جستجوی مقالات مرتبط با کلیدواژه "عمق بیهوشی" در نشریات گروه "پزشکی"

Monitoring the depth of anesthesia (DOA) takes an important role for anesthetists in order avoiding undesirable reactions such as intraoperative awareness, prolonged recovery and increased risk of postoperative complications.The Central Nervous System (CNS) is the main target of anesthetic drugs, hence EEG signal processing during anesthesia is helpful for monitoring DOA. In order to study and interpret charactheristics of signals, assessment of orrelation between neurophysiological signals is an usful tool.

This study applies nonlinear interdependence and Cross recurrence analysis measures to analyze EEG signals recorded from eight human volunteers under a brief Propofol anesthesia and compared with Cross correlation measure. The prediction probability (Pk) was used to assess the performance of measures for predictiong BIS. In order to evaluate the efficiency of all measures in distinguishing different anesthetic states, box plots of EEG-derived measures were compared with Kruskal–Wallis test. Moreover, the coefficient of variation (mean±SD) was employed to describe the index stability during different states. Correlation coefficient (R) between each index and bispectral index (BIS) is measured to investigate their performance.

Nonlinear measures demonstrates the less variability at the loss of consciousness in comparison with BIS (standard deviation of 0.09) and show that P values less than 0.05 and the highest Pk and higher correlation coefficient with BIS index.

Nonlinear measures demonstrates the less variability at the loss of consciousness in comparison with BIS (standard deviation of 0.09). Furthermore, these measures demonstrate good performance to differentiate anesthetic states and had higher correlation with BIS and better robustness to noise in comparison with linear measure.

In cataract surgery, given that most patients are older people, surgery with general anesthesia requires better hemodynamic control along with maintaining the depth of anesthesia. The present study was conducted to compare the effects of propofol and isoflurane on hemodynamic variations and depth of anesthesia in cataract surgery patients.

The present clinical trial was conducted among 60 patients who were cataract surgery candidates. The patients were randomly assigned to propofol group (n = 30) and isoflurane group (n = 30). One µg/kg fentanyl and one mg/kg intravenous lidocaine were administered in both groups and anesthesia was induced using 1.5 – 2.5 mg/kg propofol. In order to maintain anesthesia, 50 – 75 µg/kg/min propofol was administered in the first group and 1% isoflurane was administered in the second group. Depth of anesthesia, hemodynamic variations, recovery time, wake-up time, nausea and vomiting were recorded and compared in the two groups.

Depth of anesthesia was similarly below 60 in both groups at different times. Hemodynamic variations were not significantly different in the two groups. Mean recovery time in propofol and isoflurane groups was 20.56 and 15.4 minutes, respectively (p<0.001), and wake-up time in the two groups was 8.83 and 7.16 minutes, respectively (p= 0.004).

The results showed that there was no difference between the effects of these two drugs on hemodynamics and depth of anesthesia, but recovery time and wake-up time in propofol group were significantly higher than isoflurane group.
 

Backgraound: It is recommended to use BIS (BISpectral) to determine anesthesia levels. Currently, due to low capacity in Iran, anesthesiologists use cardiac indices, such as pulse rates and blood pressure to detect anesthesia levels. This study was designed to assess association of cardiac parameters with anesthesia levels measured by brain function.

In this descriptive study, 14 patients candidate for operation in Milad hospital were studied. Patients’ information, including systolic blood pressure, pulse rate and BIS (BISpectral) index were simultaneously registered by Rugloop software using Datex-ohmeda S5. Cut-off of 75 percent by Delphi method was considered as agreement, and percent of disagreement of 3 cardiac parameters, including blood pressure, pulse rate and both blood pressure and pulse rate were assessed.

14 patients with mean age (± standard deviation) of 43.3±12.6 years were studied. All patients experienced moderate (BIS 35-65) and mild (65-85) level of anesthesia during operation. Percent agreement of BIS with systolic blood pressure, pulse rate and both systolic blood pressure and pulse rate was 7.1%, 21.4% and 14.3%, respectively. Mean percent agreement of BIS with systolic blood pressure, pulse rate and both systolic blood pressure and pulse rate was 51.4%, 58.2% and 60.6%, respectively.

It seems that cardiac parameters are not able to determine anesthesia levels. So, it is better to use BIS tools and processors of brain signals.