In the Trendelenburg position, the body is laid supine, or flat on the back on a 15–30 degree incline with the feet elevated above the head.
The reverse Trendelenburg position, similarly, places the body supine on an incline but with the head now being elevated.
The Trendelenburg position is used during surgery, especially of the abdomen and genitourinary system:
allowing better access to the pelvic organs as gravity pulls the intra-abdominal organs away from the pelvis.
Evidence does not support its use in hypovolemic shock, with concerns for negative effects on the lungs and brain.
The Trendelenburg position can be used to treat a venous air embolism: it places the right ventricular outflow tract inferior to the right ventricular cavity, causing the air to migrate superiorly, within the right ventricle from which air is less likely to embolize.
The Reverse Trendelenburg position has been used in minimally invasive glaucoma surgery, also known as MIGS.
The Trendelenburg position combined with the Valsalva maneuver, (modified-Valsalva maneuver) , can also be used for the cardioversion of supraventricular tachycardia.
The position is helpful in surgical reduction of an abdominal hernia, when placing a central venous catheter in the internal jugular or subclavian vein.
Gravity assists in the filling and distension of the upper central veins, as well as the external jugular vein.
The Trendelenburg position allows used better perfusion in respiratory patients.
It may be used for drainage images during endoscopic retrograde cholangiopancreatography.
Its useful in umbilical cord prolapse, until C-section.
A meta-analysis found adverse consequences to the use of the Trendelenburg position in hypotension, and recommended it be avoided.
The Trendelenburg position used to be the standard first aid position for shock.
Trendelenburg position can be used to treat decompression sickness or arterial gas embolism, but current scuba first aid professionals no longer advocate elevating the feet higher than the head.
The Trendelenburg position in this case increases regurgitation and airway problems, causes the brain to swell, increases breathing difficulty, and has not been proven to be of any value.