A cirurgia laparoscópica requer a criação de um espaço de trabalho intraabdominal, através do pneumoperitônio, e para isto utiliza-se o dióxido de carbono (CO2). As alterações sistêmicas relacionadas ao sistema respiratório ocorrem pelo aumento da pressão intra-abdominal, resultando em diminuição da complacência pulmonar, atelectasia, hipercarbia e hipóxia. A insuflação de CO2 com pressões intraabdominais acima de 8 mmHg produz alterações hemodinâmicas significantes, caracterizadas por decréscimo do débito cardíaco, elevação da pressão arterial. Para que a homeostase hemodinâmica e respiratória seja mantida são necessários protocolos anestésicos adequados e métodos de ventilação mecânica como, por exemplo, a pressão expiratória final positiva final (PEEP). O presente trabalho teve por objetivo avaliar e comparar quatro protocolos anestésicos e ventilatórios distintos em cadelas submetidas à ovariohisterectomia videolaparoscópica eletiva, com uso de pneumoperitônio com CO2 e 12 mmHg de pressão intra-abdominal, sob anestesia geral total intravenosa. Para isso, 16 caninos foram distribuídos em quatro grupos: no grupo 1 (Zeepbloq) os animais receberam atracúrio (0,5 mg.kg-1), propofol (5 mg.kg-1) e fentanil (2 mcg.kg-1), todos em bolus, por via intravenosa, e seguiu-se com infusão contínua de atracúrio (0,5 mg.kg-1/hora), propofol (0,4 mg.kg-1/minuto) e fentanil (2 mcg.kg-1/hora) por bomba de infusão, e não foi realizada PEEP; no grupo 2 (Peepbloq) administrou-se o mesmo protocolo anestésico, porém realizou-se a PEEP de 10 cm de água; no grupo 3 (Zeep) os animais receberam o mesmo protocolo anestésico, com exceção bloqueador neuromuscular, e não foi realizada PEEP; no grupo 4 (PEEP) os indivíduos receberam o mesmo protocolo do grupo 3, porém realizou-se PEEP. Para o procedimento cirúrgico foi realizado pneumoperitônio de 12 mmHg com CO2 com duração variável. Foram avaliadas as seguintes variáveis: pressão arterial média, freqüência respiratória, saturação de oxigênio na hemoglobina, pressão parcial de dióxido de carbono expirado, freqüência cardíaca, eletrocardiografia e tempo do procedimento anestésico, do pneumoperitônio. Para hemogasometria foi realizada a coleta de sangue arterial, sendo obtidas variáveis de pH, pressão parcial de O2 e CO2, bicarbonato, CO2 total, excesso/déficit de bases e saturação arterial de oxigênio na hemoglobina. Não foram observados valores que representassem diferença estatística significativa entre os grupos (p<0,05). No entanto, houve diferença significativa (p<0,05) entre momentos avaliados a para pressão arterial de oxigênio, a pressão arterial média e a temperatura, independente do protocolo empregado. Ambos os protocolos empregados, anestésico e de ventilação, foram satisfatórios e, de acordo com a metodologia empregada, pode-se concluir que animais submetidos à ventilação com PEEP não apresentaram benefícios significativos quando comparados com animais ventilados com ZEEP, independente do uso ou não de bloqueador neuromuscular. / The laparoscopic surgery requires the creation of a space in the abdominal cavity through pneumoperitoneum and that using the carbon dioxide (CO2). The systemic changes related to the respiratory system occur by increased intra-abdominal pressure, resulting in decreased lung compliance, atelectasis, hypercarbia and hypoxia. The CO2 insufflation with intra-abdominal pressure over 8 mmHg produces significant hemodynamic changes, characterized by decreased cardiac output, blood pressure elevation. For the hemodynamic and respiratory homeostasis is maintained anesthetic protocols are necessary and appropriate methods of mechanical ventilation, such as the positive end-expiratory pressure (PEEP). This study aimed to evaluate and compare four different protocols anesthetics and ventilatory in female dogs submitted to ovariohysterectomy videolaparoscopic elective, with the use of pneumoperitoneum with CO2 and 12 mmHg of intra-abdominal pressure, under general anesthesia total intravenous. A total of 16 dogs were distributed into four groups: in group 1 (Zeepbloq) the animals received atracurium (0.5 mg.kg-1), propofol (5 mg.kg-1) and fentanyl (2 mcg . kg-1), all bolus, intravenously, and followed up with continuous infusion of atracurium (0.5 mg.kg-1/hour), propofol (0.4 mg.kg-1/minute) and fentanyl (2 mcg.kg-1/hour) by infusion pump, and was not held PEEP, in group 2 (Peepbloq) administered to the same protocol anesthetic, but was held on PEEP of 10 cm of water, in group 3 (Zeep) the animals received the same protocol anesthetic, except neuromuscular blocker, and was not held PEEP, and in group 4 (PEEP) individuals received the same protocol as the group 3, but was held PEEP. For the surgical procedure was performed abdominal pressure of 12 mmHg with CO2. We evaluated the following variables: mean arterial pressure, respiratory rate, oxygen saturation in hemoglobin, end tidal of carbon dioxide expired, heart rate, electrocardiography and time of the anesthetic procedure and of the pneumoperitoneum. Arterial blood was sampled for arterial blood gas analyses, and variables obtained from pH, arterial pressure of CO2 and O2, bicarbonate, CO2 total, balance of bases and arterial oxygen saturation in hemoglobin. There were no evaluate parameters that represented statistically significant difference between groups (p <0.05). However, there was a significant difference (p <0.05) between moments evaluated for the blood pressure of oxygen, the mean blood pressure and temperature, independent of protocol employee. Both protocols employees, anaesthetic and ventilation, were satisfactory and in accordance with the methodology employed, we can conclude that animals treated with ventilation PEEP did not show significant benefits when compared with animals ventilated with ZEEP, regardless of whether or not to use atracurium.

Die Durchführung einer maschinellen Beatmungstherapie im Rahmen eines akuten Lungenversagens birgt die Gefahr potenzieller Nebenwirkungen und Komplikationen. Oberste Priorität ist, die Lunge durch die maschinelle Beatmung nicht zusätzlich zu schädigen und einen beatmungs-induzierten/-assoziierten Lungenschaden (VILI/VALI) zu vermeiden. Forschungsergebnisse konnten zeigen, dass Beatmungsstrategien mit niedrigem positivem endexspiratorischem Druck (PEEP) sowie hohen Tidalvolumina (VT) zu einer vermehrten Überdehnung der Alveolen sowie vermehrtem zyklischen Öffnen und Kollabieren instabiler Alveolarregionen führt, wodurch Scherkräfte entstehen, welche die Lunge schädigen. Dies kann den Verlauf der Erkrankung maßgeblich beeinflussen und zudem zu einer erhöhten Letalität führen. Uneinigkeit besteht weiterhin bezüglich der Wahl des für den individuellen Patienten adäquaten PEEP. So ermöglicht die Verwendung der ARDSnet-Tabelle zwar eine unkomplizierte bettseitige Auswahl des PEEP anhand der erforderlichen inspiratorischen Sauerstoffkonzentration, berücksichtigt jedoch nicht die individuellen atemmechanischen Gegebenheiten. Verfahren zur bettseitigen Ermittlung individueller krankheitsspezifischer und atemmechanischer Charakteristika sind deutlich aufwendiger und bedürfen eines hohen Maßes an praktischer Erfahrung. In der hier vorliegenden Studie wurde ein tierexperimenteller Langzeitversuch (24 h) mit Auslösung eines akuten Lungenversagens (ARDS) durch ein Salzsäure-Aspirationsmodell am Schwein durchgeführt. Es erfolgte der randomisierte Vergleich dreier Beatmungsstrategien: ARDS-low-PEEP-Tabelle (ARDSnet-Gruppe), Open Lung Concept (OLC-Gruppe) sowie Elektroimpedanztomographie (EIT-Gruppe), zur Findung der optimalen Beatmungsstrategie im Rahmen eines akuten Lungenversagens. Die Versuchsreihe wurde durch die Tierschutzbehörde der Landesdirektion Leipzig nach §8 des Tierschutzgesetztes (Aktenzeichen TVV 35/11) genehmigt und in der Veterinärmedizinischen Fakultät der Universität Leipzig durchgeführt.:Inhaltsverzeichnis Abkürzungs- und Akronymverzeichnis 1 Einführung in die Thematik 1.1 Einleitung 1.2 Das akute Lungenversagen - Acute Respiratory Distress Syndrome (ARDS) - Definition und Pathophysiologie 1.3 Salzsäure-Aspiration als ARDS-Modell 1.4 Dynamische Parameter der Atemmechanik und deren Bedeutung im ARD 1.4.1 Bedeutung der Compliance und ihre Messung 1.4.2 Driving Pressure (∆p) 1.5 Maschinelle Beatmung 1.6 Verglichene Beatmungsstrategien 1.6.1 ARDSnetwork Protokoll (ARDSnet-Gruppe) 1.6.2 Open Lung Concept (OLC-Gruppe) 1.6.3 Elektroimpedanztomographie (EIT-Gruppe) 1.7 Quantitative Auswertung der Computertomographie (CT) - Tidale Rekrutierung 2 Zielstellung 3 Publikationsmanuskript 4 Zusammenfassung der Arbeit 5 Ergänzendes Material 6 Literaturverzeichnis 7 Darstellung des eigenen Beitrags 8 Selbstständigkeitserklärung 9 Teilnahmebescheinigung der Vorlesung: „Gute wissenschaftliche Praxis“ an der medizinischen Fakultät der Universität Leipzig 10 Curriculum Vitae - Lebenslauf 11 Publikationen 12 Danksagung

Diese kumulative Habilitation untersucht die Rolle des Renin-Angiotensin-Aldosteron-Systems (RAAS) bei chronischen und akuten Regelvorgänge im Salz-Wasser-Haushalt an wachen Hunden. Nach einer Einführung in die Methodik der Langzeitstudien werden zunächst die zirkardianen und ultradianen Veränderungen der Natriumausscheidung beschrieben, die wir bei den Hunden beobachten konnten. Es scheint, als sei das Natriumausscheidungsmuster bei Hunden das Resultat endogener Rhythmizität und exogen, reaktiver Prozesse. Beide Komponenten scheinen zur Aufrechterhaltung der Natriumhomöostase beizutragen. Bei der Infusion natriumretinierender Hormone wie Aldosteron und Angiotensin II verschob sich ein größerer Anteil der täglichen Natrium- und Wasserausscheidung in die Abend- und Nachtstunden. Wir haben dieses Phänomen als "Nachtverschiebung" bezeichnet. In Bilanzstudien über vier Tage wurde dann der Frage nachgegangen, ob das Ganz-Körper-(GK)-Natrium eine kontrollierte Variable ist. Wir konnten zeigen, dass zwei Faktoren bei der Kontrolle des GK-Natriums eine wesentliche Rolle spielen, die Aktivität des RAAS und der renale Perfusionsdruck. Ist nur eine dieser Komponenten gestört, kann sie durch die andere - was das Einstellen eines 24-Stunden Bilanzgleichgewichtes angeht - ausgeglichen werden, allerdings nur unter Inkaufnahme eines veränderten GK-Natriumbestands. Ebenfalls über vier Tage wurde die Bedeutung des NO (Stickoxid) für die langfristige Regelung des Natriumbestandes untersucht. Dabei wurde gefunden, dass die Plasma-Renin-Aktivität (PRA) während NO-Synthase-Inhibition durchweg niedriger als bei intaktem NO-System war. Der Aldosteron / PRA Quotient war unter NOS-Inhibition deutlich größer als in den jeweiligen Protokollen ohne NOS-Inhibition. In Kurzzeitstudien (3-4 Stunden) wurden wache Hunde während akuter Hypoxie, die akut mit einer Verminderung des Natrium- und Wasserbestandes einhergehen kann ("Höhendiurese"), sowie während kontrollierter maschineller Beatmung mit hohen positiv-end-exspiratorischen (PEEP) Drucken, die zur Natrium- und Wasserretention führen kann, untersucht. Unter Hypoxie zeigte sich, dass das in niedrigen Plasma-Konzentrationen als Adenosin-1-Rezeptorantagonist wirkende Theophyllin den Abfall der PRA und des Angiotensin II unter Hypoxie verhindern kann. Auf der anderen Seite fiel die Plasma-Aldosteron-Konzentration während Hypoxie unabhängig davon, ob Theophyllin infundiert wurde, wahrscheinlich wegen einer verminderten Aktivität der 18-Hydroxylase während Hypoxie. Die Untersuchungen unter PEEP-Beatmung ergaben u.a., dass bei bilateral denervierten, wachen Hunden, deren Natriumzufuhr normal ist, den Nierennerven keine wesentliche Rolle für die zu beobachtende Wasser- und Natriumretention während maschineller Beatmung zukommt. / This cumulative thesis investigates on conscious dogs the role of the renin-angiotensin-aldosterone system (RAAS) during chronic and acute challenges of salt and water homeostasis. After introducing the methods of long term studies in dogs, circadian and ultradian oscillations of sodium excretion are being described. We demonstrated, that the sodium excretion pattern in dogs is the result of endogenous rhythms and exogenous reactive processes. Both components seem to contribute to sodium homeostasis. When infusing sodium retaining hormones, such as aldosterone and angiotensin II, a greater share of the daily sodium and water excretion was shifted towards the evening and the night. This phenomenon was termed "night shift". In balance studies over four days it was investigated whether the total body sodium is a controlled variable. Two factors were identified to play a pivotal role in controlling total body sodium: the activity of the RAAS and renal perfusion pressure. If only one of these components is disturbed, the respective other component is able to equilibrate the 24 h sodium balance, but only on a different level of total body sodium. Also over a period of four days the significance of NO (nitric oxide) for the long-term regulation of sodium balance was investigated. Among others, it was found that compared to an intact NO system, the plasma-renin activity (PRA) was always lower during NO synthase (NOS) inhibition, and the aldosterone / PRA ratio was greater during NOS inhibition. In short-term studies (lasting 3-4 hours) awake dogs were studied during hypoxia - which is usually combined with a reduced total body sodium and water ("high altitude diuresis") - as well as during controlled mechanical ventilation with positive-end-expiratory pressure (PEEP) - which often leads to sodium and water retention. It was demonstrated that the decline in PRA and angiotensin II during hypoxia - which is a typical finding in conscious dogs - can be prevented by theophyllin, which acts as an adenosin-1-receptor antagonist in lower concentrations. On the other hand, plasma aldosterone concentration declined during hypoxia independent of whether theophyllin was infused or not, probably due to a reduced 18-hydroxylase activity during hypoxia. The PEEP studies demonstrated among others, that in bilaterally denervated conscious dogs - whose sodium intake was normal - the renal nerves play no substantial role for the water and sodium retention observed during PEEP ventilation.

In patients affected by acute respiratory failure or acute respiratory distress syndrome (ARDS) the leading cause of death is failure of different vital organs other than the lungs, so called multiple organ dysfunction syndrome (MODS). The abdominal organs have a crucial role in the pathogenesis of this syndrome. There is a lack of knowledge regarding the mechanisms by which mechanical ventilation can affect the abdominal compartment. One hypothesis is that mechanical ventilation can interfere with abdominal fluid balance causing edema and inflammation. We addressed the question whether different levels of ventilatory support (mechanical ventilation with different levels of positive end-expiratory pressure, PEEP, and spontaneous breathing with or without PEEP) can influence abdominal edema and inflammation in both healthy and endotoxin-exposed animals. The effect on lymphatic drainage from the abdomen exerted by different degrees of ventilatory support was evaluated (paper I). We demonstrated that endotoxin increases abdominal lymph production, that PEEP and mechanical ventilation increase lymph production but also impede lymphatic drainage; spontaneous breathing improves lymphatic drainage from the abdomen. By adapting a non-invasive nuclear medicine imaging technique and validating it (paper II), we have been able to evaluate extravascular fluid accumulation (edema formation) in the abdomen over time (paper III) demonstrating that edema increases during endotoxemia, mimicking a sepsis-like condition, and that spontaneous breathing, compared to mechanical ventilation, reduces extravascular fluid. Pro-inflammatory cytokines TNF-α and IL-6 in intestinal biopsies are reduced during spontaneous breathing compared to mechanical ventilation. Abdominal edema results in increased intra-abdominal pressure (IAP): in paper IV we analyzed the effect of increased intra-abdominal pressure on the respiratory system. Pulmonary shunt fraction increased with high IAP both in healthy and LPS animals, resulting in decreased level of oxygenation. These changes are only partially reversible by reducing IAP. In conclusion, mechanical ventilation is a life-saving tool but the possible side effect at the extra-pulmonary level should be considered, and the introduction of some degree of spontaneous breathing when clinically possible is a suggested choice.

Submitted by Jéssica Corrêa Rodrigues (espertavet@yahoo.com.br) on 2016-03-22T20:48:14Z No. of bitstreams: 1 Dissertação Mestrado Jéssica FINAL 22.03.pdf: 945644 bytes, checksum: 8ab008754823edb4eabe2f684cb7148a (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-03-23T16:15:21Z (GMT) No. of bitstreams: 1 rodrigues_jc_me_bot.pdf: 945644 bytes, checksum: 8ab008754823edb4eabe2f684cb7148a (MD5) / Made available in DSpace on 2016-03-23T16:15:21Z (GMT). No. of bitstreams: 1 rodrigues_jc_me_bot.pdf: 945644 bytes, checksum: 8ab008754823edb4eabe2f684cb7148a (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A realização da laparoscopia cirúrgica requer a insuflação de gás carbônico (CO2) na cavidade abdominal. O pneumoperitônio formado eleva a pressão intra-abdominal (PIA), deslocando o diafragma em sentido cranial, o que resulta em diminuição da complacência pulmonar e consequentemente formação de áreas atelectásicas. Este estudo objetivou investigar os efeitos do pneumoperitônio e de uma manobra de recrutamento alveolar (MRA) seguida por aplicação de pressão positiva ao final da expiração (PEEP) na função cardiorrespiratória em ovinos. Em um delineamento prospectivo aleatório cruzado, nove ovinos (36–52 kg) foram anestesiados com isoflurano e fentanil e submetidos à ventilação com volume controlado (volume corrente: 12 mL/kg) com o emprego do bloqueador neuromuscular atracúrio. Cada animal recebeu três tratamentos com intervalo de dez dias entre cada experimento: Controle (sem intervenção); Pneumo (pneumoperitônio mantido por 120 minutos sob PIA de 15 mmHg); Pneumo+MRA/PEEP (pneumoperitônio mantido por 120 minutos sob PIA de 15 mmHg e realização de uma MRA aos 60 minutos após insuflação abdominal seguida por 10 cmH2O de PEEP). A MRA consistiu em aumentos progressivos na pressão expiratória a cada minuto até alcançar o valor de 20 cmH2O de PEEP. As variáveis estudadas foram coletadas até 30 minutos após a interrupção do pneumoperitônio. A insuflação abdominal com CO2 diminuiu significativamente (P < 0.05) os valores de PaO2 de 435–462 mmHg (intervalo dos valores médios observados) no tratamento Controle para 377–397 mmHg e 393–413 mmHg nos tratamentos Pneumo e Pneumo+MRA/PEEP, respectivamente. A complacência estática (Cstat, mL/cmH2O/kg) diminuiu significativamente de 0,83–0,86 (Controle) para 0,49–0,52 (Pneumo) e 0,51–0,54 (Pneumo+MRA/PEEP) após a indução do pneumoperitônio. A MRA/PEEP elevou significativamente a PaO2 (429–444 mmHg) e a Cstat (0,68–0,72) quando comparada com o os animais sob pneumoperitônio que não receberam a MRA/PEEP (PaO2: 383–385 mmHg e Cstat: 0,48–0,49). A realização do pneumoperitônio aumentou significativamente a formação de “shunt” intrapulmonar; porém após a aplicação da MRA/PEEP houve uma diminuição significativa nos valores de “shunt”. Trinta minutos após a desinsuflação abdominal, a PaO2 e a Cstat encontravam-se significativamente menores e o “shunt” intrapulmonar significativamente maior no tratamento Pneumo quando comparado ao tratamento Controle. Durante os últimos 60 minutos de pneumoperitônio (Pneumo e Pneumo+MRA/PEEP), os valores médios de índice cardíaco (IC) foram 20–28 % menores (P < 0.05) que os valores observados no tratamento Controle. Após a MRA/PEEP, a pressão média da artéria pulmonar (PMAP) apresentou-se significativamente maior (47-56%) e a pressão arterial média (PAM) apresentou-se significativamente menor (16%) em relação ao tratamento Controle. Concluiu-se que a desinsuflação abdominal não foi suficiente para reverter os impactos negativos na função pulmonar associados à realização do pneumoperitônio e que a realização de uma MRA seguida por PEEP foi capaz de melhorar a complacência do sistema pulmonar e reverter o prejuízo na oxigenação ocasionados pela insuflação abdominal, sem, no entanto, induzir alterações hemodinâmicas inaceitáveis. / Laparoscopic surgical procedures usually require carbon dioxide (CO2) insufflation into the peritoneal cavity. The pneumoperitoneum increases intra-abdominal pressure (IAP) displaces the diaphragm cranially, and decreases respiratory system compliance, leading to the development of atelectasis. This study aimed to investigate the effects of pneumoperitoneum and of an alveolar recruitment maneuver (ARM) followed by positive end-expiratory pressure PEEP on cardiopulmonary function in sheep. In a prospective randomized crossover study, nine sheep (36–52 kg) received 3 treatments with 10-day intervals during isoflurane-fentanyl anesthesia and volume-controlled ventilation (tidal volume: 12 mL/kg): Control (no intervention); Pneumo (120 minutes of CO2 pneumoperitoneum until achieving an intra-abdominal pressure of 15 mmHg); Pneumo+ARM/PEEP (same pneumoperitoneum protocol with an ARM after 60 minutes of abdominal inflation). The ARM consisted of stepwise increases in end-expiratory pressures every minute until 20 cmH2O of PEEP, followed by 10 cmH2O of PEEP. Data were recorded until 30 minutes after abdominal deflation. Abdominal inflation significantly (P < 0.05) decreased PaO2 from 435–462 mmHg (range of recorded mean values) in controls to 377–397 mmHg and 393–413 mmHg in the Pneumo and Pneumo+ARM/PEEP treatments, respectively. Static compliance (Cstat, mL/cmH2O/kg) was significantly decreased from 0.83–0.86 (Control) to 0.49–0.52 (Pneumo), and 0.51–0.54 (Pneumo+ARM/PEEP) after induction of pneumoperitoneum. The ARM/PEEP significantly increased PaO2 [429–444 mmHg and Cstat (0.68–0.72)] from values recorded during pneumoperitoneum alone [PaO2: 383–385 mmHg and Cstat: 0.48–0.49]. Pneumoperitoneum significantly increased intrapulmonary Shunt; while the ARM/PEEP significantly decreased the Shunt. Thirty minutes after abdominal deflation (Pneumo), PaO2 and Cstat were significantly lower and the Shunt was higher than in controls. During the last 60 minutes of pneumoperitoneum (Pneumo and Pneumo+ARM/PEEP), cardiac index values were 20–28 % lower than in controls. After the ARM/PEEP, mean pulmonary artery pressure was significantly higher (47-56%) and mean systemic arterial pressure was significantly lower (16%) than controls. It was concluded that abdominal deflation is not enough to reverse the impairment in pulmonary function associated with pneumoperitoneum and the ARM/PEEP may improve respiratory system compliance and reverse the oxygenation impairment induced by pneumoperitoneum with clinically acceptable hemodynamic changes.

The general purpose of this study is to develop a series of peep shows, or visual models, which will enable the young student to understand what the laws of perspective are, how they were found, and why his drawings will appear to have three dimensions if he follows the rules. The study is based upon a widely accepted idea--that it is much easier for most people to understand and remember a principle when they can actually see how it works. When rules are merely memorized, one is not assisted by reason, which is essential for useful retention.

No description available.

INTRODUÇÃO: A doença pulmonar obstrutiva crônica (DPOC) leva à obstrução crônica do fluxo aéreo e retenção de ar, fatores que afetam a ação diafragmática, colocando-o em desvantagem mecânica e exigindo-o recrutamento da musculatura acessória da respiração. Alguns estudos indicam que a aplicação de Pressão Positiva Expiratória nas Vias Aéreas (EPAP) reduziria a hiperinsuflação e a atividade da musculatura inspiratória acessória. OBJETIVO: Analisar o efeito da aplicação da EPAP de 10 e 15 cmH2O sobre a atividade dos músculos esternocleidomastóideo (ECM) e paraesternal em pacientes com DPOC estável. MÉTODOS: Em um ensaio clínico randomizado, composto por vinte e um pacientes com DPOC, que foram alocados em Grupo 10 cmH2O (n=10) e Grupo 15 cmH2O (n=11), avaliamos o comportamento da atividade eletromiográfica (EMG) dos músculos ECM e paraesternal em respiração espontânea (Pré-EPAP), durante a aplicação de 20 minutos da EPAP, através de máscara facial, e 10 minutos após sua retirada. RESULTADOS: Observamos que a aplicação da EPAP de 10 cmH2O promoveu uma redução da atividade EMG do músculo ECM (p<0,0001) e aumento no músculo paraesternal (p<0,0001). Já o grupo que utilizou 15 cmH2O de EPAP apresentou uma tendência ao aumento da atividade EMG do músculo ECM e uma redução significativa no músculo paraesternal (p= 0,005). CONCLUSÕES: Nossos resultados apontaram para um benefício da aplicação da EPAP de 10 cmH2O em reduzir a atividade da musculatura inspiratória acessória e potencializar a ação dos músculos paraesternais em pacientes com DPOC estável. No entanto, este benefício não foi alcançado quando a EPAP de 15 cmH2O foi aplicada, onde os pacientes apresentaram um aumento da atividade da musculatura inspiratória acessória, já acentuada na DPOC. / Introduction: Chronic obstructive pulmonary disease (COPD) leads to chronic airway obstruction and air trapping, affecting diaphragmatic action and placing it at a mechanical disadvantage, requiring the recruitment of accessory muscles. Some studies indicate that expiratory positive airway pressure (EPAP) decreased hyperinflation and inspiratory accessory muscle activity. Objective: To investigate the effect of 10 and 15 cmH2O EPAP on the activity of sternocleidomastoid (SCM) and parasternal muscles in patients with stable COPD. Methods: A randomized clinical trial with twenty-one COPD patients. Subjects were randomly allocated to two groups: 10 cmH2O Group (n=10) and a 15 cmH2O Group (n=11). We evaluated the electromyographic (EMG) activity of SCM and parasternal muscles in spontaneous breathing (Pre-EPAP), during application of EPAP by face mask for 20 minutes, and for 10 minutes after mask removal (Post-EPAP). Results: The application of 10 cmH2O EPAP promoted reduction EMG activity in the SCM muscle (p<0.0001) and increased parasternal muscle activity (p<0.0001). The group submitted to 15 cmH2O EPAP showed a tendency towards greater EMG activity in the SCM muscle and a significant decrease in activity of the parasternal muscle (p= 0.005). Conclusions: In patients with stable COPD, 10 cmH2O EPAP induced a significant decreased in activity of the inspiratory accessory muscle and increased parasternal muscle activity after the application. This may be of practical benefit to reverse the extensive use of the chest wall muscles and reduce their mechanical disadvantage in patients with COPD.

INTRODUÇÃO: A doença pulmonar obstrutiva crônica (DPOC) leva à obstrução crônica do fluxo aéreo e retenção de ar, fatores que afetam a ação diafragmática, colocando-o em desvantagem mecânica e exigindo-o recrutamento da musculatura acessória da respiração. Alguns estudos indicam que a aplicação de Pressão Positiva Expiratória nas Vias Aéreas (EPAP) reduziria a hiperinsuflação e a atividade da musculatura inspiratória acessória. OBJETIVO: Analisar o efeito da aplicação da EPAP de 10 e 15 cmH2O sobre a atividade dos músculos esternocleidomastóideo (ECM) e paraesternal em pacientes com DPOC estável. MÉTODOS: Em um ensaio clínico randomizado, composto por vinte e um pacientes com DPOC, que foram alocados em Grupo 10 cmH2O (n=10) e Grupo 15 cmH2O (n=11), avaliamos o comportamento da atividade eletromiográfica (EMG) dos músculos ECM e paraesternal em respiração espontânea (Pré-EPAP), durante a aplicação de 20 minutos da EPAP, através de máscara facial, e 10 minutos após sua retirada. RESULTADOS: Observamos que a aplicação da EPAP de 10 cmH2O promoveu uma redução da atividade EMG do músculo ECM (p<0,0001) e aumento no músculo paraesternal (p<0,0001). Já o grupo que utilizou 15 cmH2O de EPAP apresentou uma tendência ao aumento da atividade EMG do músculo ECM e uma redução significativa no músculo paraesternal (p= 0,005). CONCLUSÕES: Nossos resultados apontaram para um benefício da aplicação da EPAP de 10 cmH2O em reduzir a atividade da musculatura inspiratória acessória e potencializar a ação dos músculos paraesternais em pacientes com DPOC estável. No entanto, este benefício não foi alcançado quando a EPAP de 15 cmH2O foi aplicada, onde os pacientes apresentaram um aumento da atividade da musculatura inspiratória acessória, já acentuada na DPOC. / Introduction: Chronic obstructive pulmonary disease (COPD) leads to chronic airway obstruction and air trapping, affecting diaphragmatic action and placing it at a mechanical disadvantage, requiring the recruitment of accessory muscles. Some studies indicate that expiratory positive airway pressure (EPAP) decreased hyperinflation and inspiratory accessory muscle activity. Objective: To investigate the effect of 10 and 15 cmH2O EPAP on the activity of sternocleidomastoid (SCM) and parasternal muscles in patients with stable COPD. Methods: A randomized clinical trial with twenty-one COPD patients. Subjects were randomly allocated to two groups: 10 cmH2O Group (n=10) and a 15 cmH2O Group (n=11). We evaluated the electromyographic (EMG) activity of SCM and parasternal muscles in spontaneous breathing (Pre-EPAP), during application of EPAP by face mask for 20 minutes, and for 10 minutes after mask removal (Post-EPAP). Results: The application of 10 cmH2O EPAP promoted reduction EMG activity in the SCM muscle (p<0.0001) and increased parasternal muscle activity (p<0.0001). The group submitted to 15 cmH2O EPAP showed a tendency towards greater EMG activity in the SCM muscle and a significant decrease in activity of the parasternal muscle (p= 0.005). Conclusions: In patients with stable COPD, 10 cmH2O EPAP induced a significant decreased in activity of the inspiratory accessory muscle and increased parasternal muscle activity after the application. This may be of practical benefit to reverse the extensive use of the chest wall muscles and reduce their mechanical disadvantage in patients with COPD.

INTRODUÇÃO: A doença pulmonar obstrutiva crônica (DPOC) leva à obstrução crônica do fluxo aéreo e retenção de ar, fatores que afetam a ação diafragmática, colocando-o em desvantagem mecânica e exigindo-o recrutamento da musculatura acessória da respiração. Alguns estudos indicam que a aplicação de Pressão Positiva Expiratória nas Vias Aéreas (EPAP) reduziria a hiperinsuflação e a atividade da musculatura inspiratória acessória. OBJETIVO: Analisar o efeito da aplicação da EPAP de 10 e 15 cmH2O sobre a atividade dos músculos esternocleidomastóideo (ECM) e paraesternal em pacientes com DPOC estável. MÉTODOS: Em um ensaio clínico randomizado, composto por vinte e um pacientes com DPOC, que foram alocados em Grupo 10 cmH2O (n=10) e Grupo 15 cmH2O (n=11), avaliamos o comportamento da atividade eletromiográfica (EMG) dos músculos ECM e paraesternal em respiração espontânea (Pré-EPAP), durante a aplicação de 20 minutos da EPAP, através de máscara facial, e 10 minutos após sua retirada. RESULTADOS: Observamos que a aplicação da EPAP de 10 cmH2O promoveu uma redução da atividade EMG do músculo ECM (p<0,0001) e aumento no músculo paraesternal (p<0,0001). Já o grupo que utilizou 15 cmH2O de EPAP apresentou uma tendência ao aumento da atividade EMG do músculo ECM e uma redução significativa no músculo paraesternal (p= 0,005). CONCLUSÕES: Nossos resultados apontaram para um benefício da aplicação da EPAP de 10 cmH2O em reduzir a atividade da musculatura inspiratória acessória e potencializar a ação dos músculos paraesternais em pacientes com DPOC estável. No entanto, este benefício não foi alcançado quando a EPAP de 15 cmH2O foi aplicada, onde os pacientes apresentaram um aumento da atividade da musculatura inspiratória acessória, já acentuada na DPOC. / Introduction: Chronic obstructive pulmonary disease (COPD) leads to chronic airway obstruction and air trapping, affecting diaphragmatic action and placing it at a mechanical disadvantage, requiring the recruitment of accessory muscles. Some studies indicate that expiratory positive airway pressure (EPAP) decreased hyperinflation and inspiratory accessory muscle activity. Objective: To investigate the effect of 10 and 15 cmH2O EPAP on the activity of sternocleidomastoid (SCM) and parasternal muscles in patients with stable COPD. Methods: A randomized clinical trial with twenty-one COPD patients. Subjects were randomly allocated to two groups: 10 cmH2O Group (n=10) and a 15 cmH2O Group (n=11). We evaluated the electromyographic (EMG) activity of SCM and parasternal muscles in spontaneous breathing (Pre-EPAP), during application of EPAP by face mask for 20 minutes, and for 10 minutes after mask removal (Post-EPAP). Results: The application of 10 cmH2O EPAP promoted reduction EMG activity in the SCM muscle (p<0.0001) and increased parasternal muscle activity (p<0.0001). The group submitted to 15 cmH2O EPAP showed a tendency towards greater EMG activity in the SCM muscle and a significant decrease in activity of the parasternal muscle (p= 0.005). Conclusions: In patients with stable COPD, 10 cmH2O EPAP induced a significant decreased in activity of the inspiratory accessory muscle and increased parasternal muscle activity after the application. This may be of practical benefit to reverse the extensive use of the chest wall muscles and reduce their mechanical disadvantage in patients with COPD.