Right Heart Hemodynamics During Weaning from Mechanical Ventilation
Review TypeNone: Degree-based Submission
Repository Posting Date2019-11-20T17:48:29Z
Author(s)Frazier, Susan Kay
Author DetailsDr. Susan K. Frazier, RN,PhD
Level of EvidenceOther
Research ApproachQuantitative Research
CINAHL HeadingsRespiration, Artificial; Ventilator Weaning; Dogs; Hemodynamics; Heart Ventricle, Right; Respiration, Artificial--Evaluation; Ventilator Weaning--Evaluation; Hemodynamics--Physiology
It is estimated that 9-37% of all mechanically ventilated patients experience difficulty during weaning from mechanical ventilation (MV). Weaning may be problematic for individuals with co-existing cardiac dysfunction, since hemodynamic instability is one proposed cause of weaning failure. Hemodynamic instability during weaning may develop with transition from positive intrathoracic pressure (ITP) during inspiration with MV to the negative ITP with spontaneous ventilation. This ITP shift may induce changes in right ventricular preload, afterload and contractility. The purpose of this study was to describe changes in right heart hemodynamics associated with weaning. Twenty instrumented, anesthetized, canines were randomly assigned to Group 1, normal ventricular function (n = 10), or Group 2, propranolol induced biventricular failure (n = 10). Each subject was randomly exposed to 4 weaning permutations: spontaneous ventilation (T-piece), spontaneous ventilation with a resistor (Resistor), pressure support 5 cm. H$\sb2$O pressure (PS) and continuous positive airway pressure 5 cm. H$\sb2$O pressure (CPAP). Dependent variables were measured on baseline MV and following a 5 minute transition period to each permutation. Data were analyzed with repeated measures ANOVA. Both groups significantly increased cardiac output with T-piece, Resistor and CPAP. Neither group demonstrated significant changes in heart rate. Stroke volume increased in both groups with T-piece, Resistor and CPAP. Right ventricular end-diastolic volume (preload) increased in both groups with T-piece, Resistor and CPAP. Pulmonary vascular resistance (afterload) was reduced in both groups with T-piece and Resistor, but unchanged with PS and CPAP. Right ventricular stroke work (contractility) increased with T-piece, Resistor and CPAP, but was unchanged with PS. These data indicate right heart hemodynamics were influenced by weaning from MV using T-piece, Resistor and CPAP. Similar changes in humans, particularly those with preexisting cardiac dysfunction, may induce cardiovascular instability and reduce oxygen delivery. Weaning by PS produced minimal hemodynamic change and may be more suitable for weaning individuals with cardiac dysfunction.
DescriptionThis dissertation has also been disseminated through the ProQuest Dissertations and Theses database. Dissertation/thesis number: 9630891; ProQuest document ID: 304285184. The author still retains copyright.
Advisor(s)Stone, Kathleen S.
Degree GrantorThe Ohio State University
NotesThis item has not gone through this repository's peer-review process, but has been accepted by the indicated university or college in partial fulfillment of the requirements for the specified degree.
Visits vs Downloads
Visitors - World Map
Top Visiting Countries
Top Visiting Cities
Visits (last 6 months)
Downloads (last 6 months)
Popular Works for Frazier, Susan Kay by View
Popular Works for Frazier, Susan Kay by Download
The citations below are meant to be used as guidelines. Patrons must make any necessary corrections before using. Pay special attention to personal names, capitalization, and dates. Always consult appropriate citation style resources for the exact formatting and punctuation guidelines.