Dynamic cerebral autoregulation during early orthostatic exercise in patients with severe traumatic brain injury: Further exploratory analyses from a randomized clinical feasibility trial

Abstract

In patients with severe traumatic brain injury, there is limited evidence of the clinical effect of early orthostatic exercise, although such exercise may strengthen systemic or cerebral hemodynamic responses to head-up tilt, thereby minimizing orthostatic intolerance. We measured dynamic cerebral autoregulation (dCA) and the occurrence of orthostatic intolerance after four weeks of regular orthostatic exercise by head-up tilt using a tilt table with integrated stepping using the ERIGO Ò tilt-table and comparing it to standard care. Thirty-four patients with severe traumatic brain injury admitted to a neurocritical care unit were included in this randomized clinical trial. Middle cerebral artery blood flow velocity (MCAv), non-invasive mean arterial pressure, heart rate and PaCO 2 were recorded; dCA was measured by the non-invasive mean flow index (nMxa). Transition from the supine position to head-up tilt triggered a 10-16% decrease in MCAv and increased nMxa in both groups at all time points (P < 0.05), with no differences between groups. There was no difference in the number of episodes with orthostatic intolerance (5 vs 3; 1 vs 2; 1 vs 0) at baseline, two weeks and four weeks, respectively, and no association between changes in PaCO 2 -adjusted nMxa and the occurrence of orthostatic reactions (P = 0.35). Early orthostatic exercise does not affect dynamic cerebral autoregulation and does not protect against orthostatic intolerance in patients with severe traumatic brain injury. Trial registration: ClinicalTrials.gov identifier: NCT02924649. Registered on 3rd October 2016.

Diagnostic and prognostic performance of Mxa and transfer function analysis-based dynamic cerebral autoregulation metrics

“…The present retrospective work is based on data from five studies, which have previously been published elsewhere, 18–23 and describes entirely separate analyses to address an independent working hypothesis. All studies were approved by either the Scientific Ethical Committee of Copenhagen and Frederiksberg Municipalities or the Capital Region of Copenhagen (file numbers HA-2009020 and H-2201004, H-32013024, H-16042103, and H-16041794), and conformed to the standards set by the Declaration of Helsinki; no additional ethical approval was necessary for this retrospective study.…”

“…Studies A 19 and B 20,21 recorded invasive ABP in the left radial artery and MCAv by TCD-insonation in healthy volunteers and patients admitted to the intensive care unit with severe sepsis; all subjects were placed in the supine position with slight head elevation (20°). Study C 22 , D , 18 and E 23 recorded ABP non-invasively with photoplethysmographic continuous beat-to-beat measurement, and MCAv measured by TCD-insonation while lying supine without head elevation. Recordings from baseline sessions were extracted for all subjects.…”

“…The present retrospective work is based on data from five studies, which have previously been published elsewhere, [18][19][20][21][22][23]…”

“…18 The data collection is described in full in the original articles. [18][19][20][21][22][23] Data pre-processing Recordings were extracted from LabChart (ADInstruments, Sidney, Australia) into a tabdelimited file in the original resolution of 1,000 Hz and were visually inspected for artefacts; periods with artefacts were deleted, ensuring that such periods always started and ended in a nadir. Subsequently, recordings were divided into blocks and epochs using four pre-processing approaches that have been previously reported in the literature 6,17,18 here designated 3-60-F, 6-240-F, 10-300-F, and 10-300-60.…”

Robotic Verticalization plus Music Therapy in Chronic Disorders of Consciousness: Promising Results from a Pilot Study

“…Postural changes are known to alter intracranial pressure, modifying the venous outflow (and thus the cerebral blood volume) through the valveless jugular veins [ 7 ]. In fact, in order to avoid episodes of orthostatic hypotension, verticalization must be achieved with precocity and gradualness (from 0° to 45° and then up to 90°) and with a constant monitoring of blood pressure and heart rate [ 8 ]. It is demonstrated that robot-based neurorehabilitation improves motor performance by boosting brain plasticity, which plays a crucial role in motor and cognitive recovery.…”