pH homeostasis during cardiopulmonary resuscitation in critically ill patients.

We investigated the effect of repeated administration of sodium bicarbonate on acid-base balance and serum chemistry in a group of patients who developed cardiac arrest. A mixed acidosis persisted throughout the duration of resuscitation in the majority of patients in spite of the large ventilatory volume and multiple doses of bicarbonate they received. However, the repeated administration of bicarbonate prevented a severe fall in serum pH. Our study demonstrated the beneficial role of bicarbonate in the treatment of metabolic acidosis associated with cardiac arrest of prolonged duration. Analysis of our data strongly indicated that the primary factors which determine the serum pH during cardiopulmonary resuscitation are the duration of circulatory arrest, adequacy of ventilation and circulation, pH immediately before arrest, and quantity of bicarbonate administered and its volume of distribution in the various fluid and tissue compartments.