title: Forehead reflectance oximetry: a clinical comparison with conventional digit sensors during laparotomic and laparoscopic abdominal surgery.
abstract: OBJECTIVE
  This study compared the performance of forehead reflectance and conventional pulse oximetry (SpO(2)) in mechanically ventilated, anesthetized patients undergoing major abdominal surgery with either laparoscopic or laparotomic techniques.
  
  
  METHODS
  SpO(2) was continuously measured both with a forehead reflectance and a conventional digit sensor in 20 ASA physical status I-III, anesthetized patients undergoing either a laparotomic (group Laparotomy, n = 10) or laparoscopic (group Laparoscopy, n = 10) major abdominal surgery. SpO(2) values measured with the two sensors were continuously recorded at 10-second intervals during the entire procedure, and then analyzed for consistency.
  
  
  RESULTS
  In group Laparotomy finger and forehead readings remained consistently similar during the study period; on the contrary, in group Laparoscopy forehead SpO(2) readings showed a much wider variability. The mean (95% Confidence Intervals) difference between finger and forehead SpO(2) readings was 2.0% (-1.3% to +6.0%) in group Laparotomy and 2.5% (-3.5% to +8.4%) in group Laparoscopy (p = 0.001); however, in group Laparoscopy the mean difference between digit and forehead SpO(2) values increased from 0.2% (CI(95): -2.1% to +2.5%) during the first hour to 4.5% (CI(95): -2.5% to +11-5%) in the second hour (p = 0.0005), and 3.1% (CI(95): -2.4% to + 8.6%) in the third hour of surgery (p = 0.0005). Clinically relevant desaturation (decrease of SpO(2) < 89% for > or =30 s) detected with the forehead sensor in the Laparoscopy group was significantly more frequent and longer lasting than with conventional digit sensor. No differences were observed in group Laparotomy.
  
  
  CONCLUSIONS
  Forehead reflectance oximetry is as accurate as conventional digit based oximetry in mechanically ventilated patients undergoing laparotomic surgery in the supine position, but is significantly influenced by patient positioning and pneumoperitoneum during laparoscopic surgery.
authors: Department of Anesthesiology, Critical Care and Pain Medicine, University of Parma, Italy.
authors: Andrea
authors: A
authors: Casati
authors: Grazia
authors: G
authors: Squicciarini
authors: Marco
authors: M
authors: Baciarello
authors: Marta
authors: M
authors: Putzu
authors: Alessandra
authors: A
authors: Salvadori
authors: Guido
authors: G
authors: Fanelli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003082:Colectomy; D005385:Fingers / Q000098:blood supply; D005546:Forehead / Q000098:blood supply; D005743:Gastrectomy; D006801:Humans; D010535:Laparoscopy; D007813:Laparotomy; D008875:Middle Aged; D010092:Oximetry / Q000379:methods*; D011446:Prospective Studies
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