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Right ventricular function during high-frequency oscillatory ventilation in adults with acute respiratory distress syndrome . OBJECTIVE To evaluate the effect of mean airway pressure under high-frequency oscillatory ventilation on right ventricular function . DESIGN Prospective randomized study . SETTING Intensive care unit of a tertiary care hospital . PATIENTS Sixteen consecutive patients within the first 48 hrs of mainly pulmonary acute respiratory distress syndrome . INTERVENTIONS After a 6-hr-period of protective conventional mechanical ventilation , patients were submitted to three 1-hr periods of high-frequency oscillatory ventilation ( +5 , +10 , +15 ) in a randomized order , with a mean airway pressure level determined by adding 5 , 10 , or 15 cm H2O to the mean airway pressure recorded during conventional mechanical ventilation . MEASUREMENTS AND MAIN RESULTS Mean airway pressure was 18±3 cm H2O during conventional mechanical ventilation and was increased until 33±3 cm H2O at high-frequency oscillatory ventilation+15 . Right ventricular function was assessed using transesophageal echocardiography . During conventional mechanical ventilation , nine patients presented a right ventricular dysfunction ( right ventricular end-diastolic area/left ventricular end-diastolic area ratio > 0.6 ) of whom four patients had a right ventricular failure ( right ventricular end-diastolic area/left ventricular end-diastolic area ratio > 0.9 ) . High-frequency oscillatory ventilation+10 and +15 further worsened right ventricular function , resulting in about a 40 % increase in right ventricular end-diastolic area/left ventricular end-diastolic area ratio and a 30 % increase in end-diastolic eccentricity index when compared with conventional mechanical ventilation or high-frequency oscillatory ventilation+5 periods . At high-frequency oscillatory ventilation+15 , 15 patients had right ventricular dysfunction and nine had right ventricular failure . High-frequency oscillatory ventilation did not improve oxygenation whatever the mean airway pressure level . A significant redistribution of tidal variation to the posterior parts of the lung was observed on electrical impedance tomography measurements when increasing mean airway pressure . However , this redistribution was not observed in patients who presented a worsening of right ventricular function ( right ventricular end-diastolic area/left ventricular end-diastolic area increase > 40 % ) at high-frequency oscillatory ventilation+15 . CONCLUSIONS In patients with mainly pulmonary acute respiratory distress syndrome , using high mean airway pressure under high-frequency oscillatory ventilation can worsen right ventricular function when compared with protective conventional mechanical ventilation , notably in patients in whom high-frequency oscillatory ventilation produced less alveolar recruitment of the posterior parts of the lungs . This study highlights the interest of monitoring right ventricular function during high-frequency oscillatory ventilation .
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Intervention_Physical
high-frequency oscillatory ventilation
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Intervention_Physical
high-frequency oscillatory ventilation
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Intervention_Physical
protective conventional mechanical ventilation
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Intervention_Physical
three 1-hr periods of high-frequency oscillatory ventilation
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Outcome_Mental
Mean airway pressure
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Participant_Condition
adults with acute respiratory distress syndrome .
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Participant_Condition
Sixteen consecutive patients within the first 48 hrs of mainly pulmonary acute respiratory distress syndrome .