comparison study of high frequency percussive ventilation with conventional ventilation

Conditions: Respiratory Distress Syndrome, Adult; Pneumonia; Mechanical Ventilation

Summary: this study is designed to exam the effects of early management with high frequency percussive ventilation (hfpv) on patients with lung injury. patients at risk for acute respiratory distress syndrome (ards) will be enrolled and randomized to one of two groups. one group will be managed with hfpv. the second group will be managed with conventional ventilation utilizing lung protective techniques. the primary endpoint of the study is rate of ventilator associated pneumonia. we hypothesized that use of hfpv in patients at risk for the development of ards will decrease the rate of ventilator associated pneumonia when compared to patients managed with conventional ventilation.

specific aim 1: this prospective randomized trial will enroll 180 patients with ali/ards over a forty-eight month period. one cohort will receive conventional mechanical ventilation adhering to our well defined protocol of protective lung strategies. a second cohort will have these same strategies applied utilizing the vdr/hfpv. out come measures will include; icu/hospital length of stay, pulmonary infectious complications, airway pressure related complications, pao2/paco2 levels, hemodynamic profiles, and ventilators days. we hypothesize that patients with acute lung injury (ali )and/or acute respiratory distress syndrome (ards) managed primarily with hfpv will have fewer ventilators days, fewer infectious complications, and shorter icu/hospital lengths of stay than patients managed with conventional mechanical ventilation techniques, while maintaining similar oxygenation (pao2), ventilation (paco2), metabolic (ph), and hemodynamic (cardiac output) parameters. ards and ali have been shown to cause elevations in circulating inflammatory mediators as well as local (alveolar) mediators. the presence of increased amounts of both circulating and alveolar cytokines (inflammatory mediators) has been associated with increased mortality in patients with ards/ali. the pulmonary capillary bed is a rich source of these inflammatory cytokines and the effects of ventilator strategies on circulating and compartmentalized (alveolar) cytokine levels may affect outcome. specific aim 2: circulating and alveolar inflammatory mediators (il-6, il-1-beta, il-10, and tnf-alpha) will be measured, and activation of other markers of increased synthesis of inflammatory mediators (nf-kappa b and p38 map kinase) will be determined in isolated peripheral blood and alveolar leukocytes. we hypothesize that patients with ali/ards managed with hfpv will have lower levels of circulating and alveolar pro-inflammatory cytokines (il-6, il-1-beta and tnf-alpha) as well as less activation of nf-kappa b and p38 map kinase from peripheral blood and alveolar leukocytes.

Eligibility criteria:
inclusion criteria: * pao2/fio2 \< 300 for less than 24 hours (ratio of partial pressure of oxygen to fraction of inspired oxygen) exclusion criteria: * documented pneumonia, * documented congestive heart failure, * immunosuppression, * enrolled in other interventional trial,

Keywords: acute lung injury acute respiratory distress syndrome high frequency percussive ventilation ventilator associated pneumonia