BACKGROUND: Adequate humidification of anesthetic gases has been recommended both for the prevention of pulmonary damage during endotracheal anesthesia and for the maintenance of body temperature, especially in long-duration operated patients. Partial rebreathing anesthesia technique frequently lacks adequate humidity. So, this study was designed to compare inspired humidities in partial rebreathing anesthesia method with and without humidifier in the system. METHODS: The author examined inspired humidity using a controlled partial rebreathing anesthesia method with and without Bird humidifier in 10 and 22 healthy adult patients respectively. The patients were divided into two groups (1 and 2). All patients were anesthetized with pancuronium, halothane or enflurane, nitrous oxide-oxygen, 50-50 per cent, and their lungs were mechanically ventilated. Inspired humidity was measured for three hours at 30-min intervals in both groups. RESULTS: Significant differences were found among group 1- and 2-inspired humidities for 3 hours. While group 2-inspired humidity remained constant between 13 and 16 mgH2O/L during entire anesthesia procedure group 1-inspired humidity remained under 9 mgH2O/L. CONCLUSIONS: The humidities in all partial rebreathing anesthesia method with Bird humidifier not only exceeded those of method without humidifier but also seemed to be high enough to prevent dysfunction of tracheobronchial ciliated epithelium, while the standard partial rebreathing anesthesia method does not provide adequate inspired humidity.
Adult ; Anesthesia ; Anesthesia, Closed-Circuit* ; Anesthetics, Inhalation ; Birds* ; Body Temperature ; Enflurane ; Epithelium ; Gases* ; Halothane ; Humans ; Humidity* ; Lung ; Pancuronium

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

With the increased concern regarding air pollution in the operation theatre and the high cost of vapor anesthetics, closed circuit anesthesia has much to commend it. Since the demise of flammable anesthetics such as diethyl ether and cyclopropane, closed circuit anesthesia has been applied infrequently. Ernst and Lowe recently established a theoretic basis and reported quantitative data and a formula for closed circuit anesthesia. This involves frequent calculations to adjust the nitrous oxide flow and the vaporizer disls in accordance with the elapsed time. We attempted to evaluate their formula against our simplified method of adjusting only the N2O flow according to the N2O uptake rate calculated by Severinghaus. This method allows the output of the vapor from the plenum type vaporizer to diminish according to the decrease of N2O flow. Eighty patients undergoing closed circuit anesthesia were randomly divided into 4 groups of 20 patients each follows: Group l: Adjustment of the N2O flow and the halothane vaporizer dial by elapsed time, according to Ernst and Lowe. Group ll: Adjustment of the N2O flow and the enflurane vaporizer dial by elapsed time, according to Ernst and Lowe. Group lll: Adjustment of the N2O flow only and fixed dial setting on the halothane vaporizer, calculated from the measured end-tidal concentration at 16 min. Group lV: Adjustment of the N2O flow only and a fixed setting on the enflurane vaporizer, calculated from the measured end-tidal concentration at 16 min. The results were as follows: 1) In group l & ll, the inhalation anesthetic concentration decreased gradually and in 10 of 40 patients failed to maintain a satisfactory anesthetic condition after 50 minutes, requiring adjustment of the vaporizer dial setting. No failure occurred in groups lll & lV. 2) There were no abnormal values for the inspired oxygen fraction or the end-tidal CO2 tension at any time. 3) There were no significant differences between groups in the amount of a neuromuscular blocking agent, pancuronium, required. In conclusion, the method of closed circuit anesthesia when administer by adjusting only the flow of N20 and setting the vaporizer dial to a fixed point determined at 15 min may be convenient and efficacious. Attention to the patients safety can be maintained by the use of monitoring devices to measure the inspired oxygen fraction, the end-tidal CO2 tension and vital signs even without monitoring the anesthetic vapor concentration.
Air Pollution ; Anesthesia, Closed-Circuit* ; Anesthetics ; Enflurane ; Ether ; Halothane ; Humans ; Inhalation ; Nebulizers and Vaporizers ; Neuromuscular Blockade ; Nitrous Oxide ; Oxygen ; Pancuronium ; Vital Signs

A number of reports have documented that air-filled cavities in the body will expand if the gas within the space is less soluble in blood than the gas respired. Since an air inflated endotracheal tube cuff within the trachea represents an air-filled body cavity the intracuff gas volume and pressure may be altered during general Inhalation anesthesia. This study was conducted to determine the degree of intracuff pressure and volume changes during general anesthesia. The results were as follows; 1) Twenty three patients, ranging in age from 17 to 73 years, in ASA physical status class 1.ll were reviewed. There were 9 male and 14 females with 19 cases from the general surgical department and 4 from the gynecological department. 2) The duration. of annesthesia ranged was from 120 to 205.7m minutes. 3) Significant intracuff pressure changes develeped in Groups IA and IB (p <7.75), and a significant difference was noted between group 1 and 2. 4) Intracuff gas volume was increased in Groups IA (50% 02, 50% N27) and 1B (33.3% 02, 66.7%N20) with a p value<7.05, but a singificiant time sequential intracuff pressure difference was not observed between the two groups.
Anesthesia, General ; Anesthesia, Inhalation* ; Female ; Humans ; Inhalation* ; Male ; Trachea

One of the most popular types of vaporizer mounting sytems is Selectatec, as it possesses a simple detachment mechanism. Detachable units can loosen between the vaporizer and anesthetic machine, which can cause vapor leakage. A locking system was subsequently developed to prevent this issue; however, we report a case of an unexpected vapor leakage from a locked vaporizer.
Anesthesia ; Anesthetics ; Inhalation ; Nebulizers and Vaporizers

Any factor which increases rebreathing (such as a decrease in inflow rate or an increase in ventilation) or increase uptake (such as an increase in solubility or in cardiac output) will lower the inspired anesthetic concentration. This in turn, will be reflected in an slower rate of anesthesia induction. In a circle absorption system, the inspired anesthetic concentration may be reduced from the inflowing concentration by rebreathing of anesthetic depleted gas. Semiclosed system, most widely used modern anesthetic system was tested to determine what effect the inflow rate had on the rate of rise of anesthetizing alveolar concentration of halothane and enflurane. The results were as follows: 1) High fresh gas inflow rate put the inspired anesthetic concentration close to that of inflow more rapidly. 2) In halothane anesthesia with 4 and 6 L/min of fresh gas flow, the anesthesia induction time was about 20 and 15 minutes respectively. But there was marked delay of the development of anesthesia by 2 L/min of fresh gas fiow. 3) In enflurane anesthesia, the anesthesia induction time was within about 10 minutes without respect to inflow rate. With these results, in general inhalation anesthesia with halothane or enflurane when a semiclosed technique and 100% oxygen are employed, a total gas flow at 4 to 6L per minute is recommended to establish a satisfactory induction and maintenance level of anesthesia.
Absorption ; Anesthesia ; Anesthesia, Inhalation ; Anesthetics, Inhalation* ; Enflurane ; Halothane ; Inhalation* ; Oxygen ; Solubility

A 2 day old male infant, with congenital diaphragmatic herniation on the left side, received diethyl ether inhalation anesthesia, through a 14F endotracheal tube connected with a Jackson-Ree's system for repair of herniation. Throughout anesthesia, the anesthetic gases were not humidified. Signs of high airway obstruction (intercostal space and sternal notch retraction during inspiration, with wheezing and cyanosis) were revealed at the end of operation. Because of in effectiveness of endotracheal suction, immediately the endotracheal tube was extubated, and endotracheal tube obstruction with a dry mucous crust at the tip of the lumen was found. It is strongly suggested that the etiological causes of tube obstruction might be mainly the anesthesia method which has inadequate humidification during anesthesia. This case of endotracheal tube obstruction due to dry mucous crust during inhalation anesthesia was presented and the literature and management are discussed.
Airway Obstruction ; Anesthesia ; Anesthesia, Inhalation* ; Anesthetics, Inhalation ; Ether ; Humans ; Infant ; Inhalation* ; Male ; Methods ; Respiratory Sounds ; Suction

There is some controversy regarding the effect of general inhalation anesthesia on platelet function. In 20 patients undergoing long operations over 3 hours, and anesthetized with either nitrous oxide-oxygen and enflurane (A group) or nitrous oxide-oxygen and halothane (B group), we could not find any clinically significant impairment of coagulation. Platelet functions were consecutively evaluated on the samples collected at preinduction, during anesthesia (3 hours) and at postoperation (24 hours) using an aggregometer and several aggregating agents including ADP, epinephrine, collagen and ristocetin. There were no statistically significant changes between the maximum aggregation rate of preinduction and that duirng anesthesia in either group.
Adenosine Diphosphate ; Anesthesia ; Anesthesia, Inhalation ; Anesthetics, Inhalation* ; Blood Platelets* ; Collagen ; Enflurane ; Epinephrine ; Halothane ; Humans ; Inhalation* ; Ristocetin

BACKGROUND: The bispectral index (BIS) has been designed to objectively measure the degree of sedation and hypnosis for anesthesia. Although it has been well-known that BIS correlates highly with the concentration of inhalation anesthetics, it is not clear whether analgesic potency expressed as MAC is comparable to hypnotic potency described as BIS50 in inhaled anesthetics. This study was conducted to examine the degree of correspondence by correlating the changes of BIS according to the different MAC of commonly used inhalation anesthetics. METHODS: One hundred ASA class 1 or 2 patients, scheduled for laparoscopic knee surgery were included. Patients were equally divided into 4 groups (n = 25 each) according to the inhalational agent enflurane, isoflurane, desflurane, or sevoflurane. Anesthetic depth for each individual agent was controlled to 2.0, 1.75, 1.5, 1.25, 1.0, 0.75 and 0.5 MAC, respectively. After equilibration for each concentration, BIS values were measured three times at 30 second intervals and an average was obtained. In addition, MAC values for each agent were measured when the bispectral index showed 50. RESULTS: The concentrations of inhaled agents vs. BIS showed high negative correlations (enflurane; -0.91, isoflurane; -0.94, desflurane; -0.84, and sevoflurane; -0.86). BIS50 for each agent was enflurane, 0.93 (1.6 vol%); isoflurane, 0.71 (0.9 vol%); desflurane, 0.95 (5.7 vol%); and sevoflurane, 0.84 MAC (1.7 vol%). Isoflurane-BIS50 showed a significant difference to the others (P<0.05). CONCLUSIONS: We concluded that the MAC of inhalation anesthetics showed poor correlation with BIS, suggesting a difference between the hypnotic and analgesic potency of individual inhaled anesthetic agents.
Anesthesia ; Anesthetics ; Anesthetics, Inhalation* ; Enflurane ; Humans ; Hypnosis ; Inhalation* ; Isoflurane ; Knee

BACKGROUND: Sevoflurane anesthesia may show emergence agitation and delirium in children, compared to other inhalation agents. Therefore, we studied the effect of low dose sevoflurane on recovery time and emergence agitation in children. METHODS: We studied 50 patients who were planned for surgery under general anesthesia, aged between 2 and 8 years. They were randomly divided into two groups. Patients of group S were anesthetized with sevoflurane 2.5-3 vol%, whereas those of group R were given sevoflurane 1.2-1.5 vol% and continuous intravenous infusion of remifentanil 0.1-0.2microgram/kg/min. All patients received N2O:O2 50:50 during maintenance of anesthesia. After the surgery, the anesthesiologist recorded recovery time and determined agitation score using 5-point scoring scale in both groups. Agitation score, incidence of emergence agitation and recovery time were compared with each other between the two groups. RESULTS: The agitation scores were 2.72 +/- 0.98 and 2.64 +/- 0.95 in S and R groups, respectively, showing statistical insignificance. The incidence of emergence agitation score 4 or 5 was not significantly different, either. The recovery time was statistically shorter in R group (P<0.05). CONCLUSIONS: Compared with sevoflurane inhalation anesthesia alone, the use of sevoflurane and remifentanil in combination provided shorter recovery time, but no effect on emergence agitation.
Anesthesia* ; Anesthesia, General ; Anesthesia, Inhalation ; Child* ; Delirium ; Dihydroergotamine* ; Humans ; Incidence ; Infusions, Intravenous ; Inhalation