Potential risk factors for postoperative vomiting (POV) are important for daily anesthesia practice. To identify the risk factors associated with POV we retrospectively reviewed 553 adult patients who underwent scheduled simple laparoscopic cholecystectomy under sevoflurane-based general anesthesia between January and December 2018. Patients who experienced POV were predominantly women, had lower body weight, and higher ASA (American Society of Anesthesiologists) physical status. The POV group showed female sex predominance, lower body weight, and higher ASA physical status, with a significant difference when compared with the non-POV group. In univariate analysis, female sex and Apfel scores of 2, 3, and 4 were associated with a higher POV incidence. Age > 70 years, higher body weight, and ASA physical status III were associated with a lower POV incidence. In multivariate logistic regression, sex, age, Apfel score, and intraoperative crystalloid infusion rate were POV predictive factors. Receiver operating characteristic analysis showed a negative association between the intraoperative crystalloid infusion rate and POV occurrence with an area under the curve of 0.73 (p = 0.001). The cutoff intraoperative crystalloid infusion rate was 2 mL/kg/h with 82% sensitivity and 49% specificity (≥2 mL/kg/h was associated with a lower POV incidence vs. <2 mL/kg/h (OR, 95% CI; 0.52 [0.33–0.83])). To decrease POV in these patients, identifying high-risk factors and an intraoperative crystalloid administration of ≥2 mL/kg/h should be considered in patients undergoing LC under sevoflurane-based general anesthesia.

Adductor canal block (ACB) has gained popularity for postoperative pain control after total knee arthroplasty (TKA). However, its role in TKA has been questioned recently. Our study aimed to clarify the role of ACB in reducing postoperative pain after TKA and to elucidate an optimal timing to perform ACB for better outcomes. We conducted a comprehensive review of the perioperative records of 652 patients undergoing primary TKA from January 2019 to December 2019. Patients were divided into three groups: Group A received general anesthesia without ACB, Group B received ACB before inducing general anesthesia, and Group C received ACB at the post-anesthesia recovery unit (PACU). Patients in Groups B and C had lower pain visual analogue scale (VAS) scores than patients in Group A at the PACU. Opioid consumption was similar among the three groups; however, a slightly higher dose was required by Group A patients. Higher VAS scores were recorded in the ward in Group A than in Groups B and C with the leg at rest. In addition, higher VAS scores were recorded in Group A than in Groups B and C with the leg in continuous passive motion (CPM) training. More patients in Group A (34.9%) quit their first CPM training after a few cycles than those in Groups B (27.0%) and C (20.1%). Group A patients required a higher per kg dose of opioids in the ward than Groups B and C patients. Additionally, the hourly consumption of sevoflurane was similar among the three groups of patients, while Group A and C patients required a higher hourly per kg dose of intraoperative opioids than Group B patients. More patients in Group A (67.6%) and C (61.7%) developed intraoperative hypertension than patients in Group B (52.7%). There was no significant difference in PON (postoperative nausea), POV (postoperative vomiting), postoperative dizziness, or patient satisfaction among the three groups of patients. Group A patients had a longer length of hospital stay compared to Group B and C patients. In conclusion, preoperative ACB could be a better choice for patients undergoing TKA as it decreases intraoperative opioid consumption and facilitates a stable hemodynamic state during surgery.

Numerous studies on postoperative nausea and vomiting (PONV) have been carried out since the early days of contemporary surgery. The incidence of PONV has been greatly reduced in recent years and new drugs for PONV keep evolving in the market; however, a substantial number of patients are still under the threat of PONV. Female gender, non-smokers, a history of PONV/motion sickness, and postoperative opioid use are four well-recognized risk factors of PONV. Many potential risk factors reported in previous studies were not consistently presented as predictors for PONV. Two questions then arise; are risk factors clinical setting dependent and are risk factors modifiable? We attempted to answer the questions through a comprehensive review of perioperative records of surgical patients from the Trauma Department of our hospital. As nausea is subjective and no standard is applicable for its measurement, postoperative vomiting (POV) was used as an endpoint in this study. To the best of our knowledge, this is the first study to address the POV issue in surgical trauma patients. A total of 855 patients were enrolled in this study after excluding age below 20 years old, total intravenous anesthesia, desflurane anesthesia, or records with missing data. Our results showed that female gender (OR 4.89) is the strongest predicting factor, followed by a less potent predicting factor—more intraoperative opioid consumption (OR 1.07)—which favor more POV. More intraoperative crystalloid supply (OR 0.71) and a higher body weight (OR 0.9) favor less POV. Other potential risk factors did not reach statistical significance in this study as independent risk factors. Our results also showed that when the intraoperative crystalloid infusion rate is greater than 4 mL/kg/h (OR 0.20), it favors a lower rate of POV; when intraoperative opioid consumption is greater than 12 mg morphine equivalents, MME (OR 1.87), it favors a higher rate of POV. We concluded that dominance of any independent risk factor over other risk factors depends on how individual factors interact with the clinical setting. Some risk factors could be modified, and a cut-off value could be derived to facilitate a better plan for POV prevention.

The adductor canal block (ACB) is effective for treating postoperative pain during arthroscopic knee surgery, but its impact on anesthesia course and the optimal administration timing are unknown. This retrospective study addressed these questions. The aim of this study was to compare the effects of preoperative ACB and postoperative ACB on anesthesia course and postoperative recovery. We allocated 215 adult patients who underwent arthroscopic knee surgery under sevoflurane anesthesia between January 2019 and December 2019 to three groups. Group A received general anesthesia without ACB, Group B received ACB before general anesthesia induction, and Group C received ACB in the post-anesthesia recovery unit (PACU). Group B consumed significantly less sevoflurane (0.19 mL/kg/h) and milligram morphine equivalents (0.08 MME) intraoperatively than Groups A (0.22 mL/kg/h; 0.10 MME, respectively) and C (0.22 mL/kg/h; 0.09 MME, respectively). Groups B and C had lower visual analogue scale (VAS) scores upon PACU discharge than Group A. Dynamic, but not at-rest VAS scores, were significantly higher in Group A. Opioid consumption was similar in the ward, but Group A requested more intravenous parecoxib for pain relief. Length of hospital stay was similar. Thus, preoperative ACB reduced the amount of volatile anesthetic required and maintained stable hemodynamics intraoperatively. Preoperative or postoperative ACB improved postoperative pain control. Consequently, preoperative ACB is optimal for intraoperative stress suppression and postoperative pain control.

The study of postoperative nausea and vomiting (PONV) has been ongoing since the early days of general anesthesia. The search for risk factors of PONV and the development of new agents to treat PONV are the two main strategies to combat the adverse side effects of general anesthesia. Female sex, non-smoking status, a history of PONV/motion sickness, and postoperative opioid use are the four independent risk factors for PONV derived after a series of prospective studies, evidence-based systematic reviews, and meta-analyses. The two frequently asked questions that arise ask whether risk factors apply to different clinical settings and whether prevention measures of PONV can be surgery dependent. We conducted a comprehensive review of 665 patients who underwent primary total knee arthroplasty (TKA) between January and December 2019. As nausea is subjective and its measurement is not standardized, postoperative vomiting (POV) was used as a study endpoint. The exclusion criteria were desflurane anesthesia, spinal anesthesia, anesthesia without bispectral index monitoring, and day surgery. Three well-recognized risk factors, consisting of body weight, sevoflurane consumption, and postoperative opioid consumption, were not considered as independent risk factors of POV, while female sex, preoperative adductor canal block (ACB), and dexamethasone were identified as being so in this study. The risk of POV in the female sex was 2.49 times that in the male sex; however, when dexamethasone was used, this risk was reduced by >40% compared with no antiemetic use, and by >50% when patients received preoperative ACB compared with those without the block. The clinical characteristics of our TKA patients—female dominance, old age, and their fairly constant body weights that were distinct from those of other surgical patients—suggested that age may play a crucial role in determining the relative contributions of the different risk factors of POV. We concluded that risk factors of POV are dependent on clinical settings. Based on these results, it is reasonable to speculate that a surgery-dependent plan for the prevention of POV is feasible for patients in similar clinical settings.