Non-instrumental clinical monitoring does not guarantee an adequate course of general anesthesia. A prospective clinical study

Abstract

Background. Clinical monitoring is the most common method of adjusting the appropriate level of general anesthesia. However, episodes of intraoperative awareness (AWR) are still reported, suggesting that clinical observations may not be sufficient in some cases. The objective of this study was to compare the efficacy of clinical and instrumental neuromonitoring with auditory evoked potentials (AEP) in an intraoperative analysis of the proper level of general anesthesia. Methods. Patients scheduled for elective surgery were randomly divided into two groups. Subjects in the first group underwent intravenous, in the second group volatile anesthesia. The adequacy of anesthesia was analyzed using clinical parameters. All the participants were instrumentally monitored with the autoregressive AEP index (AAI). After the anesthesia, patients filled out a questionnaire on possible AWR. Results. Data of 208 patients (87 in the first, and 121 in the second group) were analyzed. Before surgery there were no changes in AAI values between groups (80 vs. 78, P=0.5192). The mean values of clinical parameters changed, but five minutes after the nociceptive stimuli. The mean values of AAI at analyzed time points were specific for general anesthesia. In patients under intravenous anesthesia, we found more episodes of too low (46/608 vs.15/847, P<0.000) anesthesia. One case of AWR was found in the TIVA group. Conclusions. AAI index is good indicator of patients' level of consciousness during general anesthesia. Standard clinical monitoring provides appropriate level of the procedure. However, it is insufficient during TIVA and does not prevent episodes of AWR.

Anaesthesia personnels’ perspectives on digital anaesthesia information management systems – a qualitative study

“…Hence, the digital AIMS was seen as a supplement to balanced anaesthesia. This approach has been supported in several other studies [ 4 , 6 , 41 ]. Only four of the participants claimed that the old paper-based documentation system took the focus off of the patient, whereas most of the participants claimed that the digital AIMS decreased vigilance, especially in relation to induction and emergence of anaesthesia.…”

A Crossover Comparison of the Sensitivity and the Specificity between BIS and AEP in Predicting Unconsciousness in General Anesthesia

“…AEP showed poorer performance than BIS in our study. With a P K of 0.56 with sevoflurane, AEP became doubtful as an anesthetic depth monitor which means the prediction powers of BIS and AEP do not seem as good as some papers mentioned [21,22,28,29]. Considering the difference results between this study and previous ones, different protocols of studies might be the reason [22,[28][29][30].…”

“…With a P K of 0.56 with sevoflurane, AEP became doubtful as an anesthetic depth monitor which means the prediction powers of BIS and AEP do not seem as good as some papers mentioned [21,22,28,29]. Considering the difference results between this study and previous ones, different protocols of studies might be the reason [22,[28][29][30]. We use detected more drug concentrations at more time points with more accurate statistical methods, but we still think we need more studies to verify the results.…”

“…e performance of the anesthetic depth monitors was better when propofol was used. Very wide variation was found in the combination of AEP and sevoflurane [22,25,[31][32][33]. It seems the monitors are at best at giving the EC50, at which there is a 50% chance that the patient has reached the end point, and we have not yet found an anesthetic depth monitor that has high sensitivity and specificity and not affected by the anesthetic technique.…”

“…Middle-latency auditory evoked potentials (AEPs) also quantify the action of anesthetic drugs and detect the transition from consciousness to unconsciousness [19][20][21][22][23].…”