Ketones vs. Lactic Acid

Ketones and Lactic Acid are important lab values when trying to determine the chemistry of a patient. Both Ketones and Lactic Acid can help to guide your thinking, on what is wrong with a patient, and what you need to do, in order to try to resolve the diagnosis of the patient. However, in the prehospital setting, there is nothing that we can do for these patients. The hospital is able to help the patient more, because they are able to obtain the lab values and have an endless supply of medications that they can administer to the patient. During an ALS transfer (hospital to hospital), the paramedic may need to monitor the medications that are being administered to the patient. At the same times, if a paramedic is transferring a patient from a nursing home, where the labs have been drawn, and taking the patient to the ER, the paramedic should have an understanding on what Ketones and Lactic Acid is and how they effects the body. In some cases, Ketones and Lactic Acid labs values can help to determine how severe the patient is, and if they need more advanced care and be transported at a higher-level of priority.

First, let's look at Ketones. Ketones is a substance that is made when the body has to break down fat, in order to make energy. Normally, the body will break down carbohydrates, but in some cases (diabetics, lack of carbohydrate intake, anorexia, dieting, dehydration), the body has to break down the fat in the body, in order to get the energy that it need to continue.

Ketones can be tested via the blood and the urine. Normally, their should be no ketones noted in the body (MedlinePlus 1). However, if there are Ketones in the body, the labs can be broken down into three different categories: small, moderate, and large (MedlinePlus 1). Small value would be <20mg/dL; Moderate value would be 30-40mg/dL; and a Large value would be >80mg/dL (MedlinePlus 1).

Now, lets talk about Lactic Acid. Lactic Acid is an acid that is produced when the carbohydrates in the body are broken down. The common causes of a high Lactic Acid is when their is a lack of oxygen in the body, thus causing the body to breakdown the carbohydrates for energy (MedlinePlus 2). In a normal case, when oxygen levels are normal, the body will break down the carbohydrates into water and CO2. Lactic Acid build up is caused by strenuous exercise, sepsis, heart failure, and liver issues (MedlinePlus 2). Unlike Ketones, Lactic Acid will always be in the body. The normal value of Lactic Acid in the body is 4.5 - 19.8 mg/dL (MedlinePlus 2). If a Lab Value is greater than 19.8mg/dL, than the patient is in lactic acidosis.

Both Ketones and Lactic Acid lab values are vital to help with the diagnosis and severity of a patient. Even though lab values do not do much for paramedics in the prehospital setting, they are still vital components to know when taking a patient to the ER (say from a nursing home), or performing an ALS transfer (from hospital to hospital); these lab values will help guide the paramedic in determining how critical the patient is, and if they needed higher level of care, and a higher level of priority.



Sources:
Ketones: https://www.nlm.nih.gov/medlineplus/ency/article/003585.htm

Lactic Acid: https://www.nlm.nih.gov/medlineplus/ency/article/003507.htm