Lower vs Higher Fluid Volumes in Adult Patients With Sepsis: An Updated Systematic Review With Meta-Analysis and Trial Sequential Analysis

BACKGROUND

IV fluids are recommended for adults with sepsis. However, the optimal strategy for IV fluid management in sepsis is unknown, and clinical equipoise exists.

RESEARCH QUESTION

Do lower vs higher fluid volumes improve patient-important outcomes in adult patients with sepsis?

STUDY DESIGN AND METHODS

We updated a systematic review with meta-analysis and trial sequential analysis of randomized clinical trials assessing lower vs higher IV fluid volumes in adult patients with sepsis. The coprimary outcomes were all-cause mortality, serious adverse events, and health-related quality of life. We followed the recommendations from the Cochrane Handbook and used the Grading of Recommendations Assessment, Development and Evaluation approach. Primary conclusions were based on trials with low risk of bias if available.

RESULTS

We included 13 trials (N = 4,006) with four trials (n = 3,385) added to this update. The meta-analysis of all-cause mortality in eight trials with low risk of bias showed a relative risk of 0.99 (97% CI, 0.89-1.10; moderate certainty evidence). Six trials with predefined definitions of serious adverse events showed a relative risk of 0.95 (97% CI, 0.83-1.07; low certainty evidence). Health-related quality of life was not reported.

INTERPRETATION

Among adult patients with sepsis, lower IV fluid volumes probably result in little to no difference in all-cause mortality compared with higher IV fluid volumes, but the interpretation is limited by imprecision in the estimate, which does not exclude potential benefit or harm. Similarly, the evidence suggests lower IV fluid volumes result in little to no difference in serious adverse events. No trials reported on health-related quality of life.

TRIAL REGISTRATION

PROSPERO; No.: CRD42022312572; URL: https://www.crd.york.ac.uk/prospero/.

Restriction of Intravenous Fluid in ICU Patients with Septic Shock

BACKGROUND

Intravenous fluids are recommended for the treatment of patients who are in septic shock, but higher fluid volumes have been associated with harm in patients who are in the intensive care unit (ICU).

METHODS

In this international, randomized trial, we assigned patients with septic shock in the ICU who had received at least 1 liter of intravenous fluid to receive restricted intravenous fluid or standard intravenous fluid therapy; patients were included if the onset of shock had been within 12 hours before screening. The primary outcome was death from any cause within 90 days after randomization.

RESULTS

We enrolled 1554 patients; 770 were assigned to the restrictive-fluid group and 784 to the standard-fluid group. Primary outcome data were available for 1545 patients (99.4%). In the ICU, the restrictive-fluid group received a median of 1798 ml of intravenous fluid (interquartile range, 500 to 4366); the standard-fluid group received a median of 3811 ml (interquartile range, 1861 to 6762). At 90 days, death had occurred in 323 of 764 patients (42.3%) in the restrictive-fluid group, as compared with 329 of 781 patients (42.1%) in the standard-fluid group (adjusted absolute difference, 0.1 percentage points; 95% confidence interval [CI], -4.7 to 4.9; P = 0.96). In the ICU, serious adverse events occurred at least once in 221 of 751 patients (29.4%) in the restrictive-fluid group and in 238 of 772 patients (30.8%) in the standard-fluid group (adjusted absolute difference, -1.7 percentage points; 99% CI, -7.7 to 4.3). At 90 days after randomization, the numbers of days alive without life support and days alive and out of the hospital were similar in the two groups.

CONCLUSIONS

Among adult patients with septic shock in the ICU, intravenous fluid restriction did not result in fewer deaths at 90 days than standard intravenous fluid therapy. (Funded by the Novo Nordisk Foundation and others; CLASSIC ClinicalTrials.gov number, NCT03668236.).

Conservative vs. liberal fluid therapy in septic shock - Protocol for secondary Bayesian analyses of the CLASSIC trial

Background

Clinical equipoise exists regarding intravenous (IV) fluid volumes in sepsis. The Conservative vs. Liberal Approach to fluid therapy of Septic Shock in Intensive Care (CLASSIC) trial investigates the effect of restricted vs. standard IV fluid therapy in 1554 adult intensive care unit patients with septic shock.

Methods

This protocol describes secondary Bayesian analyses of the primary outcome (90‐day all‐cause mortality) and three secondary outcomes at day 90. We will analyse all binary outcomes with adjusted Bayesian logistic regressions and present results as conditional relative risks and risk differences with 95% credibility intervals (CrIs). The secondary count outcome will be analysed using adjusted Bayesian linear regression with results summarised as conditional mean differences and ratios of means with 95% Crls. We will use weakly informative priors for the primary analyses, and sceptical and evidence‐based priors in the sensitivity analyses. Exact probabilities will be presented for any benefit/harm, clinically important benefit/harm and no clinically important difference. We will assess whether heterogeneity of treatment effects on mortality is present using Bayesian hierarchical models in subgroups and on the continuous scale using models with interactions according to five baseline variables assessing the overall severity of illness and the degree of circulatory and renal impairment.

Discussion

The outlined analyses will supplement the primary analysis of the CLASSIC trial by describing probabilities of beneficial and harmful effects and evaluating heterogeneity of treatment effects in a framework that may be easier to interpret for researchers and clinicians.

Neutrophil Gelatinase-Associated Lipocalin Measured on Clinical Laboratory Platforms for the Prediction of Acute Kidney Injury and the Associated Need for Dialysis Therapy: A Systematic Review and Meta-analysis

RATIONALE & OBJECTIVE

The usefulness of measures of neutrophil gelatinase-associated lipocalin (NGAL) in urine or plasma obtained on clinical laboratory platforms for predicting acute kidney injury (AKI) and AKI requiring dialysis (AKI-D) has not been fully evaluated. We sought to quantitatively summarize published data to evaluate the value of urinary and plasma NGAL for kidney risk prediction.

STUDY DESIGN

Literature-based meta-analysis and individual-study-data meta-analysis of diagnostic studies following PRISMA-IPD guidelines.

SETTING & STUDY POPULATIONS

Studies of adults investigating AKI, severe AKI, and AKI-D in the setting of cardiac surgery, intensive care, or emergency department care using either urinary or plasma NGAL measured on clinical laboratory platforms.

SELECTION CRITERIA FOR STUDIES

PubMed, Web of Science, Cochrane Library, Scopus, and congress abstracts ever published through February 2020 reporting diagnostic test studies of NGAL measured on clinical laboratory platforms to predict AKI.

DATA EXTRACTION

Individual-study-data meta-analysis was accomplished by giving authors data specifications tailored to their studies and requesting standardized patient-level data analysis.

ANALYTICAL APPROACH

Individual-study-data meta-analysis used a bivariate time-to-event model for interval-censored data from which discriminative ability (AUC) was characterized. NGAL cutoff concentrations at 95% sensitivity, 95% specificity, and optimal sensitivity and specificity were also estimated. Models incorporated as confounders the clinical setting and use versus nonuse of urine output as a criterion for AKI. A literature-based meta-analysis was also performed for all published studies including those for which the authors were unable to provide individual-study data analyses.

RESULTS

We included 52 observational studies involving 13,040 patients. We analyzed 30 data sets for the individual-study-data meta-analysis. For AKI, severe AKI, and AKI-D, numbers of events were 837, 304, and 103 for analyses of urinary NGAL, respectively; these values were 705, 271, and 178 for analyses of plasma NGAL. Discriminative performance was similar in both meta-analyses. Individual-study-data meta-analysis AUCs for urinary NGAL were 0.75 (95% CI, 0.73-0.76) and 0.80 (95% CI, 0.79-0.81) for severe AKI and AKI-D, respectively; for plasma NGAL, the corresponding AUCs were 0.80 (95% CI, 0.79-0.81) and 0.86 (95% CI, 0.84-0.86). Cutoff concentrations at 95% specificity for urinary NGAL were>580ng/mL with 27% sensitivity for severe AKI and>589ng/mL with 24% sensitivity for AKI-D. Corresponding cutoffs for plasma NGAL were>364ng/mL with 44% sensitivity and>546ng/mL with 26% sensitivity, respectively.

LIMITATIONS

Practice variability in initiation of dialysis. Imperfect harmonization of data across studies.

CONCLUSIONS

Urinary and plasma NGAL concentrations may identify patients at high risk for AKI in clinical research and practice. The cutoff concentrations reported in this study require prospective evaluation.

An international comparison of the cost of fluid resuscitation therapies

OBJECTIVE

Fluid resuscitation is a ubiquitous intervention in the management of patients treated in the intensive care unit, which has implications for intensive care unit resourcing and budgets. Our objective was to calculate the relative cost of resuscitation fluids in several countries to inform future economic evaluations.

METHODS

We collected site-level data regarding the availability and cost of fluids as part of an international survey. We normalised costs to net present values using purchasing power parities and published inflation figures. Costs were also adjusted for equi-effective dosing based on intravascular volume expansion effectiveness and expressed as US dollars (USD) per 100 mL crystalloid equivalent.

RESULTS

A total of 187 sites had access to cost data. Between countries, there was an approximate six fold variation in the cost of crystalloids and colloids overall. The average cost for crystalloids overall was less than 1 USD per 100 mL. In contrast, colloid fluids had higher average costs (59 USD per 100 mL). After adjusting for equi-effective dosing, saline was ∼27 times less costly than albumin (saline: 0.6 USD per 100 mL crystalloid equivalent; albumin 4-5%: 16.4 USD; albumin 20-25%: 15.8 USD) and ∼4 times less costly than hydroxyethyl starch solution (saline: 0.6 USD; hydroxyethyl starch solution: 2.5 USD). Buffered salt solutions, such as compound sodium acetate solutions (e.g., Plasmalyte®), had the highest average cost of crystalloid fluids, costing between 3 and 4 USD per 100 mL.

CONCLUSION

The cost of fluid varies substantially between fluid types and between countries, although normal (0.9%) saline is consistently less costly than colloid preparations and some buffered salt solutions. These data can be used to inform future economic evaluations of fluid preparations.

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.

Pantoprazole in Patients at Risk for Gastrointestinal Bleeding in the ICU

BACKGROUND

Prophylaxis for gastrointestinal stress ulceration is frequently given to patients in the intensive care unit (ICU), but its risks and benefits are unclear.

METHODS

In this European, multicenter, parallel-group, blinded trial, we randomly assigned adults who had been admitted to the ICU for an acute condition (i.e., an unplanned admission) and who were at risk for gastrointestinal bleeding to receive 40 mg of intravenous pantoprazole (a proton-pump inhibitor) or placebo daily during the ICU stay. The primary outcome was death by 90 days after randomization.

RESULTS

A total of 3298 patients were enrolled; 1645 were randomly assigned to the pantoprazole group and 1653 to the placebo group. Data on the primary outcome were available for 3282 patients (99.5%). At 90 days, 510 patients (31.1%) in the pantoprazole group and 499 (30.4%) in the placebo group had died (relative risk, 1.02; 95% confidence interval [CI], 0.91 to 1.13; P=0.76). During the ICU stay, at least one clinically important event (a composite of clinically important gastrointestinal bleeding, pneumonia, Clostridium difficile infection, or myocardial ischemia) had occurred in 21.9% of patients assigned to pantoprazole and 22.6% of those assigned to placebo (relative risk, 0.96; 95% CI, 0.83 to 1.11). In the pantoprazole group, 2.5% of patients had clinically important gastrointestinal bleeding, as compared with 4.2% in the placebo group. The number of patients with infections or serious adverse reactions and the percentage of days alive without life support within 90 days were similar in the two groups.

CONCLUSIONS

Among adult patients in the ICU who were at risk for gastrointestinal bleeding, mortality at 90 days and the number of clinically important events were similar in those assigned to pantoprazole and those assigned to placebo. (Funded by Innovation Fund Denmark and others; SUP-ICU ClinicalTrials.gov number, NCT02467621 .).

Common Sense Approach to Managing Sepsis

Sepsis results in many deaths, prolonged suffering among survivors and relatives, and high use of resources both in developed and developing countries. The updated Surviving Sepsis Campaign guidelines should aid clinicians in improving the identification and management of these patients, but many uncertainties remain because most of the guidance is based on low-quality evidence. This article discusses how to use some of the specific items of the guidelines together with a common-sense approach to aid clinical management of patients with sepsis while trying to balance the potential benefit and harm of the items.

Restricting volumes of resuscitation fluid in adults with septic shock after initial management: the CLASSIC randomised, parallel-group, multicentre feasibility trial

PURPOSE

We assessed the effects of a protocol restricting resuscitation fluid vs. a standard care protocol after initial resuscitation in intensive care unit (ICU) patients with septic shock.

METHODS

We randomised 151 adult patients with septic shock who had received initial fluid resuscitation in nine Scandinavian ICUs. In the fluid restriction group fluid boluses were permitted only if signs of severe hypoperfusion occurred, while in the standard care group fluid boluses were permitted as long as circulation continued to improve.

RESULTS

The co-primary outcome measures, resuscitation fluid volumes at day 5 and during ICU stay, were lower in the fluid restriction group than in the standard care group [mean differences -1.2 L (95 % confidence interval -2.0 to -0.4); p < 0.001 and -1.4 L (-2.4 to -0.4) respectively; p < 0.001]. Neither total fluid inputs and balances nor serious adverse reactions differed statistically significantly between the groups. Major protocol violations occurred in 27/75 patients in the fluid restriction group. Ischaemic events occurred in 3/75 in the fluid restriction group vs. 9/76 in the standard care group (odds ratio 0.32; 0.08-1.27; p = 0.11), worsening of acute kidney injury in 27/73 vs. 39/72 (0.46; 0.23-0.92; p = 0.03), and death by 90 days in 25/75 vs. 31/76 (0.71; 0.36-1.40; p = 0.32).

CONCLUSIONS

A protocol restricting resuscitation fluid successfully reduced volumes of resuscitation fluid compared with a standard care protocol in adult ICU patients with septic shock. The patient-centred outcomes all pointed towards benefit with fluid restriction, but our trial was not powered to show differences in these exploratory outcomes.

TRIAL REGISTRATION

NCT02079402.

Gone fishing in a fluid trial

OBJECTIVE

To maximise the yield of existing data by assessing the effect on mortality of being born under the zodiac sign Pisces in a trial of intravenous (IV) fluids.

DESIGN, SETTING AND PARTICIPANTS

A retrospective observational study, with no predefined hypothesis or statistical analysis plan, of 26 Scandinavian intensive care units between 2009 and 2011. Patients aged 18 years or older with severe sepsis and in need of fluid resuscitation, randomised in the Scandinavian Starch for Severe Sepsis/ Septic Shock (6S) trial.

MAIN OUTCOME MEASURE

Ninety-day mortality.

RESULTS

We included all 798 randomised patients in our study; 70 (9%) were born under the sign of Pisces. The primary outcome (death within 90 days after randomisation) occurred in 25 patients (35.7%) in the Pisces group, compared with 348 patients (48%) in the non-Pisces group (relative risk, 0.75; 95% CI, 0.54-1.03; one-sided P = 0.03).

CONCLUSIONS

In a multicentre randomised clinical trial of IV fluids, being born under the sign of Pisces was associated with a decreased risk of death. Our study shows that with convenient use of statistics and an enticing explanatory hypothesis, it is possible to achieve significant findings in post-hoc analyses of data from large trials.

Lower versus higher hemoglobin threshold for transfusion in septic shock

BACKGROUND

Blood transfusions are frequently given to patients with septic shock. However, the benefits and harms of different hemoglobin thresholds for transfusion have not been established.

METHODS

In this multicenter, parallel-group trial, we randomly assigned patients in the intensive care unit (ICU) who had septic shock and a hemoglobin concentration of 9 g per deciliter or less to receive 1 unit of leukoreduced red cells when the hemoglobin level was 7 g per deciliter or less (lower threshold) or when the level was 9 g per deciliter or less (higher threshold) during the ICU stay. The primary outcome measure was death by 90 days after randomization.

RESULTS

We analyzed data from 998 of 1005 patients (99.3%) who underwent randomization. The two intervention groups had similar baseline characteristics. In the ICU, the lower-threshold group received a median of 1 unit of blood (interquartile range, 0 to 3) and the higher-threshold group received a median of 4 units (interquartile range, 2 to 7). At 90 days after randomization, 216 of 502 patients (43.0%) assigned to the lower-threshold group, as compared with 223 of 496 (45.0%) assigned to the higher-threshold group, had died (relative risk, 0.94; 95% confidence interval, 0.78 to 1.09; P=0.44). The results were similar in analyses adjusted for risk factors at baseline and in analyses of the per-protocol populations. The numbers of patients who had ischemic events, who had severe adverse reactions, and who required life support were similar in the two intervention groups.

CONCLUSIONS

Among patients with septic shock, mortality at 90 days and rates of ischemic events and use of life support were similar among those assigned to blood transfusion at a higher hemoglobin threshold and those assigned to blood transfusion at a lower threshold; the latter group received fewer transfusions. (Funded by the Danish Strategic Research Council and others; TRISS ClinicalTrials.gov number, NCT01485315.).

Clinical review: Predictive value of neutrophil gelatinase-associated lipocalin for acute kidney injury in intensive care patients

Neutrophil gelatinase-associated lipocalin (NGAL) may be an early marker of acute kidney injury (AKI), but elevated NGAL occurs in a wide range of systemic diseases. Because intensive care patients have high levels of comorbidity, our objective was to conduct a systematic review of the literature to evaluate the value of plasma and urinary NGAL to predict AKI in these patients. We conducted a systematic electronic literature search of MEDLINE through PubMed, EMBASE, and Cochrane Library for all English language research publications evaluating the predictive value of plasma or urinary NGAL (or both) for AKI in adult intensive care patients. Two authors independently extracted data by using a standardized extraction sheet including study characteristics, type of NGAL measurements, and type of outcome measures. The primary summary measure was area under receiver operating characteristic curve (AuROC) for NGAL to predict study outcomes. Eleven studies with a total of 2,875 (range of 20 to 632) participants were included: seven studies assessed urinary NGAL and six assessed plasma NGAL. The included studies varied in design, including observation period from NGAL sampling to AKI follow-up (range of 12 hours to 7 days), definition of baseline creatinine value, and urinary NGAL quantification method (normalizing to urinary creatinine or absolute concentration). AuROC values for the prediction of AKI ranged from 0.54 to 0.98. Five studies reported AuROC for use of renal replacement therapy ranging from 0.73 to 0.89, and four studies reported AuROC for mortality ranging from 0.58 to 0.83. There were no differences in the predictive values of urinary and plasma NGAL. The heterogeneity in study design and results made it difficult to evaluate the value of NGAL to predict AKI in intensive care patients. NGAL seems to have reasonable value in predicting use of renal replacement therapy but not mortality.