Fluvial erosion incites significant bridge scour and large-scale bank erosion causing estimated $1.1 billion damage in the Midwest. Conventional, manual, field monitoring methods, typically erosion pins, cross-section resurveys or terrestrial photogrammetry, used to monitor fluvial erosion rates merely provide a net change in bank surface retreat since the previous measurement. If mass wasting has occurred, the ongoing fluvial erosion would be masked. Erosion event timing, and the precise bank response to individual flow or flow hydrograph changes, is generally uncertain. Thus, a technique that automatically quantifies bank erosion on a continuous basis is needed. This study will monitor the bank response to individual flow (i.e., fluvial erosion) using the Photo-Electronic Erosion Pin (PEEP) sensors in Clear Creek Iowa. It attends to monitor a full episode of bank change, including event timings and magnitude information for specific erosion and deposition events, which can be compared to flow discharges and hydrographs. If exploited, this method can lead to more detailed analysis of bank erosion related to temporal fluctuations in the suspected hydraulic forces.

Bakgrund: Omsorg har väckt många känslor inom forskarvärlden. En del forskare menar att omsorg ska lägga grunden för sjuksköterskans kunskapsområde istället för omvårdnad. Syfte: Syftet var att belysa innebörden i begreppet omsorg i en omvårdnadskontext. Metod: Begreppsanalys enligt Peep Koorts modell. En semantisk analys med etymologisk utredning och diskriminationsanalys av omsorgs synonymer. Resultat: Den etymologiska utredningen visade att begreppet omsorg bibehållit sin innebörd över tid. Kontexten har dock ändrats från att ofta användas i ett Bibliskt sammanhang till att idag vara något som används i folkmun och i olika yrkessammanhang. I resultatet framkommer det att skötsel och omtanke är begreppet omsorgs starkaste synonymer. I den semantiska analysen och diskriminationsanalysen av begreppet omsorg kunde två olika betydelsedimensioner tydligt påvisas: praktiskt arbete och sjuksköterskans välvilja. Möjligen är det detta som bidrar till den rådande oenigheten av begreppet. Slutsats: Begreppet omsorg har inte förändrats avsevärt mycket sedan år 1950 och framåt. I samhället generellt så förknippas begreppet omsorg med omsorgsverksamheter, samhällsvård och socialvård. Kärlek är en grundpelare för att kunna ge omsorg och kan uttrycka sig på många olika sätt i omvårdnaden.

Auto-PEEP is auto positive end-expiratory pressure due to excessive amounts of alveolar gas produced by sustained recurrent incomplete exhalation. Incomplete exhalation occurs when the exhaled breath never reaches a flow rate of 0 L/min. The objective of this dissertation is to develop an automated detection system of auto-PEEP through incomplete exhalation as revealed by ventilator graphics for mechanically ventilated adults. Auto-PEEP can cause adverse effects if allowed to linger and if not quickly identified. An automated detection system will be instrumental in helping to quickly identify auto-PEEP. A computerized algorithm was developed to detect incomplete exhalation based on the following three parameters:1) Foi, was used to represent the value of the flow at the onset of inhalation, 2) ∆T, was used to represent the value of time difference between onset inhalation to the 0 L/min mark, and 3) slope threshold, a value set for the slope of change of flow over ∆T. Optimum parameters of the algorithm were achieved for Foi = -3 L/min, ∆T = 0.2 s, and slope threshold = 90 L-s/min. A novel data set was introduced to validate the algorithm, yielding no significant difference in true positive rates (t = 1.5, df = 12.402, p-value = 0.1408) and false positive rates (t = 1.9, df = 16.765, p-value = 0.0725) as outcomes for two-tailed t-tests comparing the novel and old data set. To determine the relationship between auto-PEEP and detection of sustained incomplete exhalation, a correlation of a linear model of the novel data set between auto-PEEP and the percentage of incomplete exhalation detection out of the existing breaths (index) was investigated. A linear model should interpret the index value that corresponds to significant auto-PEEP presence; unfortunately, no significant linear model was found between incomplete exhalation index and auto-PEEP (F1,62 = 1.67, p-value = 0.2010). However, there was a relationship between the intrinsic PEEP values and the incomplete exhalation index as functions of time. The automated detection algorithm produced by this work provides a non-invasive method of automatically detecting auto-PEEP.

Introdução: A individualização da pressão positiva ao final da expiração (PEEP) pode reduzir a pressão de distensão e a formação de atelectasias em pacientes sendo submetidos a cirurgia abdominal eletiva. Objetivos: Titular a PEEP e comparar a mecânica respiratória de pacientes ventilados com PEEP titulada a pacientes ventilados com PEEP de 4 cmH2O. Após a extubação, comparar a formação de atelectasias. Métodos: Pacientes submetidos à cirurgia laparoscópica ou cirurgia aberta foram incluídos de forma não consecutiva, estratificada e randomizados em dois braços: PEEP titulada (PEEPT) e PEEP de 4 cmH2O (PEEP4). A PEEP foi titulada com tomógrafo de impedância elétrica (TIE). Dados de mecânica e três gasometrias foram coletadas durante o intraoperatório. Após extubação, os pacientes realizaram a uma tomografia computadorizada de tórax. Resultados: Vinte pacientes submetidos à cirurgia laparoscópica e vinte pacientes submetidos à cirurgia aberta foram incluídos. A mediana de PEEP titulada foi 12 cmH2O (10-14), com uma ampla variação de 6-16 (IC 95% 10-14). O uso da PEEP titulada determinou uma redução da pressão de distensão (p < 0,001), melhora da complacência (p < 0,001), melhora a oxigenação (p < 0,001) apenas dos pacientes de cirurgia laparoscópica e redução da massa de tecido pulmonar não-aerada após a extubação (P < 0,05). Conclusão: A PEEP individualizada apresentou ampla distribuição. A individualização da PEEP reduziu a quantidade de atelectasia após a extubação e, também, melhorou a mecânica respiratória e a oxigenação / Rationale: Individualized PEEP may reduce driving pressure and the formation of atelectasis in patients undergoing elective abdominal surgery. Objectives: To titrate PEEP and compare respiratory mechanics of patients submitted to titrated PEEP to PEEP 4 cmH2O. After extubation, to compare the non-aerated lung mass. Methods: Patients undergoing laparoscopic or open abdominal surgery were stratified and randomized non-consecutively to titrated PEEP (PEEPT) and PEEP 4 cmH2O. PEEP was titrated using electrical impedance tomography. Respiratory mechanics arterial blood gas analysis were performed during surgery. After extubation, the patients were submitted to a chest computadorized tomography (CT) scan. Measurements and Main Results: Twenty patients undergoing laparoscopic surgery and twenty patients undergoing open abdominal surgery were included. The median PEEP was 12 cmH2O with a wide variation from 6 to 16 (IC 95% 10-14). Titrated PEEP reduced driving pressure (p < 0.001), improved respiratory system compliance (p < 0.001), improved oxygenation (p < 0.001) (only in patients being submitted to laparoscopic surgery) and reduced non-aerated lung mass on CT scan (p < 0.05) after extubation. Conclusions: Titrated PEEP had a wide variation. PEEP individualization reduced postoperative atelectasis and also improved respiratory mechanics and oxygenation

Bei Patienten mit einem akuten Lungenversagen (ALI oder ARDS) ist der Sauerstoffverbrauch der Lunge (VO2pulm) durch pathophysiologische Prozesse insbesondere die Ausbildung von Atelektasen stark beeinträchtigt. Aufgrund der Annahme, dass eine Steigerung der Anzahl ventilierter Lungenareale zu einer Erhöhung des pulmonalen Sauerstoffverbrauchs führt, haben wir den Einfluss eines definierten Rekrutierungsmanövers (PEEP/PEAK + 10 cmH2O) auf den pulmonalen Sauerstoffverbrauch (VO2pulm), pulmonalen kapillären Blutfluss (PCBF), der den nicht geshunteten Anteil am HZV darstellt, und den transpulmonalen Shunt (Qs/Qt) untersucht. In der vorliegenden Studie wurde der VO2pulm als Differenz zwischen dem Sauerstoffverbrauch des gesamten Körpers, gemessen über die indirekte Kalorimetrie (VO2cal), und dem über das inverse Fick`sche Prinzip errechneten Sauerstoffverbrauch (VO2Fick) bestimmt. Im Rahmen einer klinisch-prospektiven Studie konnten nach Annahme des Studienprotokolls durch die zuständige Ethikkommission 13 beatmete Patienten, welche die Consensus-Kriterien eines ALI oder ARDS erfüllten, eingeschlossen werden. Nach Sicherstellung einer adäquaten Volumensituation und Messung der Ausgangsparameter wurde der PEEP um 10 cmH2O erhöht. Um ein stabiles Atemzugvolumen (VT 6-8 ml/kgKG) und damit gleichbleibende Bedingungen für die alveoläre Ventilation bis auf das von uns durchgeführte Rekrutierungsmanöver zu gewährleisten, wurde zeitgleich der Spitzendruck ebenfalls um 10 cmH2O erhöht. Nach 15 und 60 min wurden die Zieldeterminanten pulmonaler Sauerstoffverbrauch (VO2pulm), PCBF und transpulmonaler Shunt erneut bestimmt. Die Messung der indirekten Kalorimetrie (VO2cal) wurde mit dem Deltatrac TM, MBM 200® durchgeführt, VO2Fick über die Thermodilutionsmethode ermittelt, die partielle CO2-Rückatmungsmethode (David®) zur Bestimmung des PCBF genutzt und der transpulmonale Shunt (Qs/Qt) mittels der Formel nach BERGGREN berechnet. Die statistische Auswertung der Daten erfolgte mittels T-Tests für gepaarte Stichproben. Nach dem Manöver konnte eine signifikante Steigerung des PCBF von 4,44 ± 1,15 l/min auf 5,4 ± 1,68 l/min nach 15 min, respektive 5,12 ± 1,67 l/min nach 60 min nachgewiesen werden (p&amp;lt;0,025). Dieser Anstieg wurde von einer signifikanten Reduktion des transpulmonalen Shunts (Qs/Qt) von 0,24 ± 0,08 auf 0,16 ± 0,07 nach 15 min und 0,16 ± 0,07 nach 60 min begleitet (p&amp;lt;0,005). Diese Veränderungen der pulmonalen Hämodynamik gehen mit statistisch relevanten Verbesserungen der Oxygenierung sowie der Atemmechanik einher. Eine signifikante Steigerung des pulmonalen Sauerstoffverbrauchs konnte für die gesamte Studienpopulation nicht festgestellt werden. In dieser Untersuchung steigt der Sauerstoffverbrauch der Lunge deskriptiv von baseline 10,1 +/- 30,59 ml/min über 11,42 +/- 27,42 ml/min nach 15 min, respektive auf 28,69 +/- 56,75 ml/min nach 60 min an. Die signifikante Steigerung des pulmonal-kapillären Blutflusses und die konsekutive Reduktion des transpulmonalen Shunts schon 15 min nach dem Manöver impliziert einen Anstieg der an der alveolären Ventilation teilnehmenden alveolokapillären Einheiten, was einer Rekrutierung von vorher atelektatischen Lungenabschnitten entspricht. Insbesondere bei ARDS-Patienten und Respondern konnten Rekrutierungs-induzierte Veränderungen detektiert werden, wohingegen die Patienten mit ALI oder Nonresponder keinerlei statistische Unterschiede während der Intervention zeigten. Trotz stattgefundener Wiederbelüftung von Atelektasen konnte ein statistisch relevanter Unterschied bezüglich des pulmonalen Sauerstoffverbrauchs durch das Rekrutierungsmanöver für die gesamte Studienpopulation nicht festgestellt werden.

Bei Patienten mit einem akuten Lungenversagen (ALI oder ARDS) ist der Sauerstoffverbrauch der Lunge (VO2pulm) durch pathophysiologische Prozesse insbesondere die Ausbildung von Atelektasen stark beeinträchtigt. Aufgrund der Annahme, dass eine Steigerung der Anzahl ventilierter Lungenareale zu einer Erhöhung des pulmonalen Sauerstoffverbrauchs führt, haben wir den Einfluss eines definierten Rekrutierungsmanövers (PEEP/PEAK + 10 cmH2O) auf den pulmonalen Sauerstoffverbrauch (VO2pulm), pulmonalen kapillären Blutfluss (PCBF), der den nicht geshunteten Anteil am HZV darstellt, und den transpulmonalen Shunt (Qs/Qt) untersucht. In der vorliegenden Studie wurde der VO2pulm als Differenz zwischen dem Sauerstoffverbrauch des gesamten Körpers, gemessen über die indirekte Kalorimetrie (VO2cal), und dem über das inverse Fick`sche Prinzip errechneten Sauerstoffverbrauch (VO2Fick) bestimmt. Im Rahmen einer klinisch-prospektiven Studie konnten nach Annahme des Studienprotokolls durch die zuständige Ethikkommission 13 beatmete Patienten, welche die Consensus-Kriterien eines ALI oder ARDS erfüllten, eingeschlossen werden. Nach Sicherstellung einer adäquaten Volumensituation und Messung der Ausgangsparameter wurde der PEEP um 10 cmH2O erhöht. Um ein stabiles Atemzugvolumen (VT 6-8 ml/kgKG) und damit gleichbleibende Bedingungen für die alveoläre Ventilation bis auf das von uns durchgeführte Rekrutierungsmanöver zu gewährleisten, wurde zeitgleich der Spitzendruck ebenfalls um 10 cmH2O erhöht. Nach 15 und 60 min wurden die Zieldeterminanten pulmonaler Sauerstoffverbrauch (VO2pulm), PCBF und transpulmonaler Shunt erneut bestimmt. Die Messung der indirekten Kalorimetrie (VO2cal) wurde mit dem Deltatrac TM, MBM 200® durchgeführt, VO2Fick über die Thermodilutionsmethode ermittelt, die partielle CO2-Rückatmungsmethode (David®) zur Bestimmung des PCBF genutzt und der transpulmonale Shunt (Qs/Qt) mittels der Formel nach BERGGREN berechnet. Die statistische Auswertung der Daten erfolgte mittels T-Tests für gepaarte Stichproben. Nach dem Manöver konnte eine signifikante Steigerung des PCBF von 4,44 ± 1,15 l/min auf 5,4 ± 1,68 l/min nach 15 min, respektive 5,12 ± 1,67 l/min nach 60 min nachgewiesen werden (p&amp;lt;0,025). Dieser Anstieg wurde von einer signifikanten Reduktion des transpulmonalen Shunts (Qs/Qt) von 0,24 ± 0,08 auf 0,16 ± 0,07 nach 15 min und 0,16 ± 0,07 nach 60 min begleitet (p&amp;lt;0,005). Diese Veränderungen der pulmonalen Hämodynamik gehen mit statistisch relevanten Verbesserungen der Oxygenierung sowie der Atemmechanik einher. Eine signifikante Steigerung des pulmonalen Sauerstoffverbrauchs konnte für die gesamte Studienpopulation nicht festgestellt werden. In dieser Untersuchung steigt der Sauerstoffverbrauch der Lunge deskriptiv von baseline 10,1 +/- 30,59 ml/min über 11,42 +/- 27,42 ml/min nach 15 min, respektive auf 28,69 +/- 56,75 ml/min nach 60 min an. Die signifikante Steigerung des pulmonal-kapillären Blutflusses und die konsekutive Reduktion des transpulmonalen Shunts schon 15 min nach dem Manöver impliziert einen Anstieg der an der alveolären Ventilation teilnehmenden alveolokapillären Einheiten, was einer Rekrutierung von vorher atelektatischen Lungenabschnitten entspricht. Insbesondere bei ARDS-Patienten und Respondern konnten Rekrutierungs-induzierte Veränderungen detektiert werden, wohingegen die Patienten mit ALI oder Nonresponder keinerlei statistische Unterschiede während der Intervention zeigten. Trotz stattgefundener Wiederbelüftung von Atelektasen konnte ein statistisch relevanter Unterschied bezüglich des pulmonalen Sauerstoffverbrauchs durch das Rekrutierungsmanöver für die gesamte Studienpopulation nicht festgestellt werden.

Formation of atelectasis, defined as reversible collapse of aerated lung, often occurs after induction of anaesthesia with mechanical ventilation. As a consequence, there is a risk for hypoxemia, altered hemodynamics and impaired respiratory system mechanics. In certain situations, the risk for atelectasis formation is increased and its consequences may also be more difficult to manage. Anesthesia for bariatric surgery in morbidly obese patients and surgery requiring one-lung ventilation (OLV) with capnothorax are examples of such situations. In Paper I (30 patients with BMI &gt; 40 kg/m2 scheduled for bariatric surgery) a recruit­ment maneuver followed by positive end-expiratory pressure (PEEP) re­duced the amount of atelectasis and improved oxygenation for a prolonged period of time. PEEP or a recruitment maneuver alone did not reduce the amount of atelectasis. In paper II we investigated whether it is possible to predict respiratory function impairment in morbidly obese patients without pulmonary disease from a preoperative lung function test. Patients with mild signs of airway obstruction (reduced end-expiratory flow) in the preoperative spirometry developed less atelectasis during anaesthesia. In paper III we developed an experimental model of sequential OLV with capnothorax using electrical impedance tomography (EIT) that in real-time detected lung separation and dynamic changes in pulmonary ventilation and perfusion distributions. OLV to the left side caused a decrease in cardiac output, arterial oxygenation and mixed venous saturation. In paper IV we used our model of OLV with capnothorax and applied a CO2-insufflation pressure of 16 cm H2O. We demonstrated that a PEEP level of 12-16 cm H2O is needed for optimal oxygenation and lowest possible driving pressure without compromising hemodynamic variables. Thus, the optimal PEEP was closely related to the level of the capnothorax insufflation pressure. With insufficient PEEP, ventilation/perfusion mismatch in the ventilated lung and redistribution of blood flow to the non-ventilated lung occurred.

Mechanical ventilation (MV) is the primary form of therapeutic support for patients with acute respiratory failure (ARF) or acute respiratory distress syndrome (ARDS) until the underlying disease is resolved. However, as patient disease state and response to MV are highly variable, clinicians often rely on experience to set MV. The result is more variable care, as there are currently no standard approaches to MV settings. As a result of the common occurrence of MV and variability in care, MV is one of the most expensive treatments in critical care. Thus, an approach capable of guiding patient-specific MV is required and this approach could potentially save significant cost. This research focuses on developing models and model-based approaches to analyse and guide patient-specific MV care. Four models and metrics are developed, and each model is tested in experimental or clinical trials developed for the purpose. Each builds the understanding and methods necessary for an overall approach to guide MV in a wide range of patients. The first model, a minimal recruitment model, captures the recruitment of an injured lung and its response to positive end expiratory pressure (PEEP). However, the model was only previously validated in diagnosed ARDS patients, and was not proven to capture behaviours seen in healthy patients. This deficiency could potentially negate its ability to track disease state, which is crucial in providing rapid diagnosis and patient-specific MV in response to changes in patient condition. Hence, the lack of validation in disease state progression monitoring from ARDS to healthy, or vice-versa, severely limits its application in real-time monitoring and decision support. To address this issue, an experimental ARDS animal model is developed to validate the model across the transition between healthy and diseased states. The second model, a single compartment linear lung model, models the lung as a conducting airway connected to an elastic compartment. This model is used to estimate the respiratory mechanics (Elastance and Resistance) of an ARDS animal model during disease progression and recruitment manoeuvres. This model is later extended to capture high resolution, patient-specific time-varying respiratory mechanics during each breathing cycle. This extended model is tested in ARDS patients, and was used to titrate patient-specific PEEP using a minimum elastance metric that balances recruitment and the risk of lung overdistension and ventilation-induced injury. Studies have revealed that promoting patients to breathe spontaneously during MV can improve patient outcomes. Thus, there is significant clinical trend towards using partially assisted ventilation modes, rather than fully supported ventilation modes. In this study, the patient-ventilator interaction of a state of the art partially assisted ventilation mode, known as neurally adjusted ventilatory assist (NAVA), is investigated and compared with pressure support ventilation (PS). The matching of patient-specific inspiratory demand and ventilator supplied tidal volume for these two ventilation modes is assessed using a novel Range90 metric. NAVA consistently showed better matching than PS, indicating that NAVA has better ability to provide patient-specific ventilator tidal volume to match variable patient-specific demand. Hence, this new analysis highlights a critical benefit of partially assisted ventilation and thus the need to extend model-based methods to this patient group. NAVA ventilation has been shown to improve patient-ventilator interaction compared to conventional PS. However, the patient-specific, optimal NAVA level remains unknown, and the best described method to set NAVA is complicated and clinically impractical. The Range90 metric is thus extended to analyse the matching ability of different NAVA levels, where it is found that response to different NAVA levels is highly patient-specific. Similar to the fully sedated MV case, and thus requiring models and metrics to help titrate care. More importantly, Range90 is shown to provide an alternative metric to help titrate patient-specific optimal NAVA level and this analysis further highlights the need for extended model-based methods to better guide these emerging partially assisted MV modes. Traditionally, the respiratory mechanics of the spontaneously breathing (SB) patient cannot be estimated without significant additional invasive equipment and tests that interrupt normal care and are clinically intensive to carry out. Thus, respiratory mechanics and model-based methods are rarely used to guide partially assisted MV. Thus, there is significant clinical interest to use respiratory mechanics to guide MV in SB patients. The single compartment model is extended to effectively capture the trajectory of time-varying elastance for SB patients. Results show that without additional invasive equipment, the model was able estimate unique and clinically useful respiratory mechanics in SB patients. Hence, the extended single compartment model can be used as ‘a one model fits all’ means to guide patient-specific MV continuously and consistently, for all types of patient and ventilation modes, without interrupting care. Overall, the model-based approaches presented in this thesis are capable of capturing physiologically relevant patient-specific parameters, and thus, characterise patient disease state and response to MV. With additional, larger scale clinical trials to test the performance and the impact of model-based methods on clinical outcome, the models can aid clinicians to guide MV decision making in the heterogeneous ICU population. Hence, this thesis develops, extends and validates several fundamental model-based metrics, models and methods to enable standardized patient-specific MV to improve outcome and reduce the variability and cost of care.

This study examines British television situation comedy over the last fifteen years and analyses the genre as part of a discourse about the nature of modernity. In this period globalisation, technology and the rapid reassessment of formerly established social structures have created new modes of everyday existence that represent significant changes to people’s lives. The thesis argues that contemporary sitcoms address these shifts in social understanding and anxieties about contemporary British life. A wide range of texts are discussed, four in particular detail; Peep Show, Love Soup, Saxondale and Home Time; which explicitly try to form a dialogue with their audience about living in modernity. The thesis largely takes a methodological approach from Television Studies, referencing scholars from the discipline, in particular John Ellis’s concepts of “working through” and employing a significant amount of textual analysis. Chapter two looks at the context of television in this changing world and chapter three analyses how sitcom as a genre has redefined its forms. Chapter four identifies the importance of ‘tone’ in comedy and analyses how modernity demands new modes of address for comedy to meet the expectations of its audience. The study demonstrates how texts balance new approaches with continuities drawn from the existing sitcom tradition. In order to interrogate the nature of social change and its effects, chapter one engages with the work of a number of social theorists. In particular it analyses the recent writings of Richard Sennett and Zygmunt Bauman, who identify contemporary life as “the culture of the new capitalism” and “liquid modernity” respectively. They consider how such change might affect how individuals feel about themselves and their place in society. Throughout, the thesis demonstrates how this work might be applied to the study of sitcom and combines social theory with a detailed analysis of this television form in transformation, arguing that sitcom remains a resonant site for audiences to participate in a productive discourse about how we live today.

A fisioterapia respiratória veio com o objetivo de atuar diretamente no sistema ventilatório, podendo alterar a mecânica pulmonar através da complacência dinâmica e da resistência do sistema respiratório. O clearence de secreções, ou higiene das vias aéreas é um processo fisiológico normal, necessário para prevenção de complicações das vias aéreas e de infecções do trato respiratório. Pacientes intubados não conseguem eliminar secreções adequadamente, favorecendo o acúmulo destas. Entre as diversas técnicas de fisioterapia respiratória surgiu há pouco tempo a proposta da utilização do próprio ventilador mecânico, como recurso para higiene brônquica através de alterações de fluxos e pressões. A técnica denominada Positive End Expiratory Pressure (PEEP) – Zero End Expiratory Pressure (ZEEP) – (Pressão Expiratória Final Positiva; Pressão Expiratória Final Zero) proporciona a insuflação dos pulmões por meio do aumento da PEEP, seguido de uma rápida descompressão pulmonar pela redução abrupta da PEEP até zero cmH2O. Desta forma, o objetivo deste estudo foi verificar o efeito da manobra PEEP-ZEEP na remoção de secreções traqueobrônquicas, na mecânica pulmonar e nos parâmetros hemodinâmicos em pacientes submetidos a ventilação mecânica invasiva. Foi realizado um estudo randomizado cruzado com amostra não sequencial por conveniencia, com 37 pacientes internado na Unidade de Terapia Intensiva do Hospital de Clinicas de Porto Alegre, entre Abril de 2014 e Outubro de 2015, que estavam em Ventilação Mecânica Invasiva a mais de 48H. As técnicas eram aplicadas com 24H de intervalo, sendo randomizada a primeira técnica de utilização. O protocolo PA tratava-se de aspiração isolada e o PP-Z da manobra PEEP-ZEEP associada a aspiração isolada. As secreções foram coletadas após ambos os protocolos e os parâmetros hemodinâmicos pré e pós protocolo. Os resultados indicam que a manobra PEEPZEEP é uma proposta terapêutica que pode ser implementada na prática assistencial. É no mínimo tão benéfica quanto às demais técnicas conhecidas, pois promove um aumento de retirada de volume de secreção em comparado com a técnica de aspiração isolada, auxiliando na higiene brônquica. Ao mesmo tempo, ao usar o próprio ventilador como meio, proporciona uma padronização da técnica, que gera uma simplificação de recursos envolvidos e redução no tempo de aplicação, podendo assim, aperfeiçoar o atendimento da fisioterapia. / The Respiratory Therapy came in order to act directly on the respiratory system and may amend lung mechanics through the dynamic compliance and respiratory system resistance. The clearance of secretions or airway clearance is a normal physiological process, required for prevention of complications airway and respiratory tract infections. Intubated patients can not clear secretions properly, favoring the accumulation of these. Among the various techniques of respiratory physiotherapy recently it was proposed of using mechanical ventilator itself as a resource for bronchial hygiene through flows and pressures changes. The technique called Positive End Expiratory Pressure (PEEP) - Zero End Expiratory Pressure (ZEEP) provides the inflation of the lungs by increasing the PEEP, followed by a rapid lung decompression by reducing abrupt PEEP to zero cmH2O. Thus, the aim of this study was to investigate the effect of PEEP-ZEEP maneuver in removing tracheobronchial secretions in the lung mechanics and hemodynamic parameters in patients undergoing invasive mechanical ventilation. A crossover randomized study was conducted with non sequential sample for convenience with 37 patients admitted to the Intensive Care Unit of the Hospital de Clinicas de Porto Alegre, between April 2014 and October 2015, which were Ventilation Invasive Mechanical over 48H. The techniques were applied with an interval of 24H, which randomized the first technique to use. The PA protocol it was an isolated aspiration and PP-Z PEEP-ZEEP maneuver associated with isolated aspiration. Secretions were collected after both protocols and hemodynamic parameters pre and post protocol. The results indicate that the PEEP-ZEEP maneuver is a therapeutic approach that can be implemented in healthcare practice. It is at least as beneficial as the other known techniques, as it promotes an increase in secretion volume withdrawn in comparison with isolated aspiration technique, assisting in the bronchial hygiene. At the same time, to use their own fan as a means, provides a technical standardization, which creates a simplification of resources involved and reduced application time and can thus improve the care of physical therapy.