[Volume and pressure of tracheal tube cuffs filled with air or nitrous oxide.].
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.
Peña
Ernesto Leonardo Cárpio
EL
CET, SBA, ISCMSP.
Gregori
Waldemar Montoya de
WM
Piccinini Filho
Luiz
L
Vieira
Joaquim Edson
JE
Mathias
Lígia Andrade da Silva Telles
LA