Does midline shift predict postoperative nausea in brain tumor patients undergoing awake craniotomy? A retrospective analysis.

BACKGROUND: The presence of midline shift on neuroradiologic studies in brain tumor patients represents mass effect from the tumor and surrounding edema. We hypothesized that baseline cerebral edema as measured by midline shift would increase postoperative nausea (PON). We studied the incidence of PON in brain tumor patients, with and without midline shift on preoperative magnetic resonance (MRI) or computed tomographic (CT) imaging, undergoing awake craniotomy. METHODS: After IRB approval, we retrospectively extracted data from perioperative records between January 2005 and December 2010. Post-craniotomy nausea and pain scores were collected. Intraoperative anti-emetic, anesthetic, and analgesic regimens were assessed. Both the rescue anti-emetic and cumulative postoperative analgesic requirements were collected up to 12 hours postoperatively. The amount of midline shift on preoperative neuroimaging was gathered from radiology reports. Univariate comparisons between groups (no midline shift vs. midline shift) were made with t-tests for continuous variables, and chi-square tests for categorical variables. A multivariable analysis was performed to identify predictors of postoperative nausea. Limitations of this study include the retrospective design and the inability to gather accurate data regarding vomiting from the medical record. RESULTS: Data from 386 patients were available for analysis. Patients were divided into two groups: no midline shift (n = 283) and midline shift (n = 103). The mean midline shift distance was 5.96 mm (95% CI [5.32, 6.59]). There was no difference in the incidence of nausea or pain scores between the two groups. More malignant brain tumor patients were in the midline shift group, as determined by the postoperative histopathological diagnosis (P < 0.05). Patients in the midline shift group also had longer anesthesia and surgical times (P < 0.05). CONCLUSION: In patients undergoing a standardized anesthetic for awake craniotomy for tumor resection, the presence of preoperative midline shift did not correlate with postoperative nausea.

Comparison of postoperative nausea between benign and malignant brain tumor patients undergoing awake craniotomy: a retrospective analysis.

BACKGROUND: Benign and malignant brain tumors have different histopathological characteristics, including different degrees of tissue infiltration and inflammatory response. The aim of this retrospective study was to compare the incidence of postoperative nausea between the two categories of brain tumors in patients undergoing awake craniotomy. METHODS: After IRB approval, we retrospectively extracted data from perioperative records between January 2005 and December 2010. Patients were divided based on the postoperative histopathological diagnosis into two groups, benign and malignant. The incidence of nausea, rescue anti-emetics, pain scores and postoperative analgesic requirements were compared between the two groups up to 12 hours postoperatively. Intraoperative anti-emetic, anesthetic, and analgesic regimens were also assessed. Limitations of this study include the retrospective design, the arbitrary dichotomization of tumors as benign or malignant, and the inability to gather accurate data regarding vomiting from the medical record. RESULTS: Data from 415 patients were available for analysis, with 115 patients in the benign group and 300 patients in the malignant tumor group. A higher postoperative mean pain score was found in the benign brain tumor group compared to the malignant brain tumor group (P < 0.05). However, there was no difference in the incidence of nausea between the two groups. CONCLUSION: The different histopathological characteristics of brain tumors have no association with postoperative nausea in patients undergoing awake craniotomy. Patients with benign brain tumors experience more pain than patients with malignant brain tumors. This difference in postoperative pain may be due to the younger age of the patients in the benign group.