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1.
Medicine (Baltimore) ; 100(6): e23570, 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33578509

RESUMO

ABSTRACT: The Gas Man simulation software provides an opportunity to teach, understand and examine the pharmacokinetics of volatile anesthetics. The primary aim of this study was to investigate the accuracy of a cardiac output and alveolar ventilation matched Gas Man model and to compare its predictive performance with the standard pharmacokinetic model using patient data.Therefore, patient data from volatile anesthesia were successively compared to simulated administration of desflurane and sevoflurane for the standard and a parameter-matched simulation model with modified alveolar ventilation and cardiac output. We calculated the root-mean-square deviation (RMSD) between measured and calculated induction, maintenance and elimination and the expiratory decrement times during emergence and recovery for the standard and the parameter-matched model.During induction, RMSDs for the standard Gas Man simulation model were higher than for the parameter-matched Gas Man simulation model [induction (desflurane), standard: 1.8 (0.4) % Atm, parameter-matched: 0.9 (0.5) % Atm., P = .001; induction (sevoflurane), standard: 1.2 (0.9) % Atm, parameter-matched: 0.4 (0.4) % Atm, P = .029]. During elimination, RMSDs for the standard Gas Man simulation model were higher than for the parameter-matched Gas Man simulation model [elimination (desflurane), standard: 0.7 (0.6) % Atm, parameter-matched: 0.2 (0.2) % Atm, P = .001; elimination (sevoflurane), standard: 0.7 (0.5) % Atm, parameter-matched: 0.2 (0.2) % Atm, P = .008]. The RMSDs during the maintenance of anesthesia and the expiratory decrement times during emergence and recovery showed no significant differences between the patient and simulated data for both simulation models.Gas Man simulation software predicts expiratory concentrations of desflurane and sevoflurane in humans with good accuracy, especially when compared to models for intravenous anesthetics. Enhancing the standard model by ventilation and hemodynamic input variables increases the predictive performance of the simulation model. In most patients and clinical scenarios, the predictive performance of the standard Gas Man simulation model will be high enough to estimate pharmacokinetics of desflurane and sevoflurane with appropriate accuracy.


Assuntos
Débito Cardíaco/efeitos dos fármacos , Desflurano/farmacocinética , Expiração/fisiologia , Ventilação Pulmonar/fisiologia , Sevoflurano/farmacocinética , Adulto , Idoso , Algoritmos , Anestésicos Inalatórios/administração & dosagem , Anestésicos Inalatórios/farmacocinética , Débito Cardíaco/fisiologia , Ensaios Clínicos como Assunto , Simulação por Computador/estatística & dados numéricos , Desflurano/administração & dosagem , Quimioterapia Combinada , Feminino , Humanos , Pulmão/metabolismo , Pulmão/fisiologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/metabolismo , Alvéolos Pulmonares/fisiologia , Sevoflurano/administração & dosagem
2.
Zhongguo Dang Dai Er Ke Za Zhi ; 22(12): 1313-1319, 2020 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-33328003

RESUMO

OBJECTIVE: To study the percentage of the measured values of the main pulmonary ventilation function parameters in their predicted values based on Zapletal equation among healthy children aged 5-14 years in Kunming, China, and to provide a basis for accurate judgment of pulmonary ventilation function in clinical practice. METHODS: A total of 702 healthy children aged 5-14 years (352 boys and 350 girls) from Kunming were enrolled. The Jaeger spirometer was used to measure the nine indices:forced vital capacity (FVC), forced expiratory volume in one second (FEV1), ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC), maximal mid-expiratory flow (MMEF), forced expiratory flow at 25% of forced vital capacity (FEF25), forced expiratory flow at 50% of forced vital capacity (FEF50), forced expiratory flow at 75% of forced vital capacity (FEF75), peak expiratory flow (PEF), and maximal voluntary ventilation (MVV). The values obtained from the Zapletal equation of predicted values provided by the spirometer were used as the predicted values of children, and the percentage of measured values in predicted values was calculated. RESULTS: In the 702 children, the percentages of the measured values of the main pulmonary ventilation function parameters PEF, FVC, FEV1, FEV1/FVC, and MVV in their predicted values fluctuated from 102% to 114%, 94% to 108%, 98% to 113%, 98% to 107%, and 141% to 183% respectively. As for the main airway velocity parameters, the percentages of the measured values of FEF25, FEF50, FEF75, and MMEF in their predicted values fluctuated from 98% to 116%, 85% to 102%, 71% to 98%, and 83% to 100% respectively. The percentages of the measured values of PEF, FVC, FEV1, FEV1/FVC, MVV, FEF25, FEF50, FEF75, and MMEF in their predicted values had the lower limits of normal of 88.2%, 88.4%, 92.0%, 94.4%, 118.5%, 82.9%, 70.0%, 62.1%, and 70.1% respectively. CONCLUSIONS: There are differences between pulmonary ventilation function parameter levels and normal values provided by Zapletal equation in healthy children aged 5-14 years in Kunming. As for the pulmonary ventilation function parameters of PEF, FVC, FEV, FEV1/FVC, MVV, FEF25, FEF50, FEF75, and MMEF in these children, the lower limits of normal of measured values in predicted values may be determined as 88.2%, 88.4%, 92.0%, 94.4%, 118.5%, 82.9%, 70.0%, 62.1%, and 70.1% respectively.


Assuntos
Pulmão/fisiologia , Ventilação Pulmonar , Adolescente , Criança , Pré-Escolar , China , Feminino , Volume Expiratório Forçado , Humanos , Masculino , Valores de Referência , Capacidade Vital
3.
Medicine (Baltimore) ; 99(51): e23646, 2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33371099

RESUMO

ABSTRACT: This study identified the effects of pursed-lip breathing (PLB), forward trunk lean posture (FTLP), and combined PLB and FTLP on total and compartmental lung volumes, and ventilation in patients with chronic obstructive pulmonary disease (COPD). Sixteen patients with mild to moderate COPD performed 2 breathing patterns of quiet breathing (QB) and PLB during FTLP and upright posture (UP). The total and compartmental lung volumes and ventilation of these 4 tasks (QB-UP, PLB-UP, QB-FTLP, PLB-FTLP) were evaluated using optoelectronic plethysmography. Two-way repeated measures ANOVA was used to identify the effect of PLB, FTLP, and combined strategies on total and compartmental lung volumes and ventilation. End-expiratory lung volume of ribcage compartment was significantly lower in PLB-UP than QB-UP and those with FTLP (P < .05). End-inspiratory lung volume (EILV) and end-inspiratory lung volume of ribcage compartment were significantly greater during PLB-FTLP and PLB-UP than those of QB (P < .05). PLB significantly and positively changed end-expiratory lung volume of abdominal compartment (EELVAB ) end-expiratory lung volume, EILVAB, tidal volume of pulmonary ribcage, tidal volume of abdomen, and ventilation than QB (P < .05). UP significantly increased tidal volume of pulmonary ribcage, tidal volume of abdomen, and ventilation and decreased EELVAB, end-expiratory lung volume, and EILVAB than FTLP (P < .05). In conclusion, combined PLB with UP or FTLP demonstrates a positive change in total and compartmental lung volumes in patients with mild to moderate COPD.


Assuntos
Exercícios Respiratórios , Postura , Doença Pulmonar Obstrutiva Crônica/reabilitação , Ventilação Pulmonar , Terapia Respiratória/métodos , Idoso , Estudos Transversais , Humanos , Medidas de Volume Pulmonar , Pessoa de Meia-Idade
4.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 1444-1447, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018262

RESUMO

We applied our Simultaneous Multi-Source Electrical Impedance Tomography (SMS-EIT) system to detect pulmonary ventilation and pulsatile perfusion on 5 preterm newborns with respiratory distress syndrome under the nasal continuous positive airway pressure (CPAP) treatment. The results show that derived impedance changes have a potential for clinical application to evaluate effects in spontaneously breathing preterm infants with and without CPAP.


Assuntos
Recém-Nascido Prematuro , Síndrome do Desconforto Respiratório do Recém-Nascido , Pressão Positiva Contínua nas Vias Aéreas , Humanos , Lactente , Recém-Nascido , Ventilação Pulmonar , Fluxo Pulsátil , Síndrome do Desconforto Respiratório do Recém-Nascido/terapia
7.
8.
Euro Surveill ; 25(36)2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32914744

RESUMO

In March 2020, we observed an outbreak of COVID-19 among a relatively homogenous group of 199 young (median age 21 years; 87% men) Swiss recruits. By comparing physical endurance before and in median 45 days after the outbreak, we found a significant decrease in predicted maximal aerobic capacity in COVID-19 convalescent but not in asymptomatically infected and SARS-CoV-2 naive recruits. This finding might be indicative of lung injury after apparently mild COVID-19 in young adults.


Assuntos
Infecções por Coronavirus/diagnóstico , Coronavirus/isolamento & purificação , Exercício Físico/fisiologia , Lesão Pulmonar/etiologia , Consumo de Oxigênio , Resistência Física/fisiologia , Pneumonia Viral/diagnóstico , Ventilação Pulmonar/fisiologia , Adulto , Infecções Assintomáticas , Betacoronavirus , Convalescença , Coronavirus/genética , Infecções por Coronavirus/epidemiologia , Surtos de Doenças , Feminino , Humanos , Masculino , Militares , Pandemias , Resistência Física/imunologia , Aptidão Física , Pneumonia Viral/epidemiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco , Suíça/epidemiologia , Adulto Jovem
9.
Anesthesiology ; 133(5): 1093-1105, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32773690

RESUMO

BACKGROUND: Prone ventilation redistributes lung inflation along the gravitational axis; however, localized, nongravitational effects of body position are less well characterized. The authors hypothesize that positional inflation improvements follow both gravitational and nongravitational distributions. This study is a nonoverlapping reanalysis of previously published large animal data. METHODS: Five intubated, mechanically ventilated pigs were imaged before and after lung injury by tracheal injection of hydrochloric acid (2 ml/kg). Computed tomography scans were performed at 5 and 10 cm H2O positive end-expiratory pressure (PEEP) in both prone and supine positions. All paired prone-supine images were digitally aligned to each other. Each unit of lung tissue was assigned to three clusters (K-means) according to positional changes of its density and dimensions. The regional cluster distribution was analyzed. Units of tissue displaying lung recruitment were mapped. RESULTS: We characterized three tissue clusters on computed tomography: deflation (increased tissue density and contraction), limited response (stable density and volume), and reinflation (decreased density and expansion). The respective clusters occupied (mean ± SD including all studied conditions) 29.3 ± 12.9%, 47.6 ± 11.4%, and 23.1 ± 8.3% of total lung mass, with similar distributions before and after lung injury. Reinflation was slightly greater at higher PEEP after injury. Larger proportions of the reinflation cluster were contained in the dorsal versus ventral (86.4 ± 8.5% vs. 13.6 ± 8.5%, P < 0.001) and in the caudal versus cranial (63.4 ± 11.2% vs. 36.6 ± 11.2%, P < 0.001) regions of the lung. After injury, prone positioning recruited 64.5 ± 36.7 g of tissue (11.4 ± 6.7% of total lung mass) at lower PEEP, and 49.9 ± 12.9 g (8.9 ± 2.8% of total mass) at higher PEEP; more than 59.0% of this recruitment was caudal. CONCLUSIONS: During mechanical ventilation, lung reinflation and recruitment by the prone positioning were primarily localized in the dorso-caudal lung. The local effects of positioning in this lung region may determine its clinical efficacy.


Assuntos
Pulmão/fisiologia , Modelos Animais , Decúbito Ventral/fisiologia , Ventilação Pulmonar/fisiologia , Respiração Artificial/métodos , Decúbito Dorsal/fisiologia , Animais , Pulmão/diagnóstico por imagem , Suínos , Tomografia Computadorizada por Raios X/métodos
10.
PLoS One ; 15(8): e0237010, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32780739

RESUMO

This study analyzed the physiological adjustments caused by the use of the Elevation training mask® (2.0), an airflow restriction mask (ARM) during continuous exercise. Eighteen physically active participants (12 men and 6 women) were randomized to two protocols: continuous exercise with mask (CE-ARM) and continuous exercise without mask (CE). Exercise consisted of cycling for 20 minutes at 60% of maximum power. Metabolic variables, lactate, and gas concentration were obtained from arterialized blood samples at pre and post exercise. Continuous expired gases and myoelectric activity of the quadriceps were performed at rest and during the test. We observed no reduction in oxygen saturation in CE-ARM, leading to lower pH, higher carbon dioxide, and greater hematocrit (all p <0.05). The expired gas analysis shows that the CE-ARM condition presented higher oxygen uptake and expired carbon dioxide concentrations (p <0.05). The CE-ARM condition also presented lower ventilatory volume, ventilatory frequency, and expired oxygen pressure (p <0.05). No changes in electromyography activity and lactate concentrations were identified. We conclude that using ARM does not induce hypoxia and represents an additional challenge for the control of acid-base balance, and we suggest the use of ARM as being suitable for respiratory muscle training.


Assuntos
Exercício Físico/fisiologia , Consumo de Oxigênio/fisiologia , Ventilação Pulmonar/fisiologia , Adulto , Exercícios Respiratórios/métodos , Dióxido de Carbono/sangue , Teste de Esforço/métodos , Feminino , Voluntários Saudáveis , Humanos , Hipóxia/metabolismo , Pulmão/metabolismo , Masculino , Máscaras , Oxigênio/sangue , Respiração , Testes de Função Respiratória
11.
Radiologe ; 60(9): 823-830, 2020 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-32776240

RESUMO

CLINICAL/METHODOLOGICAL ISSUE: The differentiated assessment of respiratory mechanics, gas exchange and pulmonary circulation, as well as structural impairment of the lung are essential for the treatment of patients with cystic fibrosis (CF). Clinical lung function measurements are often not sufficiently specific and are often difficult to perform. STANDARD RADIOLOGICAL METHODS: The standard procedures for pulmonary imaging are chest X­ray and computed tomography (CT) for assessing lung morphology. In more recent studies, an increasing number of centers are using magnetic resonance imaging (MRI) to assess lung structure and function. However, functional imaging is currently limited to specialized centers. METHODOLOGICAL INNOVATIONS: In patients with CF, studies showed that MRI with hyperpolarized gases and Fourier decomposition/matrix pencil MRI (FD/MP-MRI) are feasible for assessing pulmonary ventilation. For pulmonary perfusion, dynamic contrast-enhanced MRI (DCE-MRI) or contrast-free methods, e.g., FD-MRI, can be used. PERFORMANCE: Functional MRI provides more accurate insight into the pathophysiology of pulmonary function at the regional level. Advantages of MRI over X­ray are its lack of ionizing radiation, the large number of lung function parameters that can be extracted using different contrast mechanisms, and ability to be used repeatedly over time. ACHIEVEMENTS: Early assessment of lung function impairment is needed as the structural changes usually occur later in the course of the disease. However, sufficient experience in clinical application exist only for certain functional lung MRI procedures. PRACTICAL RECOMMENDATIONS: Clinical application of the aforementioned techniques, except for DCE-MRI, should be restricted to scientific studies.


Assuntos
Fibrose Cística , Pulmão , Imagem por Ressonância Magnética , Meios de Contraste , Fibrose Cística/complicações , Fibrose Cística/diagnóstico por imagem , Humanos , Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Ventilação Pulmonar
14.
J Sports Sci ; 38(21): 2462-2470, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32654597

RESUMO

To establish the test-retest reliability of pulmonary oxygen uptake (V̇O2), muscle deoxygenation (deoxy[haem]) and tissue oxygen saturation (StO2) kinetics in youth elite-cyclists. From baseline pedalling, 15 youth cyclists completed 6-min step transitions to a moderate- and heavy-intensity work rate separated by 8 min of baseline cycling. The protocol was repeated after 1 h of passive rest. V̇O2 was measured breath-by-breath alongside deoxy[haem] and StO2 of the vastus lateralis by near-infrared spectroscopy. Reliability was assessed using 95% limits of agreement (LoA), the typical error (TE) and the intraclass correlation coefficient (ICC). During moderate- and heavy-intensity step cycling, TEs for the amplitude, time delay and time constant ranged between 3.5-21.9% and 3.9-12.1% for V̇O2 and between 6.6-13.7% and 3.5-10.4% for deoxy[haem], respectively. The 95% confidence interval for estimating the kinetic parameters significantly improved for ensemble-averaged transitions of V̇O2 (p < 0.01) but not for deoxy[haem]. For StO2, the TEs for the baseline, end-exercise and the rate of deoxygenation were 1.0-42.5% and 1.1-5.5% during moderate- and heavy-intensity exercise, respectively. The ICC ranged from 0.81 to 0.99 for all measures. Test-retest reliability data provide limits within which changes in V̇O2, deoxy[haem] and StO2 kinetics may be interpreted with confidence in youth athletes.


Assuntos
Consumo de Oxigênio , Ventilação Pulmonar , Músculo Quadríceps/metabolismo , Corrida/fisiologia , Adaptação Fisiológica , Adolescente , Feminino , Heme/metabolismo , Humanos , Masculino , Microcirculação , Músculo Quadríceps/irrigação sanguínea , Reprodutibilidade dos Testes , Espectroscopia de Luz Próxima ao Infravermelho
15.
J Cardiothorac Surg ; 15(1): 166, 2020 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-32641164

RESUMO

BACKGROUND: Dynamic chest radiography (DCR) is a flat-panel detector (FPD)-based functional X-ray imaging, which is performed as an additional examination in chest radiography. DCR provides objective and quantifiable information, such as diaphragm movement, pulmonary ventilation and circulation, and is reasonable for detecting tumor invasion or adhesion. CASE PRESENTATION: We present a case of Solitary Fibrous Tumor of Pleura (SFTP), preoperatively predicted visceral pleura origin using Dynamic chest radiography (DCR) and surgically resected through single-access (uniportal) video-assisted thoracoscopic surgery (UVATS). CONCLUSIONS: UVATS may be a suitable surgical option for pedunculated SFTPs. Dynamic chest radiography provides information, such as tumor invasion or adhesion and helpful for predicting origin of the tumor.


Assuntos
Neoplasias Pleurais/cirurgia , Radiografia Torácica/métodos , Tumor Fibroso Solitário Pleural/cirurgia , Cirurgia Torácica Vídeoassistida/métodos , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Pleurais/diagnóstico por imagem , Neoplasias Pleurais/patologia , Ventilação Pulmonar , Tumor Fibroso Solitário Pleural/diagnóstico por imagem , Tumor Fibroso Solitário Pleural/patologia
16.
Am J Respir Crit Care Med ; 202(7): 996-1004, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32551817

RESUMO

Rationale: Two distinct phenotypes of acute respiratory distress syndrome (ARDS) with differential clinical outcomes and responses to randomly assigned treatment have consistently been identified in randomized controlled trial cohorts using latent class analysis. Plasma biomarkers, key components in phenotype identification, currently lack point-of-care assays and represent a barrier to the clinical implementation of phenotypes.Objectives: The objective of this study was to develop models to classify ARDS phenotypes using readily available clinical data only.Methods: Three randomized controlled trial cohorts served as the training data set (ARMA [High vs. Low Vt], ALVEOLI [Assessment of Low Vt and Elevated End-Expiratory Pressure to Obviate Lung Injury], and FACTT [Fluids and Catheter Treatment Trial]; n = 2,022), and a fourth served as the validation data set (SAILS [Statins for Acutely Injured Lungs from Sepsis]; n = 745). A gradient-boosted machine algorithm was used to develop classifier models using 24 variables (demographics, vital signs, laboratory, and respiratory variables) at enrollment. In two secondary analyses, the ALVEOLI and FACTT cohorts each, individually, served as the validation data set, and the remaining combined cohorts formed the training data set for each analysis. Model performance was evaluated against the latent class analysis-derived phenotype.Measurements and Main Results: For the primary analysis, the model accurately classified the phenotypes in the validation cohort (area under the receiver operating characteristic curve [AUC], 0.95; 95% confidence interval [CI], 0.94-0.96). Using a probability cutoff of 0.5 to assign class, inflammatory biomarkers (IL-6, IL-8, and sTNFR-1; P < 0.0001) and 90-day mortality (38% vs. 24%; P = 0.0002) were significantly higher in the hyperinflammatory phenotype as classified by the model. Model accuracy was similar when ALVEOLI (AUC, 0.94; 95% CI, 0.92-0.96) and FACTT (AUC, 0.94; 95% CI, 0.92-0.95) were used as the validation cohorts. Significant treatment interactions were observed with the clinical classifier model-assigned phenotypes in both ALVEOLI (P = 0.0113) and FACTT (P = 0.0072) cohorts.Conclusions: ARDS phenotypes can be accurately identified using machine learning models based on readily available clinical data and may enable rapid phenotype identification at the bedside.


Assuntos
Aprendizado de Máquina , /classificação , Fatores Etários , Área Sob a Curva , Bicarbonatos/metabolismo , Bilirrubina/metabolismo , Biomarcadores Tumorais , Pressão Sanguínea , Dióxido de Carbono/metabolismo , Creatinina/metabolismo , Humanos , Inflamação , Molécula 1 de Adesão Intercelular/metabolismo , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Análise de Classes Latentes , Contagem de Leucócitos , Mortalidade , Oxigênio/metabolismo , Pressão Parcial , Fenótipo , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Contagem de Plaquetas , Prognóstico , Proteína C/metabolismo , Ventilação Pulmonar , Ensaios Clínicos Controlados Aleatórios como Assunto , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , /fisiopatologia , Albumina Sérica/metabolismo , Volume de Ventilação Pulmonar , Vasoconstritores/uso terapêutico , Sinais Vitais
17.
Int J Sports Med ; 41(12): 839-845, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32590846

RESUMO

The effects of wearing an intra-oral device on several ventilatory and fatigue markers have been reported for a variety of sports. The quality of the figures performed in synchronized swimming is directly affected by fatigue, and can be monitored during training sessions (TS). The aim of the study was to investigate the acute effects of wearing customized intra-oral devices on heart rate variability, rating of perceived exertion, blood lactate accumulation, and salivary cortisol production during a competitive training session. Twelve highly trained elite female athletes (age: 21.0±3.6 years) participated in the study. Fatigue markers were assessed at the beginning and at the end of the 3rd and 5th afternoon TS for that week, once with and once without an intra-oral device, in random order. Salivary cortisol levels were higher in relation to the baseline in the intra-oral device condition (P<0.05) but not in athletes without an intra-oral device. No differences between conditions were found in rating of perceived exertion (P=0.465) and blood lactate (P=0.711). No time or condition interactions or main effects were shown for heart rate variability. Thus, there is no evidence that wearing a low-arch intra-oral device is a good recommendation for high-standard athletes performing long and stressful routines.


Assuntos
Comportamento Competitivo/fisiologia , Protetores Bucais , Condicionamento Físico Humano/fisiologia , Natação/fisiologia , Desenho de Equipamento , Feminino , Frequência Cardíaca , Humanos , Hidrocortisona/metabolismo , Arcada Osseodentária , Ácido Láctico/sangue , Percepção/fisiologia , Condicionamento Físico Humano/métodos , Esforço Físico/fisiologia , Ventilação Pulmonar , Saliva/metabolismo , Adulto Jovem
18.
Am J Physiol Regul Integr Comp Physiol ; 319(2): R233-R242, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32579854

RESUMO

Continuous infusion of prostaglandin E1 (PGE1) is used to maintain ductus arteriosus patency in infants with critical congenital heart disease, but it can also cause central apnea suggesting an effect on respiratory neural control. In this study, we investigated whether 1) PGE1 inhibits the various phases of the acute hypoxic ventilatory response (HVR; an index of respiratory control dysfunction) and increases apnea incidence in neonatal rats; and 2) whether these changes would be reversible with caffeine pretreatment. Whole body plethysmography was used to assess the HVR and apnea incidence in neonatal rats 2 h following a single bolus intraperitoneal injection of PGE1 with and without prior caffeine treatment. Untreated rats exhibited a biphasic HVR characterized by an initial increase in minute ventilation followed by a ventilatory decline of the late phase (~5th minute) of the HVR. PGE1 had a dose-dependent effect on the HVR. Contrary to our hypothesis, the lowest dose (1 µg/kg) of PGE1 prevented the ventilatory decline of the late phase of the HVR. However, PGE1 tended to increase postsigh apnea incidence and the coefficient of variability (CV) of breathing frequency, suggesting increased respiratory instability. PGE1 also decreased brainstem microglia mRNA and increased neuronal nitric oxide synthase (nNOS) and platelet-derived growth factor-ß (PDGF-ß) gene expression. Caffeine pretreatment prevented these effects of PGE1, and the adenosine A2A receptor inhibitor MSX-3 had similar preventative effects. Prostaglandin appears to have deleterious effects on brainstem respiratory control regions, possibly involving a microglial-dependent mechanism. The compensatory effects of caffeine or MSX-3 treatment raises the question of whether prostaglandin may also operate on an adenosine-dependent pathway.


Assuntos
Alprostadil/farmacologia , Tronco Encefálico/efeitos dos fármacos , Cafeína/farmacologia , Ventilação Pulmonar/efeitos dos fármacos , Respiração/efeitos dos fármacos , Animais , Tronco Encefálico/metabolismo , Microglia/efeitos dos fármacos , Microglia/metabolismo , Óxido Nítrico Sintase Tipo I/metabolismo , Pletismografia Total , Proteínas Proto-Oncogênicas c-sis/genética , Proteínas Proto-Oncogênicas c-sis/metabolismo , Antagonistas de Receptores Purinérgicos P1/farmacologia , Ratos , Ratos Sprague-Dawley
19.
Phys Med Biol ; 65(16): 165010, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32575096

RESUMO

Recent changes to the guidelines for screening and early diagnosis of lung cancer have increased the interest in preserving post-radiotherapy lung function. Current investigational approaches are based on spatially mapping functional regions and generating regional avoidance plans that preferentially spare highly ventilated/perfused lung. A potentially critical, yet overlooked, aspect of functional avoidance is radiation injury to peripheral airways, which serve as gas conduits to and from functional lung regions. Dose redistribution based solely on regional function may cause irreparable damage to the 'supply chain'. To address this deficiency, we propose the functionally weighted airway sparing (FWAS) method. FWAS (i) maps the bronchial pathways to each functional sub-lobar lung volume; (ii) assigns a weighting factor to each airway based on the relative contribution of the sub-volume to overall lung function; and (iii) creates a treatment plan that aims to preserve these functional pathways. To evaluate it, we used four cases from a retrospective cohort of SAbR patients treated for lung cancer. Each patient's airways were auto-segmented from a diagnostic-quality breath-hold CT using a research virtual bronchoscopy software. A ventilation map was generated from the planning 4DCT to map regional lung function. For each terminal airway, as resolved by the segmentation software, the total ventilation within the sub-lobar volume supported by that airway was estimated and used as a function-based weighting factor. Upstream airways were weighted based on the cumulative volumetric ventilation supported by corresponding downstream airways. Using a previously developed model for airway radiosensitivity, dose constraints were determined for each airway corresponding to a <5% probability of airway collapse. Airway dose constraints, ventilation scores, and clinical dose constraints were input to a swarm optimization-based inverse planning engine to create a 3D conformal SAbR plan (CRT). The FWAS plans were compared to the patients' prescribed CRT clinical plans and the inverse-optimized clinical plans. Depending on the size and location of the tumour, the FWAS plan showed superior preservation of ventilation due to airflow preservation through open pathways (i.e. cumulative ventilation score from the sub-lobar volumes of open pathways). Improvements ranged between 3% and 23%, when comparing to the prescribed clinical plans, and between 3% and 35%, when comparing to the inverse-optimized clinical plans. The three plans satisfied clinical requirements for PTV coverage and OAR dose constraints. These initial results suggest that by sparing pathways to high-functioning lung subregions it is possible to reduce post-SAbR loss of respiratory function.


Assuntos
Neoplasias Pulmonares/radioterapia , Pulmão/fisiopatologia , Tratamentos com Preservação do Órgão/métodos , Órgãos em Risco/efeitos da radiação , Ventilação Pulmonar/fisiologia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Idoso , Algoritmos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Respiração , Estudos Retrospectivos
20.
Arq. bras. med. vet. zootec. (Online) ; 72(3): 843-852, May-June, 2020. tab
Artigo em Português | LILACS, VETINDEX | ID: biblio-1129488

RESUMO

Foi comparada a ventilação controlada à pressão com ou sem pressão positiva expiratória final (PEEP), em coelhos, distribuídos em três grupos, denominados GP (grupo ventilação ciclada à pressão), GPP (grupo ventilação ciclada à pressão com PEEP) e GE (grupo ventilação espontânea - grupo controle). Os animais foram anestesiados com isoflurano, em circuito com reinalação de gases, durante duas horas. As médias de pressão arterial média (PAM) e pressão arterial sistólica (PAS) permaneceram discretamente abaixo dos valores normais em todos os grupos. Houve diminuição significativa da PAM e da PAS no grupo submetido à PEEP (GPP) ao longo do tempo. A pressão parcial de dióxido de carbono arterial (PaCO2) foi maior no GPP quando comparado aos outros grupos no último momento, gerando acidemia respiratória após uma hora de procedimento. A concentração de dióxido de carbono ao final da expiração (ETCO2) apresentou médias discretamente elevadas no grupo não tratado com PEEP (GP) e no grupo controle, enquanto o GPP apresentou maiores médias, possivelmente, relacionadas à diminuição do volume corrente neste grupo. Com base nesses resultados, foi possível concluir que a utilização da PEEP levou à acidemia, que se agravou ao longo do tempo anestésico. Ademais, a anestesia prolongada com isoflurano promove depressão cardiorrespiratória, independentemente do modo ventilatório empregado.(AU)


Pressure controlled ventilation with or without positive end-expiratory pressure (PEEP) was compared in rabbits, which were divided into three groups denominated GP (pressure cycled ventilation group), GPP (pressure cycled ventilation with PEEP group) and GE (spontaneous ventilation group - control group). The animals were anesthetized with isoflurane in a gas rebreathing circuit for two hours. The means of mean arterial pressure (MAP) and systolic blood pressure (SBP) remained slightly below normal values ​​in all groups. There was a significant decrease in MAP and SBP in the group submitted to PEEP (GPP) over time. The partial pressure of arterial carbon dioxide (PaCO2) was higher in GPP when compared to the other groups, inducing respiratory acidosis after one hour. The end-expired carbon dioxide concentration (ETCO2) presented slightly elevated means in the GP, while the GPP presented higher means, possibly related to the decrease in tidal volume in this group. Based on these results it was concluded that the use of PEEP led to acidemia that worsened over anesthetic time. In addition, prolonged isoflurane anesthesia promotes cardiorespiratory depression, regardless the ventilatory mode employed.(AU)


Assuntos
Animais , Coelhos , Respiração com Pressão Positiva , Ventilação Pulmonar , Hemodinâmica , Isoflurano , Volume de Ventilação Pulmonar , Anestesia
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