Masters Degrees (Physiotherapy)

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Browsing Masters Degrees (Physiotherapy) by Author "Brouwer, Lindie Estelle"

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    Diaphragm contractile activity during mechanical ventilation
    (Stellenbosch : Stellenbosch University, 2018-03) Brouwer, Lindie Estelle; Hanekom, Susan D.; Koegelenberg, Coenie F. N.; Lupton-Smith, Alison; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Health & Rehabilitation Sciences. Physiotherapy.
    ENGLISH SUMMARY : Introduction: Mechanical ventilation has been shown to have detrimental effects on the diaphragm, causing extubation failure. Diaphragm ultrasound has recently been investigated as a measurement technique that could identify diaphragm dysfunction in real-time. Investigation of diaphragm function and the impact thereof on patient outcome could inform us of the behaviour of the diaphragm muscle during mechanical ventilation. Methods: A Scoping review was done to investigate the effect of mechanical ventilation on the diaphragm. Six databases were searched using a specific search strategy. Predefined inclusion criteria were used to identify papers suitable for the review. The primary investigator used a systematic process to identify suitable papers and extract data into an Excel spreadsheet. Data was used to inform the planning of the primary research study. A prospective observational cohort study was conducted to determine the effect of diaphragm contractile activity on extubation success in mechanically ventilated patients. Mechanically ventilated participants were recruited on admission to the intensive care unit. Sonographic measurements of the diaphragm were taken daily until extubation, and respiratory muscle strength measurements were taken within 24 hours of extubation. Diaphragm thickness (Tdi), diaphragm thickening fraction (DTF) and daily rate of change in both Tdi and DTF related to the previous day were calculated. Patient outcomes were reported by two variables: extubation outcome and duration of ventilation. Associations between diaphragm and inspiratory measurements were reported using Spearman’s correlations, and between-group differences were analysed by means of Mann-Whitney U tests and ANOVA graphs. A p-value of <0.05 was used to indicate significance. Results: Six hundred and thirty-seven articles were assessed for inclusion into the scoping review. Fifty-six papers were included in the review. Diaphragm assessment techniques, ventilation modes, cellular changes to the diaphragm and confounding factors were reported. Similar techniques were reported regarding diaphragm contractile activity and Tdi measurements, however results were contrasting, especially concerning patient outcome. Sixty-eight participants were included in the primary study. Fifty-four participants passed extubation. The mean age of the sample was 45.1 years (SD = 16.9). Neither age, gender, comorbidities, smoking nor alcohol use were different in success versus failed extubation groups. Baseline Tdi measurement was significantly higher in failed than successful extubation groups (p=0.033), and a significant moderately positive association was found between baseline Tdi and total duration of mechanical ventilation (r=0.412, p<0.01). Baseline DTF did not differ between failed and successful extubation groups (p>0.05). Baseline Tdi was not associated with maximal inspiratory pressure (r=0.02, p=0.901). Conclusion: Several diaphragmatic assessment techniques exist, however there are discrepancies within the results reported. Ultrasonography proves to be an easy assessment technique to visualise the diaphragm in real-time. Furthermore, we conclude that in our population, thicker diaphragms at baseline may be more prone to an increased duration of mechanical ventilation and may be linked to extubation failure. Measuring diaphragm contractile activity during tidal breathing may not be a valid indicator of extubation readiness and further research should be done to prove its value in the critically ill population.