Physiologic changes that can occur in Trendelenburg position include the following:
- Increased venous return can lead to increased right and left sided cardiac filling pressures, mean pulmonary artery pressure, and mean arterial pressure. Such changes may be poorly tolerated by patients with heart failure.
- Abdominal contents shift cephalad, which may lead to atelectasis and decreased functional residual capacity and pulmonary compliance, and ventilation/perfusion mismatching. These changes can cause difficulty with ventilation and oxygenation, particularly with abdominal insufflation for laparoscopy.
- Increased intracranial pressure can occur. Trendelenburg positioning should be avoided in patients with traumatic brain injury.
- There is increased risk of passive regurgitation of gastric contents and aspiration.
- Facial edema and airway swelling can occur.
- There is conflicting evidence on effects on intraocular pressure and the risk of postoperative visual loss after prolonged procedures.
For further information, refer to UpToDate content on patient positioning for surgery and anesthesia.
Illustration by Kiran Guthikonda, MD, PhD, Dartmouth-Hitchcock Medical Center.
