Blood volume distribution in the Trendelenburg position

Area of Science:

• Physiology
• Medical Procedures

Background:

• The Trendelenburg position is commonly employed in managing hypotensive patients.
• A presumed autotransfusion of blood to the central circulation is the basis for its use.
• Quantifying the actual central blood volume displacement remains undocumented.

Purpose of the Study:

• To investigate and quantify the central blood volume displacement caused by the Trendelenburg position.
• To assess the clinical significance of blood autotransfusion from Trendelenburg positioning.

Main Methods:

• Ten healthy volunteers participated in the study.
• Total blood volume was calculated based on body surface area.
• Radionuclide scanning was utilized to determine the distribution of blood volume.

Main Results:

• A median displacement of 1.8% of total blood volume to the central circulation was observed.
• This central displacement occurred when normovolemic volunteers were placed in the Trendelenburg position.

Conclusions:

• The autotransfusion effect of the Trendelenburg position is quantitatively small.
• The observed blood volume shift is unlikely to produce a clinically significant effect in patients.