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Introduction: As tonsillectomy operations are done in vicinity of airways, two important purposes in anesthesia are decreasing bleeding and recovery time. Because of common use of Halothane and its reported side effects, we managed a study for comparing these two factors in two methods of anesthesia with or without Halothane. Materials and Methods: In a single blinded clinical trial, 140 (4-12 years old) children undergoing tonsillectomy, were randomly allocated in two equal groups. In the control group maintenance was done with Halothane-N2O 50% but in the case group without Halothane plus hyperventilation (Liverpool technique). Bleeding volume was estimated according to preoperative and 6 hour's postoperative hematocrit. Recovery time was recorded in minutes. Data was ahalyzed using Mann-Whitney U, T, Leven and K-S tests. Results: There was not any significant difference in sex, age, and weight and operation duration in the two groups. Mean recovery time in the case group was 7.87 minutes and in the control group 15.59 minutes, which showed a significant difference (p=0.00001). Mean bleeding volume in the case group was 44.22 ml and in the control group 58.52 ml, which also showed a significant difference (p = 0.005). Conclusion: According to our study it seems that anesthesia with Halothane causes more bleeding and prolonged recovery time in comparison to Liverpool technique.

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Background: Familiarity with different methods and medications in anesthesia and producing sufficient depth of anesthesia are very important in anesthesia practice. Due to the central analgesic and sedative effect of lidocaine in the presence of the sufficient blood level, it can be used for general anesthesia. This study was carried out to compare the effect of halothane with lidocaine infusion on BIS during maintenance of anesthesia.

Materials and Methods: In this randomized double-blind controlled clinical trial, 66 patients scheduled for elective inguinal herniorrahaphy were randomized into two equal groups. For maintenance, one group received halothane (1%) with O2-N2O and another group received lidocaine infusion (100 &mug/kg/min). BIS was checked every 5 minutes for half an hour. Statistical analysis of data was done by Chi-square and T-test through SPSS software. P-values less than 0.05 were considered meaningful.

Results: Mean of BIS was 65.72 in the lidocaine group and 56.7 in the halothane group during the first 30 minutes. There was a significant statistical difference between the two groups (p<0.05).

Conclusion: Mean of BIS in lidocaine group was higher than that in the halothane group. If this indicates the presence of a light level of anesthesia, increasing the dose of hypnotics and opioids leads to an increase in the depth of anesthesia. However, since there is not any device for monitoring the effect of opioids on the central nervous system and the level of anesthesia, simultaneous monitoring of BIS and hemodynamic parameters seems to be a more reasonable idea.