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

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Date
2004-11
Authors
Phillips, Maria Jacoba Johanna
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Publisher
University of the Free State
Abstract
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)
Afrikaans: Ventilator-geassosieerde pneumonie word geassosieer met ‘n hoë sterftesyfer, morbiditeit asook hoë mediese koste en is bekend vir erge komplikasies. ‘n Insig in die patogenese van die siekte is noodsaaklik om ventilator-geassosieerde pneumonie te voorkom. Die patogenese begin met kolonisasie van die boonste lugweg en die gastroïntestinale kanaal, opeenhoping van sekresies in die subglotiese ruimte sowel as aspirasie van hierdie gekontamineerde sekresies verby die endotrageale mansjet (endogene bron van patogene). Ventilator-geassosieerde pneumonie ontwikkel namate die gasheer se verdedigingsmeganismes afgebreek word. Nuwe soorte endotrageale buise wat aspirasie van gekontamineerde sekresie in die onderste steriele lugweë voorkom deur middel van ‘n dorsale opening waardeur subglotale sekresie verwyder kan word, is ontwerp. ‘n Enkel sentrum, blinde, prospektiewe, kontrole kliniese proef is vir die doel van die studie gekies om ondersoek in te stel na die effek van drie soorte endotrageale buise in ventilator-geassosieerde pneumonie. Voor die aanvang van die studie, is goedkeuring vir die uitvoering van die studie van die Etiek Komitee van die Fakulteit Gesondheidswetenskappe van die Universiteit van die Vrystaat verkry. Verdere goedkeuring is verkry van Universitas hospitaal, die bestuurder van die intensiewe sorg eenhede en die neurochirurgiese intensiewesorg eenheid sowel as van die hoof van die departement neurochirurgie. Geskrewe ingeligte toestemming aangaande die doel, die prosedure asook die moontlike newe-effekte, wat relevant is vir die studie, is van kandidate - of indien die kandidate nie by magte was om toestemming te gee nie, van hul naasbestaandes verkry. Geskrewe toestemming is verkry. Indien die kandidate nie by magte is om self toestemming te gee en naasbestaandes nie beskikbaar was nie, is ingeligte toestemming telefonies van naasbestaandes verkry. Toestemmingsvorms was beskikbaar in Afrikaans, Engels and Suid-Sotho. Indien die kandidaat of naasbestaande nie Engels of Afrikaans magtig is nie, het ‘n geregistreerde verpleegkundige as tolk opgetree om die doel, prosedure en moontlike newe-effekte wat verband hou met die studie te verduidelik. ‘n Getuie het in alle gevalle die toestemmingsvorms geteken. Een en sewentig kandidate, wat aan die insluitingskriteria voldoen het, is vir insluiting in die studie gesif. Vier en dertig van die kandidate was suksesvol in die studie ingesluit. Proefpersone is opeenvolgend in drie studiegroepe ingedeel. Elke spesifieke studiegroep is met die tipe endotrageale buis vir die spesifieke studiegroep geïntubeer, en bestudeer vir die ontwikkeling van ventilator-geassosieerde pneumonie. Die twee eksperimentele groepe het twee-uurlikse subglotiese suiging ontvang. Een eksperimentele groep se mansjetdruk is gemeet en binne die normale perke volgehou, terwyl ‘n Lanz™ klep die ander eksperimentele groep se mansjetdruk beheer het. Die kontrole groep is met die konvensionele tipe endotrageale buis geïntubeer. Implementering het oor ‘n tydperk van 18 maande plaasgevind. Data is statisties geanaliseer en deur middel van frekwensies, mediane en vergelyking met ‘n 95% vertrouensinterval voorgestel. Die studie het bevind dat geen van die kandidate in die eksperimentele groepe wat subglotiese suiging ontvang het, in vergelyking met die 16.67% in die kontrole groep, laat aanvang ventilator-geassosieerde pneumonie opgedoen het nie. Die insidensie van vroeë aanvang van ventilator-geassosieerde pneumonie was ook veel hoër (75%) in die kontrole groep as in die eksperimentele groepe. Die relatiewe risiko vir laat aanvang van ventilator-geassosieerde pneumonie dui aan dat subglotiese suiging nie ‘n voorkomende strategie in die voorkoming van vertraagde intrede van ventilator-geassosieerde pneumonie in die eksperimentele groep was nie. Die periode van intubasie van die kontrolegroep was langer as in die eksperimentele groepe. Geen merkwaardige verskille is in die morbiditeit en mortaliteit van die drie studiegroepe bevind nie. Aanbevelings is dat ‘n verlengde studie herhaal behoort te word en dat die proefpersone vir ‘n langer periode geventileer behoort te word. Die voordele van subglotiese suiging behoort dan duideliker waarneembaar te wees. Die voordele van die LanzTM klep is ook nie voldoende bestudeer in die studie nie. As slotopmerking ‘n paar wyse woorde: “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)
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Keywords
Dissertation (M.Soc.Sc. (School of Nursing))--University of the Free State, 2004, Pneumonia, Respirators (Medical equipment), Respiratory therapy -- Complications
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