Factors associated with the level of backrest elevation in a thoracic cardiovascular intensive care unit

Ventilator-associated pneumonia is a complication of mechanical ventilation that is associated with increased length of stay, morbidity, mortality, and costs. Evidence-based guidelines to reduce the risk of ventilator-associated pneumonia recommend use of 30º to 45º backrest elevation. Despite recommendations, patients continue to be cared for in positions with a lower backrest elevation. Hemodynamic stability may be a factor in the lack of adherence, yet few data exist to confirm this hypothesis.

To determine the relationship between backrest elevation and hemodynamic instability among patients in a thoracic cardiovascular intensive care unit.

A sample of 100 patients was studied. Patients were randomly selected by time of day. A protractor was used to measure patients' backrest elevation. Mean blood pressure, time of day, and fluid and vasopressor use also were recorded.

Lower backrest elevation was associated with use of vasopressors (P = .001). Patients who received hemodynamic support also had a lower backrest elevation than did patients not receiving these therapies (mean, 19º vs 26º ; P = .01). Patients with a mean blood pressure of 64 mm Hg or less had a mean backrest elevation of 17º versus 24º for patients with a mean blood pressure greater than 65 mm Hg (P = .01). Back-rest elevations did not differ between shifts.

That backrest elevation is associated with lower mean blood pressure and vasopressor use suggests that nurses are not adhering to recommended levels of backrest elevation so as to maintain hemodynamic stability. Further studies are needed to elucidate reasons for lack of adherence to recommended levels of backrest elevation.