A dissertation submitted to the Faculty of Health Sciences, University of Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Masters of Science. Johannesburg 2012 / Background: The detrimental effects of prolonged mechanical ventilation (MV) on the respiratory muscles, especially the diaphragm, are well documented and it is crucial that MV should be discontinued as soon as possible to prevent added complications and additional risks to patients with critical illness. The spontaneous breathing stage of MV can be managed as a rehabilitation and conditioning phase for the respiratory muscles due to the fact that the respiratory muscles are more active during this stage of MV. Weaning strategies that provide insufficient respiratory work, too high a respiratory muscle load or insufficient respiratory muscle rest may lead to respiratory muscle fatigue and consequently failed weaning and extubation. The aim of this research project was to develop an individualised continuous positive airway pressure (CPAP) weaning programme and test its effects on the outcomes of extubation in the adult ventilated patient. Method: An experimental, prospective, non-randomised, sequential study of two groups of subjects was performed. Forty eight subjects [group one: n =24 (control) and group two: n = 24 (intervention)], who were mechanically ventilated for longer than 48 hours, in an open adult, general intensive care unit were recruited. Subjects in the control group were weaned according to the standard weaning programme of the test setting at the time; and those in the intervention group were weaned according to an individualised CPAP programme. This weaning programme was developed utilising three principles of muscle rehabilitation namely; daily stepwise progression, sufficient rest and recovery periods and adapted to the individual needs and progression of each subject. Objective measurements such as the rapid shallow breathing index (RSBI), RSBI rate and the maximum inspiratory pressure (MIP) were used to determine the subjects in group two’s readiness for a spontaneous breathing trial. The primary outcomes assessed were time spent in the different stages of MV, rate of failure to sustain spontaneous breathing in stage 3 of MV, successful extubation and mortality rate. Results and Discussion: The difference in rate of failure to sustain spontaneous breathing between the two groups was statistically significant (p = 0.01) with 10 events of failure in group one and three in group two. The rate of successful extubation from MV between groups one and two was 70.8% and 91.7% iv respectively (p=0.52). The mortality rate was 33.3% for group one and 8.3% for group two (p = 0.02). The difference in the total time spent on MV (days) did not differ significantly (group one = 8.6 (± 0.40) days; group two = 9.3 (±0.32) days; p = 0.75). The results yielded from this study suggest that the use of a multidisciplinary team model and an individualised CPAP programme aids successful extubation from MV as the success rate was much higher in the intervention group than in the control group without adding additional time on MV. Conclusion: Results from this study showed that the implementation of an individualised CPAP programme during the spontaneous breathing stage of MV may improve the outcomes of extubation in adult ventilated patients.

Patients in the intensive care unit (ICU) setting are prone to develop muscle weakness and the causes are multi-factorial. Muscle strength in adult, critically ill patients on mechanical ventilation decreases with immobility. The influence of muscle strength on different muscle groups and its influence on progressive mobility in the adult, critically ill patient on mechanical ventilation has not been examined. Identifying muscle strength in this patient population can benefit overall muscle health and minimize muscle deconditioning through a progressive mobility plan. The objective of this dissertation was to describe muscle strength in different muscle groups and to describe the influence of muscle strength on mobility in critically ill adult patients on mechanical ventilation (MV). Fifty ICU patients were enrolled in this descriptive, cross sectional study. Abdominal core, bilateral hand grip and extremity strength was measured using three measurement tools. Mobility was measured using the following scale: 0=lying in bed; 1=sitting on edge of bed; 2=sitting on edge of bed to standing; 3=walking to bedside chair and 4=walking >7 feet from the standing position. Predictors of mobility were examined using stepwise regression. Abdominal core, bilateral hand grip and extremity strength demonstrated statistically significant relationships with all variables. Extremity strength accounted for 82% of the variance in mobility and was the sole predictor (β=0.903; F=212.9; p=0.000). Future research addressing the outcomes of implementing a mobility protocol in this patient population and prioritizing when such a protocol should be implemented would be beneficial to ongoing plans to decrease MV, ICU and hospital days. Muscle strength tests implemented at the bedside are crucial to implementing a progressive mobility plan for critically ill adults while they are on MV therapy.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Introduction: The neuromuscular and respiratory systems are significantly affected during the sedentary aging, but these modifications can be minimized/attenuated by practice of resistance training Purpose: Compare the effects of different volumes of resistance training on the maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), functional performance, and muscle strength in elderly women. Methods: Nineteen elderly women were randomly assigned to a group performing either single sets (1-SET) or three sets (3-SET) of exercises. The sit-to-stand test, MIP, MEP, and muscle strength were assessed before and after 24 training sessions. Progressive resistance training was performed two times per week for a total of 8 12 repetitions, using the main muscle groups of the upper and lower limbs. Results: The main results showed that the participants significantly increased their MEP (p<0,05; 1-SET: 34,6%; 3-SET: 35,8%) and MIP (p<0,05; 1-SET: 13,7%; 3- SET: 11,2%). Both groups also improved in the sit-to-stand test (p<0,05; 1-SET: 10,6%; 3-SET: 17,1%). After 24 training sessions, muscle strength also significantly increased (p<0,0001; 40 80%) in both groups. An intergroup comparison did not show any statistically significant differences between the groups in any of the parameters analyzed. Conclusion: Single- and multiple-set resistance training programs increased MIP, MEP, muscle strength, and sit-to-stand test performance in elderly women after 24 sessions of training. In conclusion, our results suggested that elderly women who are not in the habit of physical activity may start with single-set resistance training programs as a short-term strategy for the maintenance of health. / Introdução: Os sistemas neuromuscular e respiratório são significativamente afetados durante o envelhecimento sedentário, contudo estas modificações podem ser minimizadas/atenuadas pela prática do treinamento resistido. Objetivo: Comparar os efeitos de diferentes volumes de treinamento resistido sobre a pressão muscular inspiratória (Pimax), pressão muscular expiratória (Pemax), desempenho funcional e força muscular de idosas. Métodos: Dezenove mulheres idosas foram divididas randomicamente em dois grupos, série simples (1-SET) ou três séries (3 SET) de exercícios resistidos. O teste de sentar e levantar, Pemax, Pimax e força muscular foram avaliados antes e após 24 sessões de treinamento. O treinamento resistido progressivo foi realizado durante 12 semanas com frequência de duas vezes por semana, entre 8-12 repetições, utilizando-se os principais grupos musculares dos membros superiores e inferiores. Resultados: Os principais resultados demonstram que ocorreram aumentos significativos na Pemax (p<0,05; 1-SET: 34,6%; 3-SET: 35,8%) e Pimax (p<0,05; 1-SET: 13,7%; 3-SET: 11,2%). Ambos os grupos também melhoraram no teste de sentar e levantar (p<0,05; 1-SET: 10.6%; 3-SET: 17.1%). Após 24 sessões de treinamento resistido, a força muscular aumentou significativamente (p<0,001; 40-80%) nos grupos. A comparação intergrupo não revelou diferença significativa em nenhum parâmetro analisado. Conclusão: Séries simples e múltiplas de treinamento resistido melhoram a Pemax, Pimax, força muscular e o desempenho funcional no teste de sentar e levantar após 24 sessões de treinamento. Estes resultados sugerem que mulheres idosas que não possuem o hábito de praticar atividade física podem iniciar programas de séries simples de treinamento resistido, como estratégia de curto tempo para a manutenção da saúde.