Utvikling av et regime for total intravenøs anestesi hos gris brukt til kirurgisk ferdighetstrening og biomedisinsk forskning

Large animal models are commonly used in biomedical research or for medical training purposes where cardiovascular instability is encountered. Pigs are frequently used as their cardiorespiratory anatomy and physiology are thought to resemble that of humans closely. General anaesthesia is mostly a legal requirement when using pigs for this purpose. There is however a paucity in the scientific literature when it comes to research on anaesthesia in pigs, with anaesthetic techniques often being extrapolated from those used in other species, including human anaesthesia. The overall aim of this work was to develop an anaesthetic regime that can be applied when anaesthetising pigs for live tissue training and biomedical research where surgically induced nociception or cardiovascular instability can be encountered. An experiment was conducted comparing total intravenous anaesthetic protocols with either propofol-ketamine-fentanyl or propofol-ketamine-dexmedetomidine. We concluded that both anaesthetic regimes provided stable cardiovascular conditions in normovolemic pigs. Additionally, solid antinociception was provided, in particular when including dexmedetomidine in the anaesthetic protocol. This experiment led to new research questions, and further experiments were conducted to examine the cardiovascular function during hypovolemia due to blood loss and the respiratory function during total intravenous anaesthesia with either propofol-ketamine-dexmedetomidine or alfaxolone-ketamine-dexmedetomidine. In addition, the difference in nociceptive response to different modalities of nociceptive stimulation between pigs given fentanyl or dexmedetomidine that was observed during the first experiment was examined further. The major findings of this experimental work are that total intravenous anaesthesia with either propofol-ketamine-dexmedetomdine or alfaxalone-ketamine dexmedetomdine are suitable anaesthetic regimes in pigs when cardiovascular instability is foreseen during live tissue training or biomedical research, and that these pigs tolerate a substantial blood loss. When using these anaesthetic regimes respiratory supportive measures must be taken. Oxygen supplementation and the ability to provide positive pressure ventilation must be available. Plasma concentrations of both propofol and alfaxalone may increase during moderate to severe blood loss, and dose adjustments can be necessary. Both dexmedetomidine and fentanyl seem to provide solid antinociception in pigs when given as a constant rate infusion. In our study population of juvenile pigs, dexmedetomidine did not negatively influence cardiovascular function to the extent that has been observed in other species.Når store forsøksdyr brukes i biomedisinsk forskning eller ved medisinsk ferdighetstrening kan kardiovaskulær instabilitet oppstå. Gris blir ofte brukt som modelldyr, ettersom det er en oppfatning av at artens kardiorespiratoriske anatomi og fysiologi likner menneskets. Generell anestesi av gris til dette formålet er relativt vanlig, men publisert forskning på effektene av ulike anestesiregimer til gris er mangelfull. Ofte ekstrapoleres anestesiteknikker fra andre arter, blant annet fra human anestesiologi. Hovedformålet med dette vitenskapelig arbeidet var å utvikle et anestesiregime til bruk på gris som anesteseres for medisinsk ferdighetstrening og biomedisinsk forskning der kirurgisk indusert nosisepsjon og kardiovaskulær instabilitet kan oppstå. I det første eksperimentet ble effektene av total intravenøs anestesi med propofol-ketamin-fentanyl og propofol-ketamin-deksmedetomidin sammenlignet. Hovedfunnet var at begge anestesiregimer gav stabil kardiovaskulær status og solid antinosisepsjon. Eksperimentet ga opphav til nye forskningsspørsmål. Videre eksperiment ble gjennomført for å undersøke kardiovaskulær funksjon ved hypovolemi og respiratorisk funksjon hos griser anestesert med enten propofol-ketamin-deksmedetomidin eller alfaxalon-ketamin-deksmedetomidin. I tillegg undersøkte vi den forskjellige nosiseptive responsen vi observerte ved ulike modaliteter for nosiseptiv stimulering hos griser som fikk enten fentanyl eller deksmedetomidin i det første eksperimentet. De viktigste funnene i våre undersøkelser er at total intravenøs anestesi med enten propofol-ketamin-deksmedetomdin eller alfaxalon-ketamin-deksmedetomidin kan brukes til generell anestesi av gris ved medisinsk ferdighetstrening eller biomedisinsk forskning når kardiovaskulær instabilitet forventes, og at disse grisene tolererer et relativt stort blodtap. Når man bruker disse anestesiregimene må respiratorisk støttebehandling være tilgjengelig, og muligheter til å gi tilskudd av oksygen og overtrykksventilering må være til stede. Plasmakonsentrasjoner av både propofol og alfaxalon kan øke ved moderat til kraftig blodtap, og dosejusteringer kan være nødvendig. Både fentanyl og deksmedetomidin gitt som en kontinuerlig infusjon ser ut til å gi solid antinosisepsjon hos gris. I vår studiepopulasjon bestående av juvenile griser så ikke deksmedetomidin ut til å påvirke kardiovaskulær funksjon like negativt hos gris som hos andre arter.Animal Health and Welfare Branch, Veterinary Inspectorate, and Force Health Protection, Norwegian Armed Forces Joint Medical Service

Development of a Multimodal Apparatus to Generate Biomechanically Reproducible Spinal Cord Injuries in Large Animals

Rodents are widespread animal models in spinal cord injury (SCI) research. They have contributed to obtaining important information. However, some treatments only tested in rodents did not prove efficient in clinical trials. This is probably a result of significant differences in the physiology, anatomy, and complexity between humans and rodents. To bridge this gap in a better way, a few research groups use pig models for SCI. Here we report the development of an apparatus to perform biomechanically reproducible SCI in large animals, including pigs. We present the iterative process of engineering, starting with a weight-drop system to ultimately produce a spring-load impactor. This device allows a graded combination of a contusion and a compression injury. We further engineered a device to entrap the spinal cord and prevent it from escaping at the moment of the impact. In addition, it provides identical resistance around the cord, thereby, optimizing the inter-animal reproducibility. We also present other tools to straighten the vertebral column and to ease the surgery. Sensors mounted on the impactor provide information to assess the inter-animal reproducibility of the impacts. Further evaluation of the injury strength using neurophysiological recordings, MRI scans, and histology shows consistency between impacts. We conclude that this apparatus provides biomechanically reproducible spinal cord injuries in pigs

Abnormal motor activity during anaesthesia in a dog: a case report

Seizures or convulsions that occur during anaesthesia in veterinary patients are infrequently reported in the literature. Consequently, the incidence of such events is unknown. Several drugs commonly used in clinical veterinary anaesthesia have been shown to induce epileptiform activity in both human clinical patients and experimental candidates. The present case report describes convulsions in a four-year old male Bernese mountain dog during maintenance of anaesthesia with isoflurane after premedication with acepromazine and methadone followed by co-induction with propofol and ketamine. The dog had no history of previous convulsions. The use of several sedative and anaesthetic drugs makes it difficult to find one single causative pharmaceutical

Orientation and Projection Center Refinement for EBSD Indexing in Python

I dette arbeidet er et sett med algoritmer for forbedring av krystallorientering og projeksjonssenter estimater spesielt etter, men ikke begrenset til, dictionary indexing av EBSD mønster presentert. Algoritmene er utviklet i programmeringsspråket Python 3 som en utvidelse av open-source Python-biblioteket kikuchipy. Algoritmene kan gjøre beregninger parallelt, og kan kjøres effektivt på en bærbar datamaskin, samt på dataklynger. I tillegg har algoritmene støtte for å arbeide med eksperimentelle datasett som er større enn tilgjengelig minne. Forbedringen kan gjøres med et vidt utvalgt av derivatfrie optimaliseringsalgoritmer som er implementert i SciPy biblioteket, både lokale og globale, som for eksempel Nelder-Mead og Differential Evolution. Implementasjonen tilbyr rimelige parametere for uerfarne brukere, samtidig som den tillater erfarne brukere å finpusse på parametere

Macrocirculatory Parameters and Oxygen Debt Indices in Pigs During Propofol Or Alfaxalone Anesthesia When Subjected to Experimental Stepwise Hemorrhage

publishedVersio

A comparison of respiratory function in pigs anaesthetised by propofol or alfaxalone in combination with dexmedetomidine and ketamine

publishedVersio

Development of a Multimodal Apparatus to Generate Biomechanically Reproducible Spinal Cord Injuries in Large Animals

Rodents are widespread animal models in spinal cord injury (SCI) research. They have contributed to obtaining important information. However, some treatments only tested in rodents did not prove efficient in clinical trials. This is probably a result of significant differences in the physiology, anatomy, and complexity between humans and rodents. To bridge this gap in a better way, a few research groups use pig models for SCI. Here we report the development of an apparatus to perform biomechanically reproducible SCI in large animals, including pigs. We present the iterative process of engineering, starting with a weight-drop system to ultimately produce a spring-load impactor. This device allows a graded combination of a contusion and a compression injury. We further engineered a device to entrap the spinal cord and prevent it from escaping at the moment of the impact. In addition, it provides identical resistance around the cord, thereby, optimizing the inter-animal reproducibility. We also present other tools to straighten the vertebral column and to ease the surgery. Sensors mounted on the impactor provide information to assess the inter-animal reproducibility of the impacts. Further evaluation of the injury strength using neurophysiological recordings, MRI scans, and histology shows consistency between impacts. We conclude that this apparatus provides biomechanically reproducible spinal cord injuries in pigs

Development of a Multimodal Apparatus to Generate Biomechanically Reproducible Spinal Cord Injuries in Large Animals

Rodents are widespread animal models in spinal cord injury (SCI) research. They have contributed to obtaining important information. However, some treatments only tested in rodents did not prove efficient in clinical trials. This is probably a result of significant differences in the physiology, anatomy, and complexity between humans and rodents. To bridge this gap in a better way, a few research groups use pig models for SCI. Here we report the development of an apparatus to perform biomechanically reproducible SCI in large animals, including pigs. We present the iterative process of engineering, starting with a weight-drop system to ultimately produce a spring-load impactor. This device allows a graded combination of a contusion and a compression injury. We further engineered a device to entrap the spinal cord and prevent it from escaping at the moment of the impact. In addition, it provides identical resistance around the cord, thereby, optimizing the inter-animal reproducibility. We also present other tools to straighten the vertebral column and to ease the surgery. Sensors mounted on the impactor provide information to assess the inter-animal reproducibility of the impacts. Further evaluation of the injury strength using neurophysiological recordings, MRI scans, and histology shows consistency between impacts. We conclude that this apparatus provides biomechanically reproducible spinal cord injuries in pigs