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BACKGROUND: Several methods exist to reduce the number of arterial blood gases (ABGs). One method, Roche v-TAC, has been evaluated in different patient groups. This paper aggregates data from these studies, in different patient categories using common analysis criteria. RESEARCH DESIGN AND METHODS: We included studies evaluating v-TAC based on paired arterial and peripheral venous blood samples. Bland-Altman analysis compared measured and calculated arterial values of pH, PCO2, and PO2. Subgroup analyses were performed for normal, chronic hypercapnia and chronic base excess, acute hyper- and hypocapnia, and acute and chronic base deficits. RESULTS: 811 samples from 12 studies were included. Bias and limits of agreement for measured and calculated values: pH 0.001 (-0.029 to 0.031), PCO2 -0.08 (-0.65 to 0.49) kPa, and PO2 0.04 (-1.71 to 1.78) kPa, with similar values for all sub-group analyses. CONCLUSION: These data suggest that v-TAC analysis may have a role in replacing ABGs, avoiding arterial puncture. Substantial data exist in patients with chronic hypercapnia and chronic base excess, acute hyper- and hypocapnia, and in patients with relatively normal acid-base status, with similar bias and precision across groups and across study data. Limited data exist for patients with acute and chronic base deficits.
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Arterias , Análisis de los Gases de la Sangre , Oxígeno , Venas , Humanos , Análisis de los Gases de la Sangre/métodos , Oxígeno/sangre , Arterias/fisiopatología , Concentración de Iones de Hidrógeno , Dióxido de Carbono/sangre , Equilibrio Ácido-Base , Hipercapnia/sangre , Hipercapnia/fisiopatología , Hipercapnia/diagnóstico , Desequilibrio Ácido-Base/sangre , Desequilibrio Ácido-Base/diagnóstico , Desequilibrio Ácido-Base/fisiopatología , Valor Predictivo de las PruebasRESUMEN
Increased ventilatory work beyond working capacity of the respiratory muscles can induce fatigue, resulting in limited respiratory muscle endurance (Tlim ). Previous resistive breathing investigations all applied square wave inspiratory pressure as fatigue-inducing pattern. Spontaneous breathing pressure pattern more closely approximate a triangle waveform. This study aimed at comparing Tlim , maximal inspiratory pressure (PImax ), and metabolism between square and triangle wave breathing. Eight healthy subjects (Wei = 76 ± 10 kg, H = 181 ± 7.9 cm, age = 33.5 ± 4.8 years, sex [F/M] = 1/7) completed the study, comprising two randomized matched load resistive breathing trials with square and triangle wave inspiratory pressure waveform. Tlim decreased with a mean difference of 8 ± 7.2 min (p = 0.01) between square and triangle wave breathing. PImax was reduced following square wave (p = 0.04) but not for triangle wave breathing (p = 0.88). Higher VO2 was observed in the beginning and end for the triangle wave breathing compared with the square wave breathing (p = 0.036 and p = 0.048). Despite higher metabolism, Tlim was significantly longer in triangle wave breathing compared with square wave breathing, showing that the pressure waveform has an impact on the function and endurance of the respiratory muscles.
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Fatiga Muscular , Insuficiencia Respiratoria , Humanos , Adulto , Fatiga Muscular/fisiología , Respiración , Músculos Respiratorios/fisiología , Frecuencia RespiratoriaRESUMEN
OBJECTIVES: To investigate the effect of CO2 during sleep on next-morning cognitive performance in young schoolchildren, the authors performed a double-blind fully balanced crossover placebo-controlled study. MATERIAL AND METHODS: The authors included 36 children aged 10-12 years in the climate chamber. The children slept at 21°C in 6 groups each at 3 different conditions separated by 7 days in a random order. Conditions were as follows: high ventilation with CO2 at 700 ppm, high ventilation with added pure CO2 at 2000-3000 ppm, and reduced ventilation with CO2 at 2-3000 ppm and bioeffluents. Children were subjected to a digital cognitive test battery (CANTAB) in the evening prior to sleep and on the next morning after breakfast. Sleep quality was monitored with wrist actigraphs. RESULTS: There were no significant exposure effects on cognitive performance. Sleep efficiency was significantly lower at high ventilation with CO2 at 700 ppm which is considered to be a chance effect. No other effects were seen, and no relation between air quality during sleep and next-morning cognitive performance was observed in the children emitting an estimated 10 lCO2/h per child. CONCLUSIONS: No effect of CO2 during sleep was found on next day cognition. The children were awakened in the morning, and spent from 45-70 min in well-ventilated rooms before they were tested. Hence, it cannot be precluded that the children have benefitted from the good indoor air quality conditions before and during the testing period. The slightly better sleep efficiency during high CO2 concentrations might be a chance finding. Hence, replication is needed in actual bedrooms controlling for other external factors before any generalizations can be made. Int J Occup Med Environ Health. 2023;36(2):177-91.
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Contaminación del Aire Interior , Dióxido de Carbono , Niño , Humanos , Contaminación del Aire Interior/efectos adversos , Contaminación del Aire Interior/análisis , Dióxido de Carbono/análisis , Cognición , Estudios Cruzados , Sueño , Ventilación , Método Doble CiegoRESUMEN
Hyper- or hypoventilation are commonly occurring stress responses to arterial puncture around the time of blood sampling and have been shown to rapidly alter arterial blood acid-base parameters. This study aimed to evaluate a physiology-based mathematical method to transform peripheral venous blood acid-base values into mathematically arterialised equivalents following acute, transient changes in ventilation. Data from thirty patients scheduled for elective surgery were analysed using the physiology-based method. These data described ventilator changes simulating 'hyper-' or 'hypoventilation' at arterial puncture and included acid-base status from simultaneously drawn blood samples from arterial and peripheral venous catheters at baseline and following ventilatory change. Venous blood was used to calculate mathematically arterialised equivalents using the physiology-based method; baseline values were analysed using Bland-Altman plots. When compared to baseline, measured arterial and calculated arterialised values at each time point within limits of pH: ± 0.03 and PCO2: ± 0.5 kPa, were considered 'not different from baseline'. Percentage of values considered not different from baseline were calculated at each sampling timepoint following hyper- and hypoventilation. For the physiological method, bias and limits of agreement for pH and PCO2 were -0.001 (-0.022 to 0.020) and -0.02 (-0.37 to 0.33) kPa at baseline, respectively. 60 s following a change in ventilation, 100% of the mathematically arterialised values of pH and PCO2 were not different from baseline, compared to less than 40% of the measured arterial values at the same timepoint. In clinical situations where transient breath-holding or hyperventilation may compromise the accuracy of arterial blood samples, arterialised venous blood is a stable representative of steady state arterial blood.
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Dióxido de Carbono , Cateterismo Periférico , Análisis de los Gases de la Sangre/métodos , Cateterismo Periférico/métodos , Humanos , Concentración de Iones de Hidrógeno , Respiración , VenasRESUMEN
Particulate matter is linked to adverse health effects, however, little is known about health effects of particles emitted from typical indoor sources. We examined acute health effects of short-term exposure to emissions from cooking and candles among asthmatics. In a randomized controlled double-blinded crossover study, 36 young non-smoking asthmatics attended three exposure sessions lasting 5 h: (a) air mixed with emissions from cooking (fine particle mass concentration): (PM2.5 : 96.1 µg/m3 ), (b) air mixed with emissions from candles (PM2.5 : 89.8 µg/m3 ), and c) clean filtered air (PM2.5 : 5.8 µg/m3 ). Health effects (spirometry, fractional exhaled Nitric Oxide [FeNO], nasal volume and self-reported symptoms) were evaluated before exposure start, then 5 and 24 h after. During exposures volatile organic compounds (VOCs), particle size distributions, number concentrations and optical properties were measured. Generally, no statistically significant changes were observed in spirometry, FeNO, or nasal volume comparing cooking and candle exposures to clean air. In males, nasal volume and FeNO decreased after exposure to cooking and candles, respectively. Participants reported additional and more pronounced symptoms during exposure to cooking and candles compared to clean air. The results indicate that emissions from cooking and candles exert mild inflammation in asthmatic males and decrease comfort among asthmatic males and females.
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Contaminantes Atmosféricos , Contaminación del Aire Interior , Contaminantes Atmosféricos/análisis , Contaminación del Aire Interior/efectos adversos , Contaminación del Aire Interior/análisis , Culinaria , Estudios Cruzados , Monitoreo del Ambiente , Femenino , Humanos , Masculino , Tamaño de la Partícula , Material Particulado/efectos adversos , Material Particulado/análisisRESUMEN
BACKGROUND: ABGs are performed in acute conditions as the reference method for assessing the acid-base status of blood. Hyperventilation and breath-holding are common ventilatory changes that occur around the time of sampling, rapidly altering the 'true' status of the blood. This is particularly relevant in emergency medicine patients without permanent arterial catheters, where the pain and anxiety of arterial punctures can cause ventilatory changes. This study aimed to determine whether peripheral venous values could be a more reliable measure of blood gases following acute changes in ventilation. METHODS: To allow for characterisation of ventilatory changes typical of acutely ill patients, but without the confounding influence of perfusion or metabolic disturbances, 30 patients scheduled for elective surgery were studied in a prospective observational study. Following anaesthesia, and before the start of the surgery, ventilator settings were altered to achieve a + 100% or - 60% change in alveolar ventilation ('hyper-' or 'hypoventilation'), changes consistent with the anticipation of a painful arterial puncture commonly encountered in the emergency room. Blood samples were drawn simultaneously from indwelling arterial and peripheral venous catheters at baseline, and at 15, 30, 45, 60, 90 and 120 s following the ventilatory change. Comparisons between the timed arterial (or venous) samples were done using repeated-measures ANOVA, with post-hoc analysis using Bonferroni's correction. RESULTS: Arterial blood pH and PCO2 changed rapidly within the first 15-30s after both hyper- and hypoventilation, plateauing at around 60s (∆pH = ±0.036 and ∆PCO2 = ±0.64 kPa (4.7 mmHg), respectively), with peripheral venous values remaining relatively constant until 60s, and changing minimally thereafter. Mean arterial changes were significantly different at 30s (P < 0.001) when compared to baseline, in response to both hyper- and hypoventilation. CONCLUSION: This study has shown that substantial differences in arterial and peripheral venous acid-base status can be due to acute changes in ventilation, commonly seen in the ER over the 30s necessary to sample arterial blood. If changes are transient, peripheral venous blood may provide a more reliable description of acid-base status.
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Equilibrio Ácido-Base , Análisis de los Gases de la Sangre , Hiperventilación/sangre , Hipoventilación/sangre , Análisis de los Gases de la Sangre/métodos , Dióxido de Carbono/sangre , Femenino , Humanos , Concentración de Iones de Hidrógeno , Masculino , Estudios Prospectivos , VenasRESUMEN
This study analyzes the complexity of female longevity improvements. As socioeconomic status is found to influence health and mortality, we partition all individuals, at each age in every year, into five socioeconomic groups based on an affluence measure that combine an individual's income and wealth. We identify the particular socioeconomic groups that have been driving the standstill for Danish females at older ages. Within each socioeconomic group, we further analyze the cause of death patterns. The decline in life expectancy for Danish females is present for four out of five subgroups, however, with particular large decreases for the low-middle and middle-affluence groups. Cancers, smoking-related lung and bronchus causes, and other diseases particularly contribute to the stagnation. For four of the five socioeconomic groups only small cardiovascular improvement are experienced during the period of stagnating life expectancy compared to an equally long and subsequent period.
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Renta , Esperanza de Vida , Adulto , Anciano , Causas de Muerte , Femenino , Humanos , Longevidad , Persona de Mediana Edad , Mortalidad , Clase Social , Factores SocioeconómicosRESUMEN
Interhospital transport of sick newborn infants is dangerous, but the risk of adverse events can be reduced, when transport is being performed by trained neonatal retrieval teams. In this review, we describe the current organisation of neonatal retrieval service in Denmark. The services are based at the neonatal intensive care units of the four university hospitals. Improved cooperation and harmonisation of operations between the teams is needed, as this is a prerequisite for the development of a national clinical consensus guideline and national quality metrics enabling benchmarking both within Denmark and abroad.
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Unidades de Cuidado Intensivo Neonatal , Transporte de Pacientes , Consenso , Dinamarca , Hospitales Universitarios , Humanos , Lactante , Recién NacidoRESUMEN
As people live longer, ages at death are becoming more similar. This dual advance over the last two centuries, a central aim of public health policies, is a major achievement of modern civilization. Some recent exceptions to the joint rise of life expectancy and life span equality, however, make it difficult to determine the underlying causes of this relationship. Here, we develop a unifying framework to study life expectancy and life span equality over time, relying on concepts about the pace and shape of aging. We study the dynamic relationship between life expectancy and life span equality with reliable data from the Human Mortality Database for 49 countries and regions with emphasis on the long time series from Sweden. Our results demonstrate that both changes in life expectancy and life span equality are weighted totals of rates of progress in reducing mortality. This finding holds for three different measures of the variability of life spans. The weights evolve over time and indicate the ages at which reductions in mortality increase life expectancy and life span equality: the more progress at the youngest ages, the tighter the relationship. The link between life expectancy and life span equality is especially strong when life expectancy is less than 70 y. In recent decades, life expectancy and life span equality have occasionally moved in opposite directions due to larger improvements in mortality at older ages or a slowdown in declines in midlife mortality. Saving lives at ages below life expectancy is the key to increasing both life expectancy and life span equality.
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Esperanza de Vida/tendencias , Longevidad , Factores de Edad , Bases de Datos Factuales , Femenino , Humanos , Masculino , Mortalidad , Dinámica Poblacional , Salud Pública , Factores Sexuales , SueciaRESUMEN
INTRODUCTION: Running injuries affect millions of persons every year and have become a substantial public health issue owing to the popularity of running. To ensure adherence to running, it is important to prevent injuries and to have an in-depth understanding of the aetiology of running injuries. The main purpose of the present paper was to describe the design of a future prospective cohort study exploring if a dose-response relationship exists between changes in training load and running injury occurrence, and how this association is modified by other variables. METHODS AND ANALYSIS: In this protocol, the design of an 18-month observational prospective cohort study is described that will include a minimum of 20 000 consenting runners who upload their running data to Garmin Connect and volunteer to be a part of the study. The primary outcome is running-related injuries categorised into the following states: (1) no injury; (2) a problem; and (3) injury. The primary exposure is change in training load (eg, running distance and the cumulative training load based on the number of strides, ground contact time, vertical oscillation and body weight). The change in training load is a time-dependent exposure in the sense that progression or regression can change many times during follow-up. Effect-measure modifiers include, but is not limited to, other types of sports activity, activity of daily living and demographics, and are assessed through questionnaires and/or by Garmin devices. ETHICS AND DISSEMINATION: The study design, procedures and informed consent have been evaluated by the Ethics Committee of the Central Denmark Region (Request number: 227/2016 - Record number: 1-10-72-189-16).
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Traumatismos en Atletas/etiología , Internacionalidad , Proyectos de Investigación , Carrera/lesiones , Humanos , Incidencia , Extremidad Inferior/lesiones , Dolor/etiología , Resistencia Física/fisiología , Estudios Prospectivos , Análisis de Regresión , Factores de Riesgo , Factores de TiempoRESUMEN
BACKGROUND: Indirect calorimetry (IC) is considered the accurate way of measuring energy expenditure (EE). IC devices often apply the Haldane transformation, introducing errors at inspiratory oxygen fraction (FiO2 ) >60%. The aim was to assess measurement reliability and agreement between an unevaluated IC (device 2) (Beacon Caresystem, Mermaid Care A/S, Noerresundby, Denmark) not using Haldane transformation and an IC that does (device 1) (Ecovx, GE, Helsinki, Finland) at varying FiO2 . METHODS: Twenty healthy male subjects participated, with 16 completing the study (33 ± 9 years, 83.3 ± 16 kg, 1.83 ± 0.08 m). Subjects were mechanically ventilated in pressure support (3cmH2 O; positive end-expiratory pressure: 3cmH2 O) at FiO2 of 21%, 50%, 85%, and 21% for 15 minutes at each FiO2 . Mean EE, oxygen consumption (VO2 ), and CO2 production (VCO2 ) were compared within and between devices across FiO2 levels. RESULTS: Device 2 showed within-device EE significant differences at 21% vs 50% FiO2 and device 1 for VCO2 at 50% vs. 85% FiO2 . For all variables, both devices showed reliable measurements at 21% and 50% FiO2 , but at 85%, FiO2 bias and limits of agreement increased. Between devices, there were significant differences for EE at both 21% and 85% FiO2 for VO2 and for VCO2 at 85% FiO2 . CONCLUSION: Both systems measured EE, VO2 , and VCO2 at 21%-85% FiO2 reliably but with bias at 85% FiO2 . The devices were in agreement at 21% and 50% FiO2 , but further studies need to confirm accuracy at high FiO2 .
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Calorimetría Indirecta/normas , Respiración Artificial/normas , Adulto , Calorimetría Indirecta/instrumentación , Metabolismo Energético , Voluntarios Sanos , Humanos , Inhalación , Masculino , Consumo de Oxígeno , Reproducibilidad de los Resultados , Respiración Artificial/métodosRESUMEN
BACKGROUND: Cross-national comparison studies on gender differences have mainly focussed on life expectancy, while less research has examined differences in health across countries. We aimed to investigate gender differences in cognitive function and grip strength over age and time across European regions. METHODS: We performed a cross-sectional study including 51 292 men and 62 007 women aged 50 + participating in the Survey of Health, Ageing and Retirement in Europe between 2004-05 and 2015. Linear regression models were used to examine associations. RESULTS: In general, women had better cognitive function than men, whereas men had higher grip strength measures. Sex differences were consistent over time, but decreased with age. Compared with men, women had higher cognitive scores at ages 50-59, corresponding to 0.17 SD (95% CI 0.14, 0.20) but slightly lower scores at ages 80-89 (0.08 SD, 95% CI 0.14, 0.00). For grip strength, the sex difference decreased from 18.8 kg (95% CI 18.5, 19.1) at ages 50-59 to 8.5 kg (95% CI 7.1, 9.9) at age 90 + . Northern Europeans had higher cognitive scores (19.6%) and grip strength measures (13.8%) than Southern Europeans. Gender differences in grip strength were similar across regions, whereas for cognitive function they varied considerably, with Southern Europe having a male advantage from ages 60-89. CONCLUSION: Our results illustrate that gender differences in health depend on the selected health dimension and the age group studied, and emphasize the importance of considering regional differences in research on cognitive gender differences.
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Factores de Edad , Cognición , Fuerza de la Mano , Encuestas Epidemiológicas/estadística & datos numéricos , Factores Sexuales , Factores Socioeconómicos , Factores de Tiempo , Anciano , Anciano de 80 o más Años , Estudios Transversales , Europa (Continente) , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
A six-month-old boy fell over, and a crochet hook penetrated his skin underneath his left eye. The hook was removed, and an emergency physician found a Glasgow Coma Scale score of 6-7. A CT scan showed no cerebral or ophthalmic injury. However, the patient was persistently apathic with head- and gaze direction towards the left and a facial nerve palsy. An MRI showed a linear intracerebral lesion stretching through pons into the cerebellar vermis. The patient had neuropaediatric rehabilitation and recovered fully within months. The case is an example of CT scan being insufficient in visualizing intracerebral parenchymal damage.
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Traumatismos Penetrantes de la Cabeza/diagnóstico por imagen , Humanos , Lactante , Imagen por Resonancia Magnética , Masculino , Tomografía Computarizada por Rayos X , Heridas PunzantesRESUMEN
The 'prospective potential support ratio' has been proposed by researchers as a measure that accurately quantifies the burden of ageing, by identifying the fraction of a population that has passed a certain measure of longevity, for example, 17â years of life expectancy. Nevertheless, the prospective potential support ratio usually focuses on the current mortality schedule, or period life expectancy. Instead, in this paper we look at the actual mortality experienced by cohorts in a population, using cohort life tables. We analyse differences between the two perspectives using mortality models, historical data, and forecasted data. Cohort life expectancy takes future mortality improvements into account, unlike period life expectancy, leading to a higher prospective potential support ratio. Our results indicate that using cohort instead of period life expectancy returns around 0.5 extra younger people per older person among the analysed countries. We discuss the policy implications implied by our cohort measures.
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Esperanza de Vida/tendencias , Longevidad , Mortalidad/tendencias , Factores de Edad , Estudios de Cohortes , Interpretación Estadística de Datos , Predicción , Humanos , Estudios ProspectivosRESUMEN
Peripartum hysterectomy is a rare but life-saving procedure. Haemorrhage, atony, placenta accreta/praevia or uterus rupture are the most common reasons for hysterectomy. This case report presents a 35-year-old woman, gravida 2, para 1, with total necrosis of the uterus and ovaries bilaterally after an acute caesarean section. Pathological examination showed thrombosis and haemorrhagic infarction. Besides pre-eclampsia the patient had no co-morbidity. Later analysis found homozygosity for factor VLeiden mutation. Hysterectomy was life-saving but the patient developed acute renal failure with late recovery.
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Factor V/genética , Homocigoto , Necrosis/cirugía , Complicaciones Cardiovasculares del Embarazo , Útero/patología , Enfermedad Aguda , Adulto , Cesárea , Femenino , Humanos , Histerectomía , Ovario/patología , Ovario/cirugía , Mutación Puntual , Embarazo , Complicaciones Cardiovasculares del Embarazo/etiología , Complicaciones Cardiovasculares del Embarazo/cirugía , Útero/cirugíaRESUMEN
CONTEXT: Eye irritation is a common complaint in indoor environment, but the causes have still not been identified among the multiple exposures in house environments. To identify the potential environmental factors responsible for eye irritation and study the possible mechanisms, an in vitro model for eye irritation is suggested. MATERIALS AND METHODS: In this study, reconstituted human corneal epithelium (HCE) tissue cultures were used to study the eye irritating and inflammatory potential of lipopolysaccharide (LPS) and dust. HCE tissue cultures were exposed to a range of concentrations of LPS for 6 h and dust for 24 h, respectively. After exposure, viability and secretion of interleukins (IL) IL-1ß, IL-8, and tumor necrosis factor (TNFα) were examined. Histology was used to indicate the morphological changes after dust exposure. RESULTS: Both LPS and dust affected HCE viability. There was an increased level of IL-8 after LPS exposure, while the concentrations of IL-1ß and TNFα remained unaffected. Dust exposure resulted in an elevation of both IL-1ß and IL-8, but not TNFα. Histology study showed increased vacuolization and reduced thickness after 24 h exposure to 5 mg/mL dust. DISCUSSION AND CONCLUSION: LPS and dust showed in vitro eye irritating and inflammatory potential, and cytokines/chemokines like IL-1ß and IL-8 may be involved in the mechanisms of eye irritation. The HCE tissue culture may be used as an in vitro model to study environmental exposure induced eye irritation and inflammation.
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Polvo , Endotoxinas/toxicidad , Epitelio Corneal/efectos de los fármacos , Interleucina-1beta/metabolismo , Interleucina-8/metabolismo , Irritantes/toxicidad , Alternativas a las Pruebas en Animales , Epitelio Corneal/inmunología , Epitelio Corneal/patología , Humanos , Técnicas In Vitro , Lipopolisacáridos/toxicidad , Técnicas de Cultivo de TejidosRESUMEN
The study aimed to investigate diaphragm respiratory drive modulation through electrical activity of the diaphragm (EADi) during progressive cycling in endurance-trained men (N=7) and to test day-to-day measurement reliability. Normalized EADi increased at exercise intensities from 40% workload (WL) to 70% and 85%WL but plateaued from 70% to 85% (p<0.05). VËO2, VËCO2, VËE, increased at all exercise intensities, where Vt and BF increased from 40% to 55% WL and from 70% to 85% and RER increased at 70% and 85% (p<0.05). Bland-Altman plots of normalized EADi showed bias of 0.9% and -6.4% and limits of agreement of ±36.0% and ±30.4% for absolute measurements and relative changes from 40% WL, respectively. Within-day variability appeared constant indicating that measurements within a trial are reliable. Results suggest that diaphragm respiratory drive increases at moderate exercise intensities, but plateaus at high intensities where other respiratory muscles might contribute significantly to the breathing effort, perhaps to "protect" against diaphragm fatigue.
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Diafragma/fisiología , Ejercicio Físico/fisiología , Resistencia Física/fisiología , Fenómenos Fisiológicos Respiratorios , Adulto , Ciclismo , Femenino , Humanos , MasculinoRESUMEN
BACKGROUND: International guidelines recommend that when changing FIO2 in patients with COPD receiving Long-Term Oxygen Therapy (LTOT), 30 minutes should be waited for steady state before measurement of arterial blood gasses. This study evaluates whether 30 minutes is really necessary, as a smaller duration might improve the logistics of care, potentially reducing the time spent by patients at the out-patient clinic. METHODS: 12 patients with severe to very severe COPD according to the GOLD guidelines were included. Patients had a median FEV1% of 23% of the predicted value (range 15-64%), median FEV1/FVC 0.43 (range 0.26-0.63), and chronic respiratory failure necessitating LTOT, 1-4 liters/minute, minimum 16 hours/day. Following a FIO2 reduction (wash out), arterial blood gases were measured at 0, 1, 2, 4, 8, 12, 17, 22, 32 and 34 minutes. FIO2 was then increased to baseline levels (wash in) and blood gasses measured at 0, 1, 2, 4, 8, 12, 17, 22, 32, and 34 minutes. Data were analyzed to examine the dynamics of arterial PO2 and saturation (SO2) wash out and wash in by calculating the time constants, tau (ô), and to evaluate the time required to reach values which might be considered clinically stable, defined as PO2 within 0.5 kPa and SO2 within 1% of equilibrium values. RESULTS: For arterial PO2 values of time constants were about 3 minutes and similar for both wash out and wash in. A median of 5 minutes was required to reach clinically stable values of PO2 in both wash out and wash in, with 7-8 minutes sufficient in 75% of patients, and in the worst case 14 minutes. For SO2, values of the time constant were 4.5 and 1.4 minutes for wash out and wash in, respectively. The time required to reach clinically stable values was different in the two phases. For wash out the median time was 7.4 minutes, and in the worst case 15.6 minutes. For wash in the median time was 2.6 minutes and in worst case 6.8 minutes. No significant changes in PCO2 or pH were seen during FIO2 changes. DISCUSSION/CONCLUSION: This study shows that oxygen equilibration relevant for clinical interpretation requires only 10 minutes following an increase and 16 minutes following a decrease in FIO2. over the range studied.
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Terapia por Inhalación de Oxígeno , Oxígeno/sangre , Enfermedad Pulmonar Obstructiva Crónica/sangre , Anciano , Análisis de los Gases de la Sangre , Femenino , Volumen Espiratorio Forzado , Humanos , Masculino , Persona de Mediana Edad , Oxígeno/administración & dosificación , Presión Parcial , Guías de Práctica Clínica como Asunto , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Enfermedad Pulmonar Obstructiva Crónica/terapia , Factores de TiempoRESUMEN
The automatic lung parameter estimator (ALPE) method was developed in 2002 for bedside estimation of pulmonary gas exchange using step changes in inspired oxygen fraction (FIO2). Since then a number of studies have been conducted indicating the potential for clinical application and necessitating systems evolution to match clinical application. This paper describes and evaluates the evolution of the ALPE method from a research implementation (ALPE1) to two commercial implementations (ALPE2 and ALPE3). A need for dedicated implementations of the ALPE method was identified: one for spontaneously breathing (non-mechanically ventilated) patients (ALPE2) and one for mechanically ventilated patients (ALPE3). For these two implementations, design issues relating to usability and automation are described including the mixing of gasses to achieve FIO2 levels, and the automatic selection of FIO2. For ALPE2, these improvements are evaluated against patients studied using the system. The major result is the evolution of the ALPE method into two dedicated implementations, namely ALPE2 and ALPE3. For ALPE2, the usability and automation of FIO2 selection has been evaluated in spontaneously breathing patients showing that variability of gas delivery is 0.3 % (standard deviation) in 1,332 breaths from 20 patients. Also for ALPE2, the automated FIO2 selection method was successfully applied in 287 patient cases, taking 7.2 ± 2.4 min and was shown to be safe with only one patient having SpO2 < 86 % when the clinician disabled the alarms. The ALPE method has evolved into two practical, usable systems targeted at clinical application, namely ALPE2 for spontaneously breathing patients and ALPE3 for mechanically ventilated patients. These systems may promote the exploration of the use of more detailed descriptions of pulmonary gas exchange in clinical practice.
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Intercambio Gaseoso Pulmonar/fisiología , Pruebas de Función Respiratoria/instrumentación , Algoritmos , Teorema de Bayes , Diseño de Equipo , Humanos , Modelos Biológicos , Monitoreo Fisiológico/instrumentación , Monitoreo Fisiológico/estadística & datos numéricos , Oxígeno/fisiología , Respiración Artificial , Pruebas de Función Respiratoria/estadística & datos numéricos , Relación Ventilacion-Perfusión/fisiologíaRESUMEN
Exposure during fetal life may have long-lasting health consequences for the child. Cohorts with biological material are necessary to investigate the possible biological mechanisms behind this potential early programming of disease. The Aarhus Birth Cohort Biobank was established in 2008 as an amendment to an ongoing research database, the Aarhus Birth Cohort. It aims to provide the opportunity to investigate the role of genetic factors, environmental exposures and lifestyles in pregnancy on the risk of disease in the offspring. All pregnant women who plan to give birth at Aarhus University Hospital, Skejby, and the fathers-to-be are invited to participate in the Aarhus Birth Cohort Biobank. Blood samples (mother 54 ml, father 4 ml) are drawn at the time of the routine ultrasound scanning in gestational week 12. At the same time, the women fill out a detailed questionnaire on medical and lifestyle factors. Immediately after birth, blood (10 ml) from the umbilical cord and umbilical cord tissue are sampled. Samples from the mothers are separated into plasma, buffy coat, erythrocyte suspension and serum before freezing at -80°C. Samples of whole blood are also stored, from both the mother and the father. Plasma, buffy coat, erythrocyte suspension and tissue from the umbilical cord are stored at -80°C. All researchers can apply for access to the database. For more details, see www.ab-biobank.dk or tbh@dadlnet.dk.