title: Effect of backrest position on mixed venous oxygen saturation in patients with mechanical ventilation after coronary artery bypass surgery.
abstract: A quasi-experimental study was conducted to examine the effect of backrest position on mixed venous oxygen saturation (SvO2) in patients with mechanical ventilation after coronary artery bypass graft surgery. A convenience sample of 30 subjects was randomly assigned to one of three positions: 20 degrees, 40 degrees, or flat (control). Baseline data were collected with patients in the flat position. The backrest was elevated according to the position designated for each group, and data were collected at 0, 5, 15, and 30 minutes. Subjects in the experimental groups were then returned to the flat position, and measurements were repeated. By use of two-way analysis of variance statistics, no significant differences from baseline were found in SvO2 among the three groups, among the measurement times, or among the positions and times. Findings support elevating the backrest up to 40 degrees according to patient comfort, for patients 6.0 to 9.5 hours after coronary artery bypass graft surgery if they are up to 70 years of age, have no lung disease, are receiving optimal ventilation with up to 5 cm H2O of positive end-expiratory pressure, have normal temperature, and are hemodynamically stable.
authors.affiliation: School of Nursing, University of Texas Health Science Center, San Antonio.
authors.forename: M L
authors.initials: ML
authors.lastname: Noll
authors.forename: R L
authors.initials: RL
authors.lastname: Fountain
mesh_terms: D002407:Catheterization, Swan-Ganz; D002985:Clinical Protocols; D001026:Coronary Artery Bypass / Q000451:nursing*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption / Q000502:physiology; D011184:Postoperative Period; D011187:Posture / Q000502:physiology*; D011897:Random Allocation; D012121:Respiration, Artificial
chemical_list: D010100:Oxygen