Glucose-based fluid creep or maintenance fluids in critically ill adult patients: a scoping review of the available evidence related to blood glucose control

Abstract Background Fluid therapy is a fundamental aspect of intensive care unit treatment, encompassing resuscitation, maintenance, nutrition, and hidden fluid "creep" to keep lines open or dilute drugs. While most research has focused on resuscitation fluids, maintenance and fluid creep are major contributors to overall fluid and electrolyte intake. Normal saline is commonly used as fluid creep, but concerns about electrolyte imbalances have led to interest in alternatives like Dextrose 5% in Water. Methods In this scoping review we aimed to map the available evidence of glucose-based vs non-glucose-based maintenance fluids/ fluid creep with regard to blood glucose levels, insulin need and further related outcomes (urinary output, length of stay in ICU) in adult ICU patients. We systematically searched PubMed, Embase and the Cochrane Library. We aimed to include prospective and retrospective clinical cohort studies and controlled trials in adult ICU patients reporting blood sugar levels or insulin use and excluded trials on resuscitation fluids or patient populations with specific requirements regarding fluid therapy (e.g., burn patients, children). We analysed risk of bias using the standardized Risk of Bias in Non-randomized Studies-of Interventions tool. Results Six observational, single-center cohort studies ( n = 6343 patients) met inclusion criteria. Overall, evidence was limited and heterogeneous, with no non-randomized controlled trials identified meeting our inclusion criteria. Findings on blood glucose levels were heterogeneous and inconclusive across studies. Findings for urinary output and ICU length of stay were inconsistent but trials were not powered to report these endpoints. The included studies were subject to confounding, incomplete outcome reporting, and variability in fluid regimens. Conclusions Current evidence on glucose-containing maintenance fluids as well as on fluid creep or combined strategies on glycemic control in critically ill adults is limited and observational. Maintenance fluids, drug diluents/fluid creep, and combined strategies are distinct exposures with different glucose loads; evidence is sparse and should not be generalized across categories. Adequately powered randomized controlled trials are needed to clarify effects on blood glucose and insulin-related outcomes as well as on patient-centered outcomes for each category. Systematic review registration PROSPERO CRD42024542262.