title: A comparison of balanced and unbalanced crystalloid solutions in surgery patient outcomes.
abstract: BACKGROUND
  The objective of this study was to evaluate adverse patient outcomes associated with the choice of intravenous fluid administered during general anaesthesia.
  
  
  METHODS
  This study was a retrospective chart review of vascular surgery patients at a Canadian tertiary care hospital. Patients were separated into three groups: those who were intraoperatively administered normal saline (NS), balanced crystalloids, or a combination of both solutions. Multivariate analysis was performed to determine association between volume of each fluid type administered and adverse outcomes including in-hospital mortality, prolonged intensive care unit admission, vasopressor requirement, ventilator requirement, hemodialysis requirement, and a composite endpoint of any of these adverse events occurring.
  
  
  RESULTS
  Overall, 796 vascular surgery patients were included in the analysis. There were 425 patients who received balanced crystalloids, 158 patients who received NS, and 213 patients received both balanced crystalloids and NS. Groups were similar in age (P=0.06), but varied in gender (P<0.001) and overall health (ASA≥2; P=0.027). The most common adverse event was ventilator requirement (NS: 27.9%, balanced: 7.5%, both: 38.0%; P<0.001). Mortality was lowest in the group that received balanced fluids (NS: 12.0%, balanced: 5.9%, both: 10.8%; P=0.018). Patients who were administered NS or both fluids were more likely to reach the composite endpoint than patients receiving balanced crystalloid alone.
  
  
  CONCLUSIONS
  The administration of an unbalanced crystalloid solution was associated with poor patient outcomes in our study population.
authors.affiliation: Department of critical care, Dalhousie university, room 377, Bethune building, 1276, South Park street, B3H 2Y9 Halifax, NS, Canada. Electronic address: tom.kuca@gmail.com.
authors.forename: Tomas
authors.initials: T
authors.lastname: Kuca
authors.affiliation: Department of critical care, department of mathematics and statistics, Dalhousie university, room 377, Bethune building, 1276, South Park street, B3H 2Y9 Halifax, Nova Scotia, Canada. Electronic address: mbbutler@dal.ca.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Butler
authors.affiliation: Trauma Nova Scotia, Nova Scotia department of health and wellness, room 1-026B, Centennial building, 1276, South Park street, B3H 2Y9 Halifax, NS, Canada. Electronic address: mete.erdogan@nshealth.ca.
authors.forename: Mete
authors.initials: M
authors.lastname: Erdogan
authors.affiliation: Department of critical care, Dalhousie university, room 377, Bethune building, 1276, South Park street, B3H 2Y9 Halifax, NS, Canada. Electronic address: greenrs@dal.ca.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Green
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003422:Critical Care; D000077324:Crystalloid Solutions; D023381:Endpoint Determination; D005260:Female; D005440:Fluid Therapy; D017052:Hospital Mortality; D006801:Humans; D007552:Isotonic Solutions / Q000009:adverse effects / Q000737:chemistry* / Q000627:therapeutic use*; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D010952:Plasma Substitutes / Q000009:adverse effects / Q000737:chemistry* / Q000627:therapeutic use*; D006435:Renal Dialysis; D012121:Respiration, Artificial; D012189:Retrospective Studies; D012965:Sodium Chloride; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures; D014662:Vasoconstrictor Agents / Q000627:therapeutic use
chemical_list: D000077324:Crystalloid Solutions; D007552:Isotonic Solutions; D010952:Plasma Substitutes; D014662:Vasoconstrictor Agents; D012965:Sodium Chloride
keywords: Balanced; Crystalloid; Intravenous; Outcome; Saline; Vascular