Hydrogen Ions as a H&T Reversible Cause of Cardiac Arrest
Hydrogen Ions is one of the Hs in the H&T reversible causes of cardiac arrest. When considering Hydrogen ions as a cause, what we’re looking at is the patient’s pH or acid/base balance and conditions that affect it. Hydrogen ion imbalance as a H&T reversible cause is today’s Pass ACLS tip topic.
The H in pH is hydrogen. pH is the negative log of H+ concentration. The pH scale goes from 0 to 14 with a pH of 7 being neutral. Different parts of the body have a different pH but when we discuss a patient’s overall pH we use blood as a reference and the pH should be between 7.35 and 7.45.
In the human body, a serum pH greater than 7.45 indicates the patient is alkalotic or in a state of alkalosis. While a pH less than 7.35 indicates the patient is acidic or in a state of acidosis.
Some common causes of acidosis include: hypoxia, hypoventilation, DKA, prolonged seizures, CHF, Aspirin overdose, drowning, and liver or kidney failure.
Some common causes of alkalosis include: excessive or prolonged vomiting, use of certain diuretic medications, a history of adrenal disease, and electrolyte imbalance.
Acidosis
Mild acidosis with an elevated CO2 may benefit by slightly increasing the rate of ventilations from 10 breaths to 12 breaths per minute by changing from one breath every six seconds to one every five. Small changes like this can have profound effects on CO2 and pH. Be sure to avoid excessive ventilation which can increase thoracic pressure and decrease the effectiveness of CPR due to compression of the vena cava.
For patients with a long hypoxic down time or a high suspicion of metabolic acidosis, Sodium Bicarbonate is indicated after we’ve ensured adequate ventilation. The dose for bicarb is 1 meq/kg. A common prefilled for bicarb is 50 meq in 50 ml. Using a 220 lbs (100 Kg) patient, 100 meq of bicarb IV push is indicated and that would require two prefilled syringes or “Amps”. Bicarb converts acids to carbon dioxide – so adequate ventilation must be maintained.
Alkalosis
Treatment of alkalosis is aimed at reversal of the underlying cause. Getting ABGs and electrolytes will aid in identifying specific imbalances that can be correlated to the patient’s history. The treatment will depend on the type of alkalosis (metabolic or respiratory).
