Altered cortical brain activity in end stage liver disease assessed by multi-channel near-infrared spectroscopy: Associations with delirium.

Delirium is a common and serious psychiatric syndrome caused by an underlying medical condition. It is associated with significant mortality and increased healthcare resource utilization. There are few biological markers of delirium, perhaps related to the etiologic heterogeneity of the syndrome. Functional near-infrared spectroscopy (fNIRS) is an optical topography system to measure changes in the concentration of oxygenated hemoglobin ([oxy-Hb]) in the cerebral cortex. We examined whether altered cortical brain activity in delirious patients with end stage liver disease (ESLD) is detected by fNIRS. We found that the [oxy-Hb] change during the verbal fluency task (VFT) was reduced in patients with ESLD compared with healthy controls (HC) in the prefrontal and bi-temporal regions. The [oxy-Hb] change during the sustained attention task (SAT) was elevated in patients with ESLD compared to HC in the prefrontal and left temporal regions. Notably, [oxy-Hb] change in the left dorsolateral prefrontal cortex during SAT showed a positive correlation with the severity of delirium. Our results suggest that [oxy-Hb] change in the prefrontal cortex during the sustained attention task measured with fNIRS might serve as a biological marker associated with delirium in ESLD patients.

Spinal Anesthesia in Elderly Patients Undergoing Lumbar Spine Surgery.

Spinal anesthesia is increasingly viewed as a reasonable alternative to general anesthesia for lumbar spine surgery. However, the results of spinal anesthesia in elderly patients undergoing lumbar spine decompression and combined decompression and fusion procedures are limited in the literature. The aim of this study was to report a single institution's experience using spinal anesthesia in elderly patients undergoing lumbar spine surgery. A retrospective review was conducted using a prospectively collected database of consecutive lumbar spine surgeries performed under spinal anesthesia in patients 70 years or older at a single center between December 2013 and October 2015. A total of 56 patients were included in the study; 27 patients (48%) underwent lumbar decompression and 29 patients (52%) underwent combined decompression and fusion procedures. Mean operative time was 101 minutes (range, 30-210 minutes), and mean operative blood loss was 187 mL (range, 20-700 mL). Mean maximum inpatient postoperative visual analog scale score was 6.2 (range, 1-10). Nausea occurred in 21% (12 of 56) of the patients. Mean length of stay was 2.4 days (range, 1-6 days). No mortality, stroke, permanent loss of function, or pulmonary embolism occurred. None of the cases required conversion to general anesthesia. All of the patients were ambulatory on either the day of the surgery or the next morning. These results demonstrate that spinal anesthesia is a viable method of anesthesia for patients 70 years and older undergoing lumbar spine surgery. They also demonstrate the safety of this method for patients older than 84 years and for surgeries lasting up to 3½ hours. [Orthopedics. 2017; 40(2):e317-e322.].

Rhesus macaque model of chronic opiate dependence and neuro-AIDS: longitudinal assessment of auditory brainstem responses and visual evoked potentials.

Our work characterizes the effects of opiate (morphine) dependence on auditory brainstem and visual evoked responses in a rhesus macaque model of neuro-AIDS utilizing a chronic continuous drug delivery paradigm. The goal of this study was to clarify whether morphine is protective, or if it exacerbates simian immunodeficiency virus (SIV)-related systemic and neurological disease. Our model employs a macrophage tropic CD4/CCR5 coreceptor virus, SIV(mac)239 (R71/E17), which crosses the blood-brain barrier shortly after inoculation and closely mimics the natural disease course of human immunodeficiency virus infection. The cohort was divided into three groups: morphine only, SIV only, and SIV + morphine. Evoked potential (EP) abnormalities in subclinically infected macaques were evident as early as 8 weeks postinoculation. Prolongations in EP latencies were observed in SIV-infected macaques across all modalities. Animals with the highest cerebrospinal fluid viral loads and clinical disease showed more abnormalities than those with subclinical disease, confirming our previous work (Raymond et al., J Neurovirol 4:512-520, 1998; J Neurovirol 5:217-231, 1999; AIDS Res Hum Retroviruses 16:1163-1173, 2000). Although some differences were observed in auditory and visual evoked potentials in morphine-treated compared to morphine-untreated SIV-infected animals, the effects were relatively small and not consistent across evoked potential type. However, morphine-treated animals with subclinical disease had a clear tendency toward higher virus loads in peripheral and central nervous system tissues (Marcario et al., J Neuroimmune Pharmacol 3:12-25, 2008) suggesting that if had been possible to follow all animals to end-stage disease, a clearer pattern of evoked potential abnormality might have emerged.