title: The effect of excess fluid balance on the mortality rate of surgical patients: a multicenter prospective study.
abstract: BACKGROUND
  In some studies including small populations of patients undergoing specific surgery, an intraoperative liberal infusion of fluids was associated with increasing morbidity when compared to restrictive strategies. Therefore, to evaluate the role of excessive fluid infusion in a general population with high-risk surgery is very important. The aim of this study was to evaluate the impact of intraoperative fluid balance on the postoperative organ dysfunction, infection and mortality rate.
  
  
  METHODS
  We conducted a prospective cohort study during one year in four ICUs from three tertiary hospitals, which included patients aged 18 years or more who required postoperative ICU after undergoing major surgery. Patients who underwent palliative surgery and whose fluid balance could change in outcome were excluded. The calculation of fluid balance was based on preoperative fasting, insensible losses from surgeries and urine output minus fluid replacement intraoperatively.
  
  
  RESULTS
  The study included 479 patients. Mean age was 61.2 ± 17.0 years and 8.8% of patients died at the hospital during the study. The median duration of surgery was 4.0 (3.2 to 5.5) h and the value of the Simplified Acute Physiology Score (SAPS) 3 score was 41.8 ± 14.5. Comparing survivors and non-survivors, the intraoperative fluid balance from non-survivors was higher (1,950 (1,400 to 3,400) mL vs. 1,400 (1,000 to 1,600) mL, P <0.001). Patients with fluid balance above 2,000 mL intraoperatively had a longer ICU stay (4.0 (3.0 to 8.0) vs. 3.0 (2.0 to 6.0), P <0.001) and higher incidence of infectious (41.9% vs. 25.9%, P = 0.001), neurological (46.2% vs. 13.2%, P <0.001), cardiovascular (63.2% vs. 39.6%, P <0.001) and respiratory complications (34.3% vs. 11.6%, P <0.001). In multivariate analysis, the fluid balance was an independent factor for death (OR per 100 mL = 1.024; P = 0.006; 95% CI 1.007 to 1.041).
  
  
  CONCLUSIONS
  Patients with excessive intraoperative fluid balance have more ICU complications and higher hospital mortality.
authors: João M
authors: JM
authors: Silva
authors: Amanda Maria Ribas Rosa
authors: AM
authors: de Oliveira
authors: Fernando Augusto Mendes
authors: FA
authors: Nogueira
authors: Pedro Monferrari Monteiro
authors: PM
authors: Vianna
authors: Marcos Cruz
authors: MC
authors: Pereira Filho
authors: Leandro Ferreira
authors: LF
authors: Dias
authors: Vivian Paz Leão
authors: VP
authors: Maia
authors: Cesar de Souza
authors: Cde S
authors: Neucamp
authors: Cristina Prata
authors: CP
authors: Amendola
authors: Maria José Carvalho
authors: MJ
authors: Carmona
authors: Luiz M Sá
authors: LM
authors: Malbouisson
mesh_terms: D000368:Aged; D005260:Female; D005440:Fluid Therapy / Q000009:adverse effects*; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D019990:Perioperative Care; D011183:Postoperative Complications / Q000401:mortality*; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D014882:Water-Electrolyte Balance