Incidence and predictors of postoperative recall of propofol injection pain: a prospective observational cohort pilot study

Background: Propofol injection pain is common during i.v. induction and is often accompanied by nociceptive behaviours. Whether this pain is subsequently remembered by patients remains poorly characterised. We aimed to estimate the incidence of postoperative day 1 (POD#1) recall of propofol injection pain and to explore unadjusted associations with patient-, procedure-, and technique-related factors in routine clinical practice. Methods: structured interview. Secondary outcomes included recalled pain intensity (0-10 numerical rating scale), comparison with i.v. catheter insertion, and associations with observed nociceptive reactions and injection technique (catheter site, gauge, lidocaine use). All regression analyses were univariate, exploratory, and unadjusted. Results: Among 1043 patients with POD#1 data, 102 patients (9.8%; 95% confidence interval, 8.1-11.8%) recalled propofol injection pain. Recall was more frequent in women in univariate analyses. Catheter site, gauge, and lidocaine use showed no unadjusted associations with recall. Nociceptive reactions were frequent but did not differentiate patients with and without recall. Among patients with recall, median pain intensity was 7/10 (interquartile range, 5-9), and 99% rated pain as equal to or worse than i.v. cannulation. Conclusions: Approximately 10% of patients recalled propofol injection pain on POD#1, typically as severe pain. Female sex showed an unadjusted association with recall, whereas injection technique and observed nociceptive reactions did not.