Management of acute cervical spinal cord injury in the non-specialist intensive care unit: a narrative review of current evidence.

Each year approximately one million people suffer spinal cord injury, which has significant physical, psychosocial and economic impacts on patients and their families. Spinal cord rehabilitation centres are a well-established part of the care pathway for patients with spinal cord injury and facilitate improvements in functional independence and reductions in healthcare costs. Within the UK, however, there are a limited number of spinal cord injury centres, which delays admission. Patients and their families often perceive that they are not receiving specialist care while being treated in non-specialist units. This review aimed to provide clinicians who work in non-specialist spinal injury centres with a summary of contemporary studies relevant to the critical care management of patients with cervical spinal cord injury. We undertook a targeted literature review including guidelines, systematic reviews, meta-analyses, clinical trials and randomised controlled trials published in English between 1 June 2017 and 1 June 2023. Studies involving key clinical management strategies published before this time, but which have not been updated or repeated, were also included. We then summarised the key management themes: acute critical care management approaches (including ventilation strategies, blood pressure management and tracheostomy insertion); respiratory weaning techniques; management of pain and autonomic dysreflexia; and rehabilitation.

Corium lavas: structure and properties of molten UO2-ZrO2 under meltdown conditions.

In the exceedingly rare event of nuclear reactor core meltdown, uranium dioxide fuel reacts with Zircaloy cladding to produce eutectic melts which can subsequently be oxidized by coolant/moderator water. Oxidized corium liquids in the xUO2·(100 - x)ZrO2 system were produced via laser melting of UO2-ZrO2 mixtures to temperatures in excess of 3000 K. Contamination was avoided by floating the droplets on a gas stream within an aerodynamic levitator and in-situ high-energy x-ray diffraction experiments allowed structural details to be elucidated. Molecular dynamics simulations well reproduced diffraction and density data, and show less compositional variation in thermal expansion and viscosity than suggested by existing measurements. As such, corium liquids maintain their highly penetrating nature irrespective of the amount of oxidized cladding dissolved in the molten fuel. Metal-oxygen coordination numbers vary with both composition and temperature. The former is due to mismatch in native values, nUO(x = 100) ≈ 7 and nZrO(x = 0) ≈ 6, and the requirement for oxygen site stabilization. The latter provides a thermal expansion mechanism.

Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials.

An aerodynamic levitator with carbon dioxide laser beam heating was integrated with a hermetically sealed controlled atmosphere chamber and sample handling mechanism. The system enabled containment of radioactive samples and control of the process atmosphere chemistry. The chamber was typically operated at a pressure of approximately 0.9 bars to ensure containment of the materials being processed. Samples 2.5-3 mm in diameter were levitated in flowing gas to achieve containerless conditions. Levitated samples were heated to temperatures of up to 3500 °C with a partially focused carbon dioxide laser beam. Sample temperature was measured using an optical pyrometer. The sample environment was integrated with a high energy (100 keV) x-ray synchrotron beamline to enable in situ structure measurements to be made on levitated samples as they were heated, melted, and supercooled. The system was controlled from outside the x-ray beamline hutch by using a LabVIEW program. Measurements have been made on hot solid and molten uranium dioxide and binary uranium dioxide-zirconium dioxide compositions.

Molten uranium dioxide structure and dynamics.

Uranium dioxide (UO2) is the major nuclear fuel component of fission power reactors. A key concern during severe accidents is the melting and leakage of radioactive UO2 as it corrodes through its zirconium cladding and steel containment. Yet, the very high temperatures (>3140 kelvin) and chemical reactivity of molten UO2 have prevented structural studies. In this work, we combine laser heating, sample levitation, and synchrotron x-rays to obtain pair distribution function measurements of hot solid and molten UO2. The hot solid shows a substantial increase in oxygen disorder around the lambda transition (2670 K) but negligible U-O coordination change. On melting, the average U-O coordination drops from 8 to 6.7 ± 0.5. Molecular dynamics models refined to this structure predict higher U-U mobility than 8-coordinated melts.

Measurement of cardiac left ventricular pressure in conscious rats using a fluid-filled catheter.

A fluid-filled catheter consisting of 100 cm of PE50 polyethylene tubing welded to 7 cm of PE10 polyethylene tubing (PE50/PE10) was constructed for the purpose of measuring the rate of left ventricular pressure development (+dP/dt) in conscious, freely moving rats. Prior to in vivo experiments, four PE50/PE10 catheters were randomly selected, and their natural frequencies and damping ratios were determined using a square wave impact. The mean (n = 4), natural frequency of these catheters was shown to be 35.0 +/- 5.5 Hz, and the mean damping ratio was 0.83 +/- 0.10. Natural frequency plotted against increasing PE50 tubing length was shown to have a slope of -0.44 Hz/cm with a correlation coefficient of 0.99. The effect of the 7-cm PE10 tubing segment on the catheter damping ratio was also demonstrated. One of the four PE50/PE10 type catheters exhibited a damping ratio of 0.74 +/- 0.09. When the 7-cm PE10 tube was removed, the damping ratio was reduced to 0.31 +/- 0.04. Left ventricular +dP/dt obtained in conscious rats with a PE50/PE10 catheter (n = 7; 6300 +/- 300 mmHg/sec) was significantly less than the +dP/dt obtained using a 100-cm PE50 catheter (n = 6; 9400 +/- 400 mmHg/sec). The results of this study make it clear that the PE50/PE10 catheter is suitable for the measurement of left ventricular +dP/dt in the conscious rat, and that catheter design has a profound influence on both the catheter natural frequency and damping ratio.

Spontaneous periodic hypothermia: diencephalic epilepsy.

The case of a patient with episodic hypothermia and profuse sweating believed to be due to diencephalic epilepsy is reported. Despite intensive investigations no other manifestations of hypothalamic dysfunction were found. Conventional antiepileptic drugs were without effect but the patient was successfully treated by total sympathectomy.