Clinical and Hematological Predictors of Propofol Injection Pain: Case-Control Study

AbstractAim: Propofol injection pain is a frequent adverse event during anesthetic induction. This study investigated whether systemic inflammatory markers, including SII, NLR, and PLR, are associated with propofol injection pain and whether clinical factors can predict its development.Methods: This observational case-control study included 84 ASA I–II adult patients undergoing elective surgery. Propofol injection pain was assessed using the McCrirrick-Hunter four-point scale and patients were categorized as pain absent or pain present. Demographic data, BMI, preoperative anxiety, and hematological inflammatory markers were recorded. Multivariable logistic regression and ROC analyses were performed.Results: Propofol injection pain was observed in 53 patients (63.1%). Pain was more frequent in female patients and in those with lower height and body weight. No significant differences were found in SII, NLR, or PLR between groups. Female sex was the only independent predictor of pain, while BMI showed a non-significant inverse trend. SII had no discriminative value, whereas a combined model of female sex and BMI showed modest predictive performance.Conclusions: Routine inflammatory markers were not associated with propofol injection pain and did not provide meaningful predictive value. Female sex appeared to be an independent risk factor, and lower BMI may increase susceptibility. These findings suggest that individual patient characteristics may be more relevant than systemic inflammatory status in predicting propofol injection pain.Keywords: Propofol; Injection Pain; Systemic Immune-Inflammation Index; Neutrophil-to-Lymphocyte Ratio; Body Mass Index; Sex Differences.