FACTORS INFLUENCING WEANING ADULTS FROM LONG-TERM POSITIVE PRESSURE MECHANICAL VENTILATORY SUPPORT (LEFT VENTRICULAR, VENTILATORY SUPPORT).
Contributors: Case Western Reserve University.
Published: 1993
Number of pages: 123
Subjects: Health Sciences, Nursing.; Health Sciences, Medicine and Surgery.
Description: Mechanical ventilatory support (MVS) is used for patients with all types of respiratory difficulties who are unable to maintain adequate ventilation or oxygenation regardless of the cause. It also is used for patients in coma and for patients postoperatively following general anesthesia for thoracic and major abdominal surgery. Premature discontinuation of MVS may lead to severe cardiopulmonary decompensation. The process of weaning from MVS can begin when the problem creating the need for mechanical ventilation has been resolved. Successful weaning occurs when patients are able to maintain adequate gas exchange with spontaneous ventilation for 48 continuous hours.

Widespread concern about mechanical ventilation and effective weaning from MVS exists. There are several reasons for the current concern including the increasing prevalence of patients unable to wean from MVS and the recognition that traditional approaches to weaning from MVS do not work. Another reason for concern is the tremendous personal and financial cost associated with failure to wean from MVS. These concerns have led to the consensus regarding the need to investigate causes of weaning failure in order to better understand factors that determine successful weaning and the relationships among these factors.

The purpose of this study was to investigate the influence of left ventricular dysfunction on the duration of long-term mechanical ventilatory support controlling for other elements of physiologic capacity. A retrospective comparative and correlational survey design was used to answer the following two research questions: (1) Is there a difference in the duration of mechanical ventilatory support for patients with evidence of left ventricular dysfunction compared to those with normal left ventricular function? (2) If there is a difference in the duration of mechanical ventilatory support between subjects with evidence of left ventricular dysfunction compared to those with normal left ventricular function, does it hold when controlling for other aspects of physiologic capacity (ventilatory muscle strength, ventilatory muscle endurance, oxygenation adequacy, and nutritional status)?.

The sample included 174 subjects, although only 26 were included in the testing of the second research question. Findings from this study indicated that the duration of MVS was longer for those subjects with evidence of left ventricular dysfunction compared to those with normal left ventricular function. Further, no one aspect of physiologic capacity adequately predicted duration of MVS or successful weaning among chronically critically ill adults. In addition to evidence of left ventricular dysfunction, the number of drugs used to treat heart failure, and fluid balance were significantly associated with either duration of MVS, success of weaning, or both. The findings further provide additional information that can be used in the further development and refinement of a theory of weaning from long-term mechanical ventilatory support.
Notes: Source: Dissertation Abstracts International, Volume: 54-12, Section: B, page: 6131.

Thesis (PH.D.)--CASE WESTERN RESERVE UNIVERSITY (HEALTH SCIENCES), 1993.

School code: 0499.