted a retrospective analysis in a tertiary hospital, to assess the ratio between fluids given as boluses and total administered fluid intake during early phases of ICU stay, and to evaluate the impact of fluid strategy on ICU mortality. Data related to fluid administration during the first four days of ICU stay were exported from an electronic health records system (ICCA®, Philips Healthcare). Demographic data, severity score, norepinephrine dose at ICU admission, overall fluid balance and the percentage of different fluid components of the overall volume administered were included in a multivariable logistic regression model, evaluating the association with ICU survival.

RESULTS

We analyzed 220 patients admitted with septic shock and sepsis-induced hypotension from 1st July 2021 to 31st December 2023. Fluid boluses and maintenance represented 49.3% ± 22.8 of the overall fluid intake, being balanced solution the most represented (40.4% ± 22.0). The fluid volume for drug infusion represented 34.0% ± 2.9 of the total fluid intake, while oral or via nasogastric tube fluid intake represented 18.0% ± 15.7 of the total fluid intake. Fluid volume given as boluses represented 8.6% of the total fluid intake over the four days, with a reduction from 25.1% ± 24.0 on Day 1 to 4.8% ± 8.7 on Day 4. A positive fluid balance [OR 1.167 (1.029-1.341); p = 0.021] was the most important factor associated with ICU mortality. Non-survivors (n = 66; 30%) received a higher amount of overall inputs than survivors only on Day 1 [2493 mL vs. 1855 mL; p = 0.022].

CONCLUSIONS

This retrospective analysis of fluids given over the early phases of septic shock and sepsis-induced hypotension showed that the overall volume given by boluses ranges from about 25% on Day 1 to about 5% on Day 4 from ICU admission. Our data confirms that a positive fluid balance over the first 4 days of ICU is associated with mortality.

Fluid accumulation syndrome in sepsis and septic shock: pathophysiology, relevance and treatment-a comprehensive review

In this review, we aimed to comprehensively summarize current literature on pathophysiology, relevance, diagnosis and treatment of fluid accumulation in patients with sepsis/septic shock. Fluid accumulation syndrome (FAS) is defined as fluid accumulation (any degree, expressed as percentage from baseline body weight) with new onset organ-failure. Over the years, many studies have described the negative impact of FAS on clinically relevant outcomes. While the relationship between FAS and ICU outcomes is well described, uncertainty exists regarding its diagnosis, monitoring and treatment. A stepwise approach is suggested to prevent and treat FAS in patients with septic shock, including minimizing fluid intake (e.g., by limiting intravenous fluid administration and employing de-escalation whenever possible), limiting sodium and chloride administration, and maximizing fluid output (e.g., with diuretics, or renal replacement therapy). Current literature implies the need for a multi-tier, multi-modal approach to de-resuscitation, combining a restrictive fluid management regime with a standardized early active de-resuscitation, maintenance fluid reduction (avoiding fluid creep) and potentially using physical measures such as compression stockings.Trial registration: Not applicable.

Optimization of kidney function in cardiac surgery patients with intra-abdominal hypertension: expert opinion

Cardiac surgery-associated acute kidney injury (CSA-AKI) affects up to 42% of cardiac surgery patients. CSA-AKI is multifactorial, with low abdominal perfusion pressure often overlooked. Abdominal perfusion pressure is calculated as mean arterial pressure minus intra-abdominal pressure (IAP). IAH decreases cardiac output and compresses the renal vasculature and renal parenchyma. Recent studies have highlighted the frequent occurrence of IAH in cardiac surgery patients and have linked the role of low perfusion pressure to the occurrence of AKI. This review and expert opinion illustrate current evidence on the pathophysiology, diagnosis, and therapy of IAH and ACS in the context of AKI.