Anesthesia progress
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Anesthesia progress · Jan 2000
Randomized Controlled Trial Clinical TrialSevoflurane and isoflurane reduce oxygen saturation in infants.
Volatile anesthetics are generally known to exert several influences on the respiratory system, but their direct effect on oxygen saturation as measured by pulse oximetry (SpO2) in infants remains unknown. In this study, 70 infants under 2 years of age who received general anesthesia were examined to determine the effects of several volatile anesthetics and nitrous oxide on SpO2. ⋯ Significantly lower SpO2 values (paired t test, P < .05) were observed when the subjects were ventilated with oxygen, 67% nitrous oxide, and sevoflurane or isoflurane--but not with oxygen, 67% nitrous oxide, and enflurane--than when they were administered oxygen, 50% nitrous oxide, and the original concentration of each volatile anesthetic. These results suggest that sevoflurane and isoflurane have different effects from enflurane on gas exchange systems.
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Anesthesia progress · Jan 2000
Comparative StudyThe use of bispectral analysis to monitor outpatient sedation.
The bispectral (BIS) index has been used to interpret partial EEG recordings to predict the level of sedation and loss of consciousness in patients undergoing general anesthesia. The author has evaluated BIS technology in determining the level of sedation in patients undergoing outpatient deep sedation. These experiences are outlined in this review article. ⋯ This can be invaluable in comparing studies of techniques. The BIS index provides additional information to standard monitoring techniques that helps guide the administration of sedative-hypnotic agents. The trend to earlier return of motor function in BIS-monitored patients warrants further investigation.
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Anesthesia progress · Jan 2000
Comparative StudyAdditional clinical observations utilizing bispectral analysis.
Additional observations were made in the use of the bispectral (BIS) index with the use of ketamine and in performing general anesthesia without the use of local anesthesia in nonintubated patients. Twenty-five subjects undergoing extraction procedures in an outpatient setting were analyzed using bispectral analysis with ketamine and midazolam. Despite repeated injections of midazolam during the procedure, only transient decreases of the BIS occurred to the 80s, with a low value of 77 in all but 1 patient where ketamine was used. ⋯ In the final study reviewed, when local anesthesia was not used during general anesthesia, bispectral analysis was a useful adjunct in helping maintain a steady state of general anesthesia in nonintubated patients undergoing third molar extractions. Bispectral analysis offers additional information on the depth of the hypnotic state and is useful in helping control the depth of anesthesia. A limitation of the index includes the inability to titrate the level of sedation induced by hypnotic agents such as midazolam when ketamine is concomitantly administered.
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Anesthesia progress · Jan 2000
Inferior alveolar nerve block by injection into the pterygomandibular space anterior to the mandibular foramen: radiographic study of local anesthetic spread in the pterygomandibular space.
We studied the spread of local anesthetic solution in the inferior alveolar nerve block by the injection of local anesthetic solution into the pterygomandibular space anterior to the mandibular foramen (anterior technique). Seventeen volunteers were injected with 1.8 mL of a mixture containing lidocaine and contrast medium utilizing the anterior technique. ⋯ The results indicate that the contrast medium mixture spreads rapidly in the pterygomandibular space to the inferior alveolar nerve in the subjects who exhibited inferior alveolar nerve block effect. We concluded that the anesthetic effect due to the anterior technique was produced by the rapid distribution of anesthetic solution in the pterygomandibular space toward the mandibular foramen, and individual differences in the time of onset of analgesia may be due to differences in the histologic perineural tissues.