Post-operative Quality of Recovery Scale: the impact of assessment method on cognitive recovery.

BACKGROUND: We measured cognitive performance and recovery with the Post-operative Quality of Recovery Scale (PQRS) at 30 and 90 min after elective ambulatory or short-stay surgery under general anaesthesia. The aim was to study the impact of the assessment algorithm, comparing the original and modified more liberal score assessment. METHOD: One hundred and ten ASA 1-2 patients scheduled for elective surgery in general anaesthesia responded to the five cognitive performance questions in the PQRS; pre-operatively, 30 and 90 min after end of anaesthesia. Assessment of cognitive recovered was performed according to the original and modified definition which includes a tolerance factor to account for performance variability. RESULTS: Cognitive recovery improved from 30 to 90 min. The modified score assessment decreased number of patients that were evaluated low because it excluded initial low scoring subjects and also dramatically increased number of patients assessed as cognitively recovered; original 9% at 30 min and 28% at 90 min vs. 54% at 30 min and 81% at 90 min, P < 0.001. There were no other significant differences identified when using either the original or modified scoring method for age > 50 years, orthopaedic vs. abdominal surgery, premedication or gender. CONCLUSIONS: The modified definition which includes a tolerance factor to account for performance variability has dramatic effects in increasing the number of patients assessed as recovered. It is from the present study not possible to comment on whether the more liberal assessment provides more or less accurate description of cognitive performance.