title: [Volume and pressure of tracheal tube cuffs filled with air or nitrous oxide.].
abstract: OBJECTIVE
  Tracheal tube cuff pressure against tracheal wall should to prevent air leaked or pulmonary aspiration, allowing adequate capillary blood flow. This study aimed at determining pressure variations of tracheal tube cuffs filled with air or 100% nitrous oxide.
  
  
  METHODS
  Participated in this study 30 patients submitted to balanced general anesthesia with tracheal intubation. Cuff was inflated according to clinical criteria. The intracuff pressure measurements were undertaken after 15 minutes of anesthesia by means of an aneroid manometer gaged in cm of H2O and have provided initial pressure and volume values. The patients was allocated in two groups: cuff inflated with air, group A, and with nitrous oxide, group B. Measurements were recorded during one hour and results were compared. Groups were homogeneous in gender and age.
  
  
  RESULTS
  Both groups have shown baseline pressure values close to 40 cmH2O with 8 ml of volume. Group filled with air had pressures increased up to 36 cmH2O in one hour. Group filled with nitrous oxide had pressures decreased below 20 cmH2O after 20 to 30 minutes of anesthesia.
  
  
  CONCLUSIONS
  100% nitrous oxide to fill tracheal tube cuffs is not a safe method resulting in progressive air leakage. The cuff air promotes volume and pressure increase, with higher chances for tracheal mucosa injury.
authors.affiliation: CET, SBA, ISCMSP.
authors.forename: Ernesto Leonardo Cárpio
authors.initials: EL
authors.lastname: Peña
authors.forename: Waldemar Montoya de
authors.initials: WM
authors.lastname: Gregori
authors.forename: Luiz
authors.initials: L
authors.lastname: Piccinini Filho
authors.forename: Joaquim Edson
authors.initials: JE
authors.lastname: Vieira
authors.forename: Lígia Andrade da Silva Telles
authors.initials: LA
authors.lastname: Mathias