Acid-base management during cardiopulmonary bypass. Current trends in the United Kingdom

Controversy exists over which method of acid-base management should be used during hypothermic cardiopulmonary bypass: the alpha-stat method or the pH-stat method. We surveyed 40 centres in the United Kingdom to assess current practice; whether practice has changed recently; and if so, why. Ten years ago, 31 centres (77.5%) used pH-stat and seven (17.5%) used alpha-stat. Currently nine centres (22.5%) are using pH-stat, 25 (62.5%) are using alpha-stat and four (10%) are using both. One centre (2.5%) has always used a modified pH-stat technique, and one continues to use alpha-stat in children and pH-stat in adults. Twenty-one of the 22 centres which have changed their practice did so because of increasing reports incriminating pH-stat in postoperative morbidity, particularly cerebral dysfunction. Our results show a marked trend towards using alpha-stat methods rather than the more traditional pH-stat approach.