DYSPNEA INTENSITY, PSYCHOLOGICAL DISTRESS, ANXIETY INTENSITY, INSPIRATORY EFFORT: EFFECTS ON VENTILATOR WEANING.
Contributors: University of California, San Francisco.
Published: 1990
Number of pages: 181
Subjects: Health Sciences, Nursing.
Description: Understanding the interactions between physiological and psychological variables provides insights into the weaning process of ventilated patients. Twenty-one subjects ventilated for three days or more were studied during both intermittent mandatory ventilation (IMV) and pressure support ventilation (PSV) weaning trials. Subjects rated the intensity of their dyspnea and anxiety on 100 mm visual analogue scales prior to and during both weaning methods. Prior to weaning, subjects also reported their psychological distress on a short version of the profile of mood states (POMS). Physiological indices of work of breathing and breathing effort were obtained during the weaning trials. Subjects were followed for 24 hours after data collection to determine whether they were extubated successfully.

Despite resting on full ventilator support prior to the start of weaning, subjects reported pre-weaning dyspnea and anxiety. Subjects also reported subjective feelings of fatigue/inertia and tension/anxiety. The feelings reported prior to weaning, did not affect dyspnea intensity, anxiety intensity, nor inspiratory effort measured during the weaning trials. The pre-weaning variables failed to identify subjects able to wean from those who could not.

During the weaning trials, dyspnea intensity and anxiety intensity were always correlated. Dyspnea intensity also correlated with inspiratory effort, but only at high work loads. In contrast, anxiety intensity correlated with inspiratory effort during PSV weaning, but not during IMV weaning. Dyspnea intensity was the only weaning process variable that related to successful weaning outcome.

Inspiratory effort was lower during PSV weaning as compared to IMV weaning. However, the difference in effort did not translate into less dyspnea or anxiety. There were no differences in dyspnea or anxiety intensities between the two methods.

In conclusion, the findings suggest that pre-weaning dyspnea, psychological distress, and anxiety do not accurately predict the weaning process, nor the weaning outcome. Dyspnea during weaning may relate more closely to anxiety than to inspiratory effort, except at high work loads. Even though inspiratory effort was less during PSV weaning, the subjects did not report less dyspnea and anxiety. Therefore, the method of weaning may be less important than a systematic approach to withdrawing ventilator support.
Notes: Source: Dissertation Abstracts International, Volume: 52-02, Section: B, page: 0749.

Thesis (D.N.SC.)--UNIVERSITY OF CALIFORNIA, SAN FRANCISCO, 1990.

School code: 0034.