Do preoperative hemoglobin and hematocrit levels predict postoperative nausea and vomiting in orthognathic surgery patients? A retrospective case-control study

Aim: Postoperative nausea and vomiting (PONV) is a common and distressing complication following orthognathic surgery. This retrospective study aimed to investigate the relationship between hemoglobin (Hgb) and hematocrit (HCT) levels and PONV occurrence in orthognathic surgery patients.Material and Methods: A total of 52 patients who underwent orthognathic surgery were included in this retrospective analysis. Patients were divided into two groups: 26 patients who experienced PONV and 26 patients who did not. Demographic and clinical characteristics, including age, sex, American Society of Anesthesiologists (ASA) class, body mass index (BMI), operation time, and visual analog scale (VAS) scores for pain were compared between the groups. Hemoglobin and hematocrit levels were also compared, and receiver operating characteristic (ROC) analysis was performed to identify the optimal cut-off values for PONV prediction.Results: No significant differences in age, sex, ASA class, or operation time were observed between the two groups. However, patients in the PONV group had significantly lower Hgb (12.9 +/- 1.0 g/dL) and HCT (39.1 +/- 3.0%) levels compared to those in the non-PONV group (14.2 +/- 1.5 g/dL and 43.05 +/- 3.5%, respectively; p < 0.001). The ROC analysis revealed that the optimal cut-off values for PONV prediction were Hgb <= 13.3 g/dL (AUC = 0.778, sensitivity = 73.08%, specificity = 69.23%, p < 0.001) and HCT <= 39.3% (AUC = 0.808, sensitivity = 65.38%, specificity = 88.46%, p < 0.001). Discussion: Lower preoperative Hgb and HCT levels were significantly associated with the occurrence of PONV in orthognathic surgery patients. These findings suggest that Hgb and HCT levels may be useful predictive factors for PONV and can potentially assist in developing targeted preventive strategies to improve patient outcomes