Cognitive Status of Patients Judged Fit for Discharge from the Post-Anaesthesia Care Unit after General Anaesthesia. A Randomized Comparison between Desflurane and Propofol Anaesthesia

Background: The Aldrete's score is used to determine when a patient can safely leave the Post-Anaesthesia Care Unit (PACU) and be transferred to the surgical ward. The Aldrete score is based on the evaluation of vital signs and consciousness. Cognitive functions at the time the patient is judged fit for discharge from the PACU (Aldrete’s score ≥9) had not yet been studied. The aim of this trial was to assess the cognitive status of inpatients emerging either from desflurane or propofol anesthesia, at the time of PACU discharge (Aldrete score ≥9). Methods: Sixty adult patients scheduled for hip or knee arthroplasty under general anesthesia were randomly allocated to receive either desflurane or propofol anesthesia. Patients were evaluated the day before surgery using Digit Symbol Substitution Test, Stroop Test and Verbal Learning Test. After surgery, the Aldrete score was checked every 5 min until reaching a score ≥9. At this time, the same battery of cognitive tests was applied. Every tests were evaluated separately. Cognitive status was reported using a combined Z score pooling together the results all 3 cognitive tests. Results: Among the 3 tests, only DSST was significantly reduced at Aldrete Score ≥9 in the Dsflurane group. Combined Z-scores at Aldrete Score ≥9 were (in medians [interquartils]): -0.2 [-1.2;+0.6] and -0.4 [-1.1;+0.4] for desflurane and propofol groups respectively ( P=0.62 ). The majority of patients did not present any cognitive dysfunction at Aldrete score ≥9 (24 patients out of 27 in the Propofol group and 23 patients out of 25 in the Desflurane group). Conclusion: An Aldrete score ≥9 was associated with satisfactory cognitive function recovery in the majority of the patients after a lower limb arthroplastic surgery under general anesthesia. No difference was observed between desflurane and propofol. This reinforces the clinical value of Aldrete score to state about ability to leave the PACU in safety conditions. Trial Registration Clinical Trials identifier NCT 02036736