Oxigenoterapia em pacientes com deficiência do sistema respiratório por obstrução crônica aos fluxos aéreos com ou sem hipercapnia: revisão sistemática / Oxygenotherapy in patients with disability of the respiratory system by chronic obstruction to air flows with or without hypercapnia: systematic review

Introdução: a deficiência no sistema por obstrução crônica aos fluxos aéreos é uma doença caracterizada por inflamação, associada a alterações anatômicas e fisiológicas, podendo ocasionar exacerbações respiratórias. A oxigenoterapia tem sido uma alternativa usada em pacientes que possuem insuficiência respiratória decorrente da obstrução crônica, como tentativa de diminuir os sintomas e as complicações geradas. Objetivo: avaliar os efeitos da oxigenoterapia em pacientes com deficiência do sistema respiratório por obstrução crônica, com e sem hipercapnia, quanto aos desfechos pressão parcial de oxigênio, frequência respiratória, tempo de internamento e qualidade de vida.Metodologia: revisão de ensaios clínicos controlados e randomizados (ECR) nas bases de dados PubMed, Cochrane e PEDro. Incluídos estudos originais que utilizaram a oxigenoterapia como intervenção em pacientes com deficiência do sistema respiratório por obstrução crônica aos fluxos aéreos ou que outras síndromes. Resultados: na busca realizada nas bases de dados foram identificados um total de 387 estudos, reduzindo para 87 quando aplicado o descritor "ensaio clínico" e 7 estudos foram incluídos publicados entre os anos de 2004 e 2019. Conclusão: A oxigenoterapia mostrou-se incremento da pressão parcial de oxigênio, frequência respiratória e redução do tempo de internamento com impactos na melhora da qualidade de vida.

Introduction: system deficiency due to chronic airflow obstruction is a disease characterized by inflammation, associated with anatomical and physiological changes, which can cause respiratory exacerbations. Oxygen therapy has been an alternative used in patients who have respiratory failure due to obstruction of the obstruction as an attempt to reduce symptoms and as complications generated. Objective: to evaluate the effects of oxygen therapy in patients with respiratory system deficiency due to chronic obstruction, with and without hypercapnia, in terms of partial oxygen pressure, respiratory rate, length of stay and quality of life. Methodology: review of controlled clinical trials and (RCT) in the PubMed, Cochrane and PEDro databases. Included original studies that used oxygen therapy as an intervention in patients with respiratory system deficiency due to obstruction to flow flows or other syndromes. Results: in the search carried out in the databases, a total of 387 studies were identified, for 87 when the descriptor "clinical trial" was projected and 7 studies were included between the years 2004 and 2019. Conclusion: oxygen therapy showed an increase in pressure partial oxygen, respiratory rate and reduction in hospital stay with impacts on improving the quality due.

Insuficiencia de la bomba ventilatoria: una perspectiva histórica / Ventilatory pump failure: historical perspective

En humanos, PaCO2 es controlada muy estrictamente. A diferencia de PaO2 y todas las pruebas funcionales respiratorias que cambian con la edad, PaCO2 permanece constante durante toda la vida. Por lo tanto, su desviación sostenida representa una alteración significativa de la homeostasis. La estructura responsable de mantener la PaCO2 dentro de límites muy estrechos es la bomba ventilatoria. Se compone de varias unidades anatómicas y funcionales que van desde la corteza cerebral hasta los músculos respiratorios. Varias condiciones clínicas que involucran estas estructuras pueden conducir a la insuficiencia de la bomba respiratoria, cuyo sello distintivo es la hipercapnia. La relevancia del concepto de bomba respiratoria ha sido reconocida a lo largo de las décadas. Unos pocos trabajos germinales abrieron la puerta a un notable número de proyectos básicos, aplicados y clínicos en torno a la insuficiencia de la bomba respiratoria y su relevancia clínica. Este artículo revisará algunos de estos estudios y narrará el camino hacia nuestro estado actual de conocimiento sobre el tema.

IIn humans, PaCO2 is very strictly controlled. Unlike PaO2 and all respiratory functional tests that change with age, PaCO2 remains constant throughout life. Therefore, its sustained deviation represents a significant alteration of homeostasis. The structure responsible for keeping PaCO2 within very narrow limits is the ventilatory pump. It consists of several anatomical and functional units that go from the cerebral cortex to the respiratory muscles. Several clinical conditions involving these structures can lead to failure of the respiratory pump, whose hallmark is hypercapnia. The relevance of the respiratory pump concept has been acknowledged for decades. A few initial works allowed for a remarkable number of basic, applied and clinical projects regarding the respiratory pump failure and its clinical relevance. This article reviews some of these studies and describes the process that lead to our current state of knowledge on the subject

Eficácia e segurança da oxigenoterapia com cânula nasal de alto fluxo na insuficiência respiratória hipercápnica moderada aguda / Efficacy and safety of high-flow nasal cannula oxygen therapy in moderate acute hypercapnic respiratory failure

RESUMO Objetivo: Avaliar a eficácia e a segurança da oxigenoterapia com uso de cânula nasal de alto fluxo no tratamento da insuficiência respiratória hipercápnica moderada em pacientes que não conseguem tolerar ou têm contraindicações para ventilação mecânica não invasiva. Métodos: Estudo prospectivo observacional de 13 meses envolvendo participantes admitidos a uma unidade de terapia intensiva com insuficiência respiratória hipercápnica ou durante o processo de seu desenvolvimento. Os parâmetros clínicos e de troca gasosa foram registrados em intervalos regulares durante as primeiras 24 horas. Os parâmetros finais foram saturação de oxigênio entre 88 e 92%, juntamente da redução do esforço respiratório (frequência respiratória) e da normalização do pH (≥ 7,35). Os participantes foram considerados não responsivos em caso de necessidade de utilização de suporte ventilatório. Resultados: Trinta participantes foram tratados utilizando oxigenoterapia com cânula nasal de alto fluxo. Esta foi uma população mista com exacerbação de doença pulmonar obstrutiva crônica, edema pulmonar cardiogênico agudo, e insuficiência respiratória aguda pós-operatória e pós-extubação. Observou-se melhora não significante na frequência respiratória (28,0 ± 0,9 versus 24,3 ± 1,5; p = 0,22), que foi aparente nas primeiras 4 horas do tratamento. Ocorreu melhora do pH, embora só se tenham obtido níveis normais após 24 horas de tratamento com cânula nasal de alto fluxo (7,28 ± 0,02 versus 7,37 ± 0,01; p = 0,02). A proporção de não responsivos foi de 13,3% (quatro participantes), dos quais um necessitou e aceitou ventilação mecânica não invasiva, e três necessitaram de intubação. A mortalidade na unidade de terapia intensiva foi de 3,3% (um participante), e um paciente morreu após a alta para a enfermaria (mortalidade hospitalar de 6,6%). Conclusão: O oxigenoterapia com cânula nasal de alto fluxo é eficaz para a insuficiência respiratória hipercápnica moderada e ajuda a normalizar os parâmetros clínicos e de troca gasosa, com taxa aceitável de não responsivos que necessitaram de suporte ventilatório.

ABSTRACT Objective: To assess the efficacy and safety of high-flow nasal cannula oxygen therapy in treating moderate hypercapnic respiratory failure in patients who cannot tolerate or have contraindications to noninvasive mechanical ventilation. Methods: A prospective observational 13-month study involving subjects admitted to an intensive care unit with or developing moderate hypercapnic respiratory failure. Clinical and gas exchange parameters were recorded at regular intervals during the first 24 hours. The endpoints were a oxygen saturation between 88 and 92% along with a reduction in breathing effort (respiratory rate) and pH normalization (≥ 7.35). Subjects were considered nonresponders if they required ventilatory support. Results: Thirty subjects were treated with high-flow nasal cannula oxygen therapy. They consisted of a mixed population with chronic obstructive pulmonary disease exacerbation, acute cardiogenic pulmonary edema, and postoperative and postextubation respiratory failure. A nonsignificant improvement was observed in respiratory rate (28.0 ± 0.9 versus 24.3 ± 1.5, p = 0.22), which was apparent in the first four hours of treatment. The pH improved, although normal levels were only reached after 24 hours on high-flow nasal cannula therapy (7.28 ± 0.02 versus 7.37 ± 0.01, p = 0.02). The rate of nonresponders was 13.3% (4 subjects), of whom one needed and accepted noninvasive mechanical ventilation and three required intubation. Intensive care unit mortality was 3.3% (1 subject), and a patient died after discharge to the ward (hospital mortality of 6.6%). Conclusion: High-flow nasal cannula oxygen therapy is effective for moderate hypercapnic respiratory failure as it helps normalize clinical and gas exchange levels with an acceptable rate of nonresponders who require ventilatory support.

Hypercapnia attenuates ventilator-induced lung injury through vagus nerve activation

Abstract Purpose: To investigate the role of vagus nerve activation in the protective effects of hypercapnia in ventilator-induced lung injury (VILI) rats. Methods: Male Sprague-Dawley rats were randomized to either high-tidal volume or low-tidal volume ventilation (control) and monitored for 4h. The high-tidal volume group was further divided into either a vagotomy or sham-operated group and each surgery group was further divided into two subgroups: normocapnia and hypercapnia. Injuries were assessed hourly through hemodynamics, respiratory mechanics and gas exchange. Protein concentration, cell count and cytokines (TNF-α and IL-8) in bronchoalveolar lavage fluid (BALF), lung wet-to-dry weight and pathological changes were examined. Vagus nerve activity was recorded for 1h. Results: Compared to the control group, injurious ventilation resulted in a decrease in PaO2/FiO2 and greater lung static compliance, MPO activity, enhanced BALF cytokines, protein concentration, cell count, and histology injury score. Conversely, hypercapnia significantly improved VILI by decreasing the above injury parameters. However, vagotomy abolished the protective effect of hypercapnia on VILI. In addition, hypercapnia enhanced efferent vagus nerve activity compared to normocapnia. Conclusion: These results indicate that the vagus nerve plays an important role in mediating the anti-inflammatory effect of hypercapnia on VILI.

Successful case of veno-venous extracorporeal membrane oxygenation in an abdominal trauma patient: A case report

A 37-year-old male visited the hospital with multiple trauma after traffic accident. Fractures of ribs, left femur, and right humerus and spleen rupture with hemoperitoneum were founded on image studies. He was moved to operation room and general anesthesia was performed for splenectomy. During the operation, excessive high peak inspiratory pressure was observed. After abdominal closure, hypoxia, hypercapnia, and respiratory acidosis were worsened. Veno-venous extracorporeal membrane oxygenation (ECMO) was initiated after the operation. Status of the patient were improved after the application of ECMO. The patient was discharged without significant complication. Despite of several limitations in applying ECMO to patients with abdominal compartment syndrome (ACS) and multiple trauma, severe pulmonary dysfunction in ACS patients may be rescued without open abdomen treatment.

Association between blood pressure, inflammation and spirometry parameters in chronic obstructive pulmonary disease

BACKGROUND/AIMS: Many systems including the cardiovascular system (ischemic heart diseases, heart failure, and hypertension) may act as comorbidities that can be seen during the course of chronic obstructive pulmonary disease (COPD). Comorbidities affect the severity and prognosis of COPD negatively. Nearly 25% of patients with COPD die due to cardiovascular diseases. In this study, we aimed to evaluate the relationship between the blood pressure, inflammation, hypoxia, hypercapnia, and the severity of airway obstruction. METHODS: We included 75 COPD patients in the study with 45 control cases. We evaluated age, sex, body mass index, smoking history, C-reactive protein levels, 24-hour ambulatory blood pressure Holter monitoring, arterial blood gas, and respiratory function tests of the patient and the control groups. RESULTS: In COPD patients, the night time systolic, diastolic blood pressures and pulse per minute and the mean blood pressures readings were significantly elevated compared to the control group (p < 0.05). In the correlation analysis, night time systolic pressure was associated with all the parameters except forced expiratory volume in 1 second (FEV₁%). Diastolic blood pressure was associated with pH and HCO₃ levels. The mean night time, day time pulse pressures and 24-hour pulse per minute values were also associated with all the parameters except FEV₁%. CONCLUSIONS: In this study we found that parameters of systolic and diastolic blood pressures and pulse pressures were significantly elevated in COPD patients compared to the control groups. Blood pressure was associated blood gas parameters and inflammation parameters in COPD patients. This, in turn, may cause understanding of the pathophysiology of COPD and its complications.

Cardiopulmonary Bypass Strategies to Maintain Brain Perfusion during Lung Transplantation in a Patient with Severe Hypercapnia / 대한흉부외과학회지

Herein, we report a case of lung transplantation in a patient with profound preoperative hypercapnia, focusing on the cardiopulmonary bypass strategy used for brain perfusion during the operation. We applied the pH-stat method for acid-base regulation, and thereby achieved the desired outcome without any neurologic deficit.

Cerebrovascular reactivity to hypercapnia during sevoflurane or desflurane anesthesia in rats / 대한마취과학회지

BACKGROUND: Hypercapnia causes dilation of cerebral vessels and increases cerebral blood flow, resulting in increased intracranial pressure. Sevoflurane is reported to preserve cerebrovascular carbon dioxide reactivity. However, the contribution of inhaled anesthetics to vasodilatory responses to hypercapnia has not been clarified. Moreover, the cerebrovascular response to desflurane under hypercapnia has not been reported. We examined the effects of sevoflurane and desflurane on vasodilatory responses to hypercapnia in rats. METHODS: A closed cranial window preparation was used to measure the changes in pial vessel diameters. To evaluate the cerebrovascular response to hypercapnia and/or inhaled anesthetics, the pial vessel diameters were measured in the following states: without inhaled anesthetics at normocapnia (control values) and hypercapnia, with inhaled end-tidal minimal alveolar concentration (MAC) of 0.5 or 1.0 of either sevoflurane or desflurane at normocapnia, and an MAC of 1.0 of sevoflurane or desflurane at hypercapnia. RESULTS: Under normocapnia, 1.0 MAC, but not 0.5 MAC, of sevoflurane or desflurane dilated the pial arterioles and venules. In addition, under both 1.0 MAC of sevoflurane and 1.0 MAC of desflurane, hypercapnia significantly dilated the pial arterioles and venules in comparison to their diameters without inhaled anesthetics. The degrees of vasodilation were similar for desflurane and sevoflurane under both normocapnia and hypercapnia. CONCLUSIONS: Desflurane induces cerebrovascular responses similar to those of sevoflurane. Desflurane can be used as safely as sevoflurane in neurosurgical anesthesia.

Central Hypoventilation Syndrome in Posterior Circulation Stroke Treated by Respiratory Rehabilitation: a Case Report

Central hypoventilation syndrome is a rare and fatal condition resulting from various central nervous system disorders that is characterized by a failure of automatic breathing. We report a case of central hypoventilation syndrome following posterior circulation stroke whose pulmonary function was improved by respiratory rehabilitation. A 59-year-old woman with a history of hemorrhagic stroke of the bilateral cerebellum was hospitalized due to pneumonia. A portable ventilator was applied via tracheostomy, recurrent episodes of apnea and hypercapnia impeded weaning. A respiratory rehabilitation program including chest wall range of motion exercise, air stacking exercise, neuromuscular electrical stimulation (NMES) on abdominal muscles, upper extremity ergometer, locomotor training, high-frequency chest wall oscillator, mechanical insufflation, and exsufflation was employed, as spirometry showed a severe restrictive pattern. A spontaneous breathing trial was started, and a portable ventilator was applied for 8 hours, only during nighttime, to prevent sudden apneic event. After 4 weeks of treatment, follow-up spirometry showed much improved respiratory parameters. This case suggests that respiratory rehabilitation can improve pulmonary function parameters and quality of life in central hypoventilation syndrome.

Consideraciones anestésicas en hipercapnia intraoperatoria, a propósito de un caso / Case report: Anesthetic considerations in intraoperative hipercapnia

Hypercapnia during the intraoperative period is one of the relevant conditions for the anesthesiologist, which can even condition the anesthetic technique, in case of an eventual complication. Where ventilatory monitoring and the interpretation of said disorder allows to diagnose, plan and treat the physiological consequences in the patient. We present the case of a 20 year old patient, scheduled for orthognathic surgery for diagnosis of mandibular body fracture, without added pathologies, no chest trauma, no ventilation disorders. It is presented with the objective of discussing the different considerations to be taken before the progressive establishment of hypercapnia, its causes, consequences and its management.

La hipercapnia durante el intraoperatorio es una de las condiciones relevantes para el anestesiólogo, la cual puede incluso condicionar la técnica anestésica ante una eventual complicación. Donde la monitorización ventilatoria y la interpretación de dicho trastorno permite diagnosticar, planificar y tratar las consecuencias fisiológicas en el paciente. Presentamos el caso de una paciente de 20 años programada para cirugía ortognática por diagnóstico de fractura de cuerpo mandibular, sin patologías añadidas no traumas torácicos, no trastornos de ventilación. Se presenta con el objetivo de discutir las diferentes consideraciones a tomar ante la instauración progresiva de hipercapnia sus causas, consecuencias así como su manejo.

Nuevo dispositivo de micronebulización con control continuo de la fracción inspirada de oxígeno ("CONTROLizer") / New micronebulizer device with continuous control of the inspired oxygen fraction ("CONTROLizer")

Resumen Una de las técnicas más comunes de tratamiento respiratorio es la nebulización de medicamentos para administrarlos por vía inhalada utilizando oxígeno como propelente, el cual a su vez es considerado un fármaco que puede generar efectos adversos relacionados con la dosificación. El objetivo de esta investigación fue diseñar, desarrollar y analizar un sistema dual de micronebulización con control preciso de la FIO2. Métodos: se diseñó, construyó y evaluó un modelo virtual y un prototipo funcional siguiendo la metodología de bioingeniería de un nuevo dispositivo de micronebulización con control de FIO2. Se evaluó el funcionamiento del dispositivo y su impacto en voluntarios sanos y pacientes hospitalizados mediante escalas psicométricas específicas. Resultados: se conceptualizó, diseñó y construyó un dispositivo que integra un micronebulizador (recipiente), que permite nebulizar suero fisiológico o soluciones de diversos fármacos basado en la presurización de un gas propelente (aire u oxígeno) junto a un mecanismo de ajuste de la fracción inspirada de O2 (mínimo 21%; máximo 99%). Los límites (máximo y mínimo) de flujo recomendado para generar el aerosol son 6-8 l/min. En ningún caso de uso se presentaron complicaciones. Conclusiones: CONTROLizer es un dispositivo integrado dual y no-invasivo para la micronebulización de soluciones respiratorias y control continuo de la fracción inspirada de oxígeno. Por sus cualidades y funcionamiento, el dispositivo fue percibido como adecuado y seguro para aplicarse en individuos sanos y pacientes ingresados tanto en salas de cuidados intensivos como de hospitalización convencional. (Acta Med Colomb 2018; 43: 90-99).

Abstract One of the most common techniques of respiratory treatment is the nebulization of medications to be administered by inhalation using oxygen as a propellant, which in turn is considered a drug that can generate adverse effects related to the dosage. The objective of this research was to design, develop and analyze a dual micronebulization system with precise control of FIO2. Methods: a virtual model and a functional prototype were designed, constructed and evaluated following the bioengineering methodology of a new micronebulizer device with FIO2 control. The functioning of the device and its impact on healthy volunteers and hospitalized patients were evaluated through specific psychometric scales. Results: a device that integrates a micronebulizer (container), which allows to nebulize physiological saline or solutions of diverse drugs based on the pressurization of a propellant gas (air or oxygen) along with a mechanism of adjustment of the fraction of inspired oxygen (minimum 21%, maximum 99%), was conceptualized, designed and constructed. The limits (maximum and minimum) of recommended flow to generate the aerosol are 6-8 l / min. In no case of use complications occurred. Conclusions: CONTROLizer is a dual and non-invasive integrated device for the micronebulization of respiratory solutions and continuous control of the fraction of inspired oxygen. Due to its qualities and functioning, the device was perceived as adequate and safe to be applied in healthy individuals and patients admitted in both intensive care and conventional hospitalization rooms. (Acta Med Colomb 2018; 43: 90-99).

Insuflação de gás traqueal como recurso terapêutico em ventilação mecânica invasiva: revisão sistemática / Tracheal gas insufflation as a therapeutic resource in invasive mechanical ventilation: a systematic review

Introdução: A unidade de terapia intensiva, pacientes que apresentam um grave comprometimento pulmonar, com alterações nos valores fisiológicos de complacência pulmonar, acabam desenvolvendo uma limitação relacionada a volumes pulmonares. Um dos problemas resultantes é a hipercapnia. Para ajudar a reduzir essas alterações, pode-se usar técnicas como a insuflação de gás traqueal (TGI), que atua minimizando o estresse pulmonar, melhorando as trocas gasosas e reduzindo o volume minuto ventilatório e a pressão. Assim, o objetivo deste estudo foi analisar e descrever o uso de TGI e a sua eficácia na redução da hipercapnia e nos parâmetros da ventilação mecânica invasiva de pacientes críticos. Métodos: Foi realizada uma revisão sistemática da literatura com busca nas bases de dados do SciELO, LILACS, PubMed e MEDLINE, com publicações de 2005 a 2016. Foram identificados um total de 1.437 artigos. Os critérios de elegibilidade foram a utilização do método de TGI isolado ou combinado a outros recursos e a inclusão de desfechos da sua efetividade em amostras experimentais ou humanas que mostravam lesão pulmonar e/ou outras alterações pulmonares, entre elas a hipercapnia. Resultados: Após a leitura e análise criteriosa dos artigos, 10 estudos foram incluídos nesta revisão. Eles abordavam a eficácia dos métodos de TGI na redução dos níveis de CO2 e as condições para a diminuição dos parâmetros da ventilação mecânica e melhora da mecânica ventilatória. Conclusão: Os estudos incluídos na presente revisão sugerem que a TGI pode ser uma técnica eficaz quando realizada em complicações pulmonares nos pacientes hipercápnicos com lesão pulmonar. Entretanto, são estudos distintos e controversos, o que compromete a análise dos resultados obtidos para total eficácia do recurso terapêutico. (AU)

Introduction: At intensive care units, patients presenting with severe pulmonary involvement, with changes in the physiological values of pulmonary compliance, develop a limitation related to pulmonary volumes, resulting in some cases in hypercapnia. In order to help decreasing these alterations, some techniques may be used such as tracheal gas insufflation (TGI), which acts minimizing pulmonary stress, improving gas exchanges and decreasing respiratory minute volume and pressure. Thus, this study aimed to analyze and to describe TGI use and efficacy in reducing hypercapnia and parameters of invasive mechanical ventilation of critically ill patients. Methods: For this systematic review, we searched SciELO, LILACS, PubMed and MEDLINE databases for articles published from 2005 to 2016. A total of 1,437 articles were found. The eligibility criteria were the use of TGI alone or together with other resources and the evaluation of its effectiveness in experimental or human samples that showed lung injury and/or other pulmonary abnormalities, including hypercapnia. Results: After careful reading and analysis of the articles, 10 studies were included in this review. They addressed the effectiveness of TGI methods in reducing levels of CO2 levels and conditions to decrease parameters of mechanical ventilation and to improve ventilation mechanics. Conclusion: The studies included in the present review suggest that TGI may be an efficient technique when applied to pulmonary complications of patients suffering from hypercapnia with pulmonary lesions. However, the studies are different and controversial, which compromises the analysis of the results obtained for total efficacy of the therapeutic resource. (AU)

The effect of Yiqi Wenyang Huoxue Huatan Fang on hypoxia-hypercarbia induced pulmonary hypertension and its mechanism / 中国应用生理学杂志

OBJECTIVE@#To investigate the effect of Yiqi Wenyang Huoxue Huatan Fang (YWHHF) on alleviating hypoxia-hypercarbia pulmonary hypertension by inhibiting endothelial-mesenchymal transition (EndoMT) BMP-7/Smads pathway.@*METHODS@#Fifty male healthy SD rats of clean grede, weighting (180~220) g, were randomly divided into 5 groups (=10):normoxia group (N), hypoxia-hypercarbia group (HH); YWHHF high dose group (YH), middle dose group (YM) and low dose group (YL). The rats in N group were kept in normal oxygen environment, the remaining four groups were intermittently exposed to hypoxia-hypercarbia environment (9%~11% O, 5%~6% CO) for 4 weeks, 6 days a week, 8 hours per day. The rats in YH, YM, YL groups were received YWHHF gavage in a dosageof 0.6, 0.3, 0.15g/kg respectively (3 ml/kg),the rats in N and HH groups were received equal volume of normal saline. After 4 weeks, the mean pulmonary arterial pressure(mPAP) was detected,the right ventricular free wall and left ventricle plus ventricular septum were isolated to determine the right ventricular hypertrophy index. Lung ultrastructural changes were surveyed under an electronic microscopy, the changes of pulmonary artery structure surveyed by immunofluorescence, the mRNA levels of alpha-smooth muscle actin (α-SMA)、platelet endothelial cell adhesion molecule-1 (CD31)、bone morphogenetic protein-7 (BMP-7)、drosophila mothers against decapentaplegic protein1/5/8 (Smad1/5/8) were detected by RT-PCR, and the protein levels of α-SMA、CD31、BMP-7、p-Smad1/5/8 and Smad1/5/8 were detected by Western blot.@*RESULTS@#Compared with N group, mPAP and the right ventricular hypertrophy index were increased,some significant injuries also were discovered under microscopic observation,the mRNA and protein expression of α-SMA was increased, and the mRNA expressions of CD31、BMP-7、Smad1/5/8 were decreased in the other four groups, the protein expressions of CD31、BMP-7、p-Smad1/5/8 were decreased(<0.05). Compared with HH group, the above changes in YH、YM、YL groups were all improved (<0.05).@*CONCLUSIONS@#YWHHF can inhibit EndoMT to alleviate pulmonary hypertension, and the mechanism may be related to the promotion of the expression of BMP-7/Smads pathway.

The role of endoplasmic reticulum stress in pulmonary hypertension in rat induced by chronic hypoxia and hypercapnia / 中国应用生理学杂志

OBJECTIVE@#To observe the pulmonary vascular remodeling in rats with pulmonary hypertension induced by hypoxia and hypercapnia, and to explore the role of endoplasmic reticulum stress in pulmonary hypertension.@*METHODS@#Forty SD rats were random-ly divided into four groups:normoxic control group (N), hypoxia hypercapnia group (HH), ERS inhibitor 4-phenylbutyric acid group (4-PBA), endoplasmic reticulum stress (ERS) pathway agonist tunicamycin group (TM), ten rats in each group.The mean pulmona-ry artery pressure (mPAP), mean carotid artery pressure (mCAP) and right ventricular hypertrophy index of rats in each group were measured.Pulmonary artery smooth muscle cells were identified by immunofluorescence α-smooth muscle actin (α-SMA).Morphologi-cal changes of lung tissue and pulmonary artery were observed by electron microscope.The apoptotic index of pulmonary artery smooth muscle cells in each group was detected by TUNEL.Reverse transcription polymerase chain reaction (RT-PCR) and Western blot were used to detect the expression of glucose-regulated protein (GRP78), C/EBP homologous protein (CHOP), c-Jun N-terminal kinase (JNK) and cysteinyl aspartate specific proteinase-12 (caspase-12) mRNA and protein in each group.@*RESULTS@#①Compared with the N group, the mPAP, the ratio of right ventricle weight to left ventricle plus ventricular septum weight[RV/(LV+S)]and the ratio of pulmonary artery wall area to total tube area (WA/TA) were increased (<0.01), and the ratio of pulmonary artery luminal area to total tube area (LA/TA) were decreased (<0.01), pulmonary artery smooth muscle cell apoptosis index were decreased (<0.05 or <0.01) in HH group, 4-PBA group and TM group.ERS related protein and mRNA expressions were increased, the differences were statistically significant.②Compared with the HH group, the mPAP, [RV/(LV+S)]and WA/TA of 4-PBA group were decreased ( <0.01), LA/TA and pulmonary artery smooth muscle cell apoptosis index were increased (<0.01, <0.05).The expressions of ERS related protein and mRNA were all decreased (<0.05 or <0.01).③Compared with the HH group, the mPAP, [RV/(LV+S)]and WA/TA of TM group were increased (<0.05 or <0.01), pulmonary artery middle layer thickened, LA/TA and pulmonary artery smooth muscle cell apoptotic index were decreased (<0.01).ERS related protein and mRNA expressions were increased with statistical significance except GRP78 protein.@*CONCLUSIONS@#Pulmonary vascular remodeling in rats with pulmonary hypertension induced by hypoxia and hypercapnia may be related to the excessive proliferation of pulmonary artery smooth muscle cells and too little apopto-sis;ERS related factors (JNK, caspase-12 and CHOP) are involved in the regulation of pulmonary hypertension induced by hypoxia hypercapnia.

Hypercapnia does not shorten emergence time from propofol anesthesia: a pilot randomized clinical study / 대한마취과학회지

BACKGROUND: The elimination of anesthetic agents is a decisive factor in the emergence from general anesthesia. In this pilot study, we hypothesized that hypercapnia would decrease the emergence time from propofol anesthesia by increasing cardiac output and cerebral blood flow. METHODS: A total of 32 patients were randomly divided into two groups based on the end-tidal carbon dioxide values: 30 mmHg (the hypocapnia group) and 50 mmHg (the hypercapnia group). Propofol and remifentanil were infused to maintain a bispectral index of 40–50. Remifentanil infusion was stopped 10 min before the discontinuation of propofol. After cessation of propofol infusion, ventilation settings in the hypocapnia group were maintained constant; a rebreathing tube was connected to the respiratory circuit in the hypercapnia group. The time to spontaneous respiration, eye opening (primary endpoint), mouth opening, and tracheal extubation was recorded and analyzed. RESULTS: Time to eye opening was 9.7 (1.3) min in the hypocapnia group and 9.0 (1.0) min in the hypercapnia group. The difference in the mean times to eye opening between groups was −0.7 min (95% CI, −4.0 to 2.7, P = 0.688). On multiple regression analysis, there was a significant difference in the mean time to eye opening between males and females. Females recovered about 3.6 min faster than males (95% CI, −6.1 to −1.1, P = 0.009). CONCLUSIONS: We could not detect a beneficial effect of hypercapnia on propofol emergence time. Irrespective of hypercapnia, females seemed to recover faster than males.

Effective Tidal Volume for Normocapnia in Very-Low-Birth-Weight Infants Using High-Frequency Oscillatory Ventilation

PURPOSE: Removal of CO₂ is much efficient during high-frequency oscillatory ventilation (HFOV) for preterm infants. However, an optimal carbon dioxide diffusion coefficient (DCO₂) and tidal volume (VT) have not yet been established due to much individual variance. This study aimed to analyze DCO₂ values, VT, and minute volume in very-low-birth-weight (VLBW) infants using HFOV and correlates with plasma CO₂ (pCO₂). MATERIALS AND METHODS: Daily respiratory mechanics and ventilator settings from twenty VLBW infants and their two hundred seventeen results of blood gas analysis were collected. Patients were treated with the Dräger Babylog VN500 ventilator (Drägerwerk Ag & Co.) in HFOV mode. The normocapnia was indicated as pCO₂ ranging from 45 mm Hg to 55 mm Hg. RESULTS: The measured VT was 1.7 mL/kg, minute volume was 0.7 mL/kg, and DCO₂ was 43.5 mL²/s. Mean results of the blood gas test were as follows: pH, 7.31; pCO₂, 52.6 mm Hg; and SpO₂, 90.5%. In normocapnic state, the mean VT was significantly higher than in hypercapnic state (2.1±0.5 mL/kg vs. 1.6±0.3 mL/kg), and the mean DCO₂ showed significant difference (68.4±32.7 mL²/s vs. 32.4±15.7 mL²/s). The DCO₂ was significantly correlated with the pCO₂ (p=0.024). In the receiver operating curve analysis, the estimated optimal cut-off point to predict the remaining normocapnic status was a VT of 1.75 mL/kg (sensitivity 73%, specificity 80%). CONCLUSION: In VLBW infants treated with HFOV, VT of 1.75 mL/kg is recommended for maintaining proper ventilation.

Blood Gas Analysis of Respiratory Depression during Sevoflurane Inhalation Induction for General Anesthesia in the Disabled Patients / 대한소아치과학회지

Tidal volume by sevoflurane in small amounts is stable due to the increase in the breathing rate. But alveolus ventilation decreases due to sevoflurane as the degree of sedation increases; this ultimately causes PaCO2 to rise. The occurrence of suppression of breath increases the risk of severe hypoxia and hypercapnia in deeply sedated patients with disabilities. Sevoflurane inhalation anesthesia has a number of risks and may have unexpected problems with hemodynamic changes depending on the underlying state of the body. This study was conducted to examine the stability of internal acid-base system caused by respiratory depression occurring when patients with disabilities are induced by sevoflurane.Anesthetic induction was carried out by placing a mask on top of the patient's face and through voluntary breathing with 4 vol% of sevoflurane, 4 L/min of nitrous oxide, and 4 L/min of oxygen. After the patient's loss of consciousness and muscle relaxation, IV line was inserted by an expert and intravenous blood gas was analyzed by extracting blood from vein.In a deeply sedated state, the average amount of pH of the entire patients was measured as 7.36 ± 0.06. The average amount of PvCO₂ of the entire patients was measured as 48.8 ± 8.50 mmHg. The average amount of HCO₃₋ of the entire patients was measured as 27.2 ± 3.0 mmol/L.In conclusion, in dental treatment of patients with disabilities, the internal acid base response to inhalation sedation using sevoflurane is relatively stable.

Usefulness of phrenic nerve conduction study in early diagnosis of isolated respiratory onset amyotrophic lateral sclerosis

Isolated respiratory onset amyotrophic lateral sclerosis (ALS) is a rare clinical manifestation and the diagnosis can be challenging. A 72-year-old man presented with dyspnea and hypercapnia that had started 11 months earlier. A phrenic nerve study was conducted and he was diagnosed promptly with ALS with no significant time delay. The phrenic nerve study is a noninvasive and useful tool in the diagnosis of respiratory onset ALS that can be applied easily in an emergency department.

Extracorporeal respiratory support in adult patients / Suporte respiratório extracorpóreo em pacientes adultos

ABSTRACT In patients with severe respiratory failure, either hypoxemic or hypercapnic, life support with mechanical ventilation alone can be insufficient to meet their needs, especially if one tries to avoid ventilator settings that can cause injury to the lungs. In those patients, extracorporeal membrane oxygenation (ECMO), which is also very effective in removing carbon dioxide from the blood, can provide life support, allowing the application of protective lung ventilation. In this review article, we aim to explore some of the most relevant aspects of using ECMO for respiratory support. We discuss the history of respiratory support using ECMO in adults, as well as the clinical evidence; costs; indications; installation of the equipment; ventilator settings; daily care of the patient and the system; common troubleshooting; weaning; and discontinuation.

RESUMO Em pacientes com insuficiência respiratória grave (hipoxêmica ou hipercápnica), o suporte somente com ventilação mecânica pode ser insuficiente para suas necessidades, especialmente quando se tenta evitar o uso de parâmetros ventilatórios que possam causar danos aos pulmões. Nesses pacientes, extracorporeal membrane oxygenation (ECMO, oxigenação extracorpórea por membrana), que também é muito eficaz na remoção de dióxido de carbono do sangue, pode manter a vida, permitindo o uso de ventilação pulmonar protetora. No presente artigo de revisão, objetivamos explorar alguns dos aspectos mais relevantes do suporte respiratório por ECMO. Discutimos a história do suporte respiratório por ECMO em adultos; evidências clínicas; custos; indicações; instalação do equipamento; parâmetros ventilatórios; cuidado diário do paciente e do sistema; solução de problemas comuns; desmame e descontinuação.