title: Factors related to blood loss during fronto-orbital advancement.
abstract: BACKGROUND
  Blood loss during fronto-orbital advancement (FOA) remains a significant potential source of morbidity. This study explored variables that might correlate with calculated blood loss (CBL) during this procedure.
  
  
  METHODS
  The authors reviewed infants with craniosynostosis who underwent primary FOA (1997-2009). Patient demographics, operative time, and mean arterial pressure (MAP) were recorded. Serial MAPs were averaged for a MAPmean and subtracted from preoperative baseline to calculate MAP%decrease. This provided indicators of both absolute and relative hypotension, respectively. Calculated blood loss was based on preoperative/postoperative hemoglobin values and transfusion volumes and accounted for hemodilutional effects.
  
  
  RESULTS
  Ninety infants underwent FOA at an average age of 10.7 ± 12.9 months and mean weight of 9.0 ± 7.0 kg. Average operative time was 4.2 hours, and intraoperative MAP was 56.1 mm Hg, 22.6% lower than baseline. Mean CBL was 259.3 mL, or 39.3% of estimated blood volume, negatively correlating with surgical age (r = -0.033, P < 0.05) and positively trending with operative time (r = 0.55, P < 0.05). Absolute hypotension was associated with greater blood loss, as demonstrated by an inverse relationship between CBL and MAPmean (r = -0.19, P < 0.05). From the perspective of relative hypotension, no association was found between CBL and MAP%decrease.
  
  
  CONCLUSIONS
  Greater operative efficiency and deferring operative correction to a later age may diminish blood loss during FOA. The study results also raise serious concerns regarding the hemodynamic benefits of controlled systemic hypotension.
authors.affiliation: Department of Plastic Surgery, Georgetown University Hospital, Washington, District of Columbia, USA.
authors.forename: Mitchel
authors.initials: M
authors.lastname: Seruya
authors.forename: Albert K
authors.initials: AK
authors.lastname: Oh
authors.forename: Gary F
authors.initials: GF
authors.lastname: Rogers
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Boyajian
authors.forename: John S
authors.initials: JS
authors.lastname: Myseros
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Yaun
authors.forename: Robert F
authors.initials: RF
authors.lastname: Keating
mesh_terms: D000704:Analysis of Variance; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data*; D001810:Blood Volume; D003398:Craniosynostoses / Q000601:surgery*; D003399:Craniotomy / Q000379:methods*; D005260:Female; D005624:Frontal Bone / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D007022:Hypotension / Q000209:etiology; D007223:Infant; D008297:Male; D009915:Orbit / Q000601:surgery*; D012044:Regression Analysis; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome