Comparison of arterial blood pressure and cardiac index-based hemodynamic management on cognitive function in elderly patients undergoing spinal surgery: a randomized clinical trial.

BACKGROUND: Postoperative delayed neurocognitive recovery (DNR) is frequent in elderly patients. Prevention of DNR is essential to achieve a better postoperative outcome. METHODS: The aim of the present study was to compare mean arterial pressure (MAP) and Cardiac Index (CI) based hemodynamic management on early cognitive function in elderly patients undergoing spinal surgery. Sixty patients aged ≥60 years were enrolled. Patients were randomized to one of two groups. In Group MAP, hemodynamic management of patients was performed according to the MAP value. In Group CI, hemodynamic management of patients was performed according to the CI value. In all patients, standard anesthesia method was used and regional cerebral oxygen saturation (rScO2) was measured. Cognitive functions of patients were assessed by Montreal cognitive assessment (MoCA) test before surgery and seven days after surgery. Change in MoCA test (ΔMoCA) was calculated. RESULTS: Postoperative MoCA score was significantly greater in Group CI (25.2±2.4) than Group MAP (23.9±2.5) (P=0.046). The ΔMoCAs were 1 (IQR, 0-3) and 3 (IQR, 2-3.5) in Group CI and MAP respectively (P<0.001). Lowest and average rScO2 values were significantly greater, and the decreased load of rScO2 below the threshold of 10% (AUCΔ10%) and 20% (AUCΔ20%) below its baseline were significantly lower in Group CI (P<0.05). CONCLUSIONS: CI-based hemodynamic management provided better postoperative cognitive function and higher intraoperative rScO2 when compared with MAP-based hemodynamic management.

Comparison of 3% Hypertonic Saline and 20% Mannitol for Reducing Intracranial Pressure in Patients Undergoing Supratentorial Brain Tumor Surgery: A Randomized, Double-blind Clinical Trial.

BACKGROUND: In the present study, we hypothesized that 3% hypertonic saline (HS) is more effective than 20% mannitol to reduce intracranial pressure (ICP) and to modify brain bulk in patients undergoing an elective supratentorial craniotomy. MATERIALS AND METHODS: After institutional review board approval, patients scheduled to undergo supratentorial craniotomy were enrolled into this prospective, randomized, double-blind study. The patients were monitored for routine hemodynamic parameters, depth of anesthesia, and ICP. They received 5 mL/kg 20% mannitol (n=20) or 3% HS (n=19) as infusion for 15 minutes. The patients' ICP values were monitored during hypertonic fluid infusion and throughout 30 minutes after infusion as a primary outcome. Secondary outcomes were hemodynamic variables, serum sodium value, blood gases, and surgeon brain relaxation assessment score (1=relaxed, 2=satisfactory, 3=firm, 4=bulging). In addition, the length of intensive care unit and hospital stay were recorded. RESULTS: Demographic and tumor characteristics were similar between groups. The basal (before hypertonic infusion, ICPT0) and last (30 min after hypertonic infusion finished, ICPT45) ICP values were 13.7±3.0 and 9.5±1.9 mm Hg, respectively, for the M group, which were comparable with the corresponding levels of 14.2±2.8 and 8.7±1.1 mm Hg in the HS group (P>0.05). The median amount of ICP reduction between T0 and T45 timepoints were 4 (1 to 7) and 5 (1 to 9) mm Hg for group M and group HS, respectively (P=0.035). Baseline central venous pressure, pulse pressure variation, and serum sodium and lactate values were similar between groups, but the last measured pulse pressure variation and lactate value were lower, and sodium value was higher in group HS than in group M (P<0.05). Duration of hospital and intensive care unit stay were similar between groups. CONCLUSIONS: Our results suggest that 3% HS provided more effective ICP reduction than 20% mannitol during supratentorial brain tumor surgery.

Characterization of Hand Clenching in Human Sensorimotor Cortex Using High-, and Ultra-High Frequency Band Modulations of Electrocorticogram.

Functional mapping of eloquent cortex before the resection of a tumor is a critical procedure for optimizing survival and quality of life. In order to locate the hand area of the motor cortex in two patients with low-grade gliomas (LGG), we recorded electrocorticogram (ECoG) from a 113 channel hybrid high-density grid (64 large contacts with diameter of 2.7 mm and 49 small contacts with diameter of 1 mm) while they executed hand clenching movements. We investigated the spatio-spectral characteristics of the neural oscillatory activity and observed that, in both patients, the hand movements were consistently associated with a wide spread power decrease in the low frequency band (LFB: 8-32 Hz) and a more localized power increase in the high frequency band (HFB: 60-280 Hz) within the sensorimotor region. Importantly, we observed significant power increase in the ultra-high frequency band (UFB: 300-800 Hz) during hand movements of both patients within a restricted cortical region close to the central sulcus, and the motor cortical "hand knob." Among all frequency bands we studied, the UFB modulations were closest to the central sulcus and direct cortical stimulation (DCS) positive site. Both HFB and UFB modulations exhibited different timing characteristics at different locations. Power increase in HFB and UFB starting before movement onset was observed mostly at the anterior part of the activated cortical region. In addition, the spatial patterns in HFB and UFB indicated a probable postcentral shift of the hand motor function in one of the patients. We also compared the task related subband modulations captured by the small and large contacts in our hybrid grid. We did not find any significant difference in terms of band power changes. This study shows initial evidence that event-driven neural oscillatory activity recorded from ECoG can reach up to 800 Hz. The spatial distribution of UFB oscillations was found to be more focalized and closer to the central sulcus compared to LFB and HFB. More studies are needed to characterize further the functional significance of UFB relative to LFB and HFB.