Chances are, you’ve experienced tunnel vision at some point during your life. When you begin working on a difficult math problem, suffer an anxiety attack, or even if you get hit on by the hottie at the end of the bar – the same hormonal responses kick in and send you down an unstoppable chemical/physical roller coaster of the adrenaline rush.
The same reaction occurs during an car accident, a violent attack, or a sudden medical emergency. That’s why it’s important to know a few things about Tunnel Vision and how our Flight or Fight response impacts our ability to see (literally) and make good decisions when seconds count.
What is Tunnel Vision?
Tunnel vision is a very real phenomenon that describes the visual changes inherent to the adrenaline rush of the fight-or-flight response. A key part of the fight-or-flight response, mydriasis (the widening of the pupils) allows more light through the pupil to the iris and improves visual acuity. While the pupils are dilating, the lens configures itself for distance vision. The end result is more focused vision on things that are slightly farther away and are in the central field of vision.
What is the purpose of Tunnel Vision?
Consider our ancestry for a moment. You’re minding your own business, gathering some nuts and berries on the edge of a forest, when a twig breaks in the open plain in front of you. You have seconds (maybe less) to collect enough information to decide if this is a threat. To aid you in figuring out what your life expectancy might be, your body initiates the Fight-or-Flight Response – the Adrenal Response.
Adrenaline pours out of the adrenal glands, dopamine levels rise and the following physiologic changes occur:
Heart rate increases
The force of each cardiac contraction increases
Blood pressure increases
Air passages dilate
Blood vessels in the kidneys and GI tract constrict
Blood flow to the skeletal muscles, heart and liver increase
The liver creates increased glucose in the blood stream
Increased heart rate, contractility and blood pressure result in increased blood (and the oxygen and glucose it carries) for the skeletal muscles, liver and heart. If you have to run or fight, you better have the juice to make it a good run or a successful fight. The liver takes the blood flow to create the glucose. Airways widen to get as much oxygen into the system as possible with each breath. We reduce blood flow to the kidneys and intestines because, stopping to pee or enjoy a bowel movement are not high on the priority list for the foreseeable future. And, for our hunter gatherer, the dilated pupils and distance focus allow him/her to scan the grassland efficiently.
All of this occurs in the fraction of a second to give our ancestor the best chance for survival.
But what is the impact of all of these changes for us?
As time has passed, our concentration on fine motor skill has increased (no hunter-gatherer ever had to navigate a 3” QWERTY keyboard!) and the environment has closed in on us slightly. City streets and closet-sized apartments have replaced the open plains and 100 acre farms. The daily threat of violence has dissipated for many as well, which translates to an increased risk of tunnel vision.
For professional responders and some members of the military, the adrenaline rush is an everyday thing. It’s impact is blunted as we develop a greater tolerance for the higher levels of adrenaline, dopamine and norepinephrine – don’t misinterpret this as a good thing, those constantly increased hormone levels have other, long lasting impacts on our health. But early on in a career, to be effective, coping mechanisms have to be learned:How can I manage Tunnel Vision during an emergency?
To help manage the impacts of an adrenaline rush, take a deep breath. Literally, take one deep breath and concentrate on it for a second or two. To thwart the effects of the sympathetic nervous system (the gas pedal for your hormones), you need to entice the parasympathetic nervous system (the brakes…sort of) to get involved. Taking that deep breath drops the diaphragm low and creates some stimulation on the Vagus Nerve (cranial nerve #10). That stimulation causes a decrease in heart rate and blood pressure (if you’ve ever coughed forcefully and seen stars, maybe got a little dizzy, that is your diaphragm stimulating the vagus nerve). The momentary decrease in pulse and blood pressure can help you get a handle on the situation.
There is some research that is showing a correlation between the heightened dopamine levels and a skewed perception of time during a high stress situation. Taking that moment to take a deep breath and force a focus on a task at hand can help realign that perspective.
Most importantly, focusing on remaining situationally aware is critical. Force yourself to stay in touch with your surroundings: "I’m on the third floor. The exits are to my right and behind me. The police and ambulance personnel will be coming from that direction.”
The amount of situational awareness and focus will be dictated by the situation. One of the first lessons I taught to new EMTs and Paramedics is, "Relax, it’s not your emergency.” This is not a lesson in callousness or some perverted survival mechanism. Consistently reminding yourself that the emergency is "theirs” and that you’re there to help solve the problem places an otherwise stressful situation in a new context. As the rescuer, it’s helpful to tune out the typical-human emotional response to the emergency (this may be tough, I get it). Humans are natural problem solvers; the more we can picture the emergency as a "problem to be solved” and less as "that horrible thing that happened,” the easier it will be to remain focused, aware and capable of making good decisions for the rescuer and the victim.
If you are a bystander during a medical emergency, who wants to help the victim, be prepared for your body to go into Fight or Flight mode. Take a deep breath, pay attention to your surroundings, and do the best you can to respond to the medical emergency at hand.