title: Effect of nail polish on oxygen saturation determined by pulse oximetry in critically ill patients.
abstract: BACKGROUND
  Nail polish of different colours may alter accuracy and precision of pulse oximetry as previous data in healthy volunteers suggest. This trial evaluates the oxygen saturation determined by pulse oximetry and haematoximetry with nail polish of nine different colours applied.
  
  
  METHODS
  Fifty critically ill and mechanically ventilated patients in an ICU were investigated in a prospective clinical-experimental trial. On nine finger nails polish of different colours was applied in a predetermined consecutive order. Functional oxygen saturation was determined by pulse oximetry (SpO2) on each finger for each colour with the finger sensor probe both in the normal position and at a 90 degrees rotation. Simultaneously oxygen saturation was determined by haematoximetry (SaO2). Accuracy (bias, DeltaS = SaO2-SpO2) and precision (standard deviation, S.D.) of pulse oximetry were analyzed with the t-test. A value of P < 0.05 was considered significant.
  
  
  RESULTS
  While black (DeltaS = +1.6+/-3.0%), purple (DeltaS = +1.2+/-2.6%) and dark blue nail polish (DeltaS = +1.1+/-3.5%, each N = 50) had the greatest effect (P < 0.05), all other colours, including colourless nail polish, had a smaller effect (mean bias +0.2 to +0.9%). A rotation of 90 degrees reduced the bias from +2.8 to +1.3% (N = 10, n.s.).
  
  
  CONCLUSIONS
  Nail polish does not alter pulse oximetry readings in mechanically ventilated patients to a clinically relevant extent. The mean error of measurement for all colours was within the manufacturers' specified range of +/-2%. A 90 degrees rotation of the sensor probe does not eliminate errors in measurement. To remove nail polish might be helpful to decrease the error of measurement in some cases.
authors.affiliation: University Clinic for Anesthesiology and Intensive Care Medicine, Faculty of Clinical Medicine Mannheim, Ruprecht-Karls-University Heidelberg, University Hospital Mannheim, Mannheim, Germany. jochen.hinkelbein@anaes.ma.uni-heidelberg.de
authors.forename: Jochen
authors.initials: J
authors.lastname: Hinkelbein
authors.forename: Harald V
authors.initials: HV
authors.lastname: Genzwuerker
authors.forename: Reiner
authors.initials: R
authors.lastname: Sogl
authors.forename: Fritz
authors.initials: F
authors.lastname: Fiedler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003116:Color; D003358:Cosmetics / Q000009:adverse effects*; D003422:Critical Care; D016638:Critical Illness; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009262:Nails; D010092:Oximetry / Q000592:standards*; D011446:Prospective Studies; D012121:Respiration, Artificial
chemical_list: D003358:Cosmetics