Dissertation committee:
Καθηγήτρια Γεωργία Γερολουκά-Κωστοπαναγιώτου (επιβλέπουσα), Καθηγήτρια Δέσποινα Περρέα, Επίκουρη Καθηγήτρια Αγγελική Πανταζή
Original Title:
Διερεύνηση της λειτουργίας της έμμεσης μνήμης κατά τη διάρκεια αναισθησίας με σεβοφλουράνιο ή προποφόλη για προγραμματισμένες επεμβάσεις με τη μέθοδο της διαχωριστικής διαδικασίας.Συσχέτιση με το βάθος αναισθησίας με τη χρήση του BIS. O ρόλος του χειρουργικού stress,της κεντρικής θερμοκρασίας, αιμοδυναμικών παραγόντων και του τελοεκπνευστικού διοξειδίου του άνθρακα.
Summary:
Objective: We used the Process Dissociation Procedure (PDP) to test memory
performance during sevoflurane and propofol anaesthesia, the relation of memory
to hypnotic depth, surgery itself, and also haemodynamic and breathing
variables.
Material-Methods: After induction of general anaesthesia for elective surgery
100 patients (50 anaesthetised with propofol and 50 with sevoflurane) listened
to a list of words. The Bispectral Index (BIS), breathing and haemodynamic
variables were recorded throughout the study. Within 36 h after word
presentation, memory was assessed using a word stem completion task, based on
Buchner’s model for memory combined with the PDP. We applied the same task to a
group of non-anaesthetized subjects.
Results: Results were derived from 45 patients from the sevoflurane group, 48
from the propofol group, and another 45 from subject who did not receive
general anaesthesia. The mean BIS (± SD) was 45,15 (± 8,97). There was evidence
of memory for words presented during light (BIS 61–80), (p=0.001) and adequate
(BIS 41–60), (p=0.008) but not deep anaesthesia (BIS 21–40), (p=0.09). The PDP
showed a significant implicit but not explicit memory contribution (mean total
explicit memory scores: 0.04±0.07 in all BIS categories; mean implicit memory
scores: 0.01±0.04, 0.1±0.08, and 0.05±0.09 at BIS=21–40, 41–60, and 61–80,
respectively). There was a statistically significant difference between the
mean implicit memory score (I) of the propofol and sevoflurane group in the BIS
category 41-60 in general (p = 0.016), and after incision (I A.I.) (p = 0.005)
in particular, with propofol depressing I more than sevoflurane in both cases.
Memory performance of nonanaesthetized participants was better, with a higher
contribution of explicit and a comparable contribution of implicit memory.
Conclusion: During general anaesthesia, implicit memory persists even in
adequate hypnotic states to a degree comparable to the absence of anaesthesia.
Sevoflurane affects the implicit memory of adequately anaesthetised subjects
less than propofol. Surgical stress reinforces implicit memory. Breathing and
haemodynamic variables seem to have no effect on memory of anaesthetised
patients.
Keywords:
Implicit memory, Dissociative procedure, Bispectral index, Propofol, Sevoflurane
