What does the alpha stat method maintain during cardiopulmonary bypass?

The alpha stat method is designed to maintain a pH that varies with the temperature of the blood during cardiopulmonary bypass. This approach recognizes that as temperature changes, so does the pH of blood due to the temperature dependency of various biochemical reactions.

By allowing the pH to adjust with temperature, the alpha stat strategy helps to optimize the patient's physiological state during hypothermia, as it aims to maintain cellular function and metabolic homeostasis. It acknowledges that the carbon dioxide levels in the blood affect pH, and thus, as the patient's temperature decreases, the anticipated changes in pH associated with hypothermia are taken into account.

This method contrasts with other strategies, such as the 'pH-stat' method, which strictly maintains a constant pH value regardless of temperature, showcasing why the alpha stat approach is distinct and practical in managing patients undergoing cardiopulmonary bypass.