Trendelenburg position and its anaesthetic considerations

What are the various indication and disadvantages of trendelenburg position and how to prevent them?

Tilting a supine patient head down, the Trendelenburg position (German surgeon, Trendelenburg, who described its use for abdominal surgery)

Indications 

Abdominal and laparoscopic surgery, and to prevent air emboli and facilitate cannulation during central line placement. 

Disadvantages 

The Trendelenburg position has significant cardiovascular and respiratory consequences.

1)  The head-down position increases central venous, intracranial, and intraocular pressures. 

2) Prolonged head-down position  can lead to swelling of the face, conjunctiva, larynx, and tongue with an increased potential for postoperative upper airway obstruction. 

3) The cephalic movement of abdominal viscera against the diaphragm worsens the ventilation–perfusion ratio by gravitational accumulation of blood in the poorly ventilated lung apices and  decreases functional residual capacity and pulmonary compliance. 

4) In spontaneously ventilating patients, the work of breathing increases. 

5) The stomach  lies above the glottis so Endotracheal intubation is often preferred to protect the airway from pulmonary aspiration related to reflux and to reduce atelectasis.

Associated care in trendelenburg position

1) Care is taken to prevent patients  sliding off operating tables with resulting head injuries. With modern surgical tables and procedural techniques, steep head-down tilt is not often warranted. 

2) Retension material or shoulder braces for arm placement is avoided in these position to prevent brachial plexus injury.

3) Ventilation should be assisted or controlled and higher inspiratory pressures are needed to expand the lung.

4) Cranial vascular congestion and increased intracranial pressure can result from head-down tilt and in patients with known or suspected intracranial disease, the position should be used only in those rare instances in which alternate posture cannot be found and  Maintenance of the position should then be as brief as possible.

4)Because of the risk of edema to the trachea and mucosa surrounding the airway during surgeries in the Trendelenburg position for prolonged periods, it may be prudent to verify an air leak around the endotracheal tube or visualize the larynx before extubation.