H: Hydrogen Ion Excess (Acidosis)

This one is always hard for me to remember. Partly because it DOESN'T ACTUALLY START WITH AN H!!!! and also because I view it as a side effect, not a cause.

Acids are a waste product of metabolism. Particularly anabolic/anaerobic metabolism (which is the kind that occurs in the absense of oxygen...so as you can imagine, a patient recovering from cardiac or respiratory arrest will have a lot of acid in their body!)

In an anaerobic state, the cells are trying to keep working, even though they don't have oxygen to act as the catalyst for the metabolic pathway that results in energy. So, they make it out of other molecules...with hydrogen's left over as junk.

In high concentrations, hydrogen acitic damage the cells. (A fact which I've pretty much taken for granate for many years, as the focus of most educational material I've exposed myself to is on acidosis (the process of producing acid) and not acidemia (the acidotic state itself))

There are two main ways the body rids itself of these acidic molecules:

Lungs via Breathing (fast acting)

Kidneys via Diuresis (slower response)

Your body produces acid when you exercise or when your body is under stress (think of leg cramps or 'burning' muscles after running) but most of the time a healthy person can deal with this by breathing more heavily...and even though you might feel sore for a couple of days, eventually your kidneys rid your body of the rest of it and it's not a problem.

Acid production is normal, it only really becomes a problem if your kidneys or lungs are diseased. This is why I often think of acidosis as a side effect, not a cause. However, it is an independent factor to consider when dealing with a  when dealing with a cardiac arrest scenario.

If the patient has been in respiratory distress, and/or is suffering from kidney failure. Acidotic condtions may persist even after optimal oxygenation has been re-established (or alternatively, kidney function has been re-established via diuretic/dialasis use) because the acid produced is still too much for the body to handle.

Most of the people I have seen who suffered from acidosis (or 'Hydrogen Ion Excess') were already very sick and experienced this condition secondary to the initial illness. It's importiant to monitor the acutely ill patient for this complication.

(Now that I think of it, I believe one individual who was suffering from alcohol overdose and malnutrition also had a form of acidosis. And people who are diabetic can suffer from ketoacidosis...hmm)

Labs that are vital to assess in a patient suffering from this type of problem are the Blood Gas Analysis. There are guidelines to help determine if the patient's acidotic/alkalotic condition is caused by respiratory failure or kidney failure depending on the ratio of the the kidney capacity indicator HCO3 and ventilation capcacity indicator PCO2, but I'll save that for the hypothetical respiratory therapy post because it's complicated and I don't feel like explaining it right now.

(Ketones, alcohol and lactic acid would probably be importiant too.)

The treatment for acidosis is dependant on the cause (if it is due to respiratory failure, the patient might need to be on a ventilator. If it is due to kidney failure, the patient might need dialysis.) The only emergency drug to treat acidosis is the base-Sodium Bicarbonate and it has been taken out of ACLS protocol and is only used under special cirumstances.