Is the NICE Guideline for maintenance fluid therapy in adults in hospital appropriate?

BACKGROUND AND AIMS: The National Institute for Health and Care Excellence's (NICE) Guideline for Maintenance Fluid Therapy in Adults in Hospital is widely used, but the recommendations have not been evaluated properly. In this study, we investigated whether the recommendation of providing 25-30 mL/kg/day of fluid and 1 mmol/kg each of sodium and potassium is sufficient for human needs. METHODS: First, we calculated the distribution of fluid between the extracellular fluid volume (ECV) and intracellular fluid volume (ICV) during a cross-over infusion experiment where 12 volunteers received 25 mL/kg/day of either a high-sodium (154 mmol/L) or low-sodium (54 mmol/L) solution over 48 h. Second, urine samples from 719 volunteers and clinical patients were used to quantify their renal water conservation and excretion of sodium and potassium. Third, retrospective analysis of a diet study was used to extrapolate how large the fluid intake and the electrolyte excretion likely had been in the 719 volunteers and hospital patients who delivered urine. RESULTS: The high-sodium fluid maintained the ECV but the ICV had decreased by 1.3 L after 48 h. The low-sodium fluid resulted in a volume deficit of 1.7 L that equally affected the ECV and the ICV. Regression equations based on the diet study suggested that the daily intake of water in the 719 subjects averaged 2.6 L and that 2 mmol/kg of sodium and 1 mmol/kg of potassium was excreted. CONCLUSION: The NICE guideline recommends too little water and sodium for a human to adequately maintain the ECV and ICV. CLINICAL TRIAL REGISTRATIONS: EudraCT 2016-001846-24 and ISRCTN 12215472.

Choice of creep or maintenance fluid type and their impact on total daily ICU sodium burden in critically ill patients: A systematic review and meta-analysis.

PURPOSE: Maintenance and hidden/creep fluids are a major source of fluid and sodium intake in intensive care unit (ICU) patients. Recent research indicates that low versus high sodium content maintenance fluids could decrease fluid and sodium burden. We conducted a systematic review (SR) with meta-analysis to summarize the impact of maintenance fluid choice on total daily sodium in ICU patients. MATERIALS AND METHODS: Systematic literature search in Pubmed, Embase, the Cochrane Library and the. CLINICAL TRIALS REGISTRY: Only controlled clinical trials were included. EXCLUSION CRITERIA: trials on resuscitation fluids, performed in the emergency department only and in pediatric patients. Primary objective was the reduction in mean total sodium intake with low versus high sodium content maintenance/creep fluids. RESULTS: Five studies (1105 patients) were included. Heterogeneity was high.Risk of bias was moderate. Mean daily sodium reduction was 117 mmol (95%Confidence Interval [CI] -174; -59; p < 0.001) with low versus high sodium content maintenance/creep fluids. Incidence of hyperchloremia was lower (OR 0.26; 95%CI 0.1; 0.64) with low sodium. There were no differences in the incidences of hyper-/hyponatremia and fluid balances. CONCLUSION: Using low sodium content maintenance/creep fluids substantially reduces daily sodium burden in adult ICU patients. Significant knowledge/research gaps exist regarding relevance and safety. TRIAL REGISTRATION: PROSPERO 2022 CRD42022300577 (February 2022).

Is it feasible to measure intra-abdominal pressure using a balloon-tipped rectal catheter? Results of a validation study.

The gold standard to measure intra-abdominal pressure (IAP) is intra-vesical measurement via the urinary bladder. However, this technique is restricted in ambulatory settings because of the risk of iatrogenic urinary tract infections. Rectal IAP measurements (IAPrect) may overcome these limitations, but requires validation. This validation study compares the IAPrect technique against gold standard intra-vesical IAP measurements (IAPves). IAPrect using an air-filled balloon catheter and IAPves using Foley Manometer Low Volume were measured simultaneously in sedated and ventilated patients. Measurements were performed twice in different positions (supine and HOB 45° elevated head of bed) and with an external abdominal pressure belt. Sixteen patients were included. Seven were not eligible for analysis due to unreliable IAPrect values. IAPrect was significantly higher than IAPves for all body positions (p < 0.01) and the correlation between IAPves and IAPrect was poor and not significant in each position (p ≥ 0.25, R2 < 0.6, Lin's CCC < 0.8, bias - 8.1 mmHg and precision of 5.6 mmHg with large limits of agreement between - 19 to 2.9 mmHg, high percentage error 67.3%, and low concordance 86.2%). Repeatability of IAPrect was not reliable (R = 0.539, p = 0.315). For both techniques, measurements with the external abdominal pressure belt were significantly higher compared to those without (p < 0.03). IAPrect has important shortcomings making IAP estimation using a rectal catheter unfeasible because the numbers cannot be trusted nor validated.

Comparison of Bioelectrical Impedance Analysis (BIA)-Derived Parameters in Healthy Volunteers and Critically Ill Patients.

OBJECTIVE: To compare bioelectrical impedance analysis (BIA)-derived parameters in healthy volunteers and critically ill patients and to assess its prognostic value in an ICU patient cohort. DESIGN: Retrospective, observational data analysis. SETTING: Single centre, tertiary-level ICU (Ziekenhuis Netwerk Antwerpen, ZNA Stuivenberg Hospital). PATIENTS: 101 patients and 101 healthy subjects, participants of International Fluid Academy Days. MEASUREMENTS AND MAIN RESULTS: Compared to healthy volunteers, both male and female ICU patients had significantly higher values for total body water (TBW), extracellular water (ECW), extracellular fluid (ECF), plasma, and interstitial fluid volumes. The phase angle was significantly lower and the malnutrition index was significantly higher in ICU patients, regardless of gender. Non-survivors in the ICU had significantly higher extracellular water content (ECW, 50.7 ± 5.1 vs. 48.9 ± 4.3%, p = 0.047) and accordingly significantly lower intracellular water (ICW, 49.2 ± 5.1 vs. 51.1 ± 4.3%, p = 0.047). The malnutrition index was also significantly higher in non-survivors compared to survivors (0.94 ± 0.17 vs. 0.87 ± 0.16, p = 0.048), as was the capillary leak index (ECW/ICW). CONCLUSIONS: Compared to healthy volunteers, this study observed a higher malnutrition index and TBW in ICU patients with an accumulation of fluids in the extracellular compartment. ICU non-survivors showed similar results, indicating that ICU patients and a fortiori non-survivors are generally overhydrated, with increased TBW and ECW, and more undernourished, as indicated by a higher malnutrition index.

Intravenous fluid therapy in patients with severe acute pancreatitis admitted to the intensive care unit: a narrative review.

Patients with acute pancreatitis (AP) often require ICU admission, especially when signs of multiorgan failure are present, a condition that defines AP as severe. This disease is characterized by a massive pancreatic release of pro-inflammatory cytokines that causes a systemic inflammatory response syndrome and a profound intravascular fluid loss. This leads to a mixed hypovolemic and distributive shock and ultimately to multiorgan failure. Aggressive fluid resuscitation is traditionally considered the mainstay treatment of AP. In fact, all available guidelines underline the importance of fluid therapy, particularly in the first 24-48 h after disease onset. However, there is currently no consensus neither about the type, nor about the optimal fluid rate, total volume, or goal of fluid administration. In general, a starting fluid rate of 5-10 ml/kg/h of Ringer's lactate solution for the first 24 h has been recommended. Fluid administration should be aggressive in the first hours, and continued only for the appropriate time frame, being usually discontinued, or significantly reduced after the first 24-48 h after admission. Close clinical and hemodynamic monitoring along with the definition of clear resuscitation goals are fundamental. Generally accepted targets are urinary output, reversal of tachycardia and hypotension, and improvement of laboratory markers. However, the usefulness of different endpoints to guide fluid therapy is highly debated. The importance of close monitoring of fluid infusion and balance is acknowledged by most available guidelines to avoid the deleterious effect of fluid overload. Fluid therapy should be carefully tailored in patients with severe AP, as for other conditions frequently managed in the ICU requiring large fluid amounts, such as septic shock and burn injury. A combination of both noninvasive clinical and invasive hemodynamic parameters, and laboratory markers should guide clinicians in the early phase of severe AP to meet organ perfusion requirements with the proper administration of fluids while avoiding fluid overload. In this narrative review the most recent evidence about fluid therapy in severe AP is discussed and an operative algorithm for fluid administration based on an individualized approach is proposed.

Fluid Management, Intra-Abdominal Hypertension and the Abdominal Compartment Syndrome: A Narrative Review.

BACKGROUND: General pathophysiological mechanisms regarding associations between fluid administration and intra-abdominal hypertension (IAH) are evident, but specific effects of type, amount, and timing of fluids are less clear. OBJECTIVES: This review aims to summarize current knowledge on associations between fluid administration and intra-abdominal pressure (IAP) and fluid management in patients at risk of intra-abdominal hypertension and abdominal compartment syndrome (ACS). METHODS: We performed a structured literature search from 1950 until May 2021 to identify evidence of associations between fluid management and intra-abdominal pressure not limited to any specific study or patient population. Findings were summarized based on the following information: general concepts of fluid management, physiology of fluid movement in patients with intra-abdominal hypertension, and data on associations between fluid administration and IAH. RESULTS: We identified three randomized controlled trials (RCTs), 38 prospective observational studies, 29 retrospective studies, 18 case reports in adults, two observational studies and 10 case reports in children, and three animal studies that addressed associations between fluid administration and IAH. Associations between fluid resuscitation and IAH were confirmed in most studies. Fluid resuscitation contributes to the development of IAH. However, patients with IAH receive more fluids to manage the effect of IAH on other organ systems, thereby causing a vicious cycle. Timing and approach to de-resuscitation are of utmost importance, but clear indicators to guide this decision-making process are lacking. In selected cases, only surgical decompression of the abdomen can stop deterioration and prevent further morbidity and mortality. CONCLUSIONS: Current evidence confirms an association between fluid resuscitation and secondary IAH, but optimal fluid management strategies for patients with IAH remain controversial.

Lung epithelial and myeloid innate immunity in influenza-associated or COVID-19-associated pulmonary aspergillosis: an observational study.

BACKGROUND: Influenza-associated pulmonary aspergillosis (IAPA) and COVID-19-associated pulmonary aspergillosis (CAPA) affect about 15% of critically ill patients with influenza or COVID-19, respectively. These viral-fungal coinfections are difficult to diagnose and are associated with increased mortality, but data on their pathophysiology are scarce. We aimed to explore the role of lung epithelial and myeloid innate immunity in patients with IAPA or CAPA. METHODS: In this observational study, we retrospectively recruited patients who had been admitted to the intensive care unit (ICU) of University Hospitals Leuven, Belgium, requiring non-invasive or invasive ventilation because of severe influenza or COVID-19, with or without aspergillosis, between Jan 1, 2011, and March 31, 2021, whose bronchoalveolar lavage samples were available at the hospital biobank. Additionally, biobanked in vivo tracheobronchial biopsy samples from patients with IAPA or CAPA and invasive Aspergillus tracheobronchitis admitted to ICUs requiring invasive ventilation between the same dates were collected from University Hospitals Leuven, Hospital Network Antwerp (Belgium), and Amiens-Picardie University Hospital (France). We did nCounter gene expression analysis of 755 genes linked to myeloid innate immunity and protein analysis of 47 cytokines, chemokines, and growth factors on the bronchoalveolar lavage samples. Gene expression data were used to infer cell fractions by use of CIBERSORTx, to perform hypergeometric enrichment pathway analysis and gene set enrichment analysis, and to calculate pathway module scores for the IL-1ß, TNF-α, type I IFN, and type II IFN (IFNγ) pathways. We did RNAScope targeting influenza virus or SARS-CoV-2 RNA and GeoMx spatial transcriptomics on the tracheobronchial biopsy samples. FINDINGS: Biobanked bronchoalveolar lavage samples were retrieved from 166 eligible patients, of whom 40 had IAPA, 52 had influenza without aspergillosis, 33 had CAPA, and 41 had COVID-19 without aspergillosis. We did nCounter gene expression analysis on bronchoalveolar lavage samples from 134 patients, protein analysis on samples from 162 patients, and both types of analysis on samples from 130 patients. We performed RNAScope and spatial transcriptomics on the tracheobronchial biopsy samples from two patients with IAPA plus invasive Aspergillus tracheobronchitis and two patients with CAPA plus invasive Aspergillus tracheobronchitis. We observed a downregulation of genes associated with antifungal effector functions in patients with IAPA and, to a lesser extent, in patients with CAPA. We found a downregulated expression of several genes encoding proteins with functions in the opsonisation, recognition, and killing of conidia in patients with IAPA versus influenza only and in patients with CAPA versus COVID-19 only. Several genes related to LC3-associated phagocytosis, autophagy, or both were differentially expressed. Patients with CAPA had significantly lower neutrophil cell fractions than did patients with COVID-19 only. Patients with IAPA or CAPA had downregulated IFNγ signalling compared with patients with influenza only or COVID-19 only, respectively. The concentrations of several fibrosis-related growth factors were significantly elevated in the bronchoalveolar lavage fluid from patients with IAPA versus influenza only and from patients with CAPA versus COVID-19 only. In one patient with CAPA, we visualised an active or very recent SARS-CoV-2 infection disrupting the epithelial barrier, facilitating tissue-invasive aspergillosis. INTERPRETATION: Our results reveal a three-level breach in antifungal immunity in IAPA and CAPA, affecting the integrity of the epithelial barrier, the capacity to phagocytise and kill Aspergillus spores, and the ability to destroy Aspergillus hyphae, which is mainly mediated by neutrophils. The potential of adjuvant IFNγ in the treatment of IAPA and CAPA should be investigated. FUNDING: Research Foundation Flanders, Coronafonds, the Max Planck Society, the Fundação para a Ciência e a Tecnologia, the European Regional Development Fund, "la Caixa" Foundation, and Horizon 2020.

Prognostic Impact of Bronchoalveolar Lavage Fluid Galactomannan and Aspergillus Culture Results on Survival in COVID-19 Intensive Care Unit Patients: a Post Hoc Analysis from the European Confederation of Medical Mycology (ECMM) COVID-19-Associated Pulmonary Aspergillosis Study.

Critically ill patients with coronavirus disease 2019 (COVID-19) may develop COVID-19-associated pulmonary aspergillosis (CAPA), which impacts their chances of survival. Whether positive bronchoalveolar lavage fluid (BALF) mycological tests can be used as a survival proxy remains unknown. We conducted a post hoc analysis of a previous multicenter, multinational observational study with the aim of assessing the differential prognostic impact of BALF mycological tests, namely, positive (optical density index of ≥1.0) BALF galactomannan (GM) and positive BALF Aspergillus culture alone or in combination for critically ill patients with COVID-19. Of the 592 critically ill patients with COVID-19 enrolled in the main study, 218 were included in this post hoc analysis, as they had both test results available. CAPA was diagnosed in 56/218 patients (26%). Most cases were probable CAPA (51/56 [91%]) and fewer were proven CAPA (5/56 [9%]). In the final multivariable model adjusted for between-center heterogeneity, an independent association with 90-day mortality was observed for the combination of positive BALF GM and positive BALF Aspergillus culture in comparison with both tests negative (hazard ratio, 2.53; 95% CI confidence interval [CI], 1.28 to 5.02; P = 0.008). The other independent predictors of 90-day mortality were increasing age and active malignant disease. In conclusion, the combination of positive BALF GM and positive BALF Aspergillus culture was associated with increased 90-day mortality in critically ill patients with COVID-19. Additional study is needed to explore the possible prognostic value of other BALF markers.

A retrospective evaluation of three ethical triage tools for the allocation of ICU resources during the first wave of the COVID-19 pandemic.

PURPOSE: To retrospectively evaluate the effect of ethical triage tools (ETT), designed to streamline the admission of patients during the first wave of the COVID-19 pandemic. We aimed to determine the characteristics and outcomes of the patients who would have been denied admission to the ICU according to these protocols, including the cumulative number of saved ICU days. METHODS: We retrospectively identified the ethical triage status in every patient who was admitted to our 31-bed mixed ICU in Antwerp, Belgium during the first wave of the COVID-19 pandemic, regardless of the reason for admission. This study was possible since the capacity of our ICU had not been threatened, still enabling our usual case-per-case decision. We evaluated three different ETTs that were designed in our and two other hospitals during the COVID-19 pandemic. RESULTS: During the 81-day study period, 182 patients were admitted to the ICU. Of the patients, 9-23% would have been denied ICU admission according to the three assessed ETTs (WBD cohort), responsible for 8-18% (n = 116-257) of the total number of ICU days. Of the WBD patients, 44-55% eventually survived their hospital stay, compared to 71-74% of the patients that would have been allowed admission. Of the WBD patients admitted for respiratory failure due to COVID-19, 18-25% survived, a number that decreased to 0-20% when these patients required mechanical ventilation. CONCLUSION: An ETT effectively reduces ICU bed occupancy but it does not accurately discriminate between survivors and non-survivors, as a substantial percentage of patients who are being denied admission to the ICU would eventually survive their hospital stay.

Risk factors and outcome of pulmonary aspergillosis in critically ill coronavirus disease 2019 patients-a multinational observational study by the European Confederation of Medical Mycology.

OBJECTIVES: Coronavirus disease 2019 (COVID-19) -associated pulmonary aspergillosis (CAPA) has emerged as a complication in critically ill COVID-19 patients. The objectives of this multinational study were to determine the prevalence of CAPA in patients with COVID-19 in intensive care units (ICU) and to investigate risk factors for CAPA as well as outcome. METHODS: The European Confederation of Medical Mycology (ECMM) conducted a multinational study including 20 centres from nine countries to assess epidemiology, risk factors and outcome of CAPA. CAPA was defined according to the 2020 ECMM/ISHAM consensus definitions. RESULTS: A total of 592 patients were included in this study, including 11 (1.9%) patients with histologically proven CAPA, 80 (13.5%) with probable CAPA, 18 (3%) with possible CAPA and 483 (81.6%) without CAPA. CAPA was diagnosed a median of 8 days (range 0-31 days) after ICU admission predominantly in older patients (adjusted hazard ratio (aHR) 1.04 per year; 95% CI 1.02-1.06) with any form of invasive respiratory support (HR 3.4; 95% CI 1.84-6.25) and receiving tocilizumab (HR 2.45; 95% CI 1.41-4.25). Median prevalence of CAPA per centre was 10.7% (range 1.7%-26.8%). CAPA was associated with significantly lower 90-day ICU survival rate (29% in patients with CAPA versus 57% in patients without CAPA; Mantel-Byar p < 0.001) and remained an independent negative prognostic variable after adjusting for other predictors of survival (HR 2.14; 95% CI 1.59-2.87, p ≤ 0.001). CONCLUSION: Prevalence of CAPA varied between centres. CAPA was significantly more prevalent among older patients, patients receiving invasive ventilation and patients receiving tocilizumab, and was an independent strong predictor of ICU mortality.

Early high antibody titre convalescent plasma for hospitalised COVID-19 patients: DAWn-plasma.

BACKGROUND: Several randomised clinical trials have studied convalescent plasma for coronavirus disease 2019 (COVID-19) using different protocols, with different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralising antibody titres, at different time-points and severities of illness. METHODS: In the prospective multicentre DAWn-plasma trial, adult patients hospitalised with COVID-19 were randomised to 4 units of open-label convalescent plasma combined with standard of care (intervention group) or standard of care alone (control group). Plasma from donors with neutralising antibody titres (50% neutralisation titre (NT50)) ≥1/320 was the product of choice for the study. RESULTS: Between 2 May 2020 and 26 January 2021, 320 patients were randomised to convalescent plasma and 163 patients to the control group according to a 2:1 allocation scheme. A median (interquartile range) volume of 884 (806-906) mL) convalescent plasma was administered and 80.68% of the units came from donors with neutralising antibody titres (NT50) ≥1/320. Median time from onset of symptoms to randomisation was 7 days. The proportion of patients alive and free of mechanical ventilation on day 15 was not different between both groups (convalescent plasma 83.74% (n=267) versus control 84.05% (n=137)) (OR 0.99, 95% CI 0.59-1.66; p=0.9772). The intervention did not change the natural course of antibody titres. The number of serious or severe adverse events was similar in both study arms and transfusion-related side-effects were reported in 19 out of 320 patients in the intervention group (5.94%). CONCLUSIONS: Transfusion of 4 units of convalescent plasma with high neutralising antibody titres early in hospitalised COVID-19 patients did not result in a significant improvement of clinical status or reduced mortality.

Effect of the First Wave of the Belgian COVID-19 Pandemic on Physician-Provided Prehospital Critical Care in the City of Antwerp (Belgium).

INTRODUCTION: There is evidence to suggest that patients delayed seeking urgent medical care during the first wave of the coronavirus disease 2019 (COVID-19) pandemic. A delay in health-seeking behavior could increase the disease severity of patients in the prehospital setting. The combination of COVID-19-related missions and augmented disease severity in the prehospital environment could result in an increase in the number and severity of physician-staffed prehospital interventions, potentially putting a strain on this highly specialized service. STUDY OBJECTIVE: The aim was to investigate if the COVID-19 pandemic influences the frequency of physician-staffed prehospital interventions, prehospital mortality, illness severity during prehospital interventions, and the distribution in the prehospital diagnoses. METHODS: A retrospective, multicenter cohort study was conducted on prehospital charts from March 14, 2020 through April 30, 2020, compared to the same period in 2019, in an urban area. Recorded data included demographics, prehospital diagnosis, physiological parameters, mortality, and COVID-status. A modified National Health Service (NHS) National Early Warning Score (NEWS) was calculated for each intervention to assess for disease severity. Data were analyzed with univariate and descriptive statistics. RESULTS: There was a 31% decrease in physician-staffed prehospital interventions during the period under investigation in 2020 as compared to 2019 (2019: 644 missions and 2020: 446 missions), with an increase in prehospital mortality (OR = 0.646; 95% CI, 0.435 - 0.959). During the study period, there was a marked decrease in the low and medium NEWS groups, respectively, with an OR of 1.366 (95% CI, 1.036 - 1.802) and 1.376 (0.987 - 1.920). A small increase was seen in the high NEWS group, with an OR of 0.804 (95% CI, 0.566 - 1.140); 2019: 80 (13.67%) and 2020: 69 (16.46%). With an overall decrease in cases in all diagnostic categories, a significant increase was observed for respiratory illness (31%; P = .004) and cardiac arrest (54%; P < .001), combined with a significant decrease for intoxications (-58%; P = .007). Due to the national test strategy at that time, a COVID-19 polymerase chain reaction (PCR) result was available in only 125 (30%) patients, of which 20 (16%) were positive. CONCLUSION: The frequency of physician-staffed prehospital interventions decreased significantly. There was a marked reduction in interventions for lower illness severity and an increase in higher illness severity and mortality. Further investigation is needed to fully understand the reasons for these changes.

Effect of sodium administration on fluid balance and sodium balance in health and the perioperative setting. Extended summary with additional insights from the MIHMoSA and TOPMAST studies.

PURPOSE: We aimed to provide an extended analysis of the physiological handling of of the sodium burden induced by maintenance fluids. MATERIALS AND METHODS: We revisited two studies that demonstrated, in healthy volunteers and in surgical patients, that maintenance fluids with 154 mmol/L of sodium lead to a more positive fluid balance than a regimen containing 54 mmol/L. We report different unpublished data on the renal handling of the imposed sodium burdens with specific attention to the resulting fluid and sodium balances. RESULTS: The kidneys adapt to the sodium-rich fluids not only by altering sodium excretion, but also by retaining extra free water by concentrating urine. Realigning urinary sodium excretion with an increased administration takes around one day in health and much longer in the clinical setting. This difference may be explained by the presence of hypovolemia-induced aldosterone secretion in the latter group. Non-osmotic storage of sodium limits an unrestrained fluid retention even when very high amounts of sodium are administered but fluid accumulation will inevitably be further prolonged. CONCLUSIONS: Sodium administration induced by sodium-rich maintenance fluids leads, especially in the clinical setting, to prolonged fluid retention when compared with a regimen that resembles a healthy dietary sodium intake, even when kidney function is normal.

Multinational Observational Cohort Study of COVID-19-Associated Pulmonary Aspergillosis1.

We performed an observational study to investigate intensive care unit incidence, risk factors, and outcomes of coronavirus disease-associated pulmonary aspergillosis (CAPA). We found 10%-15% CAPA incidence among 823 patients in 2 cohorts. Several factors were independently associated with CAPA in 1 cohort and mortality rates were 43%-52%.

Fluid-induced harm in the hospital: look beyond volume and start considering sodium. From physiology towards recommendations for daily practice in hospitalized adults.

PURPOSE: Iatrogenic fluid overload is a potential side effect of intravenous fluid therapy in the hospital. Little attention has been paid to sodium administration as a separate cause of harm. With this narrative review, we aim to substantiate the hypothesis that a considerable amount of fluid-induced harm is caused not only by fluid volume, but also by the sodium that is administered to hospitalized patients. METHODS: We show how a regular dietary sodium intake is easily surpassed by the substantial amounts of sodium that are administered during typical hospital stays. The most significant sodium burdens are caused by isotonic maintenance fluid therapy and by fluid creep, defined as the large volume unintentionally administered to patients in the form of dissolved medication. In a section on physiology, we elaborate on the limited renal handling of an acute sodium load. We demonstrate how the subsequent retention of water is an energy-demanding, catabolic process and how free water is needed to excrete large burdens of sodium. We quantify the effect size of sodium-induced fluid retention and discuss its potential clinical impact. Finally, we propose preventive measures, discuss the benefits and risks of low-sodium maintenance fluid therapy, and explore options for reducing the amount of sodium caused by fluid creep. CONCLUSION: The sodium burdens caused by isotonic maintenance fluids and fluid creep are responsible for an additional and avoidable derailment of fluid balance, with presumed clinical consequences. Moreover, the handling of sodium overload is characterized by increased catabolism. Easy and effective measures for reducing sodium load and fluid retention include choosing a hypotonic rather than isotonic maintenance fluid strategy (or avoiding these fluids when enough free water is provided through other sources) and dissolving as many medications as possible in glucose 5%.