Paediatric diaphragm function and mechanical ventilation

Terhart, Maxine Nati (2018-03)

Thesis (MScPhysio)--Stellenbosch University, 2018.

Thesis

ENGLISH SUMMARY : Introduction: A relationship between diaphragm dysfunction and poor mechanical ventilation outcomes, such as prolonged duration of mechanical ventilation, weaning difficulties and extubation failure have been identified in the adult population. Most of the research of diaphragm dysfunction during mechanical ventilation has been done in the adult population and data in the paediatric population are lacking. The aim of this thesis is to report on diaphragm function in mechanically ventilated paediatric patients. Methods: A literature overview was done to describe mechanical ventilation weaning practices in the paediatric population; as well as underlying reasons for extubation failure in the paediatric population. Available data on weaning and extubation failure in the critically ill paediatric population were summarised. A pilot study was performed to describe the inter- and intra-rater reliability of diaphragmatic ultrasound to measure diaphragm thickness in mechanically ventilated infants and children. Two researchers measured diaphragm thickness using ultrasound in five mechanically ventilated infants and children to compare measures. A prospective observational study was performed to describe diaphragm function in mechanically ventilated infants and children. Diaphragmatic ultrasound was used to measure diaphragm resting thickness and diaphragm contractile activity, and surface electromyography was used to measure diaphragm electrical activity over a period of mechanical ventilation. Serial measures were taken each day of mechanical ventilation and patients were followed up until two days after extubation. Results: The literature overview results showed no consensus in current clinical practice on weaning criteria or protocols, and most current practice is guided by results from adult studies. Several factors have been identified in the paediatric population that may predispose to extubation failure. Respiratory muscle function has been identified as a factor that should be assessed before an extubation attempt as it may be a contributing factor to successful extubation. Diaphragmatic ultrasound has shown to have excellent intra-rater (Intraclass correlation coefficients between 0.77 and 0.98) and inter-rater (Intraclass correlation coefficient: 0.94) reliability to measure diaphragm thickness in mechanically ventilated infants and children. Diaphragmatic ultrasound and surface electromyography are feasible and safe to use to measure diaphragm resting thickness, contractile activity and electrical activity in mechanically ventilated infants and children. Changes in diaphragm function occurred during mechanical ventilation in infants and children, although all measures seem to remain within a common range in the paediatric population. Scatter plots showed that changes in diaphragm contractile activity were associated with increased mechanical ventilation duration, although not statistically significant; no other associations were made between diaphragm function and mechanical ventilation outcome. Conclusion: More research will need to be done to identify how ultrasound and electromyography measures of diaphragm function are associated with mechanical ventilation outcome; and therefore how they could aid in predicting patients that may be at risk for poor mechanical ventilation outcomes. This thesis provides novel data on diaphragm function in mechanically ventilated infants and children which could be used as a basis for further research.

AFRIKAANSE OPSOMMING : Inleiding: 'n Verhouding tussen diafragma-disfunksie en swak meganiese ventilasie uitkomste, soos langdurige tydsduur van meganiese ventilasie, speenprobleme en ekstubasie mislukking, is in die volwasse bevolking geïdentifiseer. Die meeste van die ondersoeke na diafragma-disfunksie tydens meganiese ventilasie is in die volwasse bevolking gedoen en data in die pediatriese bevolking ontbreek. Die doel van hierdie tesis is om verslag oor die diafragma-funksie in meganies geventileerde pediariese pasiënte te lewer. Methode: 'n Literatuuroorsig is gedoen om meganiese ventilasie speen praktyke in die pediatriese bevolking; sowel as die onderliggende redes vir ekstubasie mislukking in die pediatriese bevolking te beskryf. Die beskikbare data oor speen- en ekstubasie-mislukking in die kritiese siek pediatriese populasie was opgesom. 'n Loodsstudie is uitgevoer om die inter- and intrarater betroubaarheid van diafragmatiese ultraklank te beskryf om diafragma dikte in meganies geventileerde babas en kinders te meet. Twee narvorsers het diafragma dikte in vyf meganiese geventileerde babas en kinders deur middel van ultraklank gemeet, en die metings vergelyk. 'n Prospektiewe studie is uitgevoer om diafragma funksie in meganies geventileerde babas en kinders te beskryf. Diafragmatiese ultraklank is gebruik om diafragma rustende dikte en diafragma kontraksie aktiwiteit te meet, en oppervlakselektromieografie is gebruik om die elektriese aktiwiteit van die diafragma te meet oor 'n tydperk van meganiese ventilasie. Opeenvolgende metings is elke dag geneem tydens meganiese ventilasie en pasiënte is opgevolg tot twee dae na ekstubasie. Resultate: Die literatuuroorsig resultate toon geen konsensus in huidige kliniese praktyk oor speenkriteria of protokolle nie, en die praktyk word meestal gelei deur die resultate van studies in die volwassende bevolking. Verskeie faktore is geïdentifiseer in die pediatriese populasie wat kan lei tot ekstubasie mislukking. Respiratoriese spierfunksie is geïdentifiseer as 'n faktor wat geassesseer moet word voor 'n ekstubasiepoging, aangesien dit 'n bydraende faktor tot suksesvolle ekstubasie kan wees. Diafragmatiese ultraklank het getoon dat dit 'n uitstekende intrarater(intraclass correlation coefficient tussen 0.77 en 0.98) en interrater (intraclass correlation coefficient 0.94) betroubaarheid het om diafragma dikte in meganies geventileerde babas en kinders te meet. Diafragmatiese ultraklank en oppervlakselektromyografie is haalbaar en veilig om te gebruik om die diafragma se dikte tydens rus, kontraksie aktiwiteit en elektriese aktiwiteit in meganies geventileerde babas en kinders te meet. Veranderinge in diafragma-funksie het plaasgevind tydens meganiese ventilasie by babas en kinders, alhoewel alle metings blyk om binne 'n algemene reikwydte vir die pediatriese populasie te bly. n’ Strooi plot verwys dat veranderinge in diafragma kontraksie aktiwiteit is geassosieer met verlengde tydeperk van meganiese ventilasie, hoewel daar geen statistiese betekenis is nie; geen ander assosiasie tussen diafragmafunksie en meganiese ventilasie uitkoms is gemaak nie. Gevolgtrekking: Ventilasie praktyke in die perdiatriese bevolking is nie gestandardiseer nie. Alhoewel ultraklank meting van die diafragma ‘n betroubare meting is, is die interpretasie van die meting steeds onduidelik. Meer navorsing moet gedoen word om te identifiseer hoe ultraklank en elektromieografie metings van diafragma funksie geassosieer kan word met meganiese ventilasie uitkoms; en of die metings kan help met die voorspelling van pasiënte wat moontlik 'n risiko vir swak meganiese ventilasie uitkomste kan hê. Hierdie tesis voorsien unieke data om diaphragma funksie in babas en kinders wat as basis vir verdere navorsing in hierdie veld gebruik kan word.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/103643
This item appears in the following collections: