The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

ASSOCIATION OF TIDAL VOLUME AND PLATEAU PRESSURE TO MORTALITY IN PATIENTS WITH SEVERE HYPOXEMIC RESPIRATORY FAILURE.

John S. Emberger1, Joel M. Brown1, Vinay Maheshwari1,2; 1Respiratory Care, Christiana Care Health System, Newark, DE; 2Medicine, Christiana Care Health System, Newark, DE

BACKGROUND: With ongoing interest in ARDSnet and lung protective strategies, we formed a PI group to examine the management of our hypoxemic population. Lung protective effort should correlate to improved outcomes. We wanted to determine the association between lung protective indices (tidal volume and plateau pressure) and the outcomes of our patients in severe hypoxemic respiratory failure. METHODS: We retrospectively reviewed all adult patients requiring mechanical ventilation from June 2008 to June 2010. Data collected included: ventilator mode, ventilator settings, tidal volume (Vt), ideal body weight based on height, plateau pressure (Plat), PEEP, FiO2 and survival. We identified severe hypoxemic respiratory failure (SHRF) as patients requiring 60% FiO2 or greater while requiring PEEP 10 cmH2O or greater. Vt (ml/kg) and Plat displayed in this study are the average value over the time the patient was experiencing SHRF. Patients were grouped in 3 levels of Plat: #1) < 25 cmH2O #2) 25 to 30 cmH2O #3) > 30 cmH2O. Patients were grouped in 3 levels of Vt (ml/kg): #1) £ 6 #2) 7 to 10 #3) > 10. RESULTS: 6385 total adult ventilator patients were identified with an overall mortality of 21.7%. 818 patients were identified as SHRF (12.8% of total ventilator patients). The SHRF patients had a mortality of 43.6%. See chart for ranges of average Vt (ml/kg) and average Plat while in SHRF versus mortality. There was a significant difference in Plat between survivors and non-survivors (23.3±4.0, 26.0±4.8, p< 0.002). There was not a significant difference in Vt between survivors and non-survivors (7.6±1.5, 7.7±1.6, p=0.13). CONCLUSION: Overall hospital mortality was comparable or more favorable than previously published outcomes of mechanical ventilator patients1. Patients in our SHRF population were managed outside of ARDSnet protective guidelines (Plat > 30cmH2O or Vt < 6 ml/kg). In this population of SHRF, increases in Plat were associated with increased mortality, but increases in Vt were not associated with increased mortality. Performance improvement efforts should be made to limit both Plat and Vt in SHRF patients in an effort to protect the lungs. REFERENCE: 1. Kahn et al, N Engl J Med 2006;355:41-50. Hospital Volume and the Outcomes of Mechanical Ventilation. Sponsored Research - None Vt (ml/kg) and Plat versus mortality in severe hypoxemic respiratory failure patients