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.

No description available.

Base teórica: O avanço no conhecimento e a introdução de tecnologias mais sofisticadas para o cuidado do paciente crítico trouxeram importante incremento na sobrevida deste grande grupo de pacientes. Por outro lado, existe um estrato de pacientes que sobrevivem à condição crítica aguda, porém permanecem dependentes de algum tipo de suporte de manutenção da vida por longos períodos. A doença crítica crônica (DCC) como é conhecida, apesar de descrita desde a década de 80, ainda não possui um critério de definição claro, levando a divergências nos resultados de estudos e prejudicando o avanço em pesquisas que investigam estratégias de tratamento. Objetivo: Avaliar a sobrevida e fatores associados à DCC em uma população de pacientes críticos comparando dois critérios de diagnóstico desta condição. Metodologia: Coorte histórica com avaliação de variáveis clínicas e desfechos durante a internação hospitalar em uma população de doentes críticos de uma única unidade de tratamento intensivo (UTI). Os pacientes foram alocados em três grupos, dois com critérios de DCC definidos por ≥14 ou ≥21 dias de ventilação mecânica (VM) e um terceiro grupo de pacientes críticos agudos (< 14 dias de VM). Recrutamento e alocação foram feitos através de um banco de dados institucional e dos registros hospitalares das internações ocorridas de janeiro de 2007 a dezembro de 2010. Resultados: No período analisado ocorreram 3.023 internações na UTI, 2.783 apresentavam os critérios de inclusão e compuseram a análise final. Em relação ao tempo de VM, 163 pacientes apresentaram ≥14 dias e 89 ≥21 dias. A mortalidade hospitalar e na UTI foi inferior no grupo de pacientes críticos agudos quando comparado com os dois grupos de DCC (≥14 e ≥21 dias de VM) (16.3% versus 55.8% e 58.4% p<0.001; 10.6% versus 47.3% e 53.9% p<0.001 respectivamente). Quando comparados os dois grupos de DCC (≥14 e ≥21 dias de VM), não houve diferença estatisticamente significativa para mortalidade hospitalar e na UTI (57.2% versus 58.4% p=0.5; 39.2% versus 53.9% p=0.18 respectivamente). O pequeno número de pacientes em cada grupo pode ter limitado o poder das análises. Ambos os grupos de DCC tiveram escores de gravidade mais altos, desenvolveram mais complicações na UTI, apresentaram maior tempo de internação hospitalar e mortalidade quando comparados aos críticos agudos. Conclusão: O estudo não mostrou diferença estatisticamente significativa quanto às características e desfechos clínicos entre as duas definições de DCC. Por outro lado, mostrou que os dois grupos de DCC apresentaram desfechos piores quando comparados com os pacientes críticos agudos. Estes resultados justificam o uso do critério de ≥14 dias de VM para a identificação mais precoce dos doentes críticos crônicos. / Theoretical basis: Progress in knowledge and the introduction of more advanced technologies for critical patient care brought about an important increase in the survival of this large group of patients. On the other side, there exists a subset of patients who survive their acute critical illness, but they remain dependent on some kind of life support for long periods. Despite being described since the 1980s, the chronic critical illness (CCI) has still not been clearly defined. This situation led to divergent studies’ results and jeopardized the progress in research focused on treatment strategies for CCI. Objective: To assess the survival and CCI-associated factors in a population of critically ill patients comparing two diagnostic criteria of this condition. Methodology: Historical cohort study assessing clinical variables and outcomes during hospital stay, in a population of critically ill patients of a single intensive care unit (ICU). The patients were divided into three groups, two of these with different criteria of CCI, defined by ≥14 or ≥21 days of mechanical ventilation (MV), and a third group with acutely critically ill patients (less than 14 days of MV). The recruitment and allocation were carried out through an institutional database and medical records of admissions occurred from January 1, 2007 to December 31, 2010. Results: In the study period 3,023 ICU admissions occurred, 2,783 met the inclusion criteria and made part of the final analysis. As far as MV days are concerned, 163 patients had ≥14 days and 89 ≥21 days. Hospital and ICU mortality were lower in the group of acutely critically ill patients compared with the two CCI groups (≥14 days and ≥21 MV days) (16.3% versus 55.8% and 58.4% p<0.001; 10.6% versus 47.3% and 53.9% p<0.001 respectively). The comparative analysis between the two CCI groups (≥14 days and ≥21 MV days, respectively) was not statistically significant for hospital and ICU mortality (57.2% versus 58.4% p=0.5; 39.2% versus 53.9% p=0.18, respectively). The small number of patients in the two groups may have limited the power of analyzes. Both CCI groups had higher severity scores, developed more ICU complications, showed higher hospital length of stay and mortality when compared with the acutely critically ill patients. Conclusion: This study did not show significant difference between the two CCI definitions regarding characteristics and clinical outcomes. However, it showed that both groups had worse outcomes when compared with the acutely critically ill patients. This result justifies the use of the CCI criteria of ≥14 days of MV for earlier identification of this subset of patients.

Base teórica: O avanço no conhecimento e a introdução de tecnologias mais sofisticadas para o cuidado do paciente crítico trouxeram importante incremento na sobrevida deste grande grupo de pacientes. Por outro lado, existe um estrato de pacientes que sobrevivem à condição crítica aguda, porém permanecem dependentes de algum tipo de suporte de manutenção da vida por longos períodos. A doença crítica crônica (DCC) como é conhecida, apesar de descrita desde a década de 80, ainda não possui um critério de definição claro, levando a divergências nos resultados de estudos e prejudicando o avanço em pesquisas que investigam estratégias de tratamento. Objetivo: Avaliar a sobrevida e fatores associados à DCC em uma população de pacientes críticos comparando dois critérios de diagnóstico desta condição. Metodologia: Coorte histórica com avaliação de variáveis clínicas e desfechos durante a internação hospitalar em uma população de doentes críticos de uma única unidade de tratamento intensivo (UTI). Os pacientes foram alocados em três grupos, dois com critérios de DCC definidos por ≥14 ou ≥21 dias de ventilação mecânica (VM) e um terceiro grupo de pacientes críticos agudos (< 14 dias de VM). Recrutamento e alocação foram feitos através de um banco de dados institucional e dos registros hospitalares das internações ocorridas de janeiro de 2007 a dezembro de 2010. Resultados: No período analisado ocorreram 3.023 internações na UTI, 2.783 apresentavam os critérios de inclusão e compuseram a análise final. Em relação ao tempo de VM, 163 pacientes apresentaram ≥14 dias e 89 ≥21 dias. A mortalidade hospitalar e na UTI foi inferior no grupo de pacientes críticos agudos quando comparado com os dois grupos de DCC (≥14 e ≥21 dias de VM) (16.3% versus 55.8% e 58.4% p<0.001; 10.6% versus 47.3% e 53.9% p<0.001 respectivamente). Quando comparados os dois grupos de DCC (≥14 e ≥21 dias de VM), não houve diferença estatisticamente significativa para mortalidade hospitalar e na UTI (57.2% versus 58.4% p=0.5; 39.2% versus 53.9% p=0.18 respectivamente). O pequeno número de pacientes em cada grupo pode ter limitado o poder das análises. Ambos os grupos de DCC tiveram escores de gravidade mais altos, desenvolveram mais complicações na UTI, apresentaram maior tempo de internação hospitalar e mortalidade quando comparados aos críticos agudos. Conclusão: O estudo não mostrou diferença estatisticamente significativa quanto às características e desfechos clínicos entre as duas definições de DCC. Por outro lado, mostrou que os dois grupos de DCC apresentaram desfechos piores quando comparados com os pacientes críticos agudos. Estes resultados justificam o uso do critério de ≥14 dias de VM para a identificação mais precoce dos doentes críticos crônicos. / Theoretical basis: Progress in knowledge and the introduction of more advanced technologies for critical patient care brought about an important increase in the survival of this large group of patients. On the other side, there exists a subset of patients who survive their acute critical illness, but they remain dependent on some kind of life support for long periods. Despite being described since the 1980s, the chronic critical illness (CCI) has still not been clearly defined. This situation led to divergent studies’ results and jeopardized the progress in research focused on treatment strategies for CCI. Objective: To assess the survival and CCI-associated factors in a population of critically ill patients comparing two diagnostic criteria of this condition. Methodology: Historical cohort study assessing clinical variables and outcomes during hospital stay, in a population of critically ill patients of a single intensive care unit (ICU). The patients were divided into three groups, two of these with different criteria of CCI, defined by ≥14 or ≥21 days of mechanical ventilation (MV), and a third group with acutely critically ill patients (less than 14 days of MV). The recruitment and allocation were carried out through an institutional database and medical records of admissions occurred from January 1, 2007 to December 31, 2010. Results: In the study period 3,023 ICU admissions occurred, 2,783 met the inclusion criteria and made part of the final analysis. As far as MV days are concerned, 163 patients had ≥14 days and 89 ≥21 days. Hospital and ICU mortality were lower in the group of acutely critically ill patients compared with the two CCI groups (≥14 days and ≥21 MV days) (16.3% versus 55.8% and 58.4% p<0.001; 10.6% versus 47.3% and 53.9% p<0.001 respectively). The comparative analysis between the two CCI groups (≥14 days and ≥21 MV days, respectively) was not statistically significant for hospital and ICU mortality (57.2% versus 58.4% p=0.5; 39.2% versus 53.9% p=0.18, respectively). The small number of patients in the two groups may have limited the power of analyzes. Both CCI groups had higher severity scores, developed more ICU complications, showed higher hospital length of stay and mortality when compared with the acutely critically ill patients. Conclusion: This study did not show significant difference between the two CCI definitions regarding characteristics and clinical outcomes. However, it showed that both groups had worse outcomes when compared with the acutely critically ill patients. This result justifies the use of the CCI criteria of ≥14 days of MV for earlier identification of this subset of patients.

Base teórica: O avanço no conhecimento e a introdução de tecnologias mais sofisticadas para o cuidado do paciente crítico trouxeram importante incremento na sobrevida deste grande grupo de pacientes. Por outro lado, existe um estrato de pacientes que sobrevivem à condição crítica aguda, porém permanecem dependentes de algum tipo de suporte de manutenção da vida por longos períodos. A doença crítica crônica (DCC) como é conhecida, apesar de descrita desde a década de 80, ainda não possui um critério de definição claro, levando a divergências nos resultados de estudos e prejudicando o avanço em pesquisas que investigam estratégias de tratamento. Objetivo: Avaliar a sobrevida e fatores associados à DCC em uma população de pacientes críticos comparando dois critérios de diagnóstico desta condição. Metodologia: Coorte histórica com avaliação de variáveis clínicas e desfechos durante a internação hospitalar em uma população de doentes críticos de uma única unidade de tratamento intensivo (UTI). Os pacientes foram alocados em três grupos, dois com critérios de DCC definidos por ≥14 ou ≥21 dias de ventilação mecânica (VM) e um terceiro grupo de pacientes críticos agudos (< 14 dias de VM). Recrutamento e alocação foram feitos através de um banco de dados institucional e dos registros hospitalares das internações ocorridas de janeiro de 2007 a dezembro de 2010. Resultados: No período analisado ocorreram 3.023 internações na UTI, 2.783 apresentavam os critérios de inclusão e compuseram a análise final. Em relação ao tempo de VM, 163 pacientes apresentaram ≥14 dias e 89 ≥21 dias. A mortalidade hospitalar e na UTI foi inferior no grupo de pacientes críticos agudos quando comparado com os dois grupos de DCC (≥14 e ≥21 dias de VM) (16.3% versus 55.8% e 58.4% p<0.001; 10.6% versus 47.3% e 53.9% p<0.001 respectivamente). Quando comparados os dois grupos de DCC (≥14 e ≥21 dias de VM), não houve diferença estatisticamente significativa para mortalidade hospitalar e na UTI (57.2% versus 58.4% p=0.5; 39.2% versus 53.9% p=0.18 respectivamente). O pequeno número de pacientes em cada grupo pode ter limitado o poder das análises. Ambos os grupos de DCC tiveram escores de gravidade mais altos, desenvolveram mais complicações na UTI, apresentaram maior tempo de internação hospitalar e mortalidade quando comparados aos críticos agudos. Conclusão: O estudo não mostrou diferença estatisticamente significativa quanto às características e desfechos clínicos entre as duas definições de DCC. Por outro lado, mostrou que os dois grupos de DCC apresentaram desfechos piores quando comparados com os pacientes críticos agudos. Estes resultados justificam o uso do critério de ≥14 dias de VM para a identificação mais precoce dos doentes críticos crônicos. / Theoretical basis: Progress in knowledge and the introduction of more advanced technologies for critical patient care brought about an important increase in the survival of this large group of patients. On the other side, there exists a subset of patients who survive their acute critical illness, but they remain dependent on some kind of life support for long periods. Despite being described since the 1980s, the chronic critical illness (CCI) has still not been clearly defined. This situation led to divergent studies’ results and jeopardized the progress in research focused on treatment strategies for CCI. Objective: To assess the survival and CCI-associated factors in a population of critically ill patients comparing two diagnostic criteria of this condition. Methodology: Historical cohort study assessing clinical variables and outcomes during hospital stay, in a population of critically ill patients of a single intensive care unit (ICU). The patients were divided into three groups, two of these with different criteria of CCI, defined by ≥14 or ≥21 days of mechanical ventilation (MV), and a third group with acutely critically ill patients (less than 14 days of MV). The recruitment and allocation were carried out through an institutional database and medical records of admissions occurred from January 1, 2007 to December 31, 2010. Results: In the study period 3,023 ICU admissions occurred, 2,783 met the inclusion criteria and made part of the final analysis. As far as MV days are concerned, 163 patients had ≥14 days and 89 ≥21 days. Hospital and ICU mortality were lower in the group of acutely critically ill patients compared with the two CCI groups (≥14 days and ≥21 MV days) (16.3% versus 55.8% and 58.4% p<0.001; 10.6% versus 47.3% and 53.9% p<0.001 respectively). The comparative analysis between the two CCI groups (≥14 days and ≥21 MV days, respectively) was not statistically significant for hospital and ICU mortality (57.2% versus 58.4% p=0.5; 39.2% versus 53.9% p=0.18, respectively). The small number of patients in the two groups may have limited the power of analyzes. Both CCI groups had higher severity scores, developed more ICU complications, showed higher hospital length of stay and mortality when compared with the acutely critically ill patients. Conclusion: This study did not show significant difference between the two CCI definitions regarding characteristics and clinical outcomes. However, it showed that both groups had worse outcomes when compared with the acutely critically ill patients. This result justifies the use of the CCI criteria of ≥14 days of MV for earlier identification of this subset of patients.