title: Postoperative hypoalbuminemia following surgery related to craniosynostosis.
abstract: BACKGROUND
  An episode of postoperative phenytoin toxicity in a patient undergoing surgery related to craniosynostosis highlighted the presence of hypoalbuminemia. We believe that hypoalbuminemia contributed to the altered pharmacokinetics of phenytoin in this case.
  
  
  OBJECTIVE
  To establish the incidence of postoperative hypoalbuminemia in patients undergoing surgery related to craniosynostosis and to investigate the likely etiology.
  
  
  METHODS
  Data on 114 patients undergoing surgery for craniosynostosis over a 2-year period at Oxford Children's Hospital, between May 2011 and May 2013, were retrospectively reviewed. Twenty-two patients were excluded due to incomplete data. This cohort represents the entire population for whom transfusion data had been formally collected at our institution. Preoperative and day 1 postoperative serum albumin levels were collected from the hospital laboratory database. Data regarding blood loss and intra-operative fluid management were reviewed from the anesthetic database. Linear regression analysis was used to establish the relationship between percentage drop in serum albumin with: (i) milliliters per kilogram (ml·kg(-1)) volume of albumin-poor fluids used intra-operatively and (ii) percentage estimated red cell mass loss.
  
  
  RESULTS
  All patients experienced a statistically significant drop in serum albumin. The mean difference in albumin was 17.1 g·l(-1), 95% CI (16.1-18.0) (P < 0.001). Expressed as a percentage, the mean reduction was 37.9% (range 16-61%), SD 9.7. The decrease in albumin was associated with an increase in estimated red cell mass loss (P < 0.001) and an increased ml·kg(-1) volume of albumin-poor fluids given (P < 0.001).
  
  
  CONCLUSIONS
  Hemodilution due to large volume blood loss and transfusion with albumin-poor fluids is strongly associated with postoperative hypoalbuminemia in patients undergoing surgery related to craniosynostosis. Practitioners should be aware of this risk and the implications of postoperative hypoalbuminemia in this population.
authors.affiliation: Nuffield Department of Anaesthesia, Oxford University Hospitals NHS Trust, Oxford, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Allison
authors.affiliation: Nuffield Department of Anaesthesia, Oxford University Hospitals NHS Trust, Oxford, UK.
authors.forename: Russell G
authors.initials: RG
authors.lastname: Evans
authors.affiliation: Oxford Craniofacial Unit, Department of Plastic Surgery, Oxford University Hospitals NHS Trust, Oxford, UK.
authors.forename: Steven
authors.initials: S
authors.lastname: Wall
authors.affiliation: Oxford Craniofacial Unit, Department of Plastic Surgery, Oxford University Hospitals NHS Trust, Oxford, UK.
authors.forename: David
authors.initials: D
authors.lastname: Johnson
authors.affiliation: Nuffield Department of Anaesthesia, Oxford University Hospitals NHS Trust, Oxford, UK.
authors.forename: Sumit
authors.initials: S
authors.lastname: Das
mesh_terms: D016063:Blood Loss, Surgical / Q000706:statistics & numerical data; D015984:Causality; D003398:Craniosynostoses; D005260:Female; D005440:Fluid Therapy / Q000706:statistics & numerical data; D006438:Hemodilution / Q000706:statistics & numerical data; D006801:Humans; D034141:Hypoalbuminemia / Q000453:epidemiology*; D015994:Incidence; D007223:Infant; D007432:Intraoperative Period; D008297:Male; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors
keywords: blood transfusion; cranial vault remodeling; craniofacial surgery; craniosynostosis; hypoalbuminemia; pediatric anesthesia; phenytoin