Background: With a density five times bigger than that of air, Xenon should increase the total resistance of the respiratory system (Rrs,tot). Methods: Ten patients, undergoing general anesthesia, were studied while they were breathing (1) pure oxygen and (2) a gas mixture of 70% Xenon - 30% Oxygen. To calculate the true Rrs, (i.e. Rrs,tot minus the tube resistance), an in vitro experiment was conducted to obtain the K1 and K2 values of the Roher's equation for different tube size. Results: Using Xenon the K2 values were higher than those obtained for a gas mixture of 70% Nitrous Oxide or Oxygen. The true Rrs increased during Xenon anesthesia due to an increase of lung resistance. The high Rrs,tot promoted the development of PEEPi when a tidal volume higher than 0.7 l was used. Conclusion: The ventilatory strategy during Xenon anesthesia to minimize PEEPi should promote the use of a long expiratory time and of an endotracheal tube with a high inner diameter.
Respiratory mechanics during xenon anesthesia. Xenon as an external PEEP?
VOLTA, Carlo Alberto;
1998
Abstract
Background: With a density five times bigger than that of air, Xenon should increase the total resistance of the respiratory system (Rrs,tot). Methods: Ten patients, undergoing general anesthesia, were studied while they were breathing (1) pure oxygen and (2) a gas mixture of 70% Xenon - 30% Oxygen. To calculate the true Rrs, (i.e. Rrs,tot minus the tube resistance), an in vitro experiment was conducted to obtain the K1 and K2 values of the Roher's equation for different tube size. Results: Using Xenon the K2 values were higher than those obtained for a gas mixture of 70% Nitrous Oxide or Oxygen. The true Rrs increased during Xenon anesthesia due to an increase of lung resistance. The high Rrs,tot promoted the development of PEEPi when a tidal volume higher than 0.7 l was used. Conclusion: The ventilatory strategy during Xenon anesthesia to minimize PEEPi should promote the use of a long expiratory time and of an endotracheal tube with a high inner diameter.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
