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

Fluid dynamics of life: exploring the physiology and importance of water in the critical illness

Water acknowledged as a vital component for life and the universal solvent, is crucial for diverse physiological processes in the human body. While essential for survival, the human body lacks the capacity to produce water, emphasizing the need for regular ingestion to maintain a homeostatic environment. The human body, predominantly composed of water, exhibits remarkable biochemical properties, playing a pivotal role in processes such as protein transport, thermoregulation, the cell cycle, and acid–base balance. This review delves into comprehending the molecular characteristics of water and its interactions within the human body. The article offers valuable insights into the intricate relationship between water and critical illness. Through a comprehensive exploration, it seeks to enhance our understanding of water’s pivotal role in sustaining overall human health.

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).

Effect of controlled hypotensive hemorrhage on plasma sodium levels in anesthetized pigs: An exploratory study

Perioperative hyponatremia, due to non-osmotic release of the antidiuretic hormone arginine vasopressin, is a serious electrolyte disorder observed in connection with many types of surgery. Since blood loss during surgery contributes to the pathogenesis of hyponatremia, we explored the effect of bleeding on plasma sodium using a controlled hypotensive hemorrhage pig model. After 30-min baseline period, hemorrhage was induced by aspiration of blood during 30 min at mean arterial pressure <50 mmHg. Thereafter, the animals were resuscitated with retransfused blood and a near-isotonic balanced crystalloid solution and monitored for 180 min. Electrolyte and water balances, cardiovascular response, renal hemodynamics, and markers of volume regulation and osmoregulation were investigated. All pigs (n = 10) developed hyponatremia. All animals retained hypotonic fluid, and none could excrete net-free water. Urinary excretion of aquaporin 2, a surrogate marker of collecting duct responsiveness to antidiuretic hormone, was significantly reduced at the end of the study, whereas lysine vasopressin, i.e., the pig antidiuretic hormone remained high. In this animal model, hyponatremia developed due to net positive fluid balance and generation of electrolyte-free water by the kidneys. A decreased urinary aquaporin 2 excretion may indicate an escape from antidiuresis.

Role of Crystalloids in the Perioperative Setting: From Basics to Clinical Applications and Enhanced Recovery Protocols

Perioperative fluid management, a critical aspect of major surgeries, is characterized by pronounced stress responses, altered capillary permeability, and significant fluid shifts. Recognized as a cornerstone of enhanced recovery protocols, effective perioperative fluid management is crucial for optimizing patient recovery and preventing postoperative complications, especially in high-risk patients. The scientific literature has extensively investigated various fluid infusion regimens, but recent publications indicate that not only the volume but also the type of fluid infused significantly influences surgical outcomes. Adequate fluid therapy prescription requires a thorough understanding of the physiological and biochemical principles that govern the body's internal environment and the potential perioperative alterations that may arise. Recently published clinical trials have questioned the safety of synthetic colloids, widely used in the surgical field. A new clinical scenario has arisen in which crystalloids could play a pivotal role in perioperative fluid therapy. This review aims to offer evidence-based clinical principles for prescribing fluid therapy tailored to the patient's physiology during the perioperative period. The approach combines these principles with current recommendations for enhanced recovery programs for surgical patients, grounded in physiological and biochemical principles.

Sánchez-Margallo F, Eugenia Candanosa-Aranda I, Poelaert J, Castellanos G, L. N. G. Malbrain M. The pathophysiological impact of intra-abdominal hypertension in pigs

BACKGROUND

Intra-abdominal hypertension and abdominal compartment syndrome are common with clinically significant consequences. We investigated the pathophysiological effects of raised IAP as part of a more extensive exploratory animal study. The study design included both pneumoperitoneum and mechanical intestinal obstruction models.

METHODS

Forty-nine female swine were divided into six groups: a control group (Cr; n = 5), three pneumoperitoneum groups with IAPs of 20mmHg (Pn20; n = 10), 30mmHg (Pn30; n = 10), 40mmHg (Pn40; n = 10), and two mechanical intestinal occlusion groups with IAPs of 20mmHg (MIO20; n = 9) and 30mmHg (MIO30; n = 5).

RESULTS

There were significant changes (p<0.05) noted in all organ systems, most notably systolic blood pressure (SBP) (p<0.001), cardiac index (CI) (p = 0.003), stroke volume index (SVI) (p<0.001), mean pulmonary airway pressure (MPP) (p<0.001), compliance (p<0.001), pO2 (p = 0.003), bicarbonate (p = 0.041), hemoglobin (p = 0.012), lipase (p = 0.041), total bilirubin (p = 0.041), gastric pH (p<0.001), calculated glomerular filtration rate (GFR) (p<0.001), and urine output (p<0.001). SVV increased progressively as the IAP increased with no obvious changes in intravascular volume status. There were no significant differences between the models regarding their impact on cardiovascular, respiratory, renal and gastrointestinal systems. However, significant differences were noted between the two models at 30mmHg, with MIO30 showing worse metabolic and hematological parameters, and Pn30 and Pn40 showing a more rapid rise in creatinine.

CONCLUSIONS

This study identified and quantified the impact of intra-abdominal hypertension at different pressures on several organ systems and highlighted the significance of even short-lived elevations. Two models of intra-abdominal pressure were used, with a mechanical obstruction model showing more rapid changes in metabolic and haematological changes. These may represent different underlying cellular and vascular pathophysiological processes, but this remains unclear.

Research priorities in perioperative fluid therapy and hemodynamic monitoring: A Delphi Consensus Survey from the Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section (SHTF) of the Spanish Society of Anesthesiology and Critical Care (SEDAR)

BACKGROUND

Research in fluid therapy and perioperative hemodynamic monitoring is difficult and expensive. The objectives of this study were to summarize these topics and to prioritize these topics in order of research importance.

METHODS

Electronic structured Delphi questionnaire over three rounds among 30 experts in fluid therapy and hemodynamic monitoring identified through the Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section of the Spanish Society of Anesthesiology and Critical Care.

RESULTS

77 topics were identified and ranked in order of prioritization. Topics were categorized into themes of crystalloids, colloids, hemodynamic monitoring and others. 31 topics were ranked as essential research priority. To determine whether intraoperative hemodynamic optimization algorithms based on the invasive or noninvasive Hypotension Prediction Index versus other management strategies could decrease the incidence of postoperative complications. As well as whether the use of renal stress biomarkers together with a goal-directed fluid therapy protocol could reduce hospital stay and the incidence of acute kidney injury in adult patients undergoing non-cardiac surgery, reached the highest consensus.

CONCLUSIONS

The Fluid Therapy and Hemodynamic Monitoring Subcommittee of the Hemostasis, Transfusion Medicine and Fluid Therapy Section of the Spanish Society of Anesthesiology and Critical Care will use these results to carry out the research.

Catabolism highly influences ICU-acquired hypernatremia in a mainly trauma and surgical cohort

PURPOSE

To further analyse causes and effects of ICU-acquired hypernatremia.

METHODS

This retrospective, single-centre study, analysed 994 patients regarding ICU-acquired hypernatremia. Non-hypernatremic patients (n = 617) were compared to early-hypernatremic (only before ICU-day 4; n = 87), prolonged-hypernatremic (before and after ICU-day 4; n = 169) and late-hypernatremic patients (only after ICU-day 4; n = 121). Trends in glomerular filtration rate (eGFR), urea-to-creatinine ratio (UCR), fraction of urea in total urine osmolality and urine sodium were compared. Risk factors for i) the development of hypernatremia and ii) mortality were determined.

RESULTS

Thirty-eight percent (n = 377) developed ICU-acquired hypernatremia. Specifically in the prolonged- and late-group, decreased eGFRs and urine sodium but increased UCR and fractions of urea in urine osmolality were present. Decreased eGFR was a risk factor for the development of hypernatremia in all groups; disease severity and increased catabolism particularly in the prolonged- and late-hypernatremic group. Increased age, SAPS-III and signs of catabolism but not the development of hypernatremia itself was identified as significant risk factor for mortality.

CONCLUSIONS

Late- and prolonged-hypernatremia is highly related to an increased protein metabolism. Besides excessive catabolism, initial disease severity and a decrease in renal function must be considered when confronted with ICU-acquired hypernatremia.

Development and validation of an audit tool for fluid management in non-critically ill adults in the emergency department

Especially in the emergency department (ED), it is critical to identify weaknesses in prescribing behavior of IV maintenance fluids to ensure a qualitative 24-h fluid management plan. The primary aim of this study was to develop an audit instrument to assess the pitfalls in documentation and prescribing habits of IV fluid therapy for non-critically ill patients admitted to the ED. In this study, an expert panel initially designed the tool. During different phases, adaptations were made to optimize inter-rater agreement (Fleiss' kappa, κ) and validity was determined based on the application of the tool on randomly selected electronic ED patient records. Second, the IV fluid prescription's appropriateness was addressed. The final tool consists of three parts: fluid status assessment, evaluation of maintenance fluid needs and, if present, a limited appropriateness check of the fluid prescription. A manual enhanced inter-rater agreement. κ-values achieved the target value (0.40) after three adaptation rounds, except for the category of 'clinical observations' in the assessment part (κ = 0.531, 95% CI 0.528-0.534), which was acceptable. A check of the IV fluid's indication and volume was only possible with an additional expert evaluation to conclude on prescription appropriateness. Criterion related validity of the final version was high (93.4%). To conclude, the instrument is considered reliable and can be used in clinical practice to evaluate ED fluid management. Thorough documentation is essential to evaluate the appropriateness of the IV fluid prescription, to improve information transfer on IV fluid therapy to the ward and to facilitate retrospective chart review of ED prescribing behavior.

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.

Intravenous Fluid Administration and the Risk of Adverse Outcomes in Sickle Cell Disease Patients Hospitalized for Vaso-Occlusive Crisis

Vaso-occlusive crisis (VOC) is the leading cause of hospitalization in sickle cell disease (SCD). Intravenous fluid (IVF) administration is the usual practice during VOC episodes to slow the sickling process. In the absence of an evidence-based, clear-cut consensus on the optimal choice, route, and rate of fluid administration, there has been a wide variability in the practice of IVF administration in the treatment of VOC. However, there are growing concerns about the safety of this practice. This systematic review summarized the current evidence on the risk of negative outcomes in SCD patients treated for VOC with IVFs. A database search of Medline/PubMed, EMBASE, Scopus, Web of Science, CINAHL, Wiley Cochrane Library, Clinicaltrials.gov, and conference proceedings of the European Hematology Association (EHA) and American Society of Hematology (ASH) were performed. The results were presented using narrative analysis of quantitative data. Of the 2,821 identified records, a total of three eligible retrospective cohort studies with a total demographic population of 549 SCD patients were included in this review. Normal saline, a frequently used IVF for VOC may be associated with adverse outcomes such as poor pain control and volume overload. Volume overload, new oxygen requirement, acute chest syndrome, and acute kidney injury are potential adverse outcomes of inappropriate IVF use in VOC. There is limited evidence supporting the current practice of IVF use in VOC. Randomized controlled trials are required to fully clarify the place and safety of IVF in the management of VOC.

Intravenous fluid therapy in perioperative and critical care setting-Knowledge test and practice: An international cross-sectional survey

PURPOSE

In the absence of recent international recommendations supported by scientific societies like Anesthesiology or Intensive Care Medicine, healthcare professionals (HCP) knowledge on IV fluid is expected to vary. We undertook a cross-sectional survey, aiming to assess prescription patterns and test the knowledge of HCP for IV fluid use in the operating room (OR) and intensive care unit (ICU).

METHODS

An online international cross-sectional survey was conducted between October 20, 2019, and November 27, 2021. The survey included multiple-choice questions on demographics, practice patterns and knowledge of IV fluids, and a hemodynamically unstable patient assessment.

RESULTS

1045 HCP, from 97 countries responded to the survey. Nearly three-quarters reported the non-existence of internal hospital or ICU-based guidelines on IV fluids. The respondents' mean score on the knowledge assessment questions was 46.4 ± 14.4. The cumulative mean scores were significantly higher among those supervising trainees (p = 0.02), specialists (p < 0.001) and those working in high-income (p < 0.001) countries. Overall performance of respondents on the knowledge testing for IV fluid was unsatisfactory with only 6.5% respondents performed above average.

CONCLUSION

There is a wide difference in the knowledge and prescription of IV fluids among the HCP surveyed. These findings reflect the urgent need for education on IV fluids.

Intravenous maintenance fluid therapy practice in the pediatric acute and critical care settings: a European and Middle Eastern survey

The ideal fluid for intravenous maintenance fluid therapy (IV-MFT) in acutely and critically ill children is controversial, and evidence-based clinical practice guidelines are lacking and current prescribing practices remain unknown. We aimed to describe the current practices in prescribing IV-MFT in the context of acute and critically ill children with regard to the amount, tonicity, composition, use of balanced fluids, and prescribing strategies in various clinical contexts. A cross-sectional electronic 27-item survey was emailed in April-May 2021 to pediatric critical care physicians across European and Middle East countries. The survey instrument was developed by an expert multi-professional panel within the European Society of Pediatric and Neonatal Intensive Care (ESPNIC). A total of 154 respondents from 35 European and Middle East countries participated (response rate 64%). Respondents were physicians in charge of acute or critically ill children. All respondents indicated they routinely use a predefined formula to prescribe the amount of IV-MFT and considered fluid balance monitoring very important in the management of acute and critically ill children. The use of balanced solution was preferred if there were altered serum sodium and chloride levels or metabolic acidosis. Just under half (42%, 65/153) of respondents believed balanced solutions should always be used. Respondents considered the use of isotonic IV solutions as important for acute and critically ill children. In terms of the indication and the composition of IV-MFT prescribed, responses were heterogeneous among centers. Almost 70% (107/154) respondents believed there was a gap between current practice and what they considered ideal IV-MFT due to a lack of guidelines and inadequate training of healthcare professionals.   Conclusions: Our study showed considerable variability in clinical prescribing practice of IV-MFT in acute pediatric settings across Europe and the Middle East. There is an urgent need to develop evidence-based guidelines for IV-MFT prescription in acute and critically ill children. What is Known: • The administration of maintenance intravenous fluid therapy is a standard of care for a lot of hospitalized children • Maintenance intravenous fluid therapy prescriptions are often based on Holliday and Segar's historical guidelines even if this practice has been associated with several complications. What is New: • This study provided information on the prescribing practice regarding fluid restriction, fluid tonicity, and balance. • This study showed considerable variability in clinical prescribing practice of intravenous maintenance fluid therapy across Europe and the Middle East.

Loop diuretics in adult intensive care patients with fluid overload: a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

BACKGROUND

Fluid overload is a risk factor for organ dysfunction and death in intensive care unit (ICU) patients, but no guidelines exist for its management. We systematically reviewed benefits and harms of a single loop diuretic, the predominant treatment used for fluid overload in these patients.

METHODS

We conducted a systematic review with meta-analysis and Trial Sequential Analysis (TSA) of a single loop diuretic vs. other interventions reported in randomised clinical trials, adhering to our published protocol, the Cochrane Handbook, and PRISMA statement. We assessed the risks of bias with the ROB2-tool and certainty of evidence with GRADE. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020184799).

RESULTS

We included 10 trials (804 participants), all at overall high risk of bias. For loop diuretics vs. placebo/no intervention, we found no difference in all-cause mortality (relative risk (RR) 0.72, 95% confidence interval (CI) 0.49-1.06; 4 trials; 359 participants; I2 = 0%; TSA-adjusted CI 0.15-3.48; very low certainty of evidence). Fewer serious adverse events were registered in the group treated with loop diuretics (RR 0.81, 95% CI 0.66-0.99; 6 trials; 476 participants; I2 = 0%; very low certainty of evidence), though contested by TSA (TSA-adjusted CI 0.55-1.20).

CONCLUSIONS

The evidence is very uncertain about the effect of loop diuretics on mortality and serious adverse events in adult ICU patients with fluid overload. Loop diuretics may reduce the occurrence of these outcomes, but large randomised placebo-controlled trials at low risk of bias are needed.

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.