Thesis submitted in fulfillment of the requirements for the degree of Masters of Science in Nursing, Faculty of Community and Health Sciences, Department of Nursing Education, University of the Witwatersrand Johannesburg, 2012 / Studies generally agree the survival of the mechanically ventilated patient in the ICU is largely reliant upon the competence of the nurse undertaking this highly specialized role (Alphonso,Quinones,Mishra,et al. 2004; Burns 2005) However, an audit undertaken by the Critical Care Society of Southern Africa (2004) revealed that 75 % of nurses working in ICU are inexperienced and do not hold an ICU qualification, and as such are unlikely to have acquired the level of competency required to care for the mechanically ventilated patient (Binnekade 2004). A high index of suspicion exists around the competence levels of nurses‟ currently working in ICU in SA as revealed by local studies (Khoza & Ehlers 1998; Scribante & Bhagwanjee 2003; Moeti, van Niekerk, van Velden, 2004; Morolong & Chabeli 2005; Windsor 2005; Perrie & Schmollgruber 2010). The purpose of the study was to determine and describe the level of competence with regard to mechanical ventilation, of nurses working in ICU, who have varying years of experience and training backgrounds, using study specific designed clinical vignettes, in two tertiary healthcare institutions in Gauteng. A descriptive two phase design was utilized for the study. Phase one comprised the development and validation of three clinical vignettes to determine the level of competence of nurses working in ICU‟s with regard to mechanical ventilation. A modified Delphi technique technique using purposively sampled experts from medical technical and nursing backgrounds was used to validate the three clinical vignettes. Content validity was strengthened by computing CVI of the instrument. In Phase two consecutive sampling was used, and data collection comprised of participants (n=136) completing three validated clinical vignettes in the ICU‟s of two tertiary healthcare institutions in Gauteng. All nurses who participated in the study completed the same three clinical vignettes and demographic data. Nurses‟ perceptions regarding their own level of competence with regard to mechanical ventilation were quantified and compared with actual scores achieved in the clinical vignettes. Descriptive and inferential statistics were used to analyse the data. The level of significance was set at <0,05 and confidence levels at 95%. The competency indicator for the vignettes was set at 75% by the expert group, and nurses‟ level of competence was graded according to vignette score outcomes using a grading scale. Statistical assistance was obtained from a statistician from the Medical Research Council (MRC). Results: Results of the study showed that nurses regardless of training background, age, or experience showed a poor level of knowledge, the average score being 48% for ICU qualified nurses and 31% for non-ICU qualified nurses. There was a small significant difference between ICU qualified and non-ICU qualified nurses‟ competence levels in mechanical ventilation when analysed using a two tailed- t- test (p=0.039). Nurses also experienced a misperception regarding their own competence levels in mechanical ventilation when compared to their actual competence levels as determined by three clinical vignettes.

Many critical clinical conditions result in respiratory failure and precipitate the use of mechanical ventilation for their management. A prolonged period of mechanical ventilation is costly for both the patient, in terms of adverse effects, and the health care service. Therefore, immediate liberation of the patient from mechanical ventilation and constitution of spontaneous breathing, a process called weaning, is vital. This daily lifesaving practice, on which nurses are taking an increasing role with the introduction of nurse-led protocols, can become complicated requiring the effective use of assessment information through decision-making processes to improve outcomes of care. Most literature on the field fails to address that weaning decisions are affected not only by the nature of the task but also by the characteristics of the decision-maker and the decision environment. This research aimed to study nurses' decision-making processes when managing the weaning of long-term ventilated patients and to explore the impact of the diverse elements of the clinical environment on this intricate practice. An ethnographic approach was used to compare weaning decision-making processes in two different culturally intensive care units (ICU). Participant observation was used to follow the weaning practices of 10 patients in a Scottish ICU and 9 patients in a Greek ICU admitted with respiratory failure due to pneumonia or COPD exacerbation. Nurses were observed in their daily weaning practice and participated in reflective interviews at the end of their shift to extrapolate how they used the information to make their decisions. Semi-structured interviews were, then, conducted with nurses, physiotherapists and medical staff to explore their perceptions on weaning practices and the factors that influenced their decisions and clinical practice. Data were analysed thematically and concept maps were developed from the reflective interviews to analyse nurses‟ decision-making processes. The concept attainment theory was used as a framework to understand nurses' thinking processes. Nurses in all ranges of experience demonstrated a similar decision-making skill, which signifies that this cognitive process is not always related to the level of experience and knowledge. Nurses' weaning care was organised around maintaining a balance of care under the 'wean as able' medical instruction. Inconsistency in the weaning decisions led to a variability of weaning approaches followed for each patient and to long periods of weaning inactivity. Various reasons, related to the working relationships, lack of nurses‟ accountability, lack of support and unstructured information flow, were responsible for the deficiency in sustainable and consistent weaning decisions. In both settings, there was lack of culture to foster a shared decision-making approach in weaning practice and encourage nurses' autonomy in decision-making. This study concluded with proposing a collaborative decision-making framework for weaning long-term ventilated patients, which will involve and appreciate the contribution of all members of the multidisciplinary team.

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg in partial fulfilment of the requirements for the degree of Master of Science in Nursing Johannesburg, 2017 / The purpose of this study was to describe the role of specialist nurses in mechanical ventilation management. The intention of the study was also to make recommendations for clinical practice and education of intensive care nurses. The setting of the study was ten (n = 10) adult intensive care units of two public hospitals in the Gauteng province. Included were trauma ICUs, cardiothoracic ICU, coronary care ICUs, major burns ICU, major injuries ICU, neurosurgery ICU and multidisciplinary ICUs. A non-experimental, descriptive, quantitative and cross-sectional survey design was used to describe the specialist nurses role in ventilation management. The final sample comprised 110 (out of 165) respondents, which yielded a response rate of 66.6% for the study. Data were collected from specialist intensive care nurses using a validated questionnaire developed by Rose et al. (2011). Data was analysed using descriptive (frequencies, means and standard deviation) and comparative statistical tests using t-tests and Chi-square analysis. Testing was done at the 0.05 level of significance. Of the 165 surveys distributed, 110 were returned (response rate 66.6%). Ninety-seven percent stated that a 1:1 ratio was used for patients receiving mechanical ventilation. Eighty-nine percent reported ventilation education for nurses was provided during ICU orientation, and 86.4% indicated ICUs provided opportunities for on-going ventilation education. Eighty-six percent of nurses reported that they had not worked in ICUs with automated weaning modes. Fifty-nine percent stated that weaning protocols were present in ICUs, and 56.4% reported the presence of protocols for weaning failure. Most nurses agreed that nurses and doctors collaborated in key ventilation decisions, but not when decisions to extubate and initial ventilation settings are made. This study showed a marginal (2%) number of nursing autonomous input made in key ventilator decisions. Seventy percent of nurses in this study agreed that responsibility for ventilation decisions lies at the level of senior registrars and above, and in their absence, only senior nurses (>80%) were perceived to be responsible for key ventilator decisions. Regarding independent titrations of ventilator settings, without medical consultation, findings showed that nurses in this study reported a frequency of >50% of the time for titration of respiratory rate, tidal volume, decreasing pressure support, increasing pressure support, titration of inspiratory pressure and ventilation mode changes. The self-perceived nursing autonomy and influence in decision making revealed a median score of 7 out of 10 points, respectively. Nurses with higher levels of autonomy, influence in decision making and years of experience scores, frequently (>50% of the time) made independent changes to ventilation settings (p<0.05). Conversely, nurses with fewer years of experience scores, infrequently (<50% of the time) made independent changes to ventilation settings without first checking with the doctor. The study concludes that nurses to re-evaluate their role in ventilation management and focus on key ventilation settings, nurses could strengthen their contribution in the collaboration of key ventilator settings. Recommendations are made for clinical practice and education of specialist nurses. / MT2018

ABSTRACT South Africa has a high incidence of violence and death due to unnatural causes. Gunshot and/or multiple stab wounds to the trunk are consequently injuries commonly seen in South African hospitals. Penetrating injuries often necessitate explorative surgical intervention to identify and treat injuries to the internal organs. Patients are managed in the intensive care unit and frequently return to theatre for abdominal lavage prior to eventual wound closure. Critical illness with prolonged mechanical ventilation and immobilization results in some degree of muscle dysfunction. Survivors of critical illness suffer from poor functional capabilities and decreased quality of life. No formal rehabilitation programmes exist in South Africa for these patients following discharge. Purpose: To determine if patients that survived penetrating trunk trauma recover adequately spontaneously following critical illness over the first six months following discharge from the hospital. Methods: A prospective, observational study was conducted. Patients with penetrating trunk trauma were recruited from four intensive care units in Johannesburg. Patients who received mechanical ventilation < 5 days were placed in Group 1 and those who received mechanical ventilation 5 days were placed in Group 2. Lung function tests, dynamometry, quality of life, six-minute walk distance and oxygen uptake tests were performed over six months following discharge from the hospital. The obtained results for dynamometry, exercise capacity and quality of life were compared between groups and to that measured for a healthy (age and sex-matched) control group. Results and Discussion: No pulmonary function abnormalities were detected for subjects in Groups 1 or 2. Distance walked during 6MWD test was significantly reduced for subjects in Group 2 compared to the control group [one-month (p = 0.00), three-months (p = 0.00)]. Morbidity correlated significantly with distance walked by subjects in Group 2 during 6MWD test [three-months (p = 0.03), six-months (p = 0.02)]. No statistically significant differences were found between subjects during the VO2peak test although subjects in Group 1 performed better clinically than those in Group 2. At one-month there was a significant reduction in upper and lower limb strength for subjects in Group 2 compared to those in Group 1 and the controls (p = 0.00 – 0.04). Similar results were detected at the three- and six-month assessments. ICU and hospital length of stay did demonstrate a significant relationship with muscle strength at one and three months following discharge for subjects in Group 2. Severity of illness and morbidity in ICU did not have a significant relation to muscle strength for subjects in Groups 1 or 2 at any of the assessments. Subjects in Group 1 had a significant reduction in right deltoid and triceps strength compared to the controls at one-month (p = 0.00 respectively) only. No significant differences in upper and lower limb muscle strength were detected between the control group and subjects in Group 1 three and six months after discharge. Subjects in both groups had similar limitations in physical and mental aspects of quality of life one-month after discharge. Subjects in Group 1 reported a quality of life comparable to the control group by three-months. Subjects in Group 2 had significant limitations in the physical components of quality of life at three- and six-months compared to those in Group 1 and the controls [p = 0.00 – 0.02]. Conclusion: Subjects in Group 1 recovered adequately on their own within three months after discharge from hospital with regard to muscle strength, exercise capacity and all aspects of quality of life. Subjects in Group 2 presented with significant limitations in exercise capacity, muscle strength and the physical aspects of quality of life even at six months after discharge. Impaired function was related to the duration of critical illness and immobility. A physiotherapist-led rehabilitation programme may be indicated for survivors of penetrating trunk trauma that received prolonged mechanical ventilation to address cardiovascular endurance and peripheral muscle strength retraining between one and three months after discharge to address the physical disabilities observed in these subjects.

A Building Integrated Photovoltaic/Thermal (BIPV/T) system that consists of a mechanically ventilated, multi-skin facade, a between-the-panes venetian blind layer, and a between-the-panes Photovoltaic (PV) panel is considered. Ambient air is drawn in and forced to flow upward through the system. As air moves through the system, it is heated by the blind layer, the glazing layers, and the PV panel. This BIPV/T system is especially attractive because it can produce electricity and thermal energy in the form of preheated fresh air and allow for adjustable daylighting. There is a need to understand, design, and optimize BIPV/T systems. The velocity and temperature fields around the blind slats were experimentally and numerically studied. Experimental observations and numerical models are essential in understanding the complex fluid dynamical and thermal system and providing design and optimization guidelines. Solar-optical and Computational Fluid Dynamics (CFD) models were developed and validated at various blind slat angles and flow mean speeds. Particle Image Velocimetry (PIV) and temperature measurements were taken inside the ventilated facade. A simple empirical one-dimensional (1–D) model was developed, based on average surface temperatures and heat transfer coefficients, to quickly calculate average surface temperatures and heat flux rates. Between-the-panes convective heat transfer coefficients were obtained from CFD and used in the 1–D model. Despite high vertical temperature stratifications along the glazing, shading, and air layers, the 1–D model can predict the surface temperatures accurately and allow for future optimization and inclusion in building energy simulation software.

A Building Integrated Photovoltaic/Thermal (BIPV/T) system that consists of a mechanically ventilated, multi-skin facade, a between-the-panes venetian blind layer, and a between-the-panes Photovoltaic (PV) panel is considered. Ambient air is drawn in and forced to flow upward through the system. As air moves through the system, it is heated by the blind layer, the glazing layers, and the PV panel. This BIPV/T system is especially attractive because it can produce electricity and thermal energy in the form of preheated fresh air and allow for adjustable daylighting. There is a need to understand, design, and optimize BIPV/T systems. The velocity and temperature fields around the blind slats were experimentally and numerically studied. Experimental observations and numerical models are essential in understanding the complex fluid dynamical and thermal system and providing design and optimization guidelines. Solar-optical and Computational Fluid Dynamics (CFD) models were developed and validated at various blind slat angles and flow mean speeds. Particle Image Velocimetry (PIV) and temperature measurements were taken inside the ventilated facade. A simple empirical one-dimensional (1–D) model was developed, based on average surface temperatures and heat transfer coefficients, to quickly calculate average surface temperatures and heat flux rates. Between-the-panes convective heat transfer coefficients were obtained from CFD and used in the 1–D model. Despite high vertical temperature stratifications along the glazing, shading, and air layers, the 1–D model can predict the surface temperatures accurately and allow for future optimization and inclusion in building energy simulation software.

Aim: The aim of this study was to describe intensive care nurses’ experiences communicating with patients during mechanical ventilation. Methods/design: A qualitative interview study. Interviews where analyzed using descriptive content analysis Setting: Nine intensive care nurses from two different intensive care units were interviewed using a semi structured interview guide. Background: Past research has shown that patients during mechanical ventilation in the intensive care unit, feel very vulnerable and the helplessness of being unable to speak. These patients feels that they are completely dependent on the nurses and their competence. It has been shown to be very important that the patient feels included, acknowledged and respected. Results: The analyzed data resulted in a theme; through communication strive to preserve patients´ dignity and three main categories; create relationship to the patient, minimize patients´ vulnerability and don´t give up. These main categories consist of nine subcategories Conclusion: Critical ill patients during mechanical ventilation have a very limited opportunity to communicate. Therefore the patient is put in a very vulnerable position and is completely dependent on the nurse. This study shows that the nurse by communicating with the patient strive to preserve the patients dignity.

Orientador: Renato Giuseppe Giovanni Terzi / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-07T22:52:07Z (GMT). No. of bitstreams: 1 Toneloto_MariaGabrielaCavicchia_M.pdf: 2138095 bytes, checksum: 18b0cb653b2350620f763efb13a4c9d7 (MD5) Previous issue date: 2006 / Resumo: O trabalho realizado em modelo experimental de fístula broncopleural (FBP) visou avaliar os efeitos fisiológicos de uma válvula de oclusão inspiratória (VOI), identificando qual a modalidade ventilatória, o volume corrente ideal e o emprego da PEEP sobre o débito da fístula e de variáveis respiratórias e hemodinâmicas. Foram estudados cinco porcos da linhagem Large White com pulmões normais e peso médio de 25 kg. Todos os animais foram anestesiados, intubados e curarizados. Após controle inicial, foi realizada toracotomia esquerda com a retirada da língula pulmonar, expondo um brônquio de aproximadamente 4 mm, de diâmetro. A seguir, o tórax foi drenado com um sistema em selo d¿água e, posteriormente, fechado. Os animais foram ventilados com volumes correntes de 4 ml/kg, 7 ml/kg e 10 ml/kg, no respirador BIRD 8400, na modalidade controlada, nos modos volume (VCV) e pressão controlados (PCV), associadas ou não à válvula de oclusão inspiratória, associando ou não a PEEP de 10 cmH2O. Foi mantida a freqüência respiratória fixa em 22 ciclos por minuto, a FiO2 em 0,4 e a relação I:E em torno de 1:2. A mecânica respiratória (CO2SMO Plus Dixtal/Novametrix®), variáveis hemodinâmicas (Swan-Ganz) e hemogasométricas (IL-1604), arteriais e venosas mistas, foram registradas nos dois modos ventilatórios (VCV e PCV), antes e após a aplicação de cada tratamento, a saber: VCV ou PCV + ZEEP; VCV ou PCV + PEEP; VOI + ZEEP (VCV ou PCV); VOI + PEEP (VCV ou PCV). Baseados nos resultados obtidos, conclui-se que, neste modelo experimental, o melhor ajuste ocorreu com VC de 10ml/kg associado à VOI com ZEEP. Os modos ventilatórios não foram diferentes. A PEEP, mesmo com volumes correntes baixos, reduz a ventilação alveolar e aumenta o débito da fístula. A PEEP, associada ao modelo de VOI estudado, interfere significativamente com a estabilidade hemodinâmica / Abstract: The objective of this work was to evaluate, in an experimental bronchopleural fistula (BPF) model, the effects of an inspiratory occlusion valve (IOV), identifying the ideal tidal volume and the effect of PEEP on the fistula output and on the respiratory and hemodynamic variables. Five Large White pigs with normal lungs with a mean weight of 25 kg were studied. All animals were anesthetized, intubated and paralyzed with curare. After stabilization, a left thoracotomy was performed and the resection of the lingula exposed a bronchial stump of approximately 4 mm in diameter. The chest wall was hermetically closed with underwater seal drainage. The animals were mechanically ventilated with tidal volumes off 4 ml/kg, 7 ml/kg e 10 ml/kg (BIRD 8400) in Volume Controlled (VCV) and Pressure Controlled (PCV) ventilation, associated, or not, to an IOV, alternating ZEEP and PEEP of 10 cmH2O. Respiratory rate was kept at 22 rpm, FiO2 at 0.4 and the I:E ratio around 1:2. Respiratory mechanics (CO2SMO Plus Dixtal/Novametrix®), hemodynamics (Swan-Ganz catheter) and blood gas parameters (IL-1604) were recorded in both ventilatory modes before and after each treatment: 1 ZEEP; 2. PEEP; 3. IOV + ZEEP; 4. IOV + PEEP. Based on our findings we conclude that, in this experimental model, the best ventilatory strategy was a tidal volume of 10 ml/kg associated with the inspiratory occlusion valve + ZEEP. No difference was observed between VCV and PCV. PEEP, even at low tidal volumes, reduces alveolar ventilation and increases fistula output. PEEP, associated with IOV, significantly interferes with hemodynamic stability / Mestrado / Pesquisa Experimental / Mestre em Cirurgia

Severe infections, trauma or major surgery can each cause a state of systemic inflammation. These causes for systemic inflammation often coexist and complicate each other. Mechanical ventilation is commonly used during major surgical procedures and when respiratory functions are failing in the intensive care setting. Although necessary, the use of mechanical ventilation can cause injury to the lungs and other organs especially under states of systemic inflammation. Moreover, a course of mechanical ventilator therapy can be complicated by ventilator-associated pneumonia, a factor greatly influencing mortality. The efforts to avoid additional ventilator-induced injury to patients are embodied in the expression ‘protective ventilation’. With the use of pig models we have examined the impact of protective ventilation on systemic inflammation, on organ-specific inflammation and on bacterial growth during pneumonia. Additionally, with a 30-hour ventilator-associated pneumonia model we examined the influence of mechanical ventilation and systemic inflammation on bacterial growth. Systemic inflammation was initiated with surgery and enhanced with endotoxin. The bacterium used was Pseudomonas aeruginosa. We found that protective ventilation during systemic inflammation attenuated the systemic inflammatory cytokine responses and reduced secondary organ damage. Moreover, the attenuated inflammatory responses were seen on the organ specific level, most clearly as reduced counts of inflammatory cytokines from the liver. Protective ventilation entailed lower bacterial counts in lung tissue after 6 hours of pneumonia. Mechanical ventilation for 24 h, before a bacterial challenge into the lungs, increased bacterial counts in lung tissue after 6 h. The addition of systemic inflammation by endotoxin during 24 h increased the bacterial counts even more. For comparison, these experiments used control groups with clinically common ventilator settings. Summarily, these results support the use of protective ventilation as a means to reduce systemic inflammation and organ injury, and to optimize bacterial clearance in states of systemic inflammation and pneumonia.

Mechanical ventilation (MV) therapy has been utilised in the intensive care unit (ICU) for 50 years to treat patients with respiratory illness by supporting the work of breathing, providing oxygen and removing carbon dioxide. MV therapy is utilised by 30-50% of ICU patients, and is a major driver of increased length of stay, increased cost and increased mortality. For patients suffering from acute respiratory distress syndrome (ARDS), the optimal MV settings are highly debated. ARDS patients suffer from a lack of recruited alveoli, and the application of positive end expiratory pressure (PEEP) is often used to maintain recruitment to maximise gas exchange and minimise lung damage. However, determining what level of PEEP is best for the patient is difficult. In particular, it involves a complex trade off between patient safety and ventilation efficacy. Currently, no clinical protocols exist to determine a patient-specific “best” PEEP. Model-based approaches provide an alternative patient-specific method to help clinical diagnosis and therapy selection. In particular, model-based methods can utilise a mix of both engineering and medical principles to create patient-specific models. The models are used for optimising ventilation settings and providing greater physiological insight into lung status than is currently available. Two model-based approaches are presented here. First, a quasi-static, minimal model of lung mechanics is presented based solely on fundamental lung physiology and mechanics. Secondly, a model of dynamic functional residual capacity (dFRC) is developed and presented based on model-based status of lung stress and strain. These models are validated with retrospective clinical data to evaluate the potential of such model-based approaches. Finally, the models are further validated with real time clinical data over a broader spectrum of pressure-volume ranges than prior studies to evaluate the clinical viability of model-based approaches to optimise MV therapy. When validated with real-time clinical trials data, the outputs of the recruitment model provide a range of optimal patient-specific values of PEEP based on different clinically and physiologically derived criteria. The recruitment model is also shown to have the ability to track the disease state of ARDS over time. The dFRC model introduces the PEEP stress parameter, β, which represents a unique population constant. The dFRC model suggests that clinically reasonable estimates of dFRC can be achieved by using this novel value of β, rather than the current, potentially hazardous, methods of deflating the lung to atmospheric pressure. Finally, a third model, combining the principles of recruitment and gas exchange is introduced. The combined model has the ability to estimate cardiac output (CO) changes with respect to PEEP changes during MV therapy. In addition, the model relates the coupled areas of circulation and pulmonary management, as well as linking these MV decision support models to oxygenation based clinical endpoints. A proof of concept is shown for this model by combining two different retrospective datasets and highlighting its ability to capture clinically expected drops in CO as PEEP increases. The model allows valuable cardiovascular circulation data to be predicted and also provides an alternative method and clinical end point by which PEEP could be optimised. The model requires further clinical validation before clinical use, but shows significant promise. The models developed and tested in this research enable rapid parameter identification from minimal, readily available clinical data, and thus provide a novel way of guiding therapy. The models can potentially provide clinicians with information to select an optimal patient-specific level of PEEP using only standard ventilation data, such as pressure-volume curves. In addition, the development of a dFRC stress model provides a unique population constant, β. Overall, the modelling approaches developed and validated in this research provide several novel methods of guiding therapy setting mechanical ventilation parameters and tracking and assess a patient’s lung condition. This research thus creates and provides novel validated methods for improving MV therapy with minimal cost or added invasiveness.