As a trauma and emergency surgeon in a busy emergency department, I treat patients nearly every day who need emergency blood transfusions. Patients with cracked spleens, injured vessels, or stomach ulcers all need blood to survive. Most of the time we have enough blood on hand to meet the demand. But I’m worried that may soon change.

We are in the midst of a scary blood shortage. Earlier this year, the Red Cross declared the first-ever “blood crisis.” Blood donation rates have significantly worsened since the pandemic as people stayed home more due to COVID-19, and this critical shortage comes at a time when the demand for blood transfusions has significantly increased.

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This blood shortage is very concerning, especially when we consider the extreme circumstances of a mass casualty event like a mass shooting (there have been more than 200 in the U.S. so far this year). In these situations, large volumes of blood products are suddenly in very high demand, and they occur with absolutely no notice.

My colleagues and I recently conducted a study that looked at whether six major U.S. cities — Baltimore, Boston, Miami, Los Angeles, Pittsburgh, and San Antonio — had an adequate blood supply to handle a mass casualty event like a bomb going off in a crowd (such as what happened during the 2013 Boston Marathon), which can injure thousands. Based on the supply available, if such an event occurred in any of these cities, five out of six would run short of platelets, two out of six would not have enough of a blood product called cryoprecipitate (which helps control bleeding), and several of them may struggle to provide enough red blood cells or plasma. Smaller cities and those that stock less blood per trauma bed are at even higher risk of running out at crucial times.

These findings mean that in the event of a mass shooting, bombing, or accident involving large numbers of people, some victims might not be saved — not because there were not enough paramedics, nurses, or doctors on hand to treat their injuries, but because there wouldn’t be enough blood for everyone who might need it.

As a physician, the possibility of not being able to give my patient the blood they need is truly unthinkable.

“If you can, take this opportunity to donate to our blood supply.”

Jeremy Cannon

To help mitigate these shortages, blood banks and transfusion experts need to rethink their approach to blood product management to better preserve donated blood and maintain a larger inventory of this precious resource. Researchers need to accelerate development of techniques that prolong the usable shelf life of all blood products while also exploring novel blood substitutes. Some examples of techniques that are being explored include deep freezing red blood cells so that they can be used for up to 10 years, freeze-drying plasma so that it becomes a powder that can be quickly reconstituted in a liquid solution for up to two years, and cooling platelets so that they remain primed to activate for up to several weeks rather than just a few days. My colleagues and I are also exploring novel blood product substitutes, such as engineered products that carry out the function of red blood cells.

But most importantly, there should be a renewed focus on encouraging people to donate, like we saw in the aftermath of the 9/11 terrorist attack, as we have seen in Ukraine, where citizens are waiting in long lines to donate blood, and very recently in Uvalde, Texas, after the horrific Robb Elementary School shooting. Unfortunately, the typical pattern after such shocking events is that very generous and well-meaning first-time donors become one-time donors. We need to find ways to convert them into sustaining donors. Some donors can return as often as several times per year.

Here in the U.S., considering the ongoing and deepening blood shortage crisis and the increasing need for blood products, we must ramp up our efforts to promote and encourage individuals to donate blood as often as possible.

June 14 is World Blood Donor Day. If you can, take this opportunity to donate to our blood supply (visit the American Red Cross website to find out where) so that my fellow surgeons and I have this precious, lifesaving resource when our patients need it most.

Jeremy Cannon is a fellow at the University of Pennsylvania Leonard Davis Institute of Health Economics and a professor of surgery at the Perelman School of Medicine.