Clinical Trial: Effects of Positive End-expiratory Pressure and Tidal Volume on Fluid Responsiveness of Acute Respiratory Distress Syndrome

Study Status: Completed
Recruit Status: Unknown status
Study Type: Observational

Official Title: Effects of Positive End-expiratory Pressure and Tidal Volume on Fluid Responsiveness of Acute Respiratory Distress Syndrome.

Brief Summary: Fluid responsiveness (FR)refers to the ability of heart to increase its stroke volume in response to volume load.Low tidal volume and high PEEP exerts contrast effect on the prediction of fluid responsiveness, the aim of this study is to compare the relative predicting power of the dynamic preload indicator (PPV, SVV), passive leg raising test, and pleth variability index (PVI) on the fluid responsiveness of acute respiratory distress syndrome ventilated with various PEEP levels or various tidal volumes.

Detailed Summary:

In septic critically ill mechanically ventilated patients with acute circulatory failure, inadequate volume resuscitation leads to multiple organ failure. Early goal-directed therapy emphasizes early and aggressive hemodynamic support in patients with severe sepsis and septic shock. On the other hand, because of increased microvascular permeability and capillary leakage, conservative fluid management and more aggressive restriction in fluid accumulation to reduce lung water and tissue edema has been suggested by acute respiratory distress syndrome net. Fluid responsiveness refers to the ability of the heart to increase its stroke volume in response to volume load. Accurately predicting volume responsiveness will be beneficial in obviating the need for unnecessary fluid loading, and in detecting patients who may benefit from a volume load.

By inducing cyclic changes in pleural and transpulmonary pressure, mechanical ventilation results in cyclic changes in the preload and afterload, and therefore, the cyclic variation in systolic and pulse pressure. Recently, a systemic review concluded that dynamic preload indicator [pulse pressure variation (PPV), stroke volume variation (SVV)] are highly accurate in predicting volume responsiveness in critically ill patients. However, this technique is limited to patients who receive controlled ventilation with adequate tidal volume (> 8 ml/Kg) and sedation or paralysis is needed to abolish the spontaneous ventilation.

For acute respiratory distress syndrome patients, protective ventilatory strategy suggested low tidal volume to 6 ml/Kg. On the contrary, high PEEP needed for acute respiratory distress syndrome to prevent VALI induces a leftward shift to the steep pat of the Frank-Starling curve and increase the fluid responsiveness. Whether the dynamic preload indicators (PPV and SVV)
Sponsor: Chang Gung Memorial Hospital

Current Primary Outcome: increase of cardiac output after volume expansion [ Time Frame: 4 hours ]

Patients are classified to be volume expansion responders or nonresponders according to whether the volume expansion induced cardiac index increase at the end of hydroxyethyl starch infusion is ≧15% or < 15% of baseline cardiac index.


Original Primary Outcome: increase of cardiac output after volume expansion [ Time Frame: 4 hours ]

Patients are classified to be VE responders or nonresponders according to whether the VE-induced CI increase at the end of HES infusion is ≧15% or < 15% of baseline CI.


Current Secondary Outcome:

Original Secondary Outcome:

Information By: Chang Gung Memorial Hospital

Dates:
Date Received: October 26, 2012
Date Started: November 2012
Date Completion:
Last Updated: November 30, 2012
Last Verified: November 2012