title: Pain management in photodynamic therapy using a nitrous oxide/oxygen mixture: a prospective, within-patient, controlled clinical trial.
abstract: BACKGROUND
  Photodynamic therapy is an effective treatment for actinic keratoses. Nevertheless, severe pain during the procedure is a serious adverse effect, which leads to interruption or even termination. Complete pain relief remains a difficult challenge.
  
  
  OBJECTIVE
  To evaluate the effect of a nitrous oxide/oxygen mixture on pain intensity during photodynamic therapy.
  
  
  METHODS
  This clinical trial has been designed as a prospective, single-centre, explorative, controlled, observational study.
  
  
  RESULTS
  We were able to detect a significant overall pain reduction of 55.2% after application of a nitrous oxide/oxygen mixture by means of an intra-individual comparison. Furthermore, the total number of therapy interruption significantly decreased by 82% after the inhalation analgesia. Additionally, treatment satisfaction ranged from 'extremely to very satisfied'.
  
  
  CONCLUSIONS
  This study shows that analgesia by means of a nitrous oxide/oxygen mixture is a very effective and well-tolerated method for achieving significant pain reduction during photodynamic therapy.
authors.affiliation: Department of Dermatology, University of Heidelberg, Heidelberg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Fink
authors.affiliation: Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Uhlmann
authors.affiliation: Department of Dermatology, University of Heidelberg, Heidelberg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Enk
authors.affiliation: Department of Dermatology, University of Heidelberg, Heidelberg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Gholam
mesh_terms: D006801:Humans; D009609:Nitrous Oxide / Q000008:administration & dosage*; D010100:Oxygen / Q000008:administration & dosage*; D059408:Pain Management / Q000379:methods*; D010778:Photochemotherapy; D011446:Prospective Studies
chemical_list: D009609:Nitrous Oxide; D010100:Oxygen