Effect of ephedrine and phenylephrine on brain oxygenation and microcirculation in anaesthetised patients with cerebral tumours: study protocol for a randomised controlled trial.

INTRODUCTION: During brain tumour surgery, vasopressor drugs are commonly administered to increase mean arterial blood pressure with the aim of maintaining sufficient cerebral perfusion pressure. Studies of the commonly used vasopressors show that brain oxygen saturation is reduced after phenylephrine administration, but unaltered by ephedrine administration. These findings may be explained by different effects of phenylephrine and ephedrine on the cerebral microcirculation, in particular the capillary transit-time heterogeneity, which determines oxygen extraction efficacy. We hypothesised that phenylephrine is associated with an increase in capillary transit-time heterogeneity and a reduction in cerebral metabolic rate of oxygen compared with ephedrine. Using MRI and positron emission tomography (PET) as measurements in anaesthetised patients with brain tumours, this study will examine whether phenylephrine administration elevates capillary transit-time heterogeneity more than ephedrine, thereby reducing brain oxygenation. METHODS AND ANALYSIS: This is a double-blind, randomised clinical trial including 48 patients scheduled for surgical brain tumour removal. Prior to imaging and surgery, anaesthetised patients will be randomised to receive either phenylephrine or ephedrine infusion until mean arterial blood pressure increases to above 60 mm Hg or 20% above baseline. Twenty-four patients were allocated to MRI and another 24 patients to PET examination. MRI measurements include cerebral blood flow, capillary transit-time heterogeneity, cerebral blood volume, blood mean transit time, and calculated oxygen extraction fraction and cerebral metabolic rate of oxygen for negligible tissue oxygen extraction. PET measurements include cerebral metabolic rate of oxygen, cerebral blood flow and oxygen extraction fraction. Surgery is initiated after MRI/PET measurements and subdural intracranial pressure is measured. ETHICS AND DISSEMINATION: This study was approved by the Central Denmark Region Committee on Health Research Ethics (12 June 2015; 1-10-72-116-15). Results will be disseminated via peer-reviewed publication and presentation at international conferences. TRIAL REGISTRATION NUMBER: NCT02713087; Pre-results. 2015-001359-60; Pre-results.

[Head injuries in Duckburg in 1959 and 2009].

Comic books have been a part of popular culture through generations. Debates concerning their graphic depictions of violence have been ongoing for nearly as long. Our aim was to examine if the violence in "Donald Duck & Co." (a weekly published Danish comic book), illustrated through the number of head injuries, increased in the period from 1959 to 2009. The comic book vintages from the years 1959 and 2009 were read, and the number of head injuries noted. The head injuries were characterized by severity, in part by a modified Glasgow Coma Scale and in part by a newly developed Comic Book Coma Scale. The number of head injuries were equal in the examined years, however, the number of head injuries per page decreased from 1/10 pages to 1/20 pages. Donald Duck sustained a better part of the injuries increasing from 17% in 1959 to 33% in 2009. The study indicates that we, with peace of mind, can read a comic book while the rest of the family takes care of the dishes at Christmas.

The role of the microcirculation in delayed cerebral ischemia and chronic degenerative changes after subarachnoid hemorrhage.

The mortality after aneurysmal subarachnoid hemorrhage (SAH) is 50%, and most survivors suffer severe functional and cognitive deficits. Half of SAH patients deteriorate 5 to 14 days after the initial bleeding, so-called delayed cerebral ischemia (DCI). Although often attributed to vasospasms, DCI may develop in the absence of angiographic vasospasms, and therapeutic reversal of angiographic vasospasms fails to improve patient outcome. The etiology of chronic neurodegenerative changes after SAH remains poorly understood. Brain oxygenation depends on both cerebral blood flow (CBF) and its microscopic distribution, the so-called capillary transit time heterogeneity (CTH). In theory, increased CTH can therefore lead to tissue hypoxia in the absence of severe CBF reductions, whereas reductions in CBF, paradoxically, improve brain oxygenation if CTH is critically elevated. We review potential sources of elevated CTH after SAH. Pericyte constrictions in relation to the initial ischemic episode and subsequent oxidative stress, nitric oxide depletion during the pericapillary clearance of oxyhemoglobin, vasogenic edema, leukocytosis, and astrocytic endfeet swelling are identified as potential sources of elevated CTH, and hence of metabolic derangement, after SAH. Irreversible changes in capillary morphology and function are predicted to contribute to long-term relative tissue hypoxia, inflammation, and neurodegeneration. We discuss diagnostic and therapeutic implications of these predictions.

[Neonatal subgaleal haemorrhage causing fatal course after vacuum-assisted extraction]. / Fatalt forløb ved neonatalt subgalealt hæmatom efter vakuumekstraktion.

We present a case that emphasizes the importance of early recognition of neonatal subgaleal haemorrhage through knowledge of risk factors and adequate communication within the health team treating the woman in labour. Especially vacuum-assisted extraction of the child significantly multiplies the incidents of subgaleal haemorrhage. The high mortality is directly associated with disseminated intravascular coagulation and bleeding. Early monitoring and treatment with replacement of blood volume is crucial. Education concerning this condition is therefore of great importance.