title: Prospective, double-blind, randomized trial of equimolar mixture of nitrous oxide/oxygen to prevent pain induced by insertion of venous access ports in cancer patients.
abstract: BACKGROUND
  To assess the efficacy of equimolar mixture of nitrous oxide/oxygen (EMNO) to prevent pain induced by venous access ports (VAPs) implantation in cancer patients.
  
  
  METHODS
  In a randomized, double-blind study on an adult population not knowing the effects of EMNO, cancer patients were randomly assigned to breath via a facial mask, EMNO or a placebo mixture comprising 50% oxygen and 50% nitrogen. The primary end-point was the patients' assessment of the severity of pain evaluated using a visual analog scale (VAS, 0 to 100) and the proportion of patients suffering pain in each group. The secondary criteria were side effects, tolerability of EMNO, and the level of satisfaction of both the patients and the medical team.
  
  
  RESULTS
  Eighty-three adults (42 in the EMNO group and 41 in the placebo group) were included. VAPs were implanted in the jugular vein in 95% of patients. In the placebo group, 78% of the patients declared that they found VAP implantation painful vs. 34% in the EMNO group (p=0.001). The severity of the pain was reduced by 50% in the EMNO group in comparison with placebo (p=0.0125). Although the median time to perform implantation was strictly identical in both groups (20 min), the estimated duration of surgery seemed longer to patients in the control group. Patient and investigator satisfaction indexes were >90% in both groups.
  
  
  CONCLUSIONS
  EMNO provides an effective solution for the prevention of pain during placement of VAPs.
authors.affiliation: Department of Anesthesiology, Hopital Saint Louis, AP-HP, Université Paris VII, 1, avenue Claude Vellefaux, 75010, Paris, France. marie-cecile.douard@sls.ap-hop-paris.fr
authors.forename: Marie Cécile
authors.initials: MC
authors.lastname: Douard
authors.forename: Mario
authors.initials: M
authors.lastname: di Palma
authors.forename: Patricia
authors.initials: P
authors.lastname: d'Agostino
authors.forename: Sylvie
authors.initials: S
authors.lastname: Chevret
authors.forename: Irène
authors.initials: I
authors.lastname: Kriegel
authors.forename: Bruno
authors.initials: B
authors.lastname: Falissard
authors.forename: Patrick
authors.initials: P
authors.lastname: Thierry
authors.forename: Brigitte
authors.initials: B
authors.lastname: George
authors.forename: Laurence
authors.initials: L
authors.lastname: Bussières
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Misset
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000627:therapeutic use*; D002406:Catheterization, Peripheral / Q000009:adverse effects*; D002408:Catheters, Indwelling / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009609:Nitrous Oxide / Q000008:administration & dosage / Q000627:therapeutic use*; D010102:Oxygen Inhalation Therapy; D010146:Pain / Q000209:etiology* / Q000517:prevention & control*; D010147:Pain Measurement; D010919:Placebos
chemical_list: D018686:Anesthetics, Intravenous; D010919:Placebos; D009609:Nitrous Oxide