Abstract
End-expiratory occlusion test (EEOT) has been proposed as a preload responsiveness test that overcomes several limitations of pulse pressure (PPV) and stroke volume (SVV) variations. We compared the ability of EEOT versus SVV and PPV to predict fluid responsiveness during the increase of the vasomotor tone in a rabbit model of hemorrhage. Ten rabbits were anesthetized, paralyzed, and mechanically ventilated during basal load (BL), after progressive blood withdrawal (BW), and after volume replacement. Other two sets of data were obtained during vasomotor increase by phenylephrine (PHE) infusion in BL and BW. We estimated the change of stroke volume (∆SVEEOT) and aortic flow (∆AoFEEOT) during the EEOT. PPV and SVV were obtained by the variation of beat-to-beat PP and SV, respectively. Baseline PPV, SVV, ∆SVEEOT, and ∆AoFEEOT increased significantly after BW, with a decrease of aortic flow (P < 0.05). PHE induced a significant decrease of PPV and SVV, but without affecting ∆SVEEOT, and ∆AoFEEOT. We conclude that ∆SV and ∆AoF during EEOT kept the ability to predict fluid responsiveness during PHE infusion in a rabbit hemorrhage model. This result may suggest the advantage of EEOT with respect to SVV and PPV in predicting fluid responsiveness during vasomotor tone increase.
Highlights
The main goal of fluid therapy is to correct hypovolemia avoiding both under and over-resuscitation, as well as the excessive use of inotropic and vasopressor drugs
PHE infusion induced a significant increase in vasomotor tone, evidenced by an increase in Eadyn from 1.1 ± 0.3 to 1.5 ± 0.7 (P < 0.05)
In a rabbit hemorrhage model, we have shown that PHE infusion (15 mcg/kg/min) induced a decrease in aortic flow with a significant stroke volume (SV) decrease after blood withdrawal (BW) compared with normovolemia
Summary
The main goal of fluid therapy is to correct hypovolemia avoiding both under and over-resuscitation, as well as the excessive use of inotropic and vasopressor drugs. By interrupting cyclic ventilation at end-expiration for a few seconds (end-expiratory occlusion, EEO), abolishing the inspiratory increase in intrathoracic pressure, and by passive leg raising tests, we can produce a self-volume challenge and increase cardiac output (CO) by a rapid and reversible increase of venous return (VR) in those patients preload-responsive[4,5]. Both tests have shown an excellent predictive value keeping their accuracy in patients with cardiac arrhythmias, with spontaneous breathing activity, with low compliance of the respiratory system and independently of positive end-expiratory pressure in acute respiratory distress syndrome patients[6,7].
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call