During this whole coronavirus pandemic, I have tried to brush up on my acid base balance. As an ICU dietitian this is important. If you are reading this and you don’t work in an ICU, this might not mean as much to you. Just know that your body is complicated and is designed to stay in a balance, that when it is thrown off can cause havoc and needs to get rectified for you to survive. When you are healthy your body works to keep your body in homeostasis. Your lungs help to remove unwanted CO2 and then your kidneys work to process bicarbonate. When you are sick or find yourself in an ICU setting this balance either respiratory, metabolic or both gets messed up. So this means your body isn’t able to maintain that balance and your body starts to go acidotic (lower pH) or alkalotic (higher pH). Your body wants to keep your pH around 7.4 and that helps ensure all your organs are able to function appropriately. The pH of your arterial blood is determined by three things: 1) your PaCO2 (that is the pressure of CO2 in your blood), 2) lactic acid which is a by product of anaerobic metabolism, and 3) the buffering capacity of your blood (the amount of bicarbonate that is present.
If there is a problem with your lungs ability to function then you can have respiratory acidosis or alkalosis. This means that your ability to clear that CO2 is altered and your pH will go down (acidosis) or up (alkalosis). If you have an issue with your kidney function then that is termed metabolic acidosis or alkalosis. This means that bicarbonate isn’t able to be processed appropriately.
https://www.medifee.com/blog/acid-base-disorders-a-look-into-balance-and-imbalance/
What does this mean for a dietitian? Being able to have an understanding of how the body reacts to stress and then critical illness impacts how you provide nutrition to help the body get through that event. A patient in the ICU with an acid-base imbalance may be on Total Parenteral Nutrition (TPN). Being able to know what time of imbalance the patient is experience (acidosis or alkalosis) and then having a working knowledge of if it is respiratory or metabolic will help in understanding the treatment methods.
Having this understanding of how the body maintains a normal acid-base balance for physiologic homeostasis and growth matters. Becoming familiar with the key components of acid-base status is important and those include PaO2, lactic acid and bicarbonate. Having a basic understanding of how these blood gases are interpreted allows clinicians to figure out what therapies are needed to normalize acid-base balance. This can help save patient’s lives and makes a difference! So whether you are an ICU provider or not, knowing that your body is incredibly complex matters.
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