A Prospective Study on the Predictability of Propofol Injection Pain

Introduction In this prospective study, we aimed to determine if there was a link between pain on propofol injection (POPI) and various hemogram parameters and ratios. Methods The study was designed to include 100 consecutive male patients undergoing surgery in a tertiary hospital in February 2017. Preoperatively collected data included patients’ age, weight, height, hemogram parameters (white blood cell (WBC) count, neutrophil count, lymphocyte count, platelet count, mean platelet volume (MPV), platelet distribution width (PDW), plateletcrit (PCT), hemoglobin, and hematocrit). All patients’ hemograms were performed using the same device. The neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, and systemic immune inflammatory score (SII) were calculated from this data. Patients received prior information that pain would be questioned during propofol injection. The pain was grouped between 0 and 3 (0 no pain, 1 mild pain, 2 moderate pain, 3 severe pain). Patients were questioned by the anesthesiologist about their level of pain at five-second intervals until loss of consciousness occurred. The same anesthesiologist also used the McCririck and Hunter’s verbal rating score (VRS) to evaluate pain. The patients’ heart rate and blood pressure were also recorded after induction. Results An extremely significant correlation was found between the presence of POPI and neutrophil-lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR) and SII ratios (p<0.001). All three parameters were found to be significant in predicting the presence of POPI. The higher area under the curve (AUC) was found for SII. The cutoff value for SII’s prediction of POPI was calculated to be 479,000, with a sensitivity of 68% and a specificity of 68%. Patients with an NLR of >497000 had a 4.63 times higher risk of POPI (odds ratio: 4.63, 95% CI: 1.6714 - 12.7982). Conclusion Our study is the first to show that POPI can be predicted by using NLR, PLR, and SII. Our data also support other studies that have reported a relationship between the inflammatory biomarker NLR and pain perception.