Diet-induced ketosis in adult patients with subacute acquired brain injury: a feasibility study.

Background: Research in animal models on cerebral metabolism after brain injury highlights the potential benefits of ketosis in reducing secondary brain injury, but studies in humans are lacking. Aim: This study aimed to examine if a 6-week ketogenic diet intervention with added medium-chain triglycerides (MCT) was feasible in adult patients with acquired brain injury in the subacute phase, whether ketosis could be achieved and maintained, and to what extent serious adverse reactions, adverse reactions, serious adverse events, and adverse events occured. Methods: Patients ≥18 years of age diagnosed with subacute acquired brain injury and an expectation of hospitalisation ≥6 weeks were included in the intervention group. Patients not included in the intervention group were included in a standard care reference group. The intervention consisted of a ketogenic diet supplemented with MCT to obtain a plasma concentration of ß-hydroxybutyrate (BHB) ≥0.5 mmol/L. Patients who were enterally fed were given KetoCal® 2.5:1 LQ MCT Multi Fiber (Nutricia A/S, Allerød, Denmark), supplemented with Liquigen® (Nutricia A/S, Allerød, Denmark). Patients consuming oral nutrition were given KetoCal® 2.5:1 LQ MCT Multi Fiber supplemented with Liquigen®, in addition to ketogenic meals. Results: During a 13-week inclusion period, 12 of 13 eligible patients (92% [95% CI: 67% to 99%]) were included in the intervention group, and 17 of 18 excluded patients (94% [95% CI: 74% to 99%]) were included in the reference group. Eight patients (67%) completed the 6-week intervention. It took a median of 1 day to achieve ketosis from starting a 100% MCT ketogenic diet, and it was maintained for 97% of the intervention period after ketosis was obtained. There were no serious adverse reactions to the MCT ketogenic diet, and patients experienced adverse reactions not considered serious in 9.5% of days with the intervention. The MCT ketogenic diet was accepted by patients on all intervention days, and in the two patients transitioning from enteral feeding to oral intake, there were no complications related to transitioning. Conclusion: Intervention with MCT ketogenic diet is feasible and tolerated for 6 weeks in hospitalised adult patients with subacute acquired brain injury. Randomised controlled trials are needed to assess the benefits and harms of the MCT ketogenic diet and the effect on patients' recovery.Clinical trial registration: ClinicalTrials.gov, identifier [NCT04308577].

Reliability of the mean flow index (Mx) for assessing cerebral autoregulation in healthy volunteers.

BACKGROUND: Mean flow index (Mxa) for evaluating dynamic cerebral autoregulation is derived using varying approaches for calculation, which may explain that the reliability ranges from poor to excellent. The comparability, repeatability, stability, and internal consistency of approaches have not previously been assessed. METHODS: We included 60 recordings from resting healthy volunteers and calculated Mxa using four different approaches: three without overlapping calculations, using intervals for averaging wave-form data (blocks) of 3, 6, and 10 s, and correlation periods (epochs) of 60, 240, and 300 s (3-60-F, 6-240-F, and 10-300-F); and one using 10-second blocks, 300 s epochs, and overlaps of 60 s (10-300-60). The comparability between the approaches was assessed using Student's t test, intraclass correlation coefficients (ICC), and Bland-Altman plot. RESULTS: Overall, 3-60-F resulted in a higher Mxa than the other indices (p < 0.001, for all). The reliability when comparing all the approaches ranged from moderate to good (ICC: 0.68; 95%CI: 0.59-0.84), which was primarily due to similarities between 10-300-F and 10-300-60 (ICC: 0.94; 95%CI: 0.86-0.98). The reliability when comparing the first and last half was poor for 10-300-F and ranged from poor to moderate for the other approaches. Additional random artifacts resulted in poor reliability for 10-300-F, while the other approaches were more stable. CONCLUSIONS: Mxa in general has a low sensitivity to artifacts, but otherwise seems highly dependent on the approach, with a repeatability that is moderate at best. The varying accuracy and precision renders Mxa unreliable for classifying impaired cerebral autoregulation when using healthy adults for comparison.

Patients with severe acquired brain injury show increased arousal in tilt-table training.

INTRODUCTION: Patients with severe acquired brain injury (ABI) are often mobilised using a tilt-table. Complications such as orthostatic intolerance have been reported. The primary objective of this study was to investigate if using a tilt-table was feasible for mobilising patients with severe ABI admitted for sub-acute rehabilitation. We also investigated change in arousal, treatment duration before termination due to orthostatic reactions and change in muscle tone. MATERIAL AND METHODS: A total of 16 patients with severe ABI were included. The patients were tilted head-up, and blood pressure, heart rate, breathing frequency and eye opening were recorded before and during the intervention. Furthermore, muscle tone was recorded before and after the intervention. RESULTS: Fifteen of the 16 patients did not complete the 20-min. session of tilt training due to orthostatic intolerance. There was a significant increase in the proportion of time that the patients had open eyes during treatment as compared with before treatment (p < 0.01). The mean time to occurrence of symptoms at the first, second and third tilt was 244 (standard deviation (SD) = ± 234) sec., 277 (SD = ± 257) sec. and 155 (SD = ± 67) sec., respectively. CONCLUSION: Patients with severe sub-acute ABI show orthostatic intolerance when mobilised on a tilt-table which results in a low mobilisation intensity. However, the patients showed a significant increase in arousal during mobilisation. FUNDING: No external funding was received for this study. All resources were provided by the Department of Neurorehabilitation, Traumatic Brain Injury Unit, Glostrup University Hospital. TRIAL REGISTRATION: not relevant.