The effect of three types of endotracheal tubees on ventilator-associated pneumonia

[摘要] English: Ventilator-associated pneumonia is associated with a high mortality, morbidity and medical cost and is common and has major complications. Prevention of ventilator-associated pneumonia is dependent on how well we understand the pathogeneses of the disease. The pathogeneses starts with the colonization of the upper airway and the gastrointestinal tract, pooling of secretions in the subglottic space and aspiration of this contaminated secretions past the endotracheal cuff (endogenous source of pathogens). As the host's defences are overcome, tventilator-associated pneumonia develops. Newer types of endotracheal tubes were designed with a dorsal lumen for the removal of subglottic secretions. This prevents the aspiration of contaminated secretion into the lower sterile airways. The aim of this research was to determine the effect of three types of endotracheal tubes on ventilator-associated pneumonia.A single center, blind, prospective, controlled clinical trial has been selected to investigate the effect of three types of endotracheal tubes on ventilator-associated pneumonia.Prior to the commencement of the study, approval for the performance of the study was obtained from the Ethics Committee of the Faculty of Health Sciences of the University of the Free State, the Universitas hospital, the manager of the intensive care units and neurosurgical intensive care unit as well as from the head of the neurosurgical department.Informed consent was obtained from candidates or if the candidates were unable to provide consent from their spouse, child or parent and information regarding the purpose, procedure, and possible adverse effects relevant to the study, were provided. Written consent was obtained. If the candidates was unable to give consent themselves and their family was unavailable, the researcher obtained telephonic consent from above-mentioned family members. The consent forms were available in Afrikaans, English and South-Sotho. If the subject did not understand English or Afrikaans, the researcher made use of a registered nurse as a translator to explain the purpose, procedure, and possible adverse effects relevant to the study. A witness co-signed all consent forms.Seventy-one candidates that met the inclusion criteria were screened for enrolment into the study. Thirty-four of these candidates were successfully enrolled. Subjects were consecutively allocated into three study groups. Each study group was intubated with the type of endotracheal tube for the specific study group and studied for the development of ventilator-associated pneumonia. The two experimental groups were subjected to two hourly subglottic suctioning. One experimental group's cuff pressures were measured and maintained within normal limits, whereas a Lanz�?valve maintained the other experimental group's cuff pressures. The control group was intubated with the conventional type of endotracheal tube. The implementation took place over a period of 18-months.Data was statistically analysed and presented by means of frequencies, medians and comparison of 95% confidence intervals. This study has found that none of the subjects in the experimental groups (received subglottic suctioning) developed late-onset ventilator-associated pneumonia compared to 16.67% in the control group. The incidence of early-onset ventilator-associated pneumonia was also much higher (75%) in the control group than the experimental groups. The relative risk for late-onset ventilator-associated pneumonia indicated that subglottic suctioning was not a preventative factor in the prevention of late-onset ventilator-associated pneumonia in the experimental groups.The time of intubation of the control group was longer than the two experimental groups. No significant difference was found in the morbidity and the mortality of the three study groups.Recommendations are that the study should be repeated with a larger study group and the subjects should be ventilated for a longer period. The benefits of subglottic suctioning may present it more clearly. The benefits of the LanzTM valve have not been investigated sufficiently in this study.In closing a repetition of some wise words:'Keep an open mind toward pneumonia. Our grandchildren will be interested and are likely to have as many differences of opinion…as we have.William Osler. 1900 (Craven & Steger, 1995:1S)

[发布机构] University of the Free State