Trendelenburg Position

The Trendelenburg (head-down) modification of the supine position places the head down, often with the knees flexed, so that the patient does not slide headward on the table. The risks of shoulder braces to the brachial plexus were discussed earlier, and they are strongly discouraged.^[2] When they cannot be avoided, nonsliding mattresses are recommended.

The head-down position moves the viscera cephalad and is used to improve exposure during lower abdominal surgery, to increase venous return after spinal anesthesia, or to increase central blood volume to facilitate jugular or subclavian cannulation. This position increases central venous pressure, intracranial and intraocular pressure, myocardial work, and pulmonary venous pressure and decreases pulmonary compliance and functional residual capacity.^[32] Nevertheless, in a study in morbidly obese patients undergoing laparoscopy, the head-down position was shown to result in few changes in respiratory mechanics.^[33] Endotracheal intubation is usually necessary to protect the airway and prevent pulmonary aspiration. There is one case report of a patient who had a cerebral hemorrhage during such a procedure and emerged with a significant neurologic deficit.^[34] Clinical swelling of the face, eyelids, conjunctiva, and tongue has been observed, along with a plethoric color of venous stasis in the head and neck. Lingual and buccal nerve neuropathy can also occur.^[35] In patients with substantial swelling, it may be prudent to delay removal of the endotracheal tube until airway swelling has resolved.