Processed electroencephalography-guided general anaesthesia to reduce postoperative delirium: a systematic review and meta-analysis.

BACKGROUND: Postoperative delirium (POD) is the most common serious postoperative complication in older adults. It has uncertain aetiology, limited preventative strategies, and poor long-term outcomes. This updated systematic review and meta-analysis aimed to estimate the effect of processed electroencephalography (pEEG)-guided general anaesthesia during surgery on POD incidence. METHODS: We performed a systematic review and meta-analysis by searching OVID MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) electronic databases. Studies of adult patients having general anaesthesia for any surgery where pEEG was used and POD was an outcome measure were included. Full-text reports of RCTs published from database inception until August 28, 2021, were included. Trials were excluded if sedation rather than general anaesthesia was administered, or the setting was intensive care. The primary outcome was POD assessed by validated tools. The study was prospectively registered with PROSPERO. RESULTS: Nine studies, which included 4648 eligible subjects, were identified. The incidence of POD in the pEEG-guided general anaesthesia or lighter pEEG target group was 19.0% (440/2310) compared with 23.3% (545/2338) in the usual care or deeper pEEG target group (pooled odds ratio=0.78; 95% confidence interval, 0.60-1.00; P=0.054). Significant heterogeneity was detected (I2=53%). CONCLUSIONS: Our primary analysis demonstrated a highly sensitive result with a pooled analysis of trials in which the intervention group adhered to manufacturer's recommended guidelines, showing reduced incidence of POD with pEEG guidance. High clinical heterogeneity limits inferences from this and any future meta-analyses. CLINICAL TRIAL REGISTRATION: CRD42020199404 (PROSPERO).

Anaesthetic depth and delirium after major surgery: a randomised clinical trial.

BACKGROUND: Postoperative delirium is a serious complication of surgery associated with prolonged hospitalisation, long-term cognitive decline, and mortality. This study aimed to determine whether targeting bispectral index (BIS) readings of 50 (light anaesthesia) was associated with a lower incidence of POD than targeting BIS readings of 35 (deep anaesthesia). METHODS: This multicentre randomised clinical trial of 655 at-risk patients undergoing major surgery from eight centres in three countries assessed delirium for 5 days postoperatively using the 3 min confusion assessment method (3D-CAM) or CAM-ICU, and cognitive screening using the Mini-Mental State Examination at baseline and discharge and the Abbreviated Mental Test score (AMTS) at 30 days and 1 yr. Patients were assigned to light or deep anaesthesia. The primary outcome was the presence of postoperative delirium on any of the first 5 postoperative days. Secondary outcomes included mortality at 1 yr, cognitive decline at discharge, cognitive impairment at 30 days and 1 yr, unplanned ICU admission, length of stay, and time in electroencephalographic burst suppression. RESULTS: The incidence of postoperative delirium in the BIS 50 group was 19% and in the BIS 35 group was 28% (odds ratio 0.58 [95% confidence interval: 0.38-0.88]; P=0.010). At 1 yr, those in the BIS 50 group demonstrated significantly better cognitive function than those in the BIS 35 group (9% with AMTS ≤6 vs 20%; P<0.001). CONCLUSIONS: Among patients undergoing major surgery, targeting light anaesthesia reduced the risk of postoperative delirium and cognitive impairment at 1 yr. CLINICAL TRIAL REGISTRATION: ACTRN12612000632897.

Usability Assessment of the Rehabilitation Lower-limb Orthopedic Assistive Device by Service Members and Veterans With Lower Limb Loss.

INTRODUCTION: Telehealth is an increasingly common approach to improve healthcare delivery, especially within the Veterans Health Administration and Department of Defense (DoD). Telehealth has diminished many challenges to direct access for clinical follow-up; however, the use of mobile telehealth for specialty rehabilitative care is emerging and is referred to as telerehabilitation. As early adopters of telehealth, the Veterans Affairs and DoD have supported collaborated efforts for programs designed to increase the access and quality of rehabilitative care while improving the functional ability of our service members (SMs) and veterans with lower limb amputation (LLA). The DoD and Veterans Health Administration collaborated on a Mobile Device Outcomes-based Rehabilitation Program (MDORP) to help injured SMs and veterans with LLA. The MDORP project utilized a mobile health system called the Rehabilitative Lower Limb Orthopedic Accommodating Device (ReLOAD) to assess walking quality. The ReLOAD system includes real-time auditory biofeedback to notify the user of their most prominent gait deviation and then recommends exercises that address specific balance and strength impairments. The purpose of this study was to describe the responses to a postintervention survey evaluating the feasibility and usability of ReLOAD completed by SMs and veterans with LLA who used the system for 5 months. MATERIALS AND METHODS: A link to an anonymous usability survey was emailed to all participants who completed MDORP. The survey was modeled after the System Usability Scale, with agreeableness to items rated on a 5-point Likert-style questionnaire in addition to open feedback. Data visualization of Likert-style questionnaires was conducted using ggplot2 and reshape2 statistical packages and was analyzed using R. We obtained institutional review board approval through both Miami Veterans Affairs Healthcare System and Walter Reed National Military Medical Center. RESULTS: The majority of participants reported that they would use the system again for home rehabilitation (65%) and that auditory biofeedback helped them walk better (59%). Participants also suggested that future work should include a greater variety of exercise options and the use of smart phones for the ReLOAD application in addition to the iPad tablet. CONCLUSIONS: The participants provided positive and constructive feedback that will enhance the value and usability of telerehabilitation interventions like the ReLOAD system for future users.

Notochordal intervertebral disc cells: sensitivity to nutrient deprivation.

OBJECTIVE: The nucleus pulposus (NP) of the intervertebral disc develops from the notochord. Humans and other species in which notochordal cells (NCs) disappear to be replaced by chondrocyte-like mature NP cells (MNPCs) frequently develop disc degeneration, unlike other species that retain NCs. The reasons for NC disappearance are unknown. In humans, the change in cell phenotype (to MNPCs) coincides with changes that decrease nutrient supply to the avascular disc. We undertook this study to test the hypothesis that the consequent nutrient stress could be associated with NC disappearance. METHODS: We measured cell densities and metabolic rates in 3-dimensional cultures of porcine NCs and bovine MNPCs, and we determined survival rates under conditions of nutrient deprivation. We used scanning electron microscopy to examine end plate porosity of discs with NCs and those with MNPCs. Nutrient-metabolite profiles and cell viability were calculated as a function of cell density and disc size in a consumption/diffusion mathematical model. RESULTS: NCs were more active metabolically and more susceptible to nutrient deprivation than were MNPCs. Hypoxia increased rates of glycolysis in NCs but not in MNPCs. Higher end plate porosity in discs with NCs suggested greater nutrient supply in keeping with higher nutritional demands. Mathematical simulations and experiments using an analog disc diffusion chamber indicated that a fall in nutrient concentrations resulting from increased diffusion distance during growth and/or a fall in blood supply through end plate changes could instigate NC disappearance. CONCLUSION: NCs demand more energy and are less resistant to nutritional stress than MNPCs, which may shed light on the fate of NCs in humans. This provides important information about prospective NC tissue engineering approaches.