I trained and worked as a surgeon for 30 years in the tri-state area, within an hour of New York City, so I thought I was fairly sophisticated about healthcare. That was until my first week of graduate school when in studying global health systems I learned that bleeding is the largest cause of maternal death in India.
In reality, 27% of all maternal deaths are due to hemorrhage (18% of which are post-partum). That is a truly humbling statistic. And let me add, that I am a vascular surgeon so I am no stranger to bleeding; in fact, in some ways, we might be considered connoisseurs of hemorrhage. In our specialty bleeding can be so fast that it can be heard or it can appear like a bowl filling up with blood.
So, it should come as no surprise that in my wanderings last week I came across an article in Wired entitled An Electric Shock Could Keep Patients From Bleeding Out. Would you believe that if I stimulate your vagus nerve, it will result in 50% less bleeding? Here is the science:
- The vagus nerve (from the Latin to wander) indeed follows a complicated course throughout the body innervating the organs of the chest and abdomen. 90% of the information carried by the vagus nerve is information about the periphery carried centrally to the brain; the remaining 10% sends signals back to the periphery.
- The vagus nerve is the neural highway for the parasympathetic nervous system – a system that can, without our conscious knowledge, regulate our heart rate or digestion.
- The vagus nerve is the neural highway for what has been termed an inflammatory reflex – allowing the brain to coordinate and activate inflammatory mediators, the signals our bodies use to indicate stress or traumatic injury.
- Branches of the vagus nerve extend to the spleen – an organ that stores and produces blood elements and for the most part thought to be involved as a filter removing damaged blood cells and platelets. Platelets are elements in the blood that initially help to plug holes in our arteries and vein while sending chemical signals to get more help.
- As part of our response to trauma, the brain sends a signal through the vagus nerve to the spleen where lymphocytes, a type of white blood cell, release chemical mediators that prepare platelets to do their thing. When it comes to bleeding, their thing is to clump together (aggregate) and plug the hole. The priming prepares them to be more adherent, and because they are primed, they do this job more quickly.
This effect of vagal stimulation has been studied in mice and pigs -- two standard animal models-- in bleeding and coagulation studies. Stimulating the vagus nerve for just a few moments resulted in up to 50% less bleeding. Coagulation studies demonstrated that these primed platelets were acting only at the site of bleeding, they had no systemic effect (and that was good because we do not want to be forming clots randomly throughout the body). For more on blood clots, take a look at this article by my colleague, Dr. Wells.
This science has been developed into a medical device by Sanguistat, and I had the opportunity to speak with the CEO, Ronald M. Burch, M.D., Ph.D. He indicated that early human clinical trials of their vagal stimulator for bleeding were scheduled to proceed in the next few months. These are Phase 3 trials were the efficacy and safety of the device will be studied with human volunteers.
The device stimulates the vagus nerve by a patch affixed to your ear, nothing invasive. But Dr. Burch did indicate that there is a bit of a learning curve to correctly placing the patch. I couldn’t stop myself from asking the next question. Was the patch's placement on the ear an acupuncture point? And the answer is yes, an acupuncture point for "the spleen." Perhaps bioelectrical medicine can help tease out the science of acupuncture from its cultural components.
The applications for this type of bioelectrical medicine go beyond saving mothers from post-partum hemorrhage – which by itself, would be huge. It may well have roles in caring for wounded soldiers, trauma patients, and for individuals with hemophilia [1] Whether this becomes a new tool in controlling bleeding for a range of conditions will have to wait, at least until with see positive results in the upcoming clinical trials.
[1] a medical condition due to an inherited lack of factor VIII, a coagulation factor resulting in a markedly reduced ability to form blood clots.
