The purpose of the study is to evaluate the influence of different durations of the end-expiratory occlusion test to predict fluid responsiveness in mechanically ventilated patients in the operating room.
The reduction of postoperative complications is an essential aspect of care in perioperative medicine. Many studies have shown that individualized hemodynamic therapy, by optimizing fluid administration and cardiac output, can reduce the risk of postoperative morbidity and mortality. A fluid challenge, consisting in the administration of a small bolus of intravenous volume of fluid over a short period of time, is one of the commonest therapeutic hemodynamic intervention to test the preload reserve and the cardiac response to an increase in intravascular volume of a patient (fluid responsiveness). However, an increase in stroke volume (or cardiac output) is only achieved in 30 to 50% of patients after a fluid challenge test. Several dynamic tests have been described to predict the response to fluid challenge, however their limits are numerous. The end-expiratory occlusion (EEO) test, consisting in a brief interruption of mechanical ventilation at end-expiration, by preventing the variation in intra-thoracic pressure, allows an increase in venous return, cardiac preload and stroke volume. Thus, an increase in stroke volume during an EEO can predict fluid responsiveness, simulating a fluid challenge though avoiding the administration of possibly unnecessary fluids. The EEO test has already been successfully evaluated in several studies in ICU patients. Only few studies were conducted in the operating room, with conflicting findings: one study, consisting of an EEO test of 30 seconds found that changes in stroke volume during an EEO can predict fluid responsiveness, whereas another one, consisting of an EEO test of 15 seconds did not. The purpose of the study is to evaluate the influence of the duration of EEO test to predict fluid responsiveness in mechanically ventilated patients in operating room.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Masking
TRIPLE
Enrollment
40
A set of respiratory and hemodynamic measurements (including cardiac output) will be recorded at each stage: * T0: baseline. * T1: At the end of the first EEO (15 sec or 30 sec) * T2: 1 minute after completion of the first EEO. Return to baseline. * T3: At the end of the second EEO (15 sec or 30 sec) * T4: 1 minute after completion of the second EEO. Return to baseline. * T5: Before the fluid challenge test (4 ml/kg of 0.9% saline over 5 min) * T6: 1 minute after the end of the fluid challenge A first set of measurements will be performed after intubation (before the surgical incision) and will be repeated, if necessary, in case of further decrease in stroke volume during surgery or in case of any clinical indication of volume expansion (i.e., arterial persistent hypotension, major hemorrhage, etc.).
CHU
Clermont-Ferrand, France
To compare the ability of an EEO over 30 sec with that of an EEO over 15 sec to predict fluid responsiveness
Comparison of the areas under the ROC (Receiver Operating Characteristic) curves.
Time frame: During surgery
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