No description available.

This thesis describes the model-based development and validation of an advisor for the maintenance of artificially ventilated patients in the intensive care unit (ICU). The advisor employs fuzzy logic to represent an anaesthetist's decision making process when adjusting ventilator settings to safely maintain a patient's blood-gases and airway pressures within desired limits. Fuzzy logic was chosen for its ability to process both quantitative and qualitative data. The advisor estimates the changes in inspired O2 fraction (FI02), peak inspiratory pressure (PEEP), respiratory rate (RR), tidal volume (VT) and inspiratory time (TIN), based upon observations of the patient state and the current ventilator settings. The advisor rules only considered the ventilation of patients on volume control (VC) and pressure regulated volume control (PRVC) modes. The fuzzy rules were handcrafted using known physiological relationships and from tacit knowledge elicited during dialogue with anaesthetists. The resulting rules were validated using a computer-based model of human respiration during artificial ventilation. This model was able to simulate a wide range of patho-physiology, and using data collected from ICU it was shown that it could be matched to real clinical data to predict the patient's response to ventilator changes. Using the model, five simulated patient scenarios were constructed via discussion with an anaesthetist. These were used to test the closed-loop performance of the prototype advisor and successfully highlighted divergent behaviour in the rules. By comparing the closed-loop responses against those produced by an anaesthetist (using the patient-model), rapid rule refinement was possible. The modified advisor demonstrated better decision matching than the prototype rules, when compared against the decisions made by the anaesthetist. The modified advisor was also tested using data collected from ICU. Direct comparisons were made between the decisions given by an anaesthetist and those produced by the advisor. Good decision matching was observed in patients with well behaved physiology but soon ran into difficulties if a patients state was changing rapidly or if the patient observations contained large measurement errors.

A research report submitted in partial fulfilment of the requirements for the degree of Master in Science in Physiotherapy in the Faculty of Medicine of the University of the Witwatersrand, Johannesburg. Johannesburg, 1994 / The manual resuscitation bag is a modality which is commonly used by physiotherapists to manually hyperinflate the lungs of mechanically ventilated patients. There is limited scientific evidence to support its use and the literature is not in agreement as to the effects of manual hyperinflation. A meta-analysis of the current research has been conducted to investigate the effects of this modality on arterial oxygen tension and lung compliance. All studies evaluating the effects of manual hyperinflation (or bagging) on arterial oxygen tensions andlor lung compliance on mechanically ventilated patients have been retrieved. Only studies which reported results in terms of mean values and standard deviation or standard error of the mean could be used in this analysis. Twelve studies were identified between the time period 1968 - 1994. Seven of these studies fitted the inclusion criteria. The mean and standard error (If the mean values for arterial oxygen tensions (Pa02) and lung compliance (Ci) have been used to calculate the 95% confidence intervals and these results were plotted on a graph. A comparative analysis has been performed un the results of the seven studies. A generally non-significant association between bagging and the Pa02 and Ci values was demonstrated. Great discrepancies were identified in the designs of the seven studies.Since the seven studies included ill this meta-analysis show an overall non-significant association, it is reasonable to assume that the manual resuscitation bag has limited capacity for increasing the Pa02 and Ci values. It is unfortunate that in the studies where a positive outcome of bagging was demonstrated. inadequate data was presented in the trials. Therefore, these studies could not be included in this meta-analysis. The studies which have been included, however, presented such divergent designs that they do not offer conclusive evidence. Recommendations are presented for a standardised, multicentre study which hopefully will clarify the therapeutic value of this elusive modality

Hypercapnia and/or hypoxia normally cause hyperventilation, The sensitivity to hypercapnia and hypoxia and the resultant hyperventilation is reduced in a patient suffering from damped respiratory centre activity. The P 0.1 method is a modification of the rebreathing technique where a patient rebreathes from a bag prefilled with a mixture of gases of known concentrations. This modification is not sensitive to airflow obstruction as is the case with the ventilatory response of the rebreathing technique. The P 0.1 method has been described by several authors during the past 8 years. There is however the need to standardise the technique. This thesis is an attempt to meet this need. The P 0.1 method involves the occlusion of the inspiratory airway for a set time after the onset of inspiration of a particular breathing cycle. The pressure (P 0.1) at this time, generated by the isometric contraction of the respiratory muscles, is recorded together with the end tidal P C02 . The valve is occluded approximately 20 times during a rebreathing trial lasting for 4 minutes. The plot of P 0.1 versus P C02 is linear and its slope gives an indication of respiratory centre activity. A low slope indicates damped respiratory centre activity. The control electronics was designed using digital logic. The occlusion valve is closed passively during the expiratory phase and then actively held for a preselected time, most frequently for 1OOms, after the onset of inspiration, during the next breathing cycle. The active occlusion period is preselectable between 50ms and 300ms. The inspiratory pressure is recorded at this time, or 10 or 20ms prior to the opening of the valve, by a sample and hold circuit. The occlusion valve can be triggered manually via a push button switch on the front panel, or periodically for preselectable periods every 5 to 30 seconds or pseudo-randomly. Ventilatory phase, pressure preset and autotrigger mode indicators are included as operator aids. In a limited number of clinical trials the equipment worked satisfactorily. During a hypercapnic study the CO2 concentration in the bag progressively increases with a resultant increase in ventilation. The hypercapnic trials carried out yielded encouraging results. The method is simple, rapid and easily reproducible. The regression line plots obtained are linear with correlation coefficients better than those presented in the literature. The sensitivity of the ventilatory drive defined as the slope of the P 0.1 versus P C02 regression line for a group of 10 healthy adult males tested was 0.79 ± 0.47 cmH 2 o/mmHg. The device is in clinical use in the Respiratory Clinic at Groote Schuur Hospital. Further work needs to be done to investigate the full meaning of the results obtained and to what extent it can be used as a noninvasive diagnostic and screening technique for respiratory disorders. The P 0.1 method will help the clinician to assess non-invasively the degree of impairment of respiratory centre output in patients suspected of having a damped respiratory centre and who may also suffer pulmonary mechanical defects because the technique is independent of airflow.

No description available.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2005. / Härtill 5 uppsatser.

Thesis (Ph. D.)--Virginia Commonwealth University, 2010. / Prepared for: School of Nursing. Title from title-page of electronic thesis. Bibliography: leaves 80-85.

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, 2016 / Mechanical ventilation is a life-saving and frequently used treatment modality in a variety of medical diagnosis in the intensive care unit (ICU). Despite that fact, mechanical ventilation can be a distressing experience for the patient, and may result in anxiety and discomfort. In recent years, light or no sedation and the practice of wake-up calls have become common approaches allowing the patient to be more awake during mechanical ventilation. Little is known about how patients experience this particular aspect of ICU treatment in light of changes in sedation practices. This study explored and described the experiences of patients on mechanical ventilation in the intensive care unit of one public sector hospital in Johannesburg. A qualitative, descriptive and explorative design was used and ten mechanically ventilated patients were recruited from the intensive care units of one public sector hospital in Johannesburg. The data was collected using audio-taped in-depth interviews to keep a record of the actual information presented by the participants. The collected data was transcribed and the information was analysed using Clarke and Braun’s (2013) descriptive method. A general expression from the participants was the fact that being connected to a ventilator induces a physical and emotional discomfort. The data analysis identified three themes which were (i) physical experiences, (ii) emotional experiences and (iii) communication. The participants described their experiences of breathlessness, mouth dryness, pain and physical discomfort as a result of being placed on the ventilator which caused the physical experiences for the patients. The experiences of bothering, fear of unknown, anxiety, feeling shocked and frightened at the moment of waking up from anaesthesia culminated into an emotional experience for the patients. The participants described that the extubation process has hard and difficult to endure, also powerlessness, loss of body image and control and near death experiences were findings of the participants. The lack of information was viewed by the participants in terms of being connected to mechanical ventilation as an important component of the recovery period, the benefit of purpose of connection during this period and the weaning process although, some of the participants alluded to receiving a measure of information but described it as inadequate to prepare them emotionally for the procedure. The short time for visitation and family presence was also evident in this study as impacting on the emotional state of the participants. In the midst of these unpleasant experiences, most of the participants appreciated the caring attitude of the ICU nursing staff which gave them a sense of comfort and safety. The findings of this study further showed that administration of sedation to some of the participants affected their memory as they could not recollect things that happen while in the ICU. Communication was the third theme that emerged from this study as findings revealed that the participants were not happy with the inability to talk as a result of the endotracheal tube. Nevertheless, the use of alternative communication methods such as the use of sign language, writing, scribbling on paper and lip reading gave the participants a bit of a relief. The findings of this study support the previous findings of the experiences of patients on mechanical ventilation. The findings add to the body of knowledge from the South African context as little is known regarding the patients experiences of mechanical ventilation from the South African context and Africa at large. As the field of intensive care nursing is growing in the African continent, it becomes imperative for research to be conducted in order to determine the clinical, educational and managerial gaps in ICU focusing more on measures to reduce these unpleasant experiences, increase evidence based practise and nursing perspectives. It may be appropriate for this study to be replicated in other private and public institution on a larger scale to compliment these findings. / MT2017

No description available.

Evidenced based practice (EBP) guidelines have been developed to reduce variation in weaning, provide quality of care and patient satisfaction. Nurse led weaning has been shown to reduce weaning time, and therefore it was important to identify whether nurses have sufficient knowledge to implement EBP regarding weaning (Hansen, Fjaelberg, Nilsen et al, 2008);(Crocker, 2002:272). Weaning protocols are associated with 25.0% reduction in the duration of mechanical ventilation time, a 78.0% reduction in weaning duration, and 10.0% reduction for length of stay in ICU (Blackwood, Alderdice, Burns et al, 2011:9). The purpose of the study was to evaluate and describe intensive care nurses’ knowledge of EBP guidelines with regard to weaning the mechanically ventilated patient. Five adult intensive care units at two tertiary public sector academic hospitals were used to conduct the study in order to determine barriers to EBP. A non-experimental, descriptive, prospective two-staged design was utilized in this two part study. In Stage I of the study, the sample size comprised six (n=6) specialist expert members selected from the ICU’s at the study site using a non-probability purposive sampling method. In Stage II of the study, the sample size comprised eighty (n=80) intensive care nurse respondents selected from the ICU’s using simple random sampling. The data collection instrument developed by the researcher comprised 40 items relevant to nursing practice derived from EBP weaning guidelines. Respondents were asked to rate all the items independently using a 4-point Likert scale. Findings indicated that intensive care nurses lack adequate knowledge on weaning the critically ill patient from the mechanical ventilator. The Dreyfuss model of skill acquisition shows that improved skill performance in nursing is based on experience as well as education, yet this study showed the opposite (Dracup & Bryan-Brown, 2004). Years of experience did not influence nurses’ knowledge level, as there was no statistical difference in these items. Differences in knowledge scores between the primary nurse and shift leaders were minimal, although significant (p<0.05), indicating that shift leaders were more knowledgeable than primary nurses.