Hypophosphatemia in critically ill adults and children - A systematic review

BACKGROUND & AIMS

Phosphate is the main intracellular anion essential for numerous biological processes. Symptoms of hypophosphatemia are non-specific, yet potentially life-threatening. This systematic review process was initiated to gain a global insight into hypophosphatemia, associated morbidity and treatments.

METHODS

A systematic review was conducted (PROSPERO CRD42020163191). Nine clinically relevant questions were generated, seven for adult and two for pediatric critically ill patients, and prevalence of hypophosphatemia was assessed in both groups. We identified trials through systematic searches of Medline, EMBASE, Scopus, Cochrane Central Register of Controlled Trials, CINAHL, and Web of Science. Quality assessment was performed using the Cochrane risk of bias tool for randomized controlled trials and the Newcastle-Ottawa Scale for observational studies.

RESULTS

For all research questions, we identified 2727 titles in total, assessed 399 full texts, and retained 82 full texts for evidence synthesis, with 20 of them identified for several research questions. Only 3 randomized controlled trials were identified with two of them published only in abstract form, as well as 28 prospective and 31 retrospective studies, and 20 case reports. Relevant risk of bias regarding selection and comparability was identified for most of the studies. No meta-analysis could be performed. The prevalence of hypophosphatemia varied substantially in critically ill adults and children, but no study assessed consecutive admissions to intensive care. In both critically ill adults and children, several studies report that hypophosphatemia is associated with worse outcome (prolonged length of stay and the need for respiratory support, and higher mortality). However, there was insufficient evidence regarding the optimal threshold upon which hypophosphatemia becomes critical and requires treatment. We found no studies regarding the optimal frequency of phosphate measurements, and regarding the time window to correct hypophosphatemia. In adults, nutrient restriction on top of phosphate repletion in patients with refeeding syndrome may improve survival, although evidence is weak.

CONCLUSIONS

Evidence on the definition, outcome and treatment of clinically relevant hypophosphatemia in critically ill adults and children is scarce and does not allow answering clinically relevant questions. High quality clinical research is crucial for the development of respective guidelines.

Sublingual Sufentanil Tablet System Versus Continuous Morphine Infusion for Postoperative Analgesia in Cardiac Surgery Patients

OBJECTIVE(S)

To assess the effectiveness and side effects of a patient-controlled sublingual sufentanil tablet system for postoperative analgesia after cardiac surgery and to compare it to a nurse-controlled continuous morphine infusion.

DESIGN

Prospective, open-label, randomized controlled trial.

SETTING

Single university academic center.

PARTICIPANTS

Adult patients undergoing cardiac surgery, which included a sternotomy.

INTERVENTIONS

Sublingual sufentanil tablet system versus nurse-controlled continuous morphine infusion.

MEASUREMENTS AND MAIN RESULTS

A total of 483 cardiac surgery patients were screened for eligibility, of whom 64 patients completed the study. No statistically significant differences were found for baseline characteristics between both groups. All mean numeric rating scale (NRS) pain scores from after extubation until intensive care unit discharge were ≤3 in both groups. The cumulative mean NRS pain score from 24 hours after extubation (primary outcome) (t = hours after extubation) was significantly different in favor of the morphine group: (t = 0-24) (0.8 [0.7] v 1.3 [0.8]; p = 0.006). Later cumulative mean pain scores were also in favor of the morphine group: (t = 24-48) (0.2 [0.3] v 0.6 [0.5]; p = 0.001) and (t = 48-63) (0.0 [0.0] v 0.1 [0.2]; p = 0.013). The cumulative opioid dose (in milligrams intravenous morphine equivalents) was significantly higher in the morphine group compared with the sublingual sufentanil group (241.94 [218.73] v 39.84 [21.96]; p = 0.0001). No differences were found for the incidences of postoperative nausea and vomiting, sedation, hypoventilation, bradycardia, or hypotension between both groups (secondary outcomes).

CONCLUSIONS

Despite resulting in statistically significantly higher pain scores, a patient-controlled sublingual sufentanil tablet system offers adequate analgesia after cardiac surgery and reduces opioid consumption when compared with continuous morphine infusion.

Intravenous fluid therapy in the perioperative and critical care setting: Executive summary of the International Fluid Academy (IFA)

Intravenous fluid administration should be considered as any other pharmacological prescription. There are three main indications: resuscitation, replacement, and maintenance. Moreover, the impact of fluid administration as drug diluent or to preserve catheter patency, i.e., fluid creep, should also be considered. As for antibiotics, intravenous fluid administration should follow the four Ds: drug, dosing, duration, de-escalation. Among crystalloids, balanced solutions limit acid–base alterations and chloride load and should be preferred, as this likely prevents renal dysfunction. Among colloids, albumin, the only available natural colloid, may have beneficial effects. The last decade has seen growing interest in the potential harms related to fluid overloading. In the perioperative setting, appropriate fluid management that maintains adequate organ perfusion while limiting fluid administration should represent the standard of care. Protocols including a restrictive continuous fluid administration alongside bolus administration to achieve hemodynamic targets have been proposed. A similar approach should be considered also for critically ill patients, in whom increased endothelial permeability makes this strategy more relevant. Active de-escalation protocols may be necessary in a later phase. The R.O.S.E. conceptual model (Resuscitation, Optimization, Stabilization, Evacuation) summarizes accurately a dynamic approach to fluid therapy, maximizing benefits and minimizing harms. Even in specific categories of critically ill patients, i.e., with trauma or burns, fluid therapy should be carefully applied, considering the importance of their specific aims; maintaining peripheral oxygen delivery, while avoiding the consequences of fluid overload.

Perioperative Quality Initiative (POQI) consensus statement on fundamental concepts in perioperative fluid management: fluid responsiveness and venous capacitance

Background

Optimal fluid therapy in the perioperative and critical care settings depends on understanding the underlying cardiovascular physiology and individualizing assessment of the dynamic patient state.

Methods

The Perioperative Quality Initiative (POQI-5) consensus conference brought together an international team of multidisciplinary experts to survey and evaluate the literature on the physiology of volume responsiveness and perioperative fluid management. The group used a modified Delphi method to develop consensus statements applicable to the physiologically based management of intravenous fluid therapy in the perioperative setting.

Discussion

We discussed the clinical and physiological evidence underlying fluid responsiveness and venous capacitance as relevant factors in fluid management and developed consensus statements with clinical implications for a broad group of clinicians involved in intravenous fluid therapy. Two key concepts emerged as follows: (1) The ultimate goal of fluid therapy and hemodynamic management is to support the conditions that enable normal cellular metabolic function in order to produce optimal patient outcomes, and (2) optimal fluid and hemodynamic management is dependent on an understanding of the relationship between pressure, volume, and flow in a dynamic system which is distensible with variable elastance and capacitance properties.

A Clinician's Guide to Management of Intra-abdominal Hypertension and Abdominal Compartment Syndrome in Critically Ill Patients

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2020. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2020. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Metrology part 1: definition of quality criteria

Any measurement is always afflicted with some degree of uncertainty. A correct understanding of the different types of uncertainty, their naming, and their definition is of crucial importance for an appropriate use of measuring instruments. However, in perioperative and intensive care medicine, the metrological requirements for measuring instruments are poorly defined and often used spuriously. The correct use of metrological terms is also of crucial importance in validation studies. The European Union published a new directive on medical devices, mentioning that in the case of devices with a measuring function, the notified body is involved in all aspects relating to the conformity of the device with the metrological requirements. It is therefore the task of the scientific societies to establish the standards in their area of expertise. Adopting the same understandings and definitions among clinicians and scientists is obviously the first step. In this metrologic review (part 1), we list and explain the most important terms defined by the International Bureau of Weights and Measures regarding quantities and units, properties of measurements, devices for measurement, properties of measuring devices, and measurement standards, with specific examples from perioperative and intensive care medicine.

Long-term patient-important outcomes after septic shock: A protocol for 1-year follow-up of the CLASSIC trial

BACKGROUND

In patients with septic shock, mortality is high, and survivors experience long-term physical, mental and social impairments. The ongoing Conservative vs Liberal Approach to fluid therapy of Septic Shock in Intensive Care (CLASSIC) trial assesses the benefits and harms of a restrictive vs standard-care intravenous (IV) fluid therapy. The hypothesis is that IV fluid restriction improves patient-important long-term outcomes.

AIM

To assess the predefined patient-important long-term outcomes in patients randomised into the CLASSIC trial.

METHODS

In this pre-planned follow-up study of the CLASSIC trial, we will assess all-cause mortality, health-related quality of life (HRQoL) and cognitive function 1 year after randomisation in the two intervention groups. The 1-year mortality will be collected from electronic patient records or central national registries in most participating countries. We will contact survivors and assess EuroQol 5-Dimension, -5-Level (EQ-5D-5L) and EuroQol-Visual Analogue Scale and Montreal Cognitive Assessment 5-minute protocol score. We will analyse mortality by logistic regression and use general linear models to assess HRQoL and cognitive function.

DISCUSSION

With this pre-planned follow-up study of the CLASSIC trial, we will provide patient-important data on long-term survival, HRQoL and cognitive function of restrictive vs standard-care IV fluid therapy in patients with septic shock.

Ventilatory support and mechanical properties of the fibrotic lung acting as a "squishy ball"

Protective ventilation is the cornerstone of treatment of patients with the acute respiratory distress syndrome (ARDS); however, no studies have yet established the best ventilatory strategy to adopt when patients with acute exacerbation of interstitial lung disease (AE-ILD) are admitted to the intensive care unit. Due to the severe impairment of the respiratory mechanics, the fibrotic lung is at high risk of developing ventilator-induced lung injury, regardless of the lung fibrosis etiology. The purpose of this review is to analyze the effects of mechanical ventilation in AE-ILD and to increase the knowledge on the characteristics of fibrotic lung during artificial ventilation, introducing the concept of “squishy ball lung”. The role of positive end-expiratory pressure is discussed, proposing a “lung resting strategy” as opposed to the “open lung approach”. The review also discusses the practical management of AE-ILD patients discussing illustrative clinical cases.

Conservative vs liberal fluid therapy in septic shock (CLASSIC) trial-Protocol and statistical analysis plan

INTRODUCTION

Intravenous (IV) fluid is a key intervention in the management of septic shock. The benefits and harms of lower versus higher fluid volumes are unknown and thus clinical equipoise exists. We describe the protocol and detailed statistical analysis plan for the conservative versus liberal approach to fluid therapy of septic shock in the Intensive Care (CLASSIC) trial. The aim of the CLASSIC trial is to assess benefits and harms of IV fluid restriction versus standard care in adult intensive care unit (ICU) patients with septic shock.

METHODS

CLASSIC trial is an investigator-initiated, international, randomised, stratified, and analyst-blinded trial. We will allocate 1554 adult patients with septic shock, who are planned to be or are admitted to an ICU, to IV fluid restriction versus standard care. The primary outcome is mortality at day 90. Secondary outcomes are serious adverse events (SAEs), serious adverse reactions (SARs), days alive at day 90 without life support, days alive and out of the hospital at day 90 and mortality, health-related quality of life (HRQoL), and cognitive function at 1 year. We will conduct the statistical analyses according to a pre-defined statistical analysis plan, including three interim analyses. For the primary analysis, we will use logistic regression adjusted for the stratification variables comparing the two interventions in the intention-to-treat (ITT) population.

DISCUSSION

The CLASSIC trial results will provide important evidence to guide clinicians' choice regarding the IV fluid therapy in adults with septic shock.

154 compared to 54 mmol per liter of sodium in intravenous maintenance fluid therapy for adult patients undergoing major thoracic surgery (TOPMAST): a single-center randomized controlled double-blind trial

PURPOSE

To determine the effects of the sodium content of maintenance fluid therapy on cumulative fluid balance and electrolyte disorders.

METHODS

We performed a randomized controlled trial of adults undergoing major thoracic surgery, randomly assigned (1:1) to receive maintenance fluids containing 154 mmol/L (Na154) or 54 mmol/L (Na54) of sodium from the start of surgery until their discharge from the ICU, the occurrence of a serious adverse event or the third postoperative day at the latest. Investigators, caregivers and patients were blinded to the treatment. Primary outcome was cumulative fluid balance. Electrolyte disturbances were assessed as secondary endpoints, different adverse events and physiological markers as safety and exploratory endpoints.

FINDINGS

We randomly assigned 70 patients; primary outcome data were available for 33 and 34 patients in the Na54 and Na154 treatment arms, respectively. Estimated cumulative fluid balance at 72 h was 1369 mL (95% CI 601-2137) more positive in the Na154 arm (p < 0.001), despite comparable non-study fluid sources. Hyponatremia < 135 mmol/L was encountered in four patients (11.8%) under Na54 compared to none under Na154 (p = 0.04), but there was no significantly more hyponatremia < 130 mmol/L (1 versus 0; p = 0.31). There was more hyperchloremia > 109 mmol/L under Na154 (24/35 patients, 68.6%) than under Na54 (4/34 patients, 11.8%) (p < 0.001). The treating clinicians discontinued the study due to clinical or radiographic fluid overload in six patients receiving Na154 compared to one patient under Na54 (excess risk 14.2%; 95% CI - 0.2-30.4%, p = 0.05).

CONCLUSIONS

In adult surgical patients, sodium-rich maintenance solutions were associated with a more positive cumulative fluid balance and hyperchloremia; hypotonic fluids were associated with mild and asymptomatic hyponatremia.

Management of peripartum intra-abdominal hypertension and abdominal compartment syndrome

Normal pregnancy leads to a state of chronically increased intra-abdominal pressure. Obstetric and non-obstetric conditions may increase intra-abdominal pressure further, causing intra-abdominal hypertension and abdominal compartment syndrome, which leads to maternal organ dysfunction and a compromised fetal state. Limited medical literature exists to guide treatment of pregnant women with these conditions. In this state-of-the-art review, we propose a diagnostic and treatment algorithm for the management of peripartum intra-abdominal hypertension and abdominal compartment syndrome, informed by newly available studies.

Incidence and outcome of invasive candidiasis in intensive care units (ICUs) in Europe: results of the EUCANDICU project

Background

The objective of this study was to assess the cumulative incidence of invasive candidiasis (IC) in intensive care units (ICUs) in Europe.

Methods

A multinational, multicenter, retrospective study was conducted in 23 ICUs in 9 European countries, representing the first phase of the candidemia/intra-abdominal candidiasis in European ICU project (EUCANDICU).

Results

During the study period, 570 episodes of ICU-acquired IC were observed, with a cumulative incidence of 7.07 episodes per 1000 ICU admissions, with important between-center variability. Separated, non-mutually exclusive cumulative incidences of candidemia and IAC were 5.52 and 1.84 episodes per 1000 ICU admissions, respectively. Crude 30-day mortality was 42%. Age (odds ratio [OR] 1.04 per year, 95% CI 1.02–1.06, p < 0.001), severe hepatic failure (OR 3.25, 95% 1.31–8.08, p 0.011), SOFA score at the onset of IC (OR 1.11 per point, 95% CI 1.04–1.17, p 0.001), and septic shock (OR 2.12, 95% CI 1.24–3.63, p 0.006) were associated with increased 30-day mortality in a secondary, exploratory analysis.

Conclusions

The cumulative incidence of IC in 23 European ICUs was 7.07 episodes per 1000 ICU admissions. Future in-depth analyses will allow explaining part of the observed between-center variability, with the ultimate aim of helping to improve local infection control and antifungal stewardship projects and interventions.

Cytokine removal in human septic shock: Where are we and where are we going?

Although improving, the mortality from septic shock still remains high despite increased international awareness. As a consequence, much effort has focused on alternative treatment strategies in an effort to improve outcomes. The application of blood purification therapies to improve immune homeostasis has been suggested as one such method, but these approaches, such as high-volume continuous haemofiltration or cytokine and/or endotoxin removal, have enjoyed little success to date. More recently, the use of sorbent technologies has attracted much attention. These adsorbers are highly effective at removing inflammatory mediators, in particular, cytokines, from the bloodstream. This narrative review is the executive summary of meetings held throughout the 6th International Fluid Academy Days in Antwerp, Belgium (Nov 23-25, 2017), focusing on the current understanding regarding the use of such adsorbers in humans with septic shock. We followed a modified Delphi approach involving a combination of evidence appraisal together with expert opinion in order to achieve recommendations for practice and, importantly, future research.

The significance of intra-abdominal pressure in neurosurgery and neurological diseases: a narrative review and a conceptual proposal

Intra-abdominal pressure (IAP) is a physiological parameter that has gained considerable attention during the last few decades. The incidence of complications arising from increased IAP, known as intra-abdominal hypertension (IAH) or abdominal compartment syndrome in critically ill patients, is high and its impact is significant. The effects of IAP in neurological conditions and during surgical procedures are largely unexplored. IAP also appears to be relevant during neurosurgical procedures (spine and brain) in the prone position, and in selected cases, IAH may affect cerebrospinal fluid drainage after a ventriculoperitoneal shunt operation. Furthermore, raised IAP is one of the contributors to intracranial hypertension in patients with morbid obesity. In traumatic brain injury, case reports described how abdominal decompression lowers intracerebral pressure. The anatomical substrate for transmission of the IAP to the brain and venous system of the spine is the extradural neural axis compartment; the first reports of this phenomenon can be found in anatomical studies of the sixteenth century. In this review, we summarize the available knowledge on how IAP impacts the cerebrospinal venous system and the jugular venous system via two pathways, and we discuss the implications for neurosurgical procedures as well as the relevance of IAH in neurological disorders.

Ventilation in patients with intra-abdominal hypertension: what every critical care physician needs to know

The incidence of intra-abdominal hypertension (IAH) is high and still underappreciated by critical care physicians throughout the world. One in four to one in three patients will have IAH on admission, while one out of two will develop IAH within the first week of Intensive Care Unit stay. IAH is associated with high morbidity and mortality. Although considerable progress has been made over the past decades, some important questions remain regarding the optimal ventilation management in patients with IAH. An important first step is to measure intra-abdominal pressure (IAP). If IAH (IAP > 12 mmHg) is present, medical therapies should be initiated to reduce IAP as small reductions in intra-abdominal volume can significantly reduce IAP and airway pressures. Protective lung ventilation with low tidal volumes in patients with respiratory failure and IAH is important. Abdominal-thoracic pressure transmission is around 50%. In patients with IAH, higher positive end-expiratory pressure (PEEP) levels are often required to avoid alveolar collapse but the optimal PEEP in these patients is still unknown. During recruitment manoeuvres, higher opening pressures may be required while closely monitoring oxygenation and the haemodynamic response. During lung-protective ventilation, whilst keeping driving pressures within safe limits, higher plateau pressures than normally considered might be acceptable. Monitoring of the respiratory function and adapting the ventilatory settings during anaesthesia and critical care are of great importance. This review will focus on how to deal with the respiratory derangements in critically ill patients with IAH.

N. G. Malbrain M, Spapen HD. Energy expenditure of patients on ECMO: A prospective pilot study

BACKGROUND

An optimal nutritional approach sustained by convenient monitoring of metabolic status and reliable assessment of energy expenditure (EE) may improve the outcome of critically ill patients on extracorporeal membrane oxygenation (ECMO). We previously demonstrated the feasibility of indirect calorimetry (IC)-the standard of care technique to determine caloric targets-in patients undergoing ECMO. This study aims to compare measured with calculated EE during ECMO treatment. We additionally provide median EE values for use in settings where IC is not available.

METHODS

IC was performed in seven stable ECMO patients. Gas exchange was analyzed at the ventilator, and ECMO side and values were introduced in a modified Weir formula to calculate resting EE. Results were compared with EE calculated with the Harris-Benedict equation and with the 25 kcal/kg/day ESPEN recommendation.

RESULTS

Total median oxygen consumption rate was 196 (Q1-Q3 158-331) mL/min, and total median carbon dioxide production was 150 (Q1-Q3 104-203) mL/min. Clinically relevant differences between calculated and measured EE were observed in all patients. The median EE was 1334 (Q1-Q3 1134-2119) kcal/24 hours or 18 (Q1-Q3 15-27) kcal/kg/day.

CONCLUSION

Compared with measured EE, calculation of EE both over- and underestimated caloric needs during ECMO treatment. Despite a median EE of 21 kcal/kg/day, large variability in metabolic rate was found and demands further investigation.

Energy expenditure and caloric targets during continuous renal replacement therapy under regional citrate anticoagulation. A viewpoint

BACKGROUND

Indirect calorimetry (IC) is the gold standard for measuring energy expenditure in critically ill patients However, continuous renal replacement therapy (CRRT) is a formal contraindication for IC use.

AIMS

To discuss specific issues that hamper or preclude an IC-based assessment of energy expenditure and correct caloric prescription in CRRT-treated patients.

METHODS

Narrative review of current literature.

RESULTS

Several relevant pitfalls for validation of IC during CRRT were identified. First, IC measures CO₂ production (VCO₂) and O₂ consumption to calculate resting energy expenditure (REE) with the Weir equation. VCO₂ measurements are influenced by CRRT because CO₂ is exchanged during the blood purification process. CO₂ exchange also depends on type of pre- and/or postdilution fluid(s). CO₂ dissolves in different forms with dynamic but unpredictable impact on VCO₂. Second, the effect of immunologic activation and heat loss on REE caused by extracorporeal circulation during CRRT is poorly documented. Third, caloric prescription should be adapted to CRRT-induced in- and efflux of different nutrients. Finally, citrate, which is the preferred anticoagulant for CRRT, is a caloric source that may influence IC measurements and REE.

CONCLUSION

Better understanding of CRRT-related processes is needed to assess REE and provide individualized nutritional therapy in this condition.

Modification of Nutrition Therapy During Continuous Renal Replacement Therapy in Critically Ill Pediatric Patients: A Narrative Review and Recommendations

Introduction

Nutrition is an important part of treatment in critically ill children. Clinical guidelines for nutrition adaptations during continuous renal replacement therapy (CRRT) are lacking. We collected and evaluated current knowledge on this topic and provide recommendations.

Methods

Questions were produced to guide the literature search in the PubMed database.

Results

Evidence is scarce and extrapolation from adult data was often required. CRRT has a direct and substantial impact on metabolism. Indirect calorimetry is the preferred method to assess resting energy expenditure (REE). Moderate underestimation of REE is common but not clinically relevant. Formula‐based calculation of REE is inaccurate and not validated in critically ill children on CRRT. The nutrition impact of nonintentional calories delivered as citrate, lactate, and glucose during CRRT must be considered. Quantifying nitrogen balance is not feasible during CRRT. Protein delivery should be increased by 25% to compensate for losses in the effluent. Fats are not removed by CRRT and should not be adapted during CRRT. Electrolyte disturbances are frequently present and should be treated accordingly. Vitamins B1, B6, B9, and C are lost in the effluent and should be adapted to the effluent dose. Trace elements, with the exception of selenium, are not cleared in relevant quantities. Manganese accumulation is of concern because of potential neurotoxicity.

Conclusion

Current recommendations regarding nutrition support in pediatric CRRT must be extrapolated from adult studies. Recommendations are provided, based on the weak level of evidence. Additional research on this topic is warranted.

Effect of isotonic versus hypotonic maintenance fluid therapy on urine output, fluid balance, and electrolyte homeostasis: a crossover study in fasting adult volunteers

Background. Daily and globally, millions of adult hospitalized patients are exposed to maintenance i.v. fluid solutions supported by limited scientific evidence. In particular, it remains unclear whether fluid tonicity contributes to the recently established detrimental effects of fluid, sodium, and chloride overload.

Methods. This crossover study consisted of two 48 h study periods, during which 12 fasting healthy adults were treated with a frequently prescribed solution (NaCl 0.9% in glucose 5% supplemented by 40 mmol litre⁻¹ of potassium chloride) and a premixed hypotonic fluid (NaCl 0.32% in glucose 5% containing 26 mmol litre⁻¹ of potassium) at a daily rate of 25 ml kg⁻¹ of body weight. The primary end point was cumulative urine volume; fluid balance was thus calculated. We also explored the physiological mechanisms behind our findings and assessed electrolyte concentrations.

Results. After 48 h, 595 ml (95% CI: 454–735) less urine was voided with isotonic fluids than hypotonic fluids (P<0.001), or 803 ml (95% CI: 692–915) after excluding an outlier with ‘exaggerated natriuresis of hypertension’. The isotonic treatment was characterized by a significant decrease in aldosterone (P<0.001). Sodium concentrations were higher in the isotonic arm (P<0.001), but all measurements remained within the normal range. Potassium concentrations did not differ between the two solutions (P=0.45). Chloride concentrations were higher with the isotonic treatment (P<0.001), even causing hyperchloraemia.

Conclusions. Even at maintenance rate, isotonic solutions caused lower urine output, characterized by decreased aldosterone concentrations indicating (unintentional) volume expansion, than hypotonic solutions and were associated with hyperchloraemia. Despite their lower sodium and potassium content, hypotonic fluids were not associated with hyponatraemia or hypokalaemia.

Clinical trial registration. ClinicalTrials.gov (NCT02822898) and EudraCT (2016-001846-24).

Impact of maintenance, resuscitation and unintended fluid therapy on global fluid load after elective coronary artery bypass surgery

INTRODUCTION

Standardized protocols are provided for maintenance and replacement fluid therapy in critically ill patients. However, unintended fluid sources (analgesics, antibiotics and other drugs) are not always taken into account when prescribing intravenous fluid therapy. We evaluated the extent to which maintenance, resuscitation and unintended fluids contributed to total fluid load in elective coronary artery bypass graft patients during their ICU stay.

METHODS

Data on intravenous and oral fluid input and output were retrospectively collected from the electronic medical files.

RESULTS

Sixty patients were included. Maintenance fluids represented 1435 ± 570mL (49%) and 2214 ± 657mL (71%), resuscitation fluids 847 ± 542mL (29%) and 338 ± 559mL (11%), unintended fluids 639 ± 162mL (22%) and 576 ± 285mL (18%) respectively on day 1 and day 2. Mean oral intake increased almost fourfold (from 258mL to 1017mL) on the second day.

CONCLUSION

Postoperative maintenance and resuscitation fluids are responsible for most of the observed total fluid load on the first two days after elective coronary artery bypass graft surgery. Unintended fluid load is underestimated and has to be taken into account during fluid prescription.