Abstract
Background: Hemodynamic changes during surgery are initially controlled by changes in dosage of anesthetics. Decreasing the dose of anesthetics in order to cope with hypotension during surgery may reduce the anesthetic depth and increases the chance of awareness. This study was designed to investigate the depth of anesthesia in patients whose anesthtics is prescribed by controlling blood pressure and is aimed to investigate the possibility of reducing the depth of anesthesia during surgery.
Materials and Methods: In this study, females candidate for hysterectomy underwent general anesthesia according to specific inclusion criteria enrolled in two types of intravenous (propofol) or inhaled (isoflurane) anesthesia. The dose of maintenance anesthetic drugs were increased or decreased during the operation by the anesthetist technician (blinded to the depth of anesthesia) according to specified protocol. At defined intervals, depth of anesthesia was recorded by the anesthetist . Mean of obtained data were analyzed.
Results: In addition to the weight and height similarity, there was no statistically significant difference in systolic, diastolic blood pressure and heart rate in two groups at intervals, between two groups. The median of recorded BIS, which showed depth of anesthesia, was not different in either of the two groups, and no patients during the operation reached the level of awakening and the number above 60.
Conclusion: The traditional method to control hemodynamic changes during surgery by changing the doses of maintenance drugs, does not result in severe changes in the depth of anesthesia and does not significantly increase the BIS to the awareness level.
 

Background and Aim: Postoperative shivering is a common complication after recovering from anesthesia, and due to its subsequent side effects, its prevention and treatment is of special importance for anesthetists. In this study, the efficacy and onset of action of meperidine (which is a potential cause of hemodynamic and respiratory complications) in treatment of post-anesthesia shivering are compared with those of ondansetron.
Methods & Materials: In this clinical trial study, patients with post-anesthetic shivering during recovery were randomly divided into two groups of meperidine (n=27) and ondansetron (n=29). Their shivering scores were recorded every minute for up to 10 minutes. After this time, if patients did not improve, meperidine was used in both groups to treat shivering.
Ethical Considerations The study obtained its ethical approval from the Research Ethics Committee of Iran University of Medical Sciences and has been registered in Iranian Registry of Clinical Trials (IRCT201109224969N3).
Results: The number of patients completely treated at 10 minutes was higher in the meperidine group (P= 0.05), and the decrease in mean shivering score occurred faster in meperidine group (P= 0.047)
Conclusion: Although ondansetron has been shown to be effective in treatment of postoperative shivering, the effectiveness and onset of action of meperidine was clearly better.