Fluid Responsiveness Tested by the Effective Pulmonary Blood Flow During a Positive End-expiratory Trial
Fluid Responsiveness Tested by the Effective Pulmonary Blood Flow During a Positive End-expiratory Trial
Fluid responsiveness is difficult to assess at the bedside. The accuracy of published
 techniques to detect preload-dependent patients have many pitfalls and limitations. The
 present study test the role of noninvasive effective pulmonary blood flow measured by expired
 carbon dioxide to detect fluid responsivess in mechanically ventilated patients.
This is a prospective and observational study designed to test the accuracy of the
 non-invasive effective pulmonary blood flow measured by the capnodynamic methodology for
 detect preload-dependent patients.

 Fourty patients undergoing mechanical ventilation during surgery will be studied.
 Preload-depency (fluid responsiveness) will be tested during an increase in end-expiratory
 pressure (PEEP) from 5 to 10 cmH2O during one minute. Pulse pressure variation will be use as
 the reference method to detect preload-dependency. The effective pulmonary blood flow will be
 continuously recorded during the PEEP maneuver. Receiver Operator Curves will be used to
 detect fluid responsiveness taking a pulse pressure variation higher than 13%.The
 corresponding cut off value for the effective pulmonary blood flow signal will be
 determined..
Inclusion Criteria:

 -  Written informed consent

 -  Programmed cardiac and noncardiac surgeries

 -  Need of invasive arterial blood pressure monitoring.

 Exclusion Criteria:

 -  Emergency surgeries.

 -  Acute pulmonary diseases

 -  Arrhytmias

 -  Congestive cardiac failure