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1.
Ann Surg Open ; 2(4): e101, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37637885

RESUMO

Objective: To evaluate the immediate effects of positive expiratory pressure therapy on oxygen saturation and ventilation after abdominal surgery. Background: Positive expiratory pressure therapy to treat postoperative hypoxia is widespread, despite a lack of evidence of effect. Methods: This randomized, sham-controlled, crossover trial investigated adults 1-2 days after abdominal surgery at Umeå University Hospital, Sweden. The intervention was positive expiratory pressure of 10-15 cm H2O. The control was a sham device. The investigations were ended with deep-breathing maneuvers. Outcomes were the gradient of changes in peripheral oxygen saturation and transcutaneous carbon-dioxide partial pressure (PtcCO2). Results: Eighty patients were included and randomized and 76 patients were analyzed. Oxygen saturation increased from a baseline mean of 92% to 95%, P < 0.001, during positive expiratory pressure breathing, while PtcCO2 decreased from a mean of 36 to 33 mm Hg, P < 0.001. This was followed by apnea, oxygen desaturations to a mean of 89%, P < 0.001, and increased PtcCO2 before returning to baseline values. The changes in oxygen saturation and PtcCO2 did not differ from sham breathing or deep-breathing maneuvers. Conclusions: Positive expiratory pressure breathing after abdominal surgery improves oxygen saturation during the maneuver because of hyperventilation, but it is followed by apnea, hypoventilation, and oxygen desaturation. The effect is not different from the expiration to a sham device or hyperventilation. It is time to stop positive expiratory pressure therapy after abdominal surgery, as there is no evidence of effect in previous trials, apart from the adverse effects reported here.

3.
Int J Epidemiol ; 49(5): 1443-1453, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32954400

RESUMO

BACKGROUND: While the COVID-19 outbreak in China now appears suppressed, Europe and the USA have become the epicentres, both reporting many more deaths than China. Responding to the pandemic, Sweden has taken a different approach aiming to mitigate, not suppress, community transmission, by using physical distancing without lockdowns. Here we contrast the consequences of different responses to COVID-19 within Sweden, the resulting demand for care, intensive care, the death tolls and the associated direct healthcare related costs. METHODS: We used an age-stratified health-care demand extended SEIR (susceptible, exposed, infectious, recovered) compartmental model for all municipalities in Sweden, and a radiation model for describing inter-municipality mobility. The model was calibrated against data from municipalities in the Stockholm healthcare region. RESULTS: Our scenario with moderate to strong physical distancing describes well the observed health demand and deaths in Sweden up to the end of May 2020. In this scenario, the intensive care unit (ICU) demand reaches the pre-pandemic maximum capacity just above 500 beds. In the counterfactual scenario, the ICU demand is estimated to reach ∼20 times higher than the pre-pandemic ICU capacity. The different scenarios show quite different death tolls up to 1 September, ranging from 5000 to 41 000, excluding deaths potentially caused by ICU shortage. Additionally, our statistical analysis of all causes excess mortality indicates that the number of deaths attributable to COVID-19 could be increased by 40% (95% confidence interval: 0.24, 0.57). CONCLUSION: The results of this study highlight the impact of different combinations of non-pharmaceutical interventions, especially moderate physical distancing in combination with more effective isolation of infectious individuals, on reducing deaths, health demands and lowering healthcare costs. In less effective mitigation scenarios, the demand on ICU beds would rapidly exceed capacity, showing the tight interconnection between the healthcare demand and physical distancing in the society. These findings have relevance for Swedish policy and response to the COVID-19 pandemic and illustrate the importance of maintaining the level of physical distancing for a longer period beyond the study period to suppress or mitigate the impacts from the pandemic.


Assuntos
COVID-19 , Controle de Doenças Transmissíveis , Custos de Cuidados de Saúde/tendências , Necessidades e Demandas de Serviços de Saúde , Mortalidade/tendências , COVID-19/economia , COVID-19/epidemiologia , COVID-19/prevenção & controle , Controle de Doenças Transmissíveis/métodos , Controle de Doenças Transmissíveis/estatística & dados numéricos , Monitoramento Epidemiológico , Necessidades e Demandas de Serviços de Saúde/organização & administração , Necessidades e Demandas de Serviços de Saúde/tendências , Humanos , Modelos Teóricos , Isolamento de Pacientes , Distanciamento Físico , SARS-CoV-2 , Suécia/epidemiologia
4.
Med Image Anal ; 38: 77-89, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28282642

RESUMO

The reconstruction of an object's shape or surface from a set of 3D points plays an important role in medical image analysis, e.g. in anatomy reconstruction from tomographic measurements or in the process of aligning intra-operative navigation and preoperative planning data. In such scenarios, one usually has to deal with sparse data, which significantly aggravates the problem of reconstruction. However, medical applications often provide contextual information about the 3D point data that allow to incorporate prior knowledge about the shape that is to be reconstructed. To this end, we propose the use of a statistical shape model (SSM) as a prior for surface reconstruction. The SSM is represented by a point distribution model (PDM), which is associated with a surface mesh. Using the shape distribution that is modelled by the PDM, we formulate the problem of surface reconstruction from a probabilistic perspective based on a Gaussian Mixture Model (GMM). In order to do so, the given points are interpreted as samples of the GMM. By using mixture components with anisotropic covariances that are "oriented" according to the surface normals at the PDM points, a surface-based fitting is accomplished. Estimating the parameters of the GMM in a maximum a posteriori manner yields the reconstruction of the surface from the given data points. We compare our method to the extensively used Iterative Closest Points method on several different anatomical datasets/SSMs (brain, femur, tibia, hip, liver) and demonstrate superior accuracy and robustness on sparse data.


Assuntos
Algoritmos , Imageamento Tridimensional/métodos , Modelos Estatísticos , Encéfalo/diagnóstico por imagem , Fêmur/diagnóstico por imagem , Quadril/diagnóstico por imagem , Humanos , Fígado/diagnóstico por imagem , Distribuição Normal , Tíbia/diagnóstico por imagem
5.
Injury ; 45(8): 1149-55, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24975481

RESUMO

BACKGROUND: The adrenal response in critically ill patients, including trauma victims, has been debated over the last decade. The aim of this study was to assess the early adrenal response after trauma. METHODS: Prospective, observational study of 50 trauma patients admitted to a level-1-trauma centre. Serum and saliva cortisol were followed from the accident site up to five days after trauma. Corticosteroid binding globulin (CBG), dehydroepiandrosterone (DHEA) and sulphated dehydroepiandrosterone (DHEAS) were obtained twice during the first five days after trauma. The effect of time and associations between cortisol levels and; severity of trauma, infusion of sedative/analgesic drugs, cardiovascular dysfunction and other adrenocorticotropic hormone (ACTH) dependent hormones (DHEA/DHEAS) were studied. RESULTS: There was a significant decrease over time in serum cortisol both during the initial 24 h, and from the 2nd to the 5th morning after trauma. A significant decrease over time was also observed in calculated free cortisol, DHEA, and DHEAS. No significant association was found between an injury severity score ≥ 16 (severe injury) and a low (< 200 nmol/L) serum cortisol at any time during the study period. The odds for a serum cortisol < 200 nmol/L was eight times higher in patients with continuous infusion of sedative/analgesic drugs compared to patients with no continuous infusion of sedative/analgesic drugs. CONCLUSION: Total serum cortisol, calculated free cortisol, DHEA and DHEAS decreased significantly over time after trauma. Continuous infusion of sedative/analgesic drugs was independently associated with serum cortisol < 200 nmol/L.


Assuntos
Sulfato de Desidroepiandrosterona/metabolismo , Desidroepiandrosterona/metabolismo , Hidrocortisona/metabolismo , Testes de Função Adreno-Hipofisária/métodos , Sistema Hipófise-Suprarrenal/metabolismo , Ferimentos e Lesões/metabolismo , Corticosteroides/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Analgésicos/uso terapêutico , Feminino , Humanos , Hipnóticos e Sedativos/uso terapêutico , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Sistema Hipófise-Suprarrenal/fisiopatologia , Guias de Prática Clínica como Assunto , Estudos Prospectivos , Suécia , Fatores de Tempo , Índices de Gravidade do Trauma , Resultado do Tratamento , Ferimentos e Lesões/tratamento farmacológico , Ferimentos e Lesões/fisiopatologia
6.
Bioelectromagnetics ; 26(4): 299-304, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15832331

RESUMO

Effects of a pulsating, half sine wave magnetic field (MF) with a frequency of 100 pps and 15 mT rms flux density, generated by the MD TEMF device (EMF Therapeutics, Inc., Chattanooga), on subjective pain rating, heart rate, and arterial blood pressure were tested in a double blind, crossover design study employing experimental muscle pain. Each of 24 healthy volunteers (12 females and 12 males, 24.7 +/- 3.2 years of age) received painful stimulation induced by the infusion of 5% hypertonic saline (HS) into the erector spinae muscle during real and sham MF exposure, in counterbalanced order. Exposure to MF differently affects subjective pain estimates in females and males. MF exposure increased averaged pain level and time integral of pain ratings in females, whereas no statistically significant difference for these characteristics was found in males. Pain related elevation of systolic and diastolic blood pressure was observed during both real and sham EMF exposure in female and male subjects.


Assuntos
Terapia por Estimulação Elétrica/métodos , Campos Eletromagnéticos , Síndromes da Dor Miofascial/diagnóstico , Síndromes da Dor Miofascial/terapia , Medição da Dor , Adulto , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Masculino , Síndromes da Dor Miofascial/induzido quimicamente , Prognóstico , Doses de Radiação , Solução Salina Hipertônica , Fatores Sexuais , Resultado do Tratamento
7.
Eur J Pain ; 9(2): 185-94, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15737811

RESUMO

Most of the previous studies on the effects of pain on Regional Cerebral Blood Flow (rCBF) had been done with brief cutaneous or intramuscular painful stimuli. The aim of the present study was to investigate the effect on rCBF of long lasting tonic experimental muscle pain. To this end we performed PET investigations of rCBF following tonic experimental low back pain induced by continuous intramuscular infusion of hypertonic (5%) saline (HS) with computer controlled infusion pump into the right erector spinae on L(3) level in 19 healthy volunteers. Changes in rCBF were measured with the use of (15)O labelled water during four conditions: Baseline (before start of infusion), Early Pain (4 min after start of infusion), Late Pain (20 min after start of infusion) and Post-Pain (>15 min after stop of infusion) conditions. Results of SPM analysis showed relative rCBF increase in the right insula and bilateral decrease in the temporo-parieto-occipital cortex during initial phase of painful stimulation (Early Pain) followed by activation of the medial prefrontal region and bilateral inhibition of insula, anterior cingulate and dorso-lateral prefrontal cortex mainly in ipsilateral hemisphere during Late Pain conditions. The results show that longer lasting tonic experimental muscle pain elicited by i.m infusion of HS results in decreases rather than increases in rCBF. Possible explanations for differences found in rCBF during tonic hypertonic saline-induced experimental muscle pain as compared with previous findings are discussed.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Circulação Cerebrovascular/fisiologia , Dor/fisiopatologia , Adulto , Estudos de Casos e Controles , Humanos , Infusões Parenterais , Injeções Intramusculares , Masculino , Tono Muscular/efeitos dos fármacos , Tono Muscular/fisiologia , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/fisiopatologia , Dor/induzido quimicamente , Dor/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Solução Salina Hipertônica/administração & dosagem
8.
Exp Brain Res ; 163(1): 65-74, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15645226

RESUMO

The concept of fatigue refers to a class of acute effects that can impair motor performance, and not to a single mechanism. A great deal is known about the peripheral mechanisms underlying the process of fatigue, but our knowledge of the roles of the central structures in that process is still very limited. During fatigue, it has been shown that peripheral apparatus is capable of generating adequate force while central structures become insufficient/sub-optimal in driving them. This is known as central fatigue, and it can vary between muscles and different tasks. Fatigue induced by submaximal isometric contraction may have a greater central component than fatigue induced by prolonged maximal efforts. We studied the changes in regional cerebral blood flow (rCBF) of brain structures after sustained isometric muscle contractions of different submaximal force levels and of different durations, and compared them with the conditions observed when the sustained muscle contraction becomes fatiguing. Changes in cortical activity, as indicated by changes in rCBF, were measured using positron emission tomography (PET). Twelve subjects were studied under four conditions: (1) rest condition; (2) contraction of the m. biceps brachii at 30% of MVC, sustained for 60 s; (3) contraction at 30% of MVC, sustained for 120 s, and; (4) contraction at 50% of MVC, sustained for 120 s. The level of rCBF in the activated cortical areas gradually increased with the level and duration of muscle contraction. The fatiguing condition was associated with predominantly contralateral activation of the primary motor (MI) and the primary and secondary somatosensory areas (SI and SII), the somatosensory association area (SAA), and the temporal areas AA and AI. The supplementary motor area (SMA) and the cingula were activated bilaterally. The results show increased cortical activation, confirming that increased effort aimed at maintaining force in muscle fatigue is associated with increased activation of cortical neurons. At the same time, the activation spread to several cortical areas and probably reflects changes in both excitatory and inhibitory cortical circuits. It is suggested that further studies aimed at controlling afferent input from the muscle during fatigue may allow a more precise examination of the roles of each particular region involved in the processing of muscle fatigue.


Assuntos
Encéfalo/fisiologia , Contração Muscular/fisiologia , Fadiga Muscular/fisiologia , Tomografia por Emissão de Pósitrons , Adulto , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular/fisiologia , Eletromiografia , Humanos , Masculino
9.
Neurosci Lett ; 335(2): 119-23, 2002 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-12459513

RESUMO

A positron emission tomography imaging study was performed on 16 healthy volunteers to reveal changes in cortical activation during acute muscle pain induced by intra-muscular injection of hypertonic saline into the left triceps brachii muscle. Changes in regional cerebral blood flow (rCBF) were measured with the use of [(15)O] labelled water during 'Rest1', 'Needle' (insertion of a needle without injection), 'Rest2' and 'Pain' conditions. Differences in rCBF were found in the comparison of Pain and Needle, and Pain and Rest2 conditions, revealing activation of the contralateral insula and putamen. The results are discussed with respect to possible differences in brain processing of muscle and cutaneous noxious inputs.


Assuntos
Córtex Cerebral/fisiologia , Músculo Esquelético/fisiopatologia , Dor/fisiopatologia , Adolescente , Adulto , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiopatologia , Circulação Cerebrovascular/efeitos dos fármacos , Análise por Conglomerados , Humanos , Masculino , Isótopos de Oxigênio , Dor/induzido quimicamente , Dor/diagnóstico por imagem , Medição da Dor , Putamen/diagnóstico por imagem , Putamen/fisiopatologia , Solução Salina Hipertônica , Inquéritos e Questionários , Tomografia Computadorizada de Emissão/métodos
10.
Exp Brain Res ; 143(3): 276-85, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11889505

RESUMO

It has been shown that the primary and secondary somatosensory cortex, as well as the supplementary motor area (SMA), are involved in central processing of proprioceptive signals during passive and active arm movements. However, it is not clear whether different cortical areas are involved in processing of different proprioceptive inputs (skin, joint, muscle receptors), what their relative contributions might be, where kinesthetic sensations are formed within the CNS, and how they interact when the full peripheral proprioceptive machinery acts. In this study we investigated the representation of the brain structures involved in the perception of passive limb movement and illusory movement generated by muscle tendon vibration. Changes in cortical activity as indicated by changes in regional cerebral blood flow (rCBF) were measured using positron emission tomography (PET). Twelve subjects were studied under four conditions: (1) passive flexion-extension movement (PM) of the left forearm; (2) induced illusions of movements (VI) similar to the real PM, induced by alternating vibration of biceps and triceps tendons (70-80 Hz) at the elbow; (3) alternating vibration of biceps and triceps tendons (with 20-50 Hz) without induced kinesthetic illusions (VN); and (4) rest condition (RE). The results show different patterns of cortex activation. In general, the activation during passive movement was higher in comparison with both kinds of vibration, and activation during vibrations with induced illusions of movement was more prominent than during vibrations without induced illusions. When the PM condition was contrasted with the other conditions we found the following areas of activation -- the primary motor (MI) and somatosensory area (SI), the SMA and the supplementary somatosensory area (SSA). In conditions where passive movements and illusory movements were contrasted with rest, some temporal areas, namely primary and associative auditory cortex, were activated, as well as secondary somatosensory cortex (SII). Our data show that different proprioceptive inputs, which induce sensation of movement, are associated with differently located activation patterns in the SI/MI and SMA areas of the cortex. In general, the comparison of activation intensities under different functional conditions indicates the involvement of SII in stimulus perception generation and of the SI/MI and SMA areas in the processing of proprioceptive input. Activation of the primary and secondary auditory cortex might reflect the interaction between somatosensory and auditory systems in movement sense generation. SSA might also be involved in movement sense generation and/or maintenance.


Assuntos
Córtex Cerebral/fisiologia , Circulação Cerebrovascular/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Ilusões/fisiologia , Cinestesia/fisiologia , Rede Nervosa/fisiologia , Adulto , Mapeamento Encefálico , Córtex Cerebral/anatomia & histologia , Córtex Cerebral/diagnóstico por imagem , Eletromiografia , Lateralidade Funcional/fisiologia , Humanos , Masculino , Contração Muscular/fisiologia , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Rede Nervosa/anatomia & histologia , Rede Nervosa/diagnóstico por imagem , Tomografia Computadorizada de Emissão , Vibração
11.
Neurosci Res ; 42(2): 91-9, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11849728

RESUMO

The aim of the present study was to investigate to what extent activation of bradykinin-sensitive nerve endings of the temporomandibular joint (TMJ) might induce changes in the muscle spindles output from neck muscles through reflex effects on cervical fusimotor neurones. To this end, 26 muscle spindle afferents (MSAs) emanating from the trapezius and splenius muscles of the anaesthetised cat (alpha-chloralose, initial dosage 60 mg/kg) were recorded during injection of Bradykinin (BK) (12.5-50 microg/ml) in the ipsilateral TMJ. Fifteen (58%) MSAs exhibited statistically significant fusimotor effects to injection of BK into the TMJ. Of the 15, ten MSAs showed a response related to activation of static fusimotor neurones, three MSAs showed a response related to an activation of both static and dynamic fusimotor neurones and two MSAs showed a inhibition of both static and dynamic fusimotor neurones. The control experiments suggests that the effects observed were due to activation of BK sensitive nerve endings in the TMJ. It seems possible that the reflex connections between TMJ nociceptors and the fusimotor-muscle spindle system of dorsal neck muscles might be involved in the pathophysiological mechanisms responsible for the sensory-motor disturbances in the neck region often found on patients with temporomandibular disorders.


Assuntos
Bradicinina/fisiologia , Fusos Musculares/fisiologia , Músculos do Pescoço/fisiologia , Articulação Temporomandibular/fisiologia , Animais , Bradicinina/farmacologia , Gatos , Injeções Intra-Articulares , Fusos Musculares/efeitos dos fármacos , Músculos do Pescoço/efeitos dos fármacos , Neurônios Aferentes/efeitos dos fármacos , Neurônios Aferentes/fisiologia , Articulação Temporomandibular/efeitos dos fármacos
12.
Exp Brain Res ; 142(3): 319-26, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11819039

RESUMO

Intramuscular injection of hypertonic saline (HS) is a procedure widely adopted to experimentally induce deep muscle pain in humans. This study was undertaken to test whether intramuscular injections of HS (5%) influence the activity of primary and secondary muscle spindle afferents (MSAs) from homonymous as well as heteronymous muscles. The experiments were performed on six cats anaesthetised with alpha-chloralose. Usually responses of two to nine MSAs from gastrocnemius medialis (GM) and/or gastrocnemius lateralis (GL) muscles were recorded simultaneously, while HS was injected either into the receptor-bearing muscle (homonymous responses) or into a close (GM/GL) or remote synergistic muscle (posterior biceps, PB, heteronymous responses). The mean rate of discharge and the depth of modulation of the MSA responses to sinusoidal stretching of the receptor-bearing muscle were calculated. Out of the 42 afferents tested (7 from GM and 35 from GL), 38 (90%) exhibited statistically significant responses to injections of HS into homonymous and/or heteronymous muscles. With injections into the homonymous muscle, the average maximal increase in mean rate of discharge was 74% and the average decrease in depth of modulation was --18%. The mean duration of the effects was 2.1 min. The corresponding values for heteronymous injections into a close synergist were 87%, -17% and 2.1 min (GM or GL), and for injections into PB 52%, -11%, and 1.8 min. The majority of the responses (72%) were compatible with reflex action on static fusimotor neurones, whereas 20% of the responses could be attributed to mixed static and dynamic fusimotor action. The remaining 8% of the responses were attributed to inhibition of fusimotor activity. There were no statistically significant differences between the responses following injections into homonymous or heteronymous muscles. Injections of Tyrode's solution did not induce any significant alterations in MSA responses, implying that they were not induced by direct and/or injury effects of the injections. HS-related changes in MSA activity were completely abolished after the nerves to corresponding muscles were cut, confirming the reflex nature of the effects. Thus, intramuscular injections of HS induce reflex changes in MSA activity from both homonymous and heteronymous muscles, most likely via fusimotor reflexes. Predominantly static fusimotor neurones were activated. The possible role of the fusimotor-muscle spindle system in altered motor control during experimentally induced muscle pain is discussed.


Assuntos
Neurônios Motores gama/fisiologia , Fusos Musculares/fisiologia , Músculo Esquelético/fisiologia , Neurônios Aferentes/fisiologia , Nociceptores/fisiologia , Dor/fisiopatologia , Reflexo de Estiramento/fisiologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Animais , Gatos , Interações Medicamentosas/fisiologia , Neurônios Motores gama/efeitos dos fármacos , Contração Muscular/efeitos dos fármacos , Contração Muscular/fisiologia , Fusos Musculares/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/inervação , Neurônios Aferentes/efeitos dos fármacos , Nociceptores/efeitos dos fármacos , Dor/induzido quimicamente , Dor/patologia , Reflexo de Estiramento/efeitos dos fármacos
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