Comparison of Bispectra Index [BIS] and AEPEX monitoring systems in coronary bypass surgery

Spontaneous recall of events during general anesthesia is called awareness. Awareness during the operation is common in coronary artery bypass grafting [CABG], especially in urgent cases and in patients with unstable hemodynamic condition before the operation. A standard method for the measurement of the depth of anesthesia [DoA] has not yet been introduced. A variety of techniques have been used for monitoring DoA like electroencephalography [EEG], monitoring muscle movement in the distal esophagus, and new methods of auditory evoked potentials [AEPs] and bispectra index [BIS]. Recently, a more sensitive method, called aepEX which is a modified form of AEPs, has been used for the monitoring and controlling of DoA. This study was designed to compare the sensitivity of the aepEX system with the BIS system for DoA monitoring using current clinical and paraclinical methods. In this prospective, controlled trial, 36 patients who were candidates for CABG were enrolled in the study. All the patients underwent a standard induction method for anesthesia with remifentanil, atracurium, and midazolam. Before anesthesia, both aepEX and BIS monitoring systems were controlled simultaneously in each patient. These systems had no effect on each other. Finally, all data about DoA, clinical data of awareness including BP, tear secretion, hemodynamic information, and demographic characteristics were collected and analyzed. This study compared the monitoring techniques for DoA, BIS, and aepEX. Results of this study were diagrams for the comparison of BIS and aepEX in different stages during CABG. According to these diagrams, essential analysis could be done about the quality of these two systems in DoA. Our data demonstrated that the aepEX monitoring system had greater sensitivity in all the stages of anesthesia compared to the BIS system

efficacy of tramadol used with ketamine or morphine in pain control after coronary artery bypass graft surgery

Sufficient analgesia after coronary artery bypass graft surgery [CABG] is important to prevent postoperative complications. One of these analgesic techniques is patient controlled analgesia [PCA], in which the patient has self-controlled administration of anesthetics. The purpose of this study was to evaluate the analgesic effect and side effects of tramadol used with ketamine or morphine for post-CABG surgery analgesia. In this prospective, controlled randomized study, we selected 150 patients who were candidates for CABG. The inclusion criteria were adult patients aged 30-60 with coronary artery disease, candidates for CABG, elective surgery, surgery using cardiopulmonary bypass, and ASA II and III. The patients with uncontrolled and significant underlying diseases [diabetes, liver and kidney disease and clotting disorders], excessive obesity and weight over 115 kg, and non-consenting patients were excluded. The patients were divided into three groups of 50 each. At the end of surgery, all the patients were transferred to the post-surgical intensive care unit, where they were extubated. PCA was commenced when the patients were able to communicate. The first group was provided with 100mg of tramadol with normal saline, the second group 50mg of tramadol plus 20mg of morphine, and the third group 50mg of tramadol plus 50mg of ketamine. During the use of the PCA pump, the patients were observed for respiratory depression [respiratory rate and SPO[2], PaCO[2] every two hours during the first 8 hours and then every 4 hours]. The severity of pain was evaluated with the visual analog scale [VAS] method, where zero was no pain and ten was severe pain. The VAS results were recorded 1, 3, 6, 12, 18, 24, 36, and 48 hours after awareness and extubation and recording the base VAS of the patients. The average respiratory rate was 14 in all the three groups and respiratory depression was not seen in any of them. At the third hour, the VAS was similar in all the groups [p value<0.05]. The decrease in VAS at 6, 12, and 18 hours was significant and the minimum VAS was seen in the second group [tramadol + morphine]. PCA is a safe and appropriate method for analgesia after CABG. It seems that the combination of tramadol plus morphine can be an effective solution for analgesia after CABG with fewer respiratory complications than other combinations