Rivers in the U.S. Midwest are dynamic systems that can be natural laboratories for understanding the different modes of bank erosion, namely fluvial erosion, mass erosion, and mass failure. Fluvial and mass erosion are hydraulically driven and semicontinuous, whereas mass failure is episodic and often catastrophic. Being catastrophic, mass failure and its driving mechanisms have received considerable attention comparatively to mass and fluvial erosion. However, the linkage between hydraulically driven erosion and mass failure has not been examined fully. We hypothesize that fluvial and mass erosion affect the memory and response of the system by creating favorable hydrogeomorphic conditions for mass failure. This dissertation addresses three major shortcomings in the bank erosion literature, including the confusion surrounding critical erosional strength values for mass and fluvial erosion (τc,m and τc,f, respectively). The herein results clearly show that these two parameters are different, with τc,m being three to five times greater than τc,m. Therefore, excluding mass erosion estimates from sediment budgets or stability analyses can lead to significant errors in quantifying or predicting bank retreat and channel geometry. In addition, this study offered a methodological improvement for measuring the τc,m in-situ using Photo-Electric Erosion Pins, which semi-automatically measure mass erosion to generate erosional strength and erodibility values that are currently missing in the literature. This study also addressed the preconceived notion in morphodynamic modeling that bank soil profiles are homogeneous and universal strength/ cohesion parameters adequately represent the bank soil profile. This study shows that bank soil heterogeneity is present and significantly affects bank stability. Therefore, heterogeneity along a bank face must be assessed in at least three locations to provide adequate input data for bank erosion models. Finally, this study suggests that Factors of Safety for mass failure must be complemented with those for fluvial and mass erosion to avoid underestimating mass failure by as much as 30%. Hence, this study provides agencies like the U.S. Department of Agriculture key data regarding the total contributions from the different modes of bank erosion and channel, itself, to the stream sediment load for strategic targeting of Best Management Practices and in-streams stabilization structures.

<p>The recognition that supportive mechanical ventilation can also damage the lung, the so called ventilation induced lung injury (VILI), has revived the more than 40 year long debate on the optimal level of PEEP to be used. It is established that the prevention of VILI improves patient outcome and that PEEP exerts protective effects by preventing unstable diseased alveoli from collapsing. Therefore, the term “open lung PEEP” (OL-PEEP) has been introduced as the end-expiratory pressure that keeps the lung open after its collapse has been eliminated by an active lung recruitment manoeuvre. The determination of such an optimal level of PEEP under clinical circumstances is difficult and remains to be investigated.</p><p>The aim of this study was to investigate the usefulness of breath by breath monitoring of dynamic compliance (Cdyn) as a clinical means to identify OL-PEEP at the bedside and to demonstrate the improvement in lung function resulting from its application.</p><p>In a porcine lung lavage model of acute lung injury PEEP at maximum Cdyn during a decremental PEEP trial after full lung recruitment was related to the onset of lung collapse and OL-PEEP could be found 2 cmH₂O above this level Ventilation at OL-PEEP was associated with improved gas exchange, efficiency of ventilation, lung mechanics and less than 5% collapse on CT scans. In addition, dead space, especially its portion related to alveolar gas changed characteristically during recruitment, PEEP titration and collapse thereby helping to identify OL-PEEP.</p><p>The beneficial effects of OL-PEEP on lung function and mechanics was demonstrated in a porcine model of VILI. OL-PEEP improved lung function and mechanics when compared to lower or higher levels prior to or after lung recruitment. By using electrical impedance tomography it could be shown that PEEPs within the range of 14 to 22 cmH₂O resulted in a similar redistribution of both ventilation and perfusion to the dorsal regions of the lung. OL-PEEP resulted in the best regional and global matching of ventilation and perfusion explaining the drastic improvements in gas exchange. Also regional compliance was greatly improved in the lower half of the lung as compared to all other situations.</p><p>In ARDS patients OL-PEEP could be identified applying the same protocol. The physiological changes described could now be reproduced and maintained during a four hours study ventilation period in real patients at four study centres.</p><p>In conclusion, the usefulness of dynamic compliance for identifying open lung PEEP during a decremental PEEP trial was demonstrated under experimental and clinical conditions. This PEEP should then be used as an essential part of any lung protective ventilation strategy. The impact of ventilating ARDS patients according to the principles described in these studies on outcome are currently being evaluated in an international randomized controlled trial.</p>

Laparoscopic liver surgery is complicated due to the structure of this organ with open sinusoids. A serious disadvantage is the risk of gas embolism (GE) due to CO2 pneumoperitoneum. CO2 can enter the vascular system through a wounded vein. A common opinion is that gas fluxes along a pressure gradient, e.g. CVP-intra abdominal pressure (IAP). The occurrence of GE could also be eased by entrainment, a ‘Venturi-like’ effect, due to cyclic differences in thoracic pressure and blood flow caused by mechanical ventilation at normal frequency. The aims of these studies were to survey, in a porcine model, the influence on respiratory and haemodynamic variables by GE, to determine at what frequency, severity and duration GE occurs during laparoscopic liver resection (LLR) and whether there are methods to influence the occurrence or severity of GE. Pulmonary and circulatory variables were monitored and measured as well as continuous blood gas monitoring. Transoesophageal echocardiogram was used to identify GE and, according to the amount of bubbles in the right outflow tract of the heart, GE was graded as 0, 1 and 2. Pneumoperitoneum was created by using CO2and IAP was set to 16 mm Hg. A single bolus dose of CO2 influenced respiratory and haemodynamic variables for at least 4 h. During LLR GE occurred in 65-70% of the animals, of which the more serious caused negative influence on cardiopulmonary variables. Elevated PEEP (15 cm H2O) increased CVP but GE occurred irrespective if CVP was lower than or exceeded IAP. In two last studies, a hepatic vein was cut and left open for 3 m before it was clipped. Interestingly, no signs of GE were seen despite an open vein and IAP &gt; CVP in 8 of 20 animals. In the last study high frequency jet ventilation was used in order to minimise the risk of entrainment. The duration of GE was shortened. The occurrence of GE seemed to be influenced by several different factors. The physiological reaction of a GE is impossible to predict for a specific patient, and depends among other factors on comorbidity, and amount, site and entrance rate of GE.

The recognition that supportive mechanical ventilation can also damage the lung, the so called ventilation induced lung injury (VILI), has revived the more than 40 year long debate on the optimal level of PEEP to be used. It is established that the prevention of VILI improves patient outcome and that PEEP exerts protective effects by preventing unstable diseased alveoli from collapsing. Therefore, the term “open lung PEEP” (OL-PEEP) has been introduced as the end-expiratory pressure that keeps the lung open after its collapse has been eliminated by an active lung recruitment manoeuvre. The determination of such an optimal level of PEEP under clinical circumstances is difficult and remains to be investigated. The aim of this study was to investigate the usefulness of breath by breath monitoring of dynamic compliance (Cdyn) as a clinical means to identify OL-PEEP at the bedside and to demonstrate the improvement in lung function resulting from its application. In a porcine lung lavage model of acute lung injury PEEP at maximum Cdyn during a decremental PEEP trial after full lung recruitment was related to the onset of lung collapse and OL-PEEP could be found 2 cmH2O above this level Ventilation at OL-PEEP was associated with improved gas exchange, efficiency of ventilation, lung mechanics and less than 5% collapse on CT scans. In addition, dead space, especially its portion related to alveolar gas changed characteristically during recruitment, PEEP titration and collapse thereby helping to identify OL-PEEP. The beneficial effects of OL-PEEP on lung function and mechanics was demonstrated in a porcine model of VILI. OL-PEEP improved lung function and mechanics when compared to lower or higher levels prior to or after lung recruitment. By using electrical impedance tomography it could be shown that PEEPs within the range of 14 to 22 cmH2O resulted in a similar redistribution of both ventilation and perfusion to the dorsal regions of the lung. OL-PEEP resulted in the best regional and global matching of ventilation and perfusion explaining the drastic improvements in gas exchange. Also regional compliance was greatly improved in the lower half of the lung as compared to all other situations. In ARDS patients OL-PEEP could be identified applying the same protocol. The physiological changes described could now be reproduced and maintained during a four hours study ventilation period in real patients at four study centres. In conclusion, the usefulness of dynamic compliance for identifying open lung PEEP during a decremental PEEP trial was demonstrated under experimental and clinical conditions. This PEEP should then be used as an essential part of any lung protective ventilation strategy. The impact of ventilating ARDS patients according to the principles described in these studies on outcome are currently being evaluated in an international randomized controlled trial.

In this master thesis, a new method for estimating the position of the moving parts of avoice coil is presented. Instead of using a position sensor the method exploits the connectionbetween the position and the inductance of the voice coil. This is done by superpositioning a small sine voltage signal and the voice coil voltage control signal. By measuring thevoltage and current and using the fourier transform, the impedance and phase difference iscalculated which are used to compute the inductance. A medical ventilator (also known as a respirator) concept is developed with a control systemwhich takes the expiratory pressure from a higher to a lower level. The position estimationalgorithm is then used in an attempt to improve the pressure control. The result is a slightlymore stable control system. The master thesis is conducted at Maquet Critical Care (MCC) in Solna, Sweden. MCC is amedical technology company working with high performance medical ventilators. The longterm goal of this work is to develop a ventilator which is more comfortable for the patient.

Background: The use of pure oxygen during preoxygenation and induction of general anaesthesia is a major cause of atelectasis. The interaction between reduced lung volume, resulting in airway closure, and varying inspiratory fractions of oxygen (FIO2) in determining the risk of developing atelectasis is still obscure. Methods: In this thesis, computed tomography (in studies I and II during anaesthesia, in studies III and IV postoperatively) was used to investigate the area of atelectasis in relation to FIO2 and varying levels of continuous positive airway pressure (CPAP) or positive end-expiratory pressure (PEEP). Study I investigated the short-term influence of reducing FIO2 during preoxygenation and induction of general anaesthesia, and the time to hypoxia during apnoea. Study II focused on the long-term effect of an FIO2 of 0.8 for preoxygenation. Study III applied CPAP/PEEP with an FIO2 of 1.0 or 0.8 for pre- and postoxygenation until extubation. After extubation, CPAP with an FIO2 of 0.3 was applied before the end of mask ventilation. Study IV compared two groups given CPAP/PEEP during anaesthesia and an FIO2 of 1.0 or 0.3 during postoxygenation, but without CPAP after extubation. Results: Study I showed a reduction in atelectasis with an FIO2 of 0.8 or 0.6, compared with 1.0, but the time to hypoxia decreased. In study II, atelectasis evolved gradually after preoxygenation. In study III, atelectasis was reduced with an FIO2 of 1.0 and CPAP/PEEP compared with an FIO2 of 1.0 without CPAP/PEEP. The intervention failed in the group given an FIO2 of 0.8, this group had more smokers. Atelectasis and age were correlated. In study IV, no difference was found between the groups. Post hoc analysis showed that smoking and ASA class increased the risk for atelectasis. Conclusion, the effect of reducing FIO2 during preoxygenation to prevent atelectasis might be short-lived. A lower FIO2 shortened the time to the appearance of hypoxia. Increasing lung volume by using CPAP/PEEP also decreased the risk of atelectasis, but the method might fail; for example in patients who are heavy smokers. In older patients care must be taken to reduce a high FIO2 before ending CPAP.

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.

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.

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.

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.