The debate over whether to use colloid or crystalloid solutions for fluid resuscitationis still ongoing. Colloid solutions consist of large molecules that generally cannot pass through healthy capillary membranes, whereas crystalloid solutions contain ions that easily move from the intravascular space to the interstitial compartment. Therefore, it is traditionally argued that colloids are more effective at expanding intravascular volume, with a suggested ratio of 1:3 compared to crystalloids. However, there is currently limited evidence to suggest that resuscitation with one type of fluid is more effective or safer than t he other. Despite these theoretically advantageousphysiological properties, colloids have not demonstrated a clear hemodynamic benefit over crystalloids. We hypothesized that these unexpected discrepancies may be attributed to different mechanical heart responses.

Inclusion Criteria:

• HealthyVolunteers with age > 18 years without medical history

Exclusion Criteria:

History of cardio vascular diseases Diabetes Hypertension Currentpregnancy Knownallergy to one of the tested products Leftventricular dysfunction discovered at baseline assessment Valvular heart or other structural diseases discovered at base line assessment