Characterization of perioperative glycemic status and dexamethasone use with associated postoperative complications in glioblastoma patients.

PURPOSE: Postoperative morbidity in glioblastoma (GBM) patients can be due to the disease course but can also come from postoperative complications. Our objective was to study the association of dexamethasone use and perioperative hyperglycemia with postoperative complications in GBM patients. METHODS: A single-center, retrospective cohort study was conducted in patients who underwent surgery for primary GBM from 2014-2018. Patients with perioperative fasting blood glucose (FBG) measurements and adequate follow-up to assess for complications were included. RESULTS: A total of 199 patients were included. More than half (53%) had poor perioperative glycemic control (FBG ≥ 7 mM for ≥ 20% perioperative days). Higher dexamethasone dose (≥ 8 mg) was associated with higher FBG on postoperative days 2-4 and 5 (p = 0.02,0.05,0.004,0.02, respectively). Poor glycemic control was associated with increased odds of 30-day any complication and 30-day infection on univariate analysis (UVA), and 30-day any complication and increased length of stay (LOS) on multivariate analysis (MVA). Higher average perioperative daily dexamethasone dose was associated with increased odds of 30-day any complication and 30-day infection on MVA. Elevated hemoglobin A1c (HgbA1c, ≥ 6.5%) was associated with increased odds of 30-day any complication, 30-day infection, and LOS on UVA. In a multivariate linear regression model, only the diagnosis of diabetes mellitus predicted perioperative hyperglycemia. CONCLUSIONS: Perioperative hyperglycemia, higher average dexamethasone use and elevated preoperative HgbA1c are associated with increased risk of postoperative complications in GBM patients. Avoiding hyperglycemia and limiting dexamethasone use in postoperative period may decrease the risk of complications. Select HgbA1c screening may allow the identification of a group of patients at higher risk of complications.

Combined Therapeutic and Monitoring Ultrasonic Catheter for Cardiac Ablation Therapies.

This study evaluated the feasibility of a combined therapeutic and diagnostic ultrasonic catheter for cardiac ablation therapies. Ultrasound can be used to determine when diseased cardiac tissues have become fully coagulated through a method known as local harmonic motion imaging (LHMI). LHMI is an imaging modality for treatment monitoring that uses acoustic radiation force, displacement tracking and the different mechanical properties of viable and ablated tissues. In this study, we developed catheters that are capable of LHMI measurements. Experiments were conducted in phantoms, ex vivo cardiac samples and the in vivo beating hearts of healthy porcine subjects. In vivo experiments revealed that four of four epicardial sonications revealed a decrease in measured displacements from LHMI experiments and that when lower power was used, no lesions formed and there was no corresponding decrease in measured displacement amplitudes. In addition, two of three endocardial lesions were confirmed and corresponded to a decrease in the measured displacement amplitude.

The evaluation of steerable ultrasonic catheters for minimally invasive MRI-guided cardiac ablation.

PURPOSE: The purpose of this study was to develop steerable MR-compatible ultrasound catheters suitable for minimally invasive MRI-guided cardiac ablation therapies. METHODS: MRI-compatible ultrasound steerable catheters were developed and tested for their overall tissue heating performance and safety. Ultrasound transducers were mounted on a monodirectional deflectable catheter tip that was made to be MRI-compatible. Catheter safety was assessed on the potential to form hot spots at the distal end of the catheter throughout fast spin echo and thermometry scans. Heating experiments were performed on phantoms and ex vivo porcine cardiac samples. RESULTS: During catheter safety experiments, a maximum temperature increase of 11.35 ± 0.83°C was evident after a 12-min, 40-s fast spin echo scan with a whole body specific absorption rate (SAR) of 1.9 W/kg and 1.07 ± 0.22°C during thermometry scans (flip angle = 90°; scan time = 12 min, 41 s; whole body SAR = 0.34 W/kg). Temperature elevations induced by the sonication were shown to be on the order of 38.1 ± 5.2°C for phantom experiments and 49.3 ± 9.7°C for ex vivo cardiac samples. CONCLUSION: Steerable ultrasound catheters have the potential to be safely placed in an MR system with little concern of catheter self-heating and driven to heat surrounding structures to cause ablations. In addition, these catheters have the added benefit of a deflectable tip that allows the treatment of multiple targets from within the bore of the MR scanner.