Acidosis and Trauma
Trauma treatment is tricky. In my previous two blogs we broke down hypothermia🥶 and coagulopathy 🩸 in relation to trauma. It just wouldn’t be right if we didn’t finish this out with a blog on acidosis. This sneaky little bastard is the silent killer 🤫🔪 of the group. We can’t see it happening but it’s there, lurking around corners and wreaking havoc on our unstable trauma patient. So much of our interventions we utilize are directed at preventing acidosis: warming our patients, applying oxygen, stopping the bleed, giving blood products and many more.
As a warning: This blog contains terribly dry jokes. I hope that while rolling your eyes you learn something too! However, the best part of this blog is going to be how sweet and to the point it is because most of things have been covered in my previous two trauma blogs on Coagulation and Hypothermia. Hope you guys enjoy!
Cellular effects of acidosis
Fun Fact: The Krebs cycle was discovered in 1937 by Sir Hans Kreb. (1)
Useless information: Growing up, I watched SpongeBob a lot, and I mean A LOT. So going through nursing school, my brain made the association of the Kreb cycle to the Krusty Krab, specifically when the body converted to anaerobic metabolism. I called this the Krusty Kreb Cycle, because well, normal aerobic metabolism isn’t working. It's krusty, rusty and dusty, having to convert to anaerobic metabolism leading to acidosis. IT’S MY MEMORY AID, no shame!! Now that we have had our fun fact and useless information for the day let’s have some F.U.N. and move on.
Our human bodies are extremely efficient in regulating cellular metabolism with a perfect balance of oxygen, carbon dioxide, temperature, glucose and acid-base balance. We have the ability to regulate and balance life with buffer systems and adequate respiratory and renal function. Our Hydrogen ions and base substances work together to maintain a pH of 7.35-7.45. Acidotic states can lead to impaired cellular activity. When a pH falls below 6.8, cell death begins to occur. Trauma with acute blood loss or altered ventilatory status can lead to altered cellular metabolism. (7)
On a typical day, our body cycles through the day in an aerobic metabolic state. We productively produce adequate amounts of Adenosine Triphosphate (ATP), creating energy for our body to function. We need two main ingredients: glucose and oxygen, for this to function properly. Glucose is needed for glycolysis to produce pyruvate. Once Pyruvate is prepped with the assist of Acetyl CoA, it enters the Kreb cycle to help in the total production of ATP, NADH and FADH+. Entering into the final stages of metabolism, we have the Electron Transport Chain (ETC). The ETC is the major consumer of Oxygen. The total net outcome of this entire process is 34 ATP. (2)
However, when we do not have oxygen, the body can no longer maintain aerobic metabolism and tries to compensate by having anaerobic metabolism pick up the slack. While the outcome is still ATP, there is only a net of 2 ATP produced as well as lots CO2 and lactic acid produced. Both of which lead to acidosis quickly or further exacerbate an already acidotic state. Acidosis impacts control of ventilation, pulmonary capillary perfusion and diffusion across the alveolar membranes and effectiveness of hemoglobin. Acidosis also decreases cardiac contractility and increases the risk of arrhythmias. Along with increased pulmonary vascular resistance, there is an increased RV afterload. Acidosis also affects vasculature, causing vasodilation that is refractory to vasopressors. Enzymatic reactions and protein function are also affected by a low pH. (3)
Acidosis in relation to trauma
Acidosis is a sneaky little shit 💩in trauma. Why? Because it can silently come and go. We as EMS and prehospital providers have no way of knowing if our interventions or lack thereof, are worsening an acidosis. We (most of us) have no way of checking an ABG, base excess or coagulation panel. However, we do have a plethora of knowledge including our ability to assess our patient and critically think with the ability to intervene. With multi system trauma, we can have an interruption in our supply of oxygen via: hypoventilation, disruption in blood flow, blood loss and or loss of cardiac pump function. All leading to a state of inadequate tissue perfusion, anaerobic cellular respiration and lactic acid build up.
Acidosis in relation to hypothermia
Being an Endotherm, our body wants to thermoregulate. In the presence of hypothermia, our metabolic rate increases which causes an increase in glucose consumption. It is one of the reasons we ideally like to check a glucose on a trauma patient if time permits. While the body attempts to thermoregulate, it will exhaust all glucose stores in an attempt to thermoregulate. The body still wants to produce ATP and most importantly the heat that is also produced with metabolism. In the absence of oxygen and glucose, the body converts to anaerobic metabolism adding to the accumulating acidosis. Check out this “Hypothermia and Trauma” blog for more information!
Acidosis in relation to Coagulopathy
The coagulopathy of the trauma triad happens to be my favorite portion of the trauma triad. It is pretty fascinating how temperature, acidosis, hemodilution and lack of blood volume all contribute to a coagulopathy state. My last blog “Coagulopathy and Trauma”, is a really nerdy read for me that I enjoyed writing. When we have a large blood loss, we are not only losing clotting factors, but also the ability to perfuse tissue adequately, leading to hypoperfusion and acidosis. There are some pretty interesting numbers related to acidosis and trauma. Notably, clotting factors: X, V and prothrombin are impaired by 70% at a pH of 7.0 and 90% at a pH of 6.8. That’s still insane to me! (4)
Interventions to Mitigate Acidosis
The goal of our interventions indirectly mitigates acidosis. Our interventions are going to be focused on restoring perfusion, aiding in maintaining thermoregulation (keeping the patient warm), and protecting the airway.
Stop the bleed, pack the wound, apply the pressure or place a tourniquet. When we stop the bleed, our goal in relation to acidosis is to maintain and retain as much blood volume as possible to help maintain aerobic metabolism. When we lose the ability to circulate oxygen, we lose are ability to maintain efficient metabolism.
Keep the patient warm. After you uncover the patient for your assessment cover them back up, preferably with more than just a sheet. My Friend Taylor always has a foil blanket in her fanny pack. ❤️🤙🚁Removing wet clothes or removing the patient from a cold environment are also impactful interventions!
*** Appropriate**** Fluid resuscitate. I can’t stress this enough. As medical providers, this one is a tough subject. Whole blood and blood products should be the fluid of choice for our hypovolemic trauma patients. Whole blood is able to not only replace volume lost by blood, but it contains oxygen carrying capabilities and clotting factors. This helps with oxygen circulation to help maintain aerobic metabolism and clot formation (to stop the bleed lol). However, I seemed to get asked this question a lot, “But what do we do if we don’t carry blood?”. Honestly my first response is to follow your local and state guidelines. Most have protocols for Normal saline boluses. To that, I say use judiciously. Normal saline has a pH of 5.5 and high levels of chloride which is acidotic. When replacing blood loss with normal saline, you contribute to the acidosis. (7) My last tid bit on fluid administration whether it be normal saline, whole blood or blood products is to warm your fluids that you are administering.
My last intervention I would like to touch on is protecting the airway. Maintaining adequate oxygenation and ventilation is important is acid base balance. Detrimental acidosis accumulates rapidly if there is a disruption in ventilation even for a few minutes (7). If the patient is unable to protect their airway or has the potential for airway compromise, we should be ready to manage their airway. Applying Oxygen, assisting with ventilation via BVM and Intubation can help us control and address a potential cause for acidosis.
Conclusion
In summary, we did it. We have successfully reviewed acidosis in relation to trauma. Remember that by effectively treating our trauma patient’s presenting signs in symptoms, we are indirectly mitigating and correcting acidosis. Correcting perfusion, ventilation and oxygenation indirectly corrects the acidosis. Time is of the essence with our trauma patients and our end goal should be definitive treatment as soon as possible.
Thanks for reading. Peace out! ✌️
Brittany Grandfield, Flight Nurse, 2013 Lorimor Watermelon Queen. 🚁🍉👸🏻
Citations:
1. “The Krebs Cycle.” Deconstructing The Tour, http://www.deconstructingthetour.group.shef.ac.uk/krebs-cycle/#:~:text=In%201937%2C%20aided%20by%20his,carbon%20dioxide%2C%20water%20and%20energy.
2. Naifeh, Jeffrey. “Biochemistry, Aerobic Glycolysis.” StatPearls [Internet]., U.S. National Library of Medicine, 10 Aug. 2021,https://www.ncbi.nlm.nih.gov/books/NBK470170/.
3. Balmaceda, Alexander. “Resuscitation from a PH of 6.5: A Case Report and Review of Pathophysiology and Management of Extreme Acidosis from Hypovolemic Shock after Trauma.” Journal of Trauma and Injury, 30 Dec. 2019, http://www.jtraumainj.org/m/makeCookie.php?url=%2Fm%2Fjournal%2Fview.php%3number.
4. Grandfield, Brittany. “Coagulopathy and Trauma.” FOAMfrat Blog, 23 Aug. 2021, https://www.foamfratblog.com/post/coagulopathy-and-trauma.
5. Grandfield, Brittany. “Hypothermia & Trauma.” FOAMfrat Blog, 30 June 2021,https://www.foamfratblog.com/post/hypothermia-trauma.
6. GC;, Kaafarani HM;Velmahos. “Damage Control Resuscitation in Trauma.” Scandinavian Journal of Surgery : SJS : Official Organ for the Finnish Surgical Society and the Scandinavian Surgical Society, U.S. National Library of Medicine, 2014, https://pubmed.ncbi.nlm.nih.gov/24777616/.
7. Pollak, Andrew MD. Critical Care Transport. 2nd ed., Jones & Bartlett Learning, 2018.