Saturday, November 20, 2010

The Story of Dr. Trendelenburg’s Position

If you look in nearly any EMS text book you will find Trendelenburg’s Position defined as “a position in which the patient’s feet and legs are higher than the head.  This is sometimes known as the 'shock position.'”
Dr. Friedrich Trendelenburg would argue that a “true” form of the position named for him involves placing the patient at a 45 degree angle with the head lower than the patient’s feet, with their legs bent at the knees and hanging off the end of a table. But he was also using the position to keep the intestines out of the pelvis during gynecological procedures and to reduce venous vein pressure during varicose vein surgeries. Little did Friedrich know that his simple to use position would later be called to use in the treatment of nearly all patients with signs of severe shock.
The March to War
It was not until the First World War, when a young American Physiologist, named Walter Cannon, was sent to Europe (with a medical team from Harvard University) that Dr. Trendelenburg’s ‘Beckenhochlagerun’ (Raised Pelvic Position) found worldwide popularity.
Dr. Cannon set out to find ways to combat the effects of shock in wounded GIs. He popularized the use of the Trendelenburg’s position to increase venous return to the heart and thus increase cardiac output (CO). The simplicity of this treatment caused it to be widely popular and easily adopted. As such, it is still taught worldwide to this day.
Unfortunately Dr. Cannon’s announcement, ten years after World War I, was not so popular. After further study Dr. Cannon found the increased CO to be detrimental, along with creating complications with pulmonary function.
How did EMS get stuck with this?
Emergency Medicine’s love affair with Trendelenburg’s Position likely stems from the same place it finds many of its standard practices; military medicine. Through the years war has been the driving factor behind many innovations in emergency medicine including MAST pants and air evacuation. The former has been widely discarded while the latter has saved countless lives.
Since the early days of EMS the “shock position” has been there, always a reliable back up to use if a patient was hypotensive. And many still widely believe it to work, every time, without consequence. EMS, as with much in the world of medicine, will defend dogma vehemently until a respected authority tells them to stop. Or said dogma is specifically banned.
I posed the question, of why Trendelenburg is so hard to let go of, to Sean O. Henderson, MD, via email in 2007. Dr. Henderson was the co-author of a 2003 Canadian Journal of Emergency Medicine piece ‘Myth: The Trendelenburg Position Improves Circulation in Cases of Shock.’
Dr. Henderson wrote to me:
“The ‘shock position’ is very popular. In the allied health professions and we do not have a central clearing house for ‘dogma’ testing. MD’s are bad enough within our own house, but to imagine the tainted information that gets out to nurses and prehospital care providers is frightening.”
That said, a simple internet search will show that there is a movement amongst EMS community discussion forums to stop using Dr. Friedrich Trendelenburg’s famous position. But, there are always opposing views that support the “old tried and true.” Like basic first aid training from the American Heart Association, which still includes “elevating the legs to prevent shock” for a traumatic injury.
At the most basic level Trendelenburg’s Position is STILL being taught as the way to treat shock.
The continuation of this is further perpetrated by the NREMT curriculum and text books. Brady’s 10th Edition EMT-Basic text  advocates the use of Trendelenburg in the event of shock, but is conscientious enough to advise the student not to use the position if the patient has a head injury. This is not only a simplistic, but dangerous view.
There seems to be a feeling of “We have always done it that way!”
Agreed, we have, but my grandparents also used to churn their own butter. Now I go to the store and buy it because it makes more sense.
Show Me the Money…er, Evidence!
-A 1967 study by Taylor and Weil found that Trendelenburg’s Position was associated with retinal detachment, brachial nerve paralysis, and cerebral edema. They also noted an alarming trend in compromised lung volume, which they attributed to the viscera placing pressure on the diaphragm.
- A 1994 study on oxygen transport found increases in left ventricle filling and blood pressure, while end tissue oxygenation was not found to be significantly changed. (So, in short, you’ve increased the blood pressure but, much of the patient’s tissues are still inadequately perfused. Which, last time I checked, is the most basic definition of “shock.”)
- A 1985 study by Bivins, Knopp, and dos Santos is even more alarming. They found that “a 1.8% (99% confidence interval, -1.3% to 4.7%) of the total blood volume was displaced centrally when subjects were placed in head-down position.” This small displacement was eventually determined to be insufficient and not indicative as an effective treatment of hypotension.
-Similarly a co-study between the Anesthesiology and Cardiac Surgery departments of Ludwig-Maximilians University, of Munich, Germany, concluded “Trendelenburg’s Position caused only slight increase of preload volume, despite marked increase in cardiac-filling pressures, without significantly improving cardiac performance.”

 Dr. Sean Henderson summed it up this way, in the conclusion of our correspondence:
“I can’t completely rule out the use of the ‘shock position’ in all cases (such as some cases of cardiogenic shock), but I cannot advocate its use for hemodynamically unstable trauma patients.”
So where does that leave us? Dr. Henderson advocated a “modified Trendelenburg’s Postion with the patient’s legs raised 15-20 degrees while at the same time elevating the patient’s head 10 degrees.” Once an agreed upon alternative to the true Trendelenburg’s Position is reached the national curriculum will need changed. And reeducation of all healthcare providers will be needed.
In the interim EMS providers should consider intracranial pressures, restriction of pulmonary volumes, and increased cardiac workloads before placing a patient in Trendelenburg’s Position.
Old habits are hard to break, and a more thoughtful use of Friedrich Trendelenburg’s position will eventually prevail over simplistic ideas of just “tilting the container.” EOR. - MW

1.) Dodd Memorial Library, Chrisitan Medical
College- Vellore, India (n.d.). Walter B. Cannon: Physiologic Invertigator. Retrieved December 14, 2007, from
Johnson, S., & Henderson, S. O. (2003, August 22). Myth: The Trendelenburg Position Improves Circulation in Cases of Shock. Canadian Journal of Emergency Medicine, 6(1):48-9, . Retrieved
September 29, 2007, from
2.) Limmer, D., O'Keefe, M. F., & Dickinson, E. T. (2007). Lifting and Moving Patients. In E. T. Dickinson (Ed.), Brady Emergency Care (10th ed., pp. 119-120).
Upper Sadle River, New Jersey: Pearson/Printice Hall.
3.)Reuter, D. A., Felbinger, T. W., Scmidt, C., Moerstedt, K., Kilger, E., & Lamm, P. et al. (2005, June 2). Trendelenburg positiong after cardiac surgery: effects on intrathoracic blood volume index and cardiac performance. European Journal of Anesthesiology , 20: 17-20, . Retrieved
October 4, 2007, from
4.) (2008, January 5). Friedric Trendelenburg (1844-1924). Retrieved
January 6, 2008, from
5.) Personal email correspondence between the author and Sean O. Henderson, MD,
University of Southern California, were used in the creation of this article. This correspondence was initiated on October 1st, 2007 and continued until October 15th, 2007.
(Note: The majority of this was written in 2007. The author apologizes for any sources that may have been lost in the exchange of file formats and hard drive replacements)


  1. Frustrating issue - cuz we see an increase in BP immediately. But we don't have good M&M data.

  2. amazing post, Matt! we discussed this issue today at UCLA's paramedic refresher. i wish i would have had this article then so i could have passed it around!

  3. Matt,
    One thing to check up on is which of the dozen or so variations on the "shock" & "trendelenburg" positions were being described in each instance, or if it was even checked. Big difference in raising the legs at the hips compared to tilting a bed caudally 15 degrees. What about beds that bend at the knee instead of just tilting up? There's so much variation that it's hard to say what's really going on. EMS "tredelenburg" tends to mean supine or close to it with the legs raised either with a lift/tilt section of the stretcher or by placing items under the lower legs (equipment bags, etc.). In most ERs around here the entire stretcher is tilted, but there's still tons of variation. Backboarded patients should be lifted by placing items under the board, not between the board and the patient, but both are regularly observed in my area. My experience is that in orthostatic and cardiogenic hypoperfused states or minor trauma it can be pretty effective in improving mental status and alleviating some symptoms. I'm much more in favor of raised legs and tilted people as a treatment modality than I am of the toothpaste tube concept (PASG/MAST, which i prefer to consider as PAST ;-)

    As with everything else, further study is needed. A-Lines and much higher levels of monitoring than our patients will get in the field for a long time are probably what's needed to really study the effects. Just like almost everything else we do.

    Bill Murphy CCEMT-P CLI

  4. Good stuff, Matt. If you haven't read it, Bryan Bledsoe also has a pretty good article on the Trendelenburg position: