Effect of intravenous infusion of lidocaine on pulmonary gas exchange function during acute lung injury in septic rats / 中华麻醉学杂志

Objective:To evaluate the effect of intravenous infusion of lidocaine on pulmonary gas exchange function during acute lung injury in septic rats.Methods:Thirty clean-grade healthy male Sprague-Dawley rats, aged 2-3 months, weighing 220-280 g, were divided into 3 groups ( n=10 each) using a random number table method: control group (C group), sepsis group (S group) and lidocaine group (L group). Model of acute lung injury in septic rats was prepared by intraperitoneal injection of LPS 10 mg/kg in S and L groups, the equal volume of normal saline was injected in group C, lidocaine was injected at a loading dose of 10 mg/kg via the tail vein at 1 min after LPS injection and then continuously infused for 3 h at a rate of 10 mg·kg -1·h -1, and the equal volume of normal saline was given instead in C and S groups. Rats were sacrificed at 24 h after LPS injection, blood samples from the abdominal aorta were collected for blood gas analysis, and the oxygenation index (OI), alveolar-arterial oxygen difference (A-aDO 2) and respiratory index (RI) were calculated. Then the chest was immediately opened, and the left lung tissues were then immediately removed to determine the levels of tumor necrosis factor-α (TNF-α), heme oxygenase-1 (HO-1) and reactive oxygen species (ROS) (by enzyme-linked immunosorbent assay). The right upper lung tissues were removed for microscopic examination of the alveolar structure and pulmonary edema with a light microscope. The right lower lung tissues were also removed to observe the vascular endothelial structure with a transmission electron microscope. Results:Compared with group C, the levels of A-aDO 2, RI, TNF-α, HO-1 and ROS were significantly increased, the PaO 2 and OI were decreased ( P<0.05), and no significant change was found in PaCO 2 in group S and group L ( P>0.05). Compared with group S, the PaO 2, OI and HO-1 were significantly increased, the levels of A-aDO 2, RI, TNF-α and ROS were decreased ( P<0.05), and no significant change was found in PaCO 2 levels in group L ( P>0.05). The pathological damages of the lung tissues were significantly attenuated in group L when compared with group S. Conclusions:Intravenous infusion of lidocaine can improve pulmonary gas exchange function during acute lung injury in septic rats.

Effect of lung protective ventilation on lung ventilation function, serum serum Clara cell protein 16 level and prognosis in patients undergoing gynecological laparoscopic surgery / 中国医师进修杂志

Objective:To analyze the effect of lung protective ventilation on lung ventilation function and serum Clara cell protein 16 (CC16) level in patients undergoing gynecological laparoscopic surgery.Methods:The clinical data of 80 gynecological patients who underwent laparoscopic surgery in Yancheng City Jianhu County People′s Hospital from October 2018 to December 2020 were randomly divided into group A and group B by random number table, each group with 40 cases. The patients in group A were treated with intermittent positive-pressure ventilation, and the patients in group B were ventilated with whole course ventilation mode. The pulmonary ventilation function, CC16 level and postoperative pulmonary complications were observed before anesthesia, 10 min of pneumoperitoneum, 30 min of pneumoperitoneum, 5 min of pneumoperitoneum stop and 2 h after operation. The patients were divided into groups according to whether with pulmonary complications, and their pulmonary ventilation function and serum CC16 level were compared. The predictive value of the above indexes for pulmonary complications was analyzed by receiver operating characteristic (ROC) curve.Results:Repeated measurement analysis of variance showed that alveolar arterial oxygen differential pressure (PA-aDO 2) were significant differences in time point factors, time point interaction factors and group factors ( P<0.05); CC16 index were significant differences in time point factor and group factor ( P<0.05). According to the observation from postoperative to discharge, 4 patients (10.0%) in group A had pulmonary complications, 15 cases (37.5%) had pulmonary complications in group B, the levels of PA-aDO 2 and CC16 in patients with complications were significantly higher than those in patients without complications: group A:(332.9 ± 2.0) mmHg (1 mmHg = 0.133 kPa) vs. (290.4 ± 13.2) mmHg, (53.5 ± 1.5) μg/L vs. (39.5 ± 6.5) μg/L; group B: (339.1 ± 8.8) mmHg vs. (305.7 ± 17.9) mmHg, (41.5 ± 4.2) μg/L vs. (39.7 ± 5.8) μg/L, there were statistical differences ( P<0.05). ROC curve analysis showed that the area under the curve(AUC) of PA-aDO 2 and CC16 in predicting pulmonary complications in group A were 0.882 and 0.833, in group B was 0.885 and 0.731. Conclusions:Lung protective ventilation has little effect on lung ventilation function and serum CC16 in patients with gynecological laparoscopic surgery, and the probability of pulmonary complications is lower. The pulmonary ventilation function and CC16 have certain value in predicting postoperative pulmonary complications.

Central venous oxygen saturation/lactate ratio and prediction of major adverse events after pediatric heart surgery

Abstract Introduction: Major adverse events (MAE) are unexpected but undesirably frequent after pediatric congenital heart surgery and contribute to poorer outcomes. The aim of this study was to test the predictive value of a ratio between central venous oxygen saturation and arterial lactate (ScvO2/lactate) for MAE after pediatric congenital heart surgery in a Brazilian university hospital. Methods: We conducted a retrospective observational study in a tertiary care university hospital, including 194 infants and children submitted to surgery for congenital heart disease. The predictive value of ScvO2, lactate, and ScvO2/lactate ratio were assessed by the area under the receiver operating characteristics curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results: The incidence of MAE was 16% — cardiac arrest/death, unplanned reoperation, and low cardiac output syndrome were the most common events. Overall, ScvO2/lactate ratio discriminated patients with and without MAE very well (AUC 0.842), performing better than either variable alone, with sensitivity of 48%, specificity of 94%, PPV of 60%, and NPV of 91%. Conclusion: A ScvO2/lactate ratio > 5 can accurately identify patients at low risk of MAE after pediatric congenital heart surgery, with very good specificity and NPV, but poor sensitivity and PPV.

Impacto de alvos de saturação liberais versus conservadores sobre os índices de troca gasosa na síndrome do desconforto respiratório agudo relacionada à COVID-19: um estudo fisiológico / Impact of liberal versus conservative saturation targets on gas exchange indices in COVID-19 related acute respiratory distress syndrome: a physiological study

RESUMO Objetivo: Comparar o comportamento dos índices de troca gasosa conforme o uso de alvos de oxigenação liberais em comparação a conservadores em pacientes com síndrome do desconforto respiratório agudo moderada a grave secundária à COVID-19 e em uso de ventilação mecânica; avaliar a influência da FiO2 elevada na mecânica do sistema respiratório. Métodos: Foram incluídos prospectivamente pacientes consecutivos com idades acima de 18 anos, diagnóstico de COVID-19 e síndrome do desconforto respiratório agudo moderada e grave. Para cada paciente, aplicou-se aleatoriamente dois protocolos de FiO2 para obter SpO2 de 88% a 92% ou 96%. Avaliaram-se os índices de oxigenação e a mecânica do sistema respiratório. Resultados: Foram incluídos 15 pacientes. Todos seus índices foram significantemente afetados pela estratégia de FiO2 (p < 0,05). A proporção PaO2/FiO2 deteriorou, o PA-aO2 aumentou e o Pa/AO2 diminuiu significantemente com a utilização de FiO2 para obter SpO2 96%. Opostamente, a fração de shunt funcional foi reduzida. A mecânica respiratória não foi afetada pela estratégia de FiO2. Conclusão: Uma estratégia com alvos liberais de oxigenação deteriorou significantemente os índices de troca gasosa, com exceção do shunt funcional, em pacientes com síndrome do desconforto respiratório agudo relacionada à COVID-19. A mecânica do sistema respiratório não foi alterada pela estratégia de FiO2. Registro Clinical Trials: NCT04486729.

ABSTRACT Objective: To compare gas exchange indices behavior by using liberal versus conservative oxygenation targets in patients with moderate to severe acute respiratory distress syndrome secondary to COVID-19 under invasive mechanical ventilation. We also assessed the influence of high FiO2 on respiratory system mechanics. Methods: We prospectively included consecutive patients aged over 18 years old with a diagnosis of COVID-19 and moderate-severe acute respiratory distress syndrome. For each patient, we randomly applied two FiO2 protocols to achieve SpO2 88% - 92% or 96%. We assessed oxygenation indices and respiratory system mechanics. Results: We enrolled 15 patients. All the oxygenation indices were significantly affected by the FiO2 strategy (p < 0.05) selected. The PaO2/FiO2 deteriorated, PA-aO2 increased and Pa/AO2 decreased significantly when using FiO2 to achieve SpO2 96%. Conversely, the functional shunt fraction was reduced. Respiratory mechanics were not affected by the FiO2 strategy. Conclusion: A strategy aimed at liberal oxygenation targets significantly deteriorated gas exchange indices, except for functional shunt, in COVID-19-related acute respiratory distress syndrome. The respiratory system mechanics were not altered by the FiO2 strategy. Clinical Trials Register: NCT04486729.

Exercise Training Improved Pulmonary Gas Exchange Abnormalities in Pulmonary Hypertension due to Heart Failure: A Case Report

Abstract Heart failure (HF) is the most common cause of pulmonary hypertension (PH), and reduced exercise capacity and exertional dyspnea are the most frequent concerns in patients with PH-HF. Indeed, carbon dioxide end-tidal partial pressure (PETCO 2 ) during exercise is a well-established noninvasive marker of ventilation/perfusion ratio in PH. We aimed to evaluate the effect of aerobic exercise training on PETCO 2 response during exercise in a 59-year-old woman with PH secondary to idiopathic dilated cardiomyopathy. The patient with chronic fatigue and dyspnea at mild-to-moderate efforts was admitted to a cardiorespiratory rehabilitation program and had her cardiorespiratory response to exercise assessed during a cardiopulmonary exercise testing performed before and after three months of a thrice-weekly aerobic exercise training program. Improvements in aerobic capacity (23.9%) and endurance time (37.5%) and reduction in ventilatory inefficiency (-20.2%) was found after intervention. Post-intervention improvements in PETCO 2 at ventilatory anaerobic threshold (23.3%) and change in PETCO 2 kinetics pattern, with progressive increases from rest to peak of exercise, were also found. Patient also improved breathing pattern and timing of ventilation. This case report demonstrated for the first time that aerobic exercise training might be able to improve PETCO 2 response during exercise in a patient with PH-HF.

Efecto del uso del recuperador celular en el intercambio gaseoso en pacientes sometidos a cirugía cardíaca / Effect of the use of operative blood salvage on the pulmonary gas exchange in patients undergoing cardiac surgery

Resumen: Introducción: Se ha sugerido que el recuperador celular reduce el contenido de citocinas proinflamatorias después de la cirugía cardíaca mejorando su equilibrio en la circulación sistémica, lo que puede minimizar la respuesta inflamatoria que contribuye a la disfunción pulmonar postoperatoria. Objetivo: Comparar el intercambio gaseoso postoperatorio de pacientes sometidos a cirugía cardíaca con y sin el uso de recuperador celular. Material y métodos: Se realizó un estudio de cohortes prospectivo que incluyó 253 pacientes sometidos a cirugía cardíaca bajo circulación extracorpórea. Los pacientes se asignaron a cada uno de los grupos de estudio dependiendo de si usaron o no recuperador celular: grupo I (sin recuperador) y grupo II (con recuperador), estimándose la PaO2/FiO2 y la morbilidad respiratoria postoperatoria. Para el análisis se utilizó estadística descriptiva e inferencial mediante t de Student o U de Mann-Whitney. Una p < 0.05 fue significativa. Los datos se procesaron con SPSS v. 24.0. Resultados: 59.29% usaron recuperador celular. La PaO2/FiO2 fue menor en el grupo II (p = 0.018). No hubo diferencias entre ambos grupos en la morbilidad respiratoria a los 30 días de postoperados (p = 0.943). Conclusión: El intercambio gaseoso postoperatorio de pacientes sometidos a cirugía cardíaca es menor con el uso de recuperador celular que sin él.

Abstract: Introduction: It has been suggested that the use of a cell saver reduces the content of proinflammatory cytokines after cardiac surgery, improving the balance of these cytokines in the systemic circulation, which in turn could minimize the inflammatory response that contributes to postoperative pulmonary dysfunction. Objective: To compare the postoperative gas exchange in patients undergoing cardiac surgery with the use of cell saver and without it. Material and methods: A prospective cohort study that included 253 patients undergoing cardiac surgery under cardiopulmonary bypass. The patients were assigned to two study groups depending on whether a cell saver was used: group I (without cell saver) and group II (with cell saver). The PaO2/FiO2 ratio and the postoperative respiratory morbidity were then estimated. The analysis was done using descriptive and inferential statistics by means of the Student t test and Mann-Whitney U test. A p < 0.05 was considered significant. The data were processed using SPSS v. 24.0. Results: 59.29% of patients underwent surgery with the use of a cell saver. The PaO2/FiO2 ratio was lower in group II (p = 0.018). There were no differences between groups in respiratory morbidity 30 days after surgery (p = 0.943). Conclusion: The postoperative gas exchange is lower in patients undergoing cardiac surgery with the use of a cell saver than without it.

Content analysis of clinical indicators for Impaired gas exchange / Análisis de contenido de indicadores clínicos para Deterioro del intercambio gaseoso / Análise de conteúdo dos indicadores clínicos para Troca de gases prejudicada

ABSTRACT Objective To analyze the relevance of clinical indicators and the clarity and precision of conceptual and operational definitions of the diagnosis Impaired gas exchange. Methods Content analysis, by 39 nurse judges, divided into the phases of conceptual definition of the phenomenon of interest, construction of the structure of the phenomenon of interest and analysis of the judges on the built structure. Results From the 22 indicators, 21 were considered relevant Impaired gas exchange. The indicators that obtained absolute relevance were Cyanosis, Hypercapnia, Hypoxemia and Tachycardia. The indicator Headache upon waking did not show any statistically significant relevance for the diagnosis. All conceptual and operational definitions were clear and precise. Conclusion The indicators listed for Impaired gas exchange were relevant to the phenomenon, except Headache upon waking because it does not correspond to a safe manifestation to identify the diagnosis, according to the analysis of the judges. Each conceptual and operational definition was adequate for its indicator.

RESUMEN Objetivo Analizar la relevancia de los indicadores clínicos y la claridad y precisión de las definiciones conceptuales y operativas del diagnóstico Deterioro del intercambio gaseoso. Métodos Análisis de contenido, realizado por 39 jueces enfermeros, dividido en las fases de definición conceptual del fenómeno de interés, construcción de la estructura del fenómeno de interés y análisis de los jueces sobre la estructura construida. Resultados De los 22 indicadores, 21 fueron considerados relevantes Deterioro del intercambio gaseoso. Los indicadores que obtuvieron relevancia absoluta fueron Cianosis, Hipercapnia, Hipoxemia y Taquicardia. El indicador Cefalea al despertar no mostró relevancia estadísticamente significativa para el diagnóstico. Todas las definiciones conceptuales y operativas fueron claras y precisas. Conclusión Los indicadores enumerados para Deterioro del intercambio gaseoso fueron relevantes para el fenómeno, excepto Cefalea al despertar porque no corresponde a una manifestación segura para identificar el diagnóstico, según el análisis de los jueces. Cada definición conceptual y operativa fue adecuada para su indicador.

RESUMO Objetivo Analisar a relevância dos indicadores clínicos e a clareza e precisão das definições conceituais e operacionais do diagnóstico Troca de gases prejudicada. Métodos Análise de conteúdo, por 39 juízes enfermeiros, dividida nas fases de definição conceitual do fenômeno de interesse, construção da estrutura do fenômeno de interesse e análise dos juízes sobre a estrutura construída. Resultados Dos 22 indicadores, 21 foram considerados relevantes Troca de gases prejudicada. Os indicadores que obtiveram relevância absoluta foram Cianose, Hipercapnia, Hipoxemia e Taquicardia. O indicador Cefaleia ao acordar não apresentou relevância estatisticamente significante para o diagnóstico. Todas as definições conceituais e operacionais foram claras e precisas. Conclusão Os indicadores elencados para Troca de gases prejudicada foram relevantes ao fenômeno, exceto Cefaleia ao acordar pois não corresponde a uma manifestação segura para identificar o diagnóstico, conforme a análise dos juízes. Cada definição conceitual e operacional foi adequada para seu referido indicador.

Capacidad de difusión de monóxido de carbono, pautas para su interpretación / Diffusing capacity for carbon monoxide, guidelines for interpretation

Resumen La capacidad de difusión de monóxido de carbono (DLCO) es, después de la espirometría, la prueba de función pulmonar rutinaria y no invasiva de mayor utilidad clínica. No obstante, hay sustanciales errores de interpretación del significado fisiológico de la DLCO, de sus medidas derivadas y por consiguiente del significado clínico de sus alteraciones. Además de la utilización de diferentes nomenclaturas, otras fuentes de confusión han contribuido a cierta visión negativa de la prueba. Los aspectos técnicos de la prueba de DLCO tienen la ventaja de estar estandarizados. Pero a diferencia de lo que ocurre con otras pruebas de función pulmonar donde disponemos de valores de referencia que permiten determinar la "normalidad o anormalidad" de las mismas, es difícil aplicar esta vía de análisis en el caso de la DLCO. El hecho central en el análisis de la DLCO, el factor de transferencia para el CO (KCO), y el volumen alveolar (VA) es que para una correcta interpretación es necesario tener en cuenta el mecanismo por el cual la patología induce el cambio. Un KCO del 100% puede ser considerado normal en unas circunstancias o patológico bajo otras y, por el momento, el informe automatizado del estudio no puede discriminar. Este artículo describirá los principios de la prueba de DLCO, presentará diferentes modelos de análisis, expondrá ejemplos concretos y ofrecerá pautas para su correcta interpretación. Se considera indispensable efectuar un análisis integrado de la prueba de DLCO en relación con otras pruebas funcionales y con los datos clínicos.

Abstract The diffusing capacity for carbon monoxide (DLCO) is, after spirometry the standard and noninvasive pulmonary function test of greater clinical use. However, there are substantial errors in the interpretation of the physiological significance of the DLCO, its derived measures and, therefore the clinical significance of its alterations. In addition to the use of different nomenclatures, other sources of confusion have contributed to some negative view of the test. The technical aspects of the DLCO test have the advantage of being well standardized. But unlike what happens with other pulmonary function tests where we have reference values which allow us to determine their "normality or abnormality", it is difficult to apply this route of analysis in the case of DLCO. The central fact in the analysis of DLCO, transference factor for CO (KCO), and alveolar volume (VA) is that for a correct interpretation it is necessary to think about the mechanism by which the pathology induces change. A KCO of 100% can be considered normal in some circumstances or pathological in others and, for the moment, the automated study report cannot discriminate. This article will address the principles of the DLCO test; present different models of analysis submit concrete examples and provide guidelines for their correct interpretation. It is considered essential to carry out an integrated analysis of the DLCO test in relation to other functional tests and clinical data.

Larger Tidal Volumes On Carbon Dioxide Elimination And Oxygen Saturations In Normal Or Overweight Patients

Obesity poses particular challenges to adequate mechanical ventilation in addition to surgical constraints, primarily by restricted lung mechanics due to excessive adiposity, frequent respiratory comorbidities (i.e. sleep apnea, asthma), and concerns of postoperative respiratory depression and other pulmonary complications. Patients with known pulmonary or cardiovascular disease were excluded. The investigations included ASAphysical status 1 or 2 patients, scheduled for abdominal surgery. Patients were considered for inclusion in the trial if they were over 18 yr age. Ventilation with larger tidal volumes with isocapnia maintained with added apparatus dead space increases the tension of oxygen and sevoflurane in arterial blood in overweight patients. Further studies are needed to better define optimum protective ventilation strategies and analyze their impact on the perioperative outcomes of surgical patients with obesity.

Ventilação mecânica variável / Variable mechanical ventilation

RESUMO Objetivo: Revisar a literatura em relação à utilização da ventilação variável e aos principais desfechos relacionados à sua utilização. Métodos: Busca, seleção e análise de todos os artigos originais sobre ventilação variável, sem restrição quanto ao período de publicação e ao idioma, nas bases de dados eletrônicas LILACS, MEDLINE® e PubMed, encontrados por meio de busca pelos termos "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". Resultados: Foram selecionados 36 artigos na busca. Após a análise, 24 artigos eram originais; destes 21 experimentais e 3 clínicos. Conclusão: Diversos estudos experimentais evidenciaram os efeitos benéficos de variadas estratégias ventilatórias variáveis sobre a função pulmonar em diferentes modelos de lesão pulmonar e em pulmões saudáveis. A ventilação variável parece ser uma estratégia viável para o aprimoramento da troca gasosa e mecânica respiratória, assim como para prevenção de lesão pulmonar associada à ventilação mecânica. Entretanto, estudos clínicos são necessários para investigar o potencial destas estratégias ventilatórias variáveis na melhora clínica dos pacientes submetidos à ventilação mecânica.

ABSTRACT Objective: To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Methods: Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". Results: A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Conclusion: Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation.

Effects of flurbiprofen axetil administered at different time points on oxygenation in patients undergoing one-lung ventilation / 中华麻醉学杂志

Objective To evaluate the effects of flurbiprofen axetil administered at different time points on oxygenation in the patients undergoing one-lung ventilation (OLV).Methods Ninety patients of both sexes,aged 45-64 yr,of American Society of Anesthesiologists physical status Ⅰ or Ⅱ,undergoing elective thoracoscope-assisted pulmonary lobectomy,were assigned into 3 groups (n =30 each) using a random number table:control group (group C),preoperative administration group (group F1) and intraoperative administration group (group F2).Flurbiprofen axetil (10 mg/ml) and fat emulsion 10 ml were injected intravenously at 15 min before operation in F1 and C groups,respectively.Flurbiprofen axetil 10 ml was intravenously injected immediately after the beginning of OLV in group F2.At 15 min before operation (T1),15 and 30 min of OLV (T2,3),and 15 min after restoration of two-lung ventilation (T4),airway peak pressure (Ppeak) and dynamic lung compliance (Cdyn) were recorded,arterial blood samples were collected for blood gas analysis.The arterial oxygen partial pressure (PaO2) was recorded,and the oxygenation index (OI) and intrapulmonary shunt (Qs/Qt) were calculated.The concentrations of thromboxane B2 (TXB2) and 6-keto-prostaglandin F1α (6-K-PGF1α) in serum were measured by enzyme-linked immunosorbent assay,and TXB2/6-K-PGF1α ratio was calculated.The development of interrupting OLV due to SpO2＜90％ and postoperative dyspnea,pulmonary infection,atelectasis and length of hospital stay were recorded.Results Compared with group C,PaO2 and OI were significantly increased,and Qs/Qt was decreased at T2,3,the serum concentrations of TXB2 and 6-K-PGF1α were decreased,and TXB2/6-K-PGF1α ratio was increased at T2-4,the incidence of interrupting OLV was decreased (P＜0.05),and no significant change was found in the parameters mentioned above in group F2 (P＞0.05).Compared with group F1,PaO2 and OI were significantly decreased at T2,3,Qs/Qt was increased at T2,and the serum concentrations of TXB2 and 6-K-PGF1α were increased,and TXB2/6-K-PGF1α ratio was decreased at T2-4 in group F2 (P＜0.05).There was no significant difference in the incidence of postoperative dyspnea,pulmonary infection and atelectasis and length of hospital stay between the three groups (P＞0.05).Conclusion Flurbiprofen axetil injected at 15 min before operation can significantly improve oxygenation and prevent the development of hyoxemia in the patients undergoing OLV,however,flurbiprofen axetil administered immediately after the beginning of OLV has no such effect.

Effect of two administration routes of Shenmai Injection () on pulmonary gas exchange function after tourniquet-induced ischemia-reperfusion / 中国结合医学杂志

<p><b>OBJECTIVE</b>To compare the effect between nebulized and intravenous administration of Shenmai Injection () on pulmonary gas exchange function of patients following tourniquet-induced lower limb ischemia-reperfusion.</p><p><b>METHODS</b>Thirty-eight patients scheduled for lower extremity surgery were randomized into three groups using the closed envelop method: Shenmai Injection was administered 30 min before tourniquet inflflation by nebulization [0.6 mL/kg in 10 mL normal saline (NS)] in the nebulization group or by intravenous drip (0.6 mL/kg dissolved in 250 mL of 10% glucose) in the intravenous drip group, and equal volume of NS was given intravenously in the NS group; 15 in each group. Arterial blood gases were analyzed, serum levels of malonaldehyde (MDA) and interleukine-6 (IL-6) and interleukine-8 (IL-8) were determined using the method of thiobarbituric acid reaction and enzyme-linked immuno sorbent assay respectively just before tourniquet inflflation (T0), and at 0.5 h (T1), 2 h (T2), 6 h (T3) after tourniquet deflflation.</p><p><b>RESULTS</b>Compared with baselines at T0, MDA levels signifificantly increased at T2, T3 in the NS group and at T3 in the nebulization group, and IL-6 and IL-8 levels were signifificantly increased at T2, T3 in NS, the intravenous drip and the nebulization groups (P <0.05). Arterial pressure of oxygen (PaO) at T3 was decreased, while alveolararterial oxygen tension showed difference (PA-aDO) at T3 in the NS group; RI at T3 in both intravenous drip and the nebulization groups were enhanced (P <0.05). Compared with the NS group, MDA and IL-8 levels at T2, T3, IL-6 at T3 in the intravenous drip group, and IL-8 at T3 in the nebulization group were all remarkably increased (P <0.05). Additionally, MDA level at T3 in the nebulization group was higher than that in the intravenous drip group (P <0.05).</p><p><b>CONCLUSIONS</b>Intravenous administration of Shenmai Injection provided a better protective effect than nebulization in mitigating pulmonary gas exchange dysfunction in patients following tourniquet-induced limb ischemia-reperfusion.</p>

Evaluation of the Efficiency of the Atraumatic Endotracheal Tube in the Pulmonary-Gas Exchange: an Experimental Study

ABSTRACT OBJECTIVE: Mechanical ventilation is frequently necessary, in which case the use of an endotracheal tube is mandatory. The tube has an inflatable balloon in its distal extremity, whose aim is, among other functions, an efficient arterialization. However, serious injuries in the place of contact of the balloon with the trachea can be frequent. Some studies point out that balloons with permanent pressure may reduce this complication. Nevertheless, air scape, expressed by the inspiratory (IV) and expiratory volume (EV) variation (Δ IV-EV), may occur, possibly leading to hypoxemia. Thus, the goal of this study was to verify the efficiency of a modified endotracheal tube on arterializations compared to the traditional endotracheal tube. METHODS: The modified endotracheal tube presents intermittent insufflation, with three drillings in the internal region of the cuff, allowing for insufflation in the inspiratory phase of the mechanical ventilation. Three animals were used for the control group, with a cuff pressure of 30 cmH2O, and seven pigs had the modified endotracheal tube. Each animal was kept under mechanical ventilation (FIO2=0.21) for 6 hours. Arterial and venous gases were measured every three hours (T0; T3; T6). RESULTS: The gases confirmed the lack of hypoxia between the Groups, with a difference in the ΔIV-EV at T0 (P=0.0486). CONCLUSIONS: In this study, the lack of hypoxia showed the efficiency of the modified endotracheal tube. However, new studies are necessary, particularly in diseased lungs, in order to evaluate the real efficiency of the mentioned device on the pulmonary gas exchange.

Effects of dexmedetomidine preconditioning on imbalance of nitric oxide/endothelin-1 and remote lung injury in patients with lower limb ischemia-reperfusion / 天津医药

Objective To investigate the effects of dexmedetomidine preconditioning on nitric oxide (NO)/endothelin (ET)-1 imbalance and remote lung injury induced by lower limb ischemia-reperfusion (LIR). Methods Sixty patients who scheduled for unilateral lower extremity surgery matched American Society of Anesthesiologists (ASA) Ⅰ-Ⅱ, were randomized into two groups:control group (R group, n=30) and dexmedetomidine preconditioning group (PD group, n=30). Lumbar plexus combined with sciatic nerve block was performed guided by a nerve stimulator in both groups. In group PD, dexmedetomidine intravenous infusion was started at a dose of 0.125 mL/kg (4 mg/L) for 10 minutes before using tourniquet, whereas group R received an equivalent volume of normal saline. Artery blood gas analysis, respiratory index and oxygenation index were measured, and NO, ET-1, interleukin-8 (IL-8) and malondialdehyde (MDA) concentrations were determined from plasma samples 10 minutes before tourniquet inflation (T0), 15 minutes (T1), 2 h (T2), 6 h (T3) and 24 h (T4) after tourniquet deflation. Results Compared with T0, RI was higher at T3 in group R and OI was lower at T2-4 (P＜0.01). There were no significant differences in RI and OI of group PD between different time points (P＞0.05). In R and PD groups, ET-1, IL-8 and MDA concentrations were increased, while NO level and NO/ET-1 ratio were significantly decreased after tourniquet deflation (P＜0.05). Compared with group R, RI was lower and OI was higher at T3 in group PD (P＜0.01). The levels of ET-1, IL-8, MDA, NO and NO/ET-1 ratio were significantly different after tourniquet deflation between group PD and group R (P＜0.05). In group R, there was positive correlation between ET-1 and IL-8 levels with RI, and negative correlation between ET-1 and IL-8 levels with OI (P＜0.01). There was positive correlation between NO level, NO/ET-1 ratio and RI level (P＜0.01). Conclusion Lung function impairment induced by tourniquet application could be attenuated by dexmedetomidine preconditioning based on protecting endothelial cells and inhibiting lipid peroxidation.

Análise comparativa entre a manobra de recrutamento alveolar e a técnica de breath stacking em pacientes com lesão pulmonar aguda / Comparative analysis between the alveolar recruitment maneuver and breath stacking technique in patients with acute lung injury

Objetivo: Comparar a eficácia da manobra de recrutamento alveolar e a técnica de breath stacking, na mecânica pulmonar e na troca gasosa, em pacientes com lesão pulmonar aguda. Métodos: Trinta pacientes foram distribuídos em dois grupos: Grupo 1 - breath stacking e Grupo 2 - manobra de recrutamento alveolar. Após receberem atendimento de fisioterapia convencional, todos os pacientes receberam ambos os tratamentos, com intervalo de 1 dia entre eles. No primeiro grupo foi aplicada primeiramente a técnica de breath stacking e, posteriormente, a manobra de recrutamento alveolar. Já os pacientes do segundo Grupo 2 foram submetidos inicialmente ao recrutamento alveolar e, após, a técnica de breath stacking. Foram avaliadas as medidas de complacência pulmonar e de resistência de vias aéreas antes e após a aplicação de ambas as técnicas. Foram coletadas gasometrias arteriais pré e pós-técnicas para avaliar a oxigenação e a troca gasosa. Resultados: Ambos os grupos apresentaram aumento significativo da complacência estática após breath stacking (p=0,021) e recrutamento alveolar (p=0,03), mas não houve diferença entre eles (p=0,95). A complacência dinâmica não aumentou para os grupos breath stacking (p=0,22) e recrutamento alveolar (p=0,074), sem diferença entre os grupos (p=0,11). A resistência de vias aéreas não diminuiu para ambos os grupos: breath stacking (p=0,91) e recrutamento alveolar (0,82), sem diferença entre os grupos p=0,39. A pressão parcial de oxigênio aumentou significantemente após breath stacking (p=0,013) e recrutamento alveolar (p=0,04); mas entre os grupos não houve diferença (p=0,073). A diferença alvéolo arterial de O2 diminuiu para ambos os grupos após intervenções breath stacking (p=0,025) ...

Objective: To compare the effectiveness of the alveolar recruitment maneuver and the breath stacking technique with respect to lung mechanics and gas exchange in patients with acute lung injury. Methods: Thirty patients were distributed into two groups: Group 1 - breath stacking; and Group 2 - alveolar recruitment maneuver. After undergoing conventional physical therapy, all patients received both treatments with an interval of 1 day between them. In the first group, the breath stacking technique was used initially, and subsequently, the alveolar recruitment maneuver was applied. Group 2 patients were initially subjected to alveolar recruitment, followed by the breath stacking technique. Measurements of lung compliance and airway resistance were evaluated before and after the use of both techniques. Gas analyses were collected before and after the techniques were used to evaluate oxygenation and gas exchange. Results: Both groups had a significant increase in static compliance after breath stacking (p=0.021) and alveolar recruitment (p=0.03), but with no significant differences between the groups (p=0.95). The dynamic compliance did not increase for the breath stacking (p=0.22) and alveolar recruitment (p=0.074) groups, with no significant difference between the groups (p=0.11). The airway resistance did not decrease for either groups, i.e., breath stacking (p=0.91) and alveolar recruitment (p=0.82), with no significant difference between the groups (p=0.39). The partial pressure of oxygen increased significantly after breath stacking (p=0.013) and alveolar recruitment (p=0.04), but there was no significant difference between the groups (p=0.073). The alveolar-arterial O2 difference decreased for both groups after the breath stacking (p=0.025) and alveolar recruitment (p=0.03) interventions, and there was no significant difference between the groups (p=0.81). Conclusion: Our data suggest that the breath stacking and alveolar ...

Adequação dos parâmetros de oxigenação em idosos submetidos à ventilação mecânica / Adequacy of oxygenation parameters in elderly patients undergoing mechanical ventilation

OBJETIVO: Comparar a PaO2 ideal com a encontrada, a PaO2 ideal/FiO2 ambiente com a encontrada e a FiO2 ideal e encontrada em idosos ventilados mecanicamente. MÉTODOS: Estudo transversal, no qual foram avaliados os idosos ventilados mecanicamente por no mínimo 72 horas e que tiveram três gasometrias seguidas. RESULTADOS: Compuseram a amostra 48 idosos, com média de idade de 74,77±9,36 anos. Houve diferença significativa entre a PaO2 ideal e a encontrada (p<0,001), da FiO2 ofertada e a corrigida (p<0,001), e entre a PaO2 ideal/FiO2 ambiente e a PaO2/FiO2 encontrada (p<0,001). CONCLUSÃO: Observou-se aumento significativo da PaO2 e da FiO2, assim como alterações de troca gasosa pelo índice PaO2/FiO2, quando comparados com parâmetros de normalidade.

OBJECTIVE: To compare ideal PaO2 with PaO2 found, ideal PaO2/FiO2 of room air with the one found, and ideal FiO2 with FiO2 found in mechanically ventilated elderly patients. METHODS: Cross-sectional study that evaluated elderly mechanically ventilated patients for at least 72 hours and who underwent three subsequent blood gas analyses. RESULTS: The sample consisted of 48 elderly with mean age of 74.77±9.36 years. There was a significant difference between the ideal PaO2 and the one found (p<0.001), between FiO2 corrected and the offered one, and also between ideal PaO2/FiO2 of room air and the PaO2/FiO2 found (p<0,001). CONCLUSION: A significant increase was seen in PaO2 and FiO2 and in alterations of gas exchange by PaO2/FiO2 index than those found in normal parameters.

Valores de referência para o teste de caminhada com carga progressiva em indivíduos saudáveis: da distância percorrida às respostas fisiológicas / Reference values for the incremental shuttle walk test in healthy subjects: from the walk distance to physiological responses

OBJETIVO: Determinar valores de referência para a distância caminhada (DC) e para respostas fisiológicas durante o teste de caminhada com carga progressiva (TCCP) e desenvolver equações preditivas para essas variáveis em adultos saudáveis. MÉTODOS: Foram avaliados 103 participantes saudáveis com idade > 40 anos (54 mulheres e 49 homens). Os participantes usaram um sistema de análise de gases durante o TCCP. Consumo de oxigênio (VO2), liberação de gás carbônico, ventilação minuto, FC, DC e velocidade máxima da caminhada (VMC) foram obtidos como desfechos primários. Avaliamos também a força de preensão manual (FPM) e a massa magra corporal (MMC). RESULTADOS: Os modelos de regressão utilizando variáveis fisiológicas, DC e VMC ajustados por idade, massa corporal, estatura e sexo apresentaram valores de R² entre 0,40 e 0,65 (para FC e pico de VO2, respectivamente). Os modelos incluindo MMC e FPM não aumentaram consideravelmente os valores de R² na previsão do pico de VO2, embora esses modelos tenham aumentado discretamente os valores do R² para DC e VMC (8% e 12%, respectivamente). As variáveis DC, VMC e DC × massa corporal, respectivamente, explicaram 76,7%, 73,3% e 81,2% da variabilidade do pico de VO2. CONCLUSÕES: Nossos resultados originaram valores de referência para a DC e respostas fisiológicas ao TCCP, que podem ser estimados adequadamente por características demográficas e antropométricas simples em adultos saudáveis com idade > 40 anos. O TCCP poderia ser utilizado na avaliação da capacidade física na população geral de adultos e no desenvolvimento de programas de caminhada individualizados.

OBJECTIVE: To determine reference values for incremental shuttle walk distance (ISWD) and peak physiological responses during the incremental shuttle walk test (ISWT), as well as to develop a series of predictive equations for those variables in healthy adults. METHODS: We evaluated 103 healthy participants > 40 years of age (54 women and 49 men). We fitted each participant with a gas analysis system for use during the ISWT. Oxygen consumption (VO2), carbon dioxide production, minute ventilation, heart rate (HR), ISWD, and maximal walking velocity (MWV) were obtained as primary outcomes. We also assessed hand grip strength (HGS) and lean body mass (LBM). RESULTS: The regression analysis models, including physiological variables, ISWD, and MWV (adjusted for age, body mass, height, and sex), produced R² values ranging from 0.40 to 0.65 (for HR and peak VO2, respectively). Using the models including LBM or HGS, we obtained no significant increase in the R² values for predicting peak VO2, although the use of those models did result in slight increases in the R² values for ISWD and MWV (of 8% and 12%, respectively). The variables ISWD, MWV, and ISWD × body mass, respectively, explained 76.7%, 73.3%, and 81.2% of peak VO2 variability. CONCLUSIONS: Our results provide reference values for ISWD and physiological responses to the ISWT, which can be properly estimated by determining simple demographic and anthropometric characteristics in healthy adults > 40 years of age. The ISWT could be used in assessing physical fitness in the general adult population and in designing individualized walking programs.

Effects of positive end-expiratory pressure after recruitment maneuvers on respiratory mechanics and gas exchange during laparoscopy in obese patients / 中华麻醉学杂志

Objective To investigate the effects of positive end-expiratory pressure (PEEP) after recruitment maneuvers (RM) on respiratory mechanics and gas exchange during laparoscopy in obese patients.Methods Sixty-three ASA physical status Ⅱ or Ⅲ patients,aged 42-64 yr,with body mass index 30-40kg/m2,were randomly allocated into 3 groups (n=21 each):PEEP0 group,PEEP5 group and PEEP10 group.PEEP was not given after RM in PEEP0 group.In PEEP5 and PEEP10 groups,a recruiting maneuver was followed by PEEP 5 and 10 cm H2 O,respectively,until the end of pneumoperitoneum.The intraabdominal pressure was set at 12mmHg in the three groups.Parameters of respiratory mechanics including peak airway pressure (Ppeak),airway plateau pressure (Peat),chest wall plateau pressure (PplatCW),airway resistance (Raw),elastance of respiratory system (ERS),elastanc of chest wall (ECW) and elastance of lung (EL) and parameters of gas exchange including oxygenation index (PaO2/FiO2),arterial to end-tidal difference in carbon dioxide (Da-ETCO2),alveolar-arterial oxygen tension difference (DA-aO2),and dead space/tidal volume ratio (VD/VT) were measured before pneumoperitoneum (T0),at 20 min of pneumoperitoneum (T1),at 10 min after the end of recruitment (T2),and at the end of pneumoperitoneum (T3).Results Da-ETCO2,ERS and Raw were decreased at T2,ECW and EL were decreased at T3 in PEEP5 group,and Da-ETCO2,VD/VT,DA-aO2,Pplatcw Raw and EL were decreased at T2.3,and PaO2/FiO2 was increased at T2,ECW was decreased at T3 in group PEEP10 as compared with that in group PEEP0 (P ＜ 0.05).Da-ETCO2 and VD/VT were decreased and PaO2/FiO2 was increased at T2,3,Raw was increased and EL was decreased at T2 in group PEEP10 as compared with that in group PEEP5 (P ＜ 0.01).Conclusion PEEP after RM can improve respiratory mechanics and gas exchange during laparoscopy in obese patients and PEEP maintained at 10 cm H2O after RM provides better efficacy than PEEP at 5 cm H2 O.

Comparison of volume-controlled versus pressure-controlled ventilation improved by PEEP during one-lung ventilation in patients undergoing thoracotomy / 中华麻醉学杂志

Objective To compare volume-controlled ventilation (VCV) versus pressure-controlled ventilation (PCV) improved by PEEP during one-lung ventilation (OLV).Methods Fifty ASA physical status Ⅰ-Ⅲ patients,aged 25-64 yr,weighing 40-80 kg,undergoing elective thoracotomy,were randomly divided into 2 groups (n =25 each) using a random number table:VCV + PEEP group (group Ⅴ) and PCV + PEEP group (group P).Those in group Ⅴ underwent OLV initially with VCV for 20 min followed by 4cm H2O PEEP for 20 min and then PEEP was removed.Those in group P underwent OLV initially with PCV for 20 min followed by 4cm H2O PEEP for 20 min and then PEEP was removed.At the beginning of two-lung ventilation before chest opening (T1),at 20 min of OLV before PEEP (T2),and at 20 min of ventilation with PEEP (T3),arterial blood samples were collected for blood gas analysis and the peak airway pressure (Ppeak) and development of SpO2 ＜ 95 ％ from beginning of OLV to T3 were recorded.Results Compared with group P,Ppeak at T2,3 and PaO2 at T3 were significantly increased in group Ⅴ (P ＜ 0.05).Compared with the baseline value at T1,PaO2 was significantly decreased and Ppeak was increased at T2.3 in Ⅴ and P groups (P ＜ 0.05).The incidence of SpO2 ＜ 95％ was significantly decreased and PaO2 was increased at T3 than at T2 in Ⅴ and P groups (P ＜ 0.05).Conclusion 4 cm H2O PEEP can improve VCV and PCV during OLV and the improved efficacy is better for VCV in patients undergoing thoracotomy.

Gasometria arterial em dois diferentes métodos de transporte intra-hospitalar no pós-operatório imediato de cirurgia cardíaca / Arterial blood gas analysis in two different intra-hospital transport methods for postoperative cardiac surgery patients

OBJETIVO: Avaliar as repercussões gasométricas de dois métodos de ventilação (ventilador de transporte e ressuscitador manual autoinflável) durante o transporte intra-hospitalar de pacientes submetidos à cirurgia cardíaca. MÉTODOS: Estudo observacional, longitudinal, prospectivo e randomizado. Foram coletadas gasometrias arteriais ao final da cirurgia e ao final do transporte do paciente. RESULTADOS: Foram incluídos 23 pacientes: 13 no Grupo ventilador de transporte e 10 no ressuscitador manual autoinflável. As características dos pacientes entre os grupos foram semelhantes, exceto pela maior gravidade no Grupo ventilador de transporte. Observaram-se diferenças significativas nas comparações das variações percentuais dos dados gasométricos: pH (VT: + 4% vs RMA: - 5%, p=0,007), PaCO2 (VT: - 8% vs RMA: + 13%, p=0,006), PaO2 (VT: + 47% vs RMA: - 34%, p=0,01) e SatO2 (VT: + 0,6% vs RMA: - 1,7%, p=0,001). CONCLUSÃO: O uso de ventilador mecânico causa menor repercussão nos gases sanguíneos no transporte intra-hospitalar de pacientes após de cirurgia cardíaca.

OBJECTIVE: To evaluate the effects on blood gases by two methods of ventilation (with transport ventilation or self-inflating manual resuscitator) during intra-hospital transport of patients after cardiac surgery. METHODS: Observational, longitudinal, prospective, randomized study. Two samples of arterial blood were collected at the end of the surgery and another at the end of patient transport. RESULTS: We included 23 patients: 13 in the Group with transport ventilation and 10 in the Group with self-inflating manual resuscitator. Baseline characteristics were similar between both groups, except for higher acute severity of illness in the Group with transport ventilation. We observed significant differences in comparisons of percentage variations of gasometric data: pH (transport ventilation + 4% x MR -5%, p=0.007), PaCO2 (-8% x +13%, p=0.006), PaO2 (+47% x -34%, p=0.01) and SatO2 (+0.6% x -1.7%, p=0.001). CONCLUSION: The use of mechanical ventilation results in fewer repercussions for blood gas analysis in the intra-hospital transport of cardiac surgery patients.