While I will be reprimanded by many in our industry for mentioning these volatile issues, I feel upset but also encouraged and hopeful. I have taken the negative experiences and positive opportunities and put them in context. There is no time for wallowing in our past disappointments, but we must contextualize the issues of the past to learn from those experiences and forever ride over the bumps of inattention and regrets moving forward.
IN THE CASE of a stroke in the settings of trauma, the compromise of blood supply to the brain requires immediate restoration in order to protect the nerve cells and the supporting cells. To illustrate, JL Saver published an article in a journal called “Stroke” in 2006, wherein he noted that when there are interruptions of major blood vessels to the brain, approximately 120 million neurons, 830 billion synapses (connections), and 714 kilometers (447 miles) of myelinated nerve fibers are lost each hour (Saver 2006).
A compromise in blood circulation, oxygen, and nutrition to the brain can result in the loss of brain cells and their connection if the circulation, oxygen, and nutrition are not restored rapidly following injury.
Secondary effects of trauma
“Time is Brain” deals with protecting neurons before and after an injury from dying and trying to restore their function in as short a time as possible. Once those neurons are lost, there is generally only limited nerve cell regeneration possible in the brain to where there can be significant difference. However, this depends on the severity of the injury, area of the brain involved, and age of the brain.
“Neuroprotection” is a term used to describe this form of protection in the nervous system.
| Image # 6 – Neuroprotection |
Estimates of the total amount of neurons in the brain depending upon age range from 10-100 billion neurons (Pakkenberg 1997).
Years of clinical research and experience gleaned from caring for patients in emergency situations have allowed us to develop some key principles to manage TBI and concussion in the field and in the hospital setting to allow for neuroprotection. While those principles are simple, they have a profound impact on the outcome. Employing these methods of early resuscitation can radically change the outcome of a critically ill patient. These principles have been established as part of the basic cardiac life support (BCLS), advanced cardiac life support (ACLS), and advance trauma life support (ATLS).
The key elements in the resuscitation of a traumatized unconscious patient are the ABCs, i.e., Airway and Breathing first, followed by the Circulation of blood. Although providing oxygen by establishing access through the breathing apparatus is critically important, it has been proven that keeping proper circulation by pumping on the chest to keep blood flowing from the heart, in situations where the heart fails to pump blood, is quite effective even if there is not an airway (Sathianathan 2016).
Addressing the critical intervention in Mario’s case (#1) in order to preserve the brain cells
The measures of neuroprotection were performed in the field by his friend and the first responders, which resulted in some degree of stabilization until Mario was transported to a major medical trauma center capable of further interventions.
Restoration of respiratory function
Mario was in a coma in the period immediately following his injury and could not breathe on his own. He needed to be intubated to ensure the cells in the brain received oxygen via his respiratory system (lungs). Oxygen is an important element in the combustion of the fuel sources, such as glucose, proteins, and fats to produce energy, and is critical for each cell in the body to stay alive and function. The energy produced by the cell is utilized to produce electric currents in the body responsible for the messaging system which allows us to function. If there is no oxygen, this combustion cannot take place, hence leading to no energy in the body. Those of you who know about engines understand that gasoline is the fuel that mixes with oxygen from the air and combusts by a spark plug to produce the energy that makes a vehicle move. The body utilizes oxygen and fuel (glucose) in the same manner to produce energy. In fact, some of the energy developed is dissipated immediately to make the vehicle move, while others are stored in a battery system for later use. In the body, when energy is produced, it is preserved in a chemical battery storage system present in every cell called adenosine triphosphate (ATP). You can only imagine now what would have happened to Mario if he was not intubated (Airway) and placed on a ventilator (breathing machine) so that his body system could continue working by acquiring oxygen. The importance of respiratory function following TBI/concussion is a critical factor in the resuscitation of patients, since the lack of oxygen prevents energy production. If not addressed early, this leads to cell death, ultimately disrupting the brain hierarchical organization and restoration process (Brenner 2012, Alai 2019).
Clinicians rarely get to see what happens in the moments following a TBI/concussion, except if you are a team doctor in the field at the time of the injury. I had the opportunity to see someone in the immediate period following a TBI/concussion and witness the events as they transpired thereafter.
I was attending a function and was about to enter the building when a young boy (Hal, Case # 7), about 12 years old without looking to the right or left, ran across the street to catch up with his friends, who had already safely crossed the street. I saw the boy running into a moving vehicle (SUV) as it came around a corner. He was thrown about 12 feet from the vehicle and ended up on the sidewalk. The first to arrive on the scene, I had the rare opportunity to see what happens in the immediate period after a TBI/concussion. The 12-year-old boy was limp, unresponsive, and not breathing, but had a normal pulse indicating that the heart was working. Meanwhile, the ABC of resuscitation was first and foremost in my mind to ensure that Hal would not suffer hypoxia (lack of oxygen) to the brain. The ambulance was at least 10 minutes away, and there was no emergency management equipment available. Within 90 seconds, the patient was breathing and hyperventilating when he opened his eyes and started looking around. In Hal’s case, the impact caused a concussion to the brain that temporarily knocked out the reticular activating system (RAS) responsible for consciousness and arousal and the chemoreceptors system responsible for breathing.
The central chemoreceptor system responsible to sense high levels of carbon dioxide and hydrogen is a center located in the brain stem, at the point where the brain and spinal cord meet, called the Medulla Oblongata (Nattie 2012). There are also peripheral chemoreceptors located in the bodies of the carotid and aortic arteries that sense carbon dioxide, oxygen, and acidity (Detweiler 2018).
Without spontaneous breathing (when breathing stops), carbon dioxide accumulates in the blood and the oxygen levels plummet. Under such conditions, carbon dioxide is not expelled if there is no expiration (breathing out), and oxygen levels plummet if there is no inspiration (breathing in). Note that from the combustion of oxygen and glucose, the result is the production of carbon dioxide, which is the gas we breathe out from the lungs primarily (think of what comes out of the muffler in your car). These chemoreceptors (sensors) in the brain stem pick up such high levels of carbon dioxide when someone stops breathing. The stimulation of the carbon dioxide chemoreceptors serves to drive the desire to breathe without even thinking of breathing. The chemoreceptor system is part of a primitive system of breathing seen in mammals, which developed as a part of our survival. We often refer to this drive to breathe as the hypercarbia drive.
A similar system exists when there are low oxygen states called the hypoxic drive. The hypoxic drive is only responsible for 10% of the