title: Extent, risk factors, and outcome of fluid overload after pediatric heart surgery*.
abstract: OBJECTIVE
  Fluid overload is associated with poor PICU outcomes in different populations. Little is known about fluid overload in children undergoing cardiac surgery. We described fluid overload after cardiac surgery, identified risk factors of worse fluid overload and also determined if fluid overload predicts longer length of PICU stay, prolonged mechanical ventilation (length of ventilation) and worse lung function as estimated by the oxygenation index.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Montreal Children's Hospital PICU, Montreal, Canada.
  
  
  METHODS
  Patients 18 years or younger undergoing cardiac surgery (2005-2007).
  
  
  METHODS
  None.
  
  
  RESULTS
  Cumulative fluid overload % was calculated as [(total fluid in - out in L)/admission weight (kg) × 100] and expressed as PICU peak cumulative fluid overload % throughout admission and PICU day 2 cumulative fluid overload %. Primary outcomes were length of stay and length of ventilation. The secondary outcome was oxygenation index. Fluid overload risk factors were evaluated using stepwise linear regression. Fluid overload-outcome relations were evaluated using stepwise Cox regression (length of stay, length of ventilation) and generalized estimating equations (daily PICU cumulative fluid overload % and oxygenation index repeated measures). There were 193 eligible surgeries. Peak cumulative fluid overload % was 7.4% ± 11.2%. Fluid overload peaked on PICU day 2. Lack of past cardiac surgery (p = 0.04), cyanotic heart disease (p = 0.03), and early postoperative fluids (p = 0.0001) was independently associated with higher day 2 fluid overload %. Day 2 fluid overload % predicted longer length of stay (adjusted hazard ratio, 0.95; 95% CI, 0.92-0.99; p = 0.009) and length of ventilation (adjusted hazard ratio, 0.97; 95% CI, 0.94-0.99; p = 0.03). In patients without cyanotic heart disease, worse daily fluid overload % predicted worse daily oxygenation index.
  
  
  CONCLUSIONS
  Fluid overload occurs early after cardiac surgery and is associated with prolonged PICU length of stay and ventilation. Future fluid overload avoidance trials may confirm or refute a true fluid overload-outcome causative association.
authors: 1Department of Pediatrics, McGill University Health Center, Montreal Children's Hospital, Montreal, QC, Canada. 2Department of Cardiac Surgery, McGill University Health Center, Montreal Children's Hospital, Montreal, QC, Canada.
authors: Jade
authors: J
authors: Seguin
authors: Benjamin
authors: B
authors: Albright
authors: Laura
authors: L
authors: Vertullo
authors: Pamela
authors: P
authors: Lai
authors: Adrian
authors: A
authors: Dancea
authors: Pierre-Luc
authors: PL
authors: Bernier
authors: Christo I
authors: CI
authors: Tchervenkov
authors: Christos
authors: C
authors: Calaritis
authors: David
authors: D
authors: Drullinsky
authors: Ronald
authors: R
authors: Gottesman
authors: Michael
authors: M
authors: Zappitelli
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology; D001826:Body Fluids / Q000378:metabolism*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D015278:Intensive Care Units, Pediatric / Q000706:statistics & numerical data*; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D011183:Postoperative Complications / Q000453:epidemiology / Q000401:mortality*; D012121:Respiration, Artificial / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors