After the patients were intubated with a low-or high-pressure cuff, the cuffs were inflated with air enough to seal the trachea. Intracuff volume and pressure were measured and the pressure exerted on the trachea were calculated. After administration of 0%, 50%, or 67% nitrous oxide the measurements were eompared with the initial values. 1) At the start the high-pressure cuff exerted a higher pressure on the trachea than the low-pressure cuff. 2) The volumes of the high-pressure cuffs were not increased after 2 hours by the increasing the coneentration of nitrous oxide, but the pressures in the cuffs were increased significantly. Volumes and pressures of low-pressure cuffs increased after 2 hours when increasing the concentration of nitrous oxide.3) The pressure exerted on the traches by the high-pressure cuff decreased without a relationship to the concentration of the nitrous oxide, but the pressure exerted on the trachea by the low-pressure cuff increased with increased concentration of nitrous oxide.
Humans ; Nitrous Oxide ; Trachea

No abstract available.
Nitrous Oxide* ; Subacute Combined Degeneration*

No abstract available.
Humans ; Neurologic Manifestations* ; Nitrous Oxide*

No abstract available.
Nitrous Oxide ; Spinal Cord Diseases

The effect of nitrous oxide on endotracheal tube cuff pressure was measured during N2O-O2-halothane anesthesia. Intracuff pressure was increased in a time-related fashion up to 150 minutes. Thereafter no significant increase was observed, The other hand, there is no endotracheal tube cuff pressure change during O2-halothane anesthesia. These findings demonstrate that nitrous oxide has the capacity to diffuse into Portex endotracheal tube cuffs in significant volumes and may result in increased intracuff pressure, and in O2-halothane anesthesia, the nitrogea in the cuff was diffused out from the cuffs.
Anesthesia ; Anesthesia, Inhalation* ; Hand ; Inhalation* ; Nitrous Oxide

A few postulated methods of regulating cuff pressure (filling anesthetic gas in the cuff, filling saline in the cuff, connecting cuff to a pressure regulating device) were compared each other after determining compliance curve of cuffs. Although there were no significant difference among slopes of linear regression curve of compliance curves of each condition, pressure range, standard deviation were most acceptable with the use of a pressure regulating device.
Anesthetics ; Compliance ; Gases ; Linear Models ; Nitrous Oxide

No abstract available.
Depression* ; Isoflurane* ; Nitrous Oxide* ; Scopolamine Hydrobromide*

BACKGROUND: Nitrous oxide is generally avoided in order to prevent either hypoxia or graft dislodgment during tympanoplasty. The aim of this study was to investigate the effect of nitrous oxide on the bispectral index during sevoflurane anesthesia at the anesthetic dose. METHODS: The bispectral index was continually measured during nitrous oxide-oxygen-sevoflurane anesthesia, discontinuation of nitrous oxide and the reintroduction of nitrous oxide. RESULTS: The bispectral index of nitrous oxide-oxygen-sevoflurane anesthesia increased after discontinuing the nitrous oxide and decreased after its reintroduction. CONCLUSIONS: Nitrous oxide decreased the bispectral index of nitrous oxide-oxygen-sevoflurane anesthesia compared with oxygen-sevoflurane anesthesia at the anesthetic dose.
Anesthesia* ; Anoxia ; Nitrous Oxide* ; Transplants ; Tympanoplasty

To evaluate the second gas effect during induction of clinical anesthesia, the ratios of the end-tidal to the inspired concentration of halothane (FET/F1) were measured in 21 children in ASA class 1. The children were divided into three groups: gorup I received 100 % O2 and 1% halothane, group II received 70% N2O, 30% O2 and 1% halothane simultaneously, and group III received 1% halothane and 100% O2 for 5 min, followed by 70% N2O, 30% O2 and 1% halothane. With or without N2O, the increases of FET/F1 were significant 3min after inhalation of halothane. The increase in FET/F1 compared with the previous value, was insignificant in gorup I, and significant for 7min and 5min in groups II and III respectively. Compared with gorup I, the remarkable second gas effect in gorup II was noticed 7 min after induction and continued during the study, but in group III, it was noticed only 9 min after induction, and disappeared rapidly. The second gas effect in this study might be due to the concentrating effect by the uptake of N2O.
Anesthesia* ; Child* ; Halothane ; Humans ; Inhalation ; Nitrous Oxide

BACKGROUND: Uncuffed endotracheal tubes are commonly used in pediatrics even when the risk of gastric aspiration is significant. But cuffed endotracheal tubes effectively protect the risk of pulmonary aspiration and completely seal the airway. This study was designed to determine the appropriate cuff volume and pressure with low risk of ischemic injury to children's airway. METHODS: We intubated cuffed endotracheal tube (internal diameter 4.5, 5.0, 5.5 mm) in 90 surgical pediatric patient from 16 to 118 months of age. After intubation, initial cuff volume and pressure were measured at the level of complete sealing in each group. Each group was administrated 50% nitrous oxide and 67% nitrous oxide and measured cuff pressure at 20 minutes, 40 minutes. RESULTS: 1) The mean initial cuff volume and pressure of 4.5 ID tube were 0.59 +/- 0.16 ml and 14.5 +/- 0.31 cmH2O (n=30). 2) The mean initial cuff volume and pressure of 5.0 ID tube were 1.00 +/- 0.38 ml and 14.3 +/- 3.55 cmH2O (n=30). 3) The mean initial cuff volume and pressure of 5.5 ID tube were 1.06 +/- 0.26 ml and 14.28 +/- 2.01 cmH2O (n=30). 4) The cuff pressure increased significantly in the course of time, but no pressure in three groups was above 30 cmH2O. CONCLUSIONS: We could determine the appropriate cuff volume of cuffed endotracheal tube in pediatric patients. Also we concluded that nitrous oxide concentration affect little intracuff pressure in brief operation.
Anesthesia, General* ; Humans ; Intubation ; Nitrous Oxide ; Pediatrics