Psychophysiological Determinants of Repeated Ventilator Weaning Failure
AdvisorDavis, Amy H.T.
Committee ChairDavis, Amy H.T.
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PublisherThe University of Arizona.
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AbstractBackground. A significant gap in prior research in the area of mechanical ventilation (MV) weaning is the paucity of studies that have investigated the adverse psychophysiological impact of a failed weaning trial, as well as relationships that may exist among psychological and physiological factors on weaning outcomes.Purpose. The purpose of this study is to test the psychophysiological ventilator weaning model (PVWM), which is theory based and empirically derived, to explain the repeated ventilator weaning failure. Methods. This was a cross-sectional design study. A convenience sample (N = 102) of mechanically ventilated patients who had failed their first weaning trial were enrolled in the study. The data collection was a prospective design. Confirmatory factor analysis (CFA) and structure equation modeling (SEM) were used to test the goodness of fit of PVWM and hypotheses of this study. Results. The results indicated that the originally specified measurement model was a misfit with the sample data. Accordingly, a modified measurement model was established by dropping four indicators for further structural model and hypothesis testing. Conditioned fear strongly affected state anxiety, but had no significant effects on respiratory function and weaning outcome. State anxiety presented non-significant effects on respiratory function and weaning outcome. Among the three psychophysiological factors in PVWM, respiratory function had the strongest effect on the length of MV. Based on the underpinning theoretical thinking, the alternative models were established by post hoc analysis and were confirmed by nested model comparison.Conclusion. The resulting model indicates that patients who have a high acquired conditioned fear from the first ventilator weaning failure will have a high state anxiety during the second weaning trial. High state anxiety will cause compromised respiratory function during the weaning process and further cause prolonged mechanical ventilation in the subsequent weaning. The outcomes in the subsequent weaning trial will also be directly determined by MV patients' state anxiety and respiratory function. Findings from the present study provide a different perspective, new insight, and a direction for health care providers to consider when managing the care of patients with repeated ventilator weaning failure.