BackgroundPostoperative nausea and vomiting (PONV) is common after painless gastroscopy. The independent predictive value of preoperative albumin, total bilirubin, Apfel score, and opioid type for PONV in decompensated cirrhosis is unknown.ObjectiveIn this exploratory post-hoc secondary analysis of a double-blind randomized controlled trial, we aimed to determine whether preoperative albumin, total bilirubin, Apfel score, and opioid type (alfentanil vs. nalbuphine) independently predict PONV within 48 h after painless gastroscopy in decompensated cirrhosis, and to compare their effects on 24 h postoperative liver function.ResultsOverall incidence of PONV was 24.00%, significantly higher with nalbuphine (P < 0.001). Univariate analysis: PONV patients were older (P = 0.012); no differences in preoperative albumin, total bilirubin, or Apfel score (all P > 0.05). Multivariable regression: preoperative albumin and total bilirubin were not independent predictors (both P > 0.05). Each 1-point increase in Apfel score gave (OR 1.40, 95% CI: 0.92–2.13; P = 0.116). Alfentanil significantly reduced PONV risk vs. nalbuphine (OR = 0.19, 95% CI: 0.08–0.47; P < 0.001); sensitivity analysis adjusted for age gave OR 0.20 (95% CI: 0.08–0.49; P < 0.001). Postoperatively, total bilirubin increased significantly in both groups (P < 0.05), whereas albumin showed no significant changes (P > 0.05). These mild fluctuations were comparable between the alfentanil and nalbuphine groups.ConclusionPreoperative albumin, total bilirubin and Apfel score did not independently predict PONV. Alfentanil was independently associated with a significantly reduced risk of PONV compared to nalbuphine. Postoperative liver function changes were mild, similar between groups and unrelated to PONV. Our findings are hypothesis-generating and require confirmation in larger studies.