Normothermic cardiopulmonary bypass is used in some centers. In a previous study, Kuntschen et al found that normothermic CPB resulted in higher blood glucose levels than hypothermic CPB. To our knowledge, this is the only study comparing glucose homeostasis during normothermic vs hypothermic CPB. As the two groups of patients studied by these authors were operated on under different conditions (different countries, types of anesthesia and methods of cardiac protection) we performed a prospective study comparing glucose homeostasis in patients operated on with the same protocol except CPB temperature.
After obtaining approval of the ethics committee of our Institution (December 27, 1987) and informed patients consent, 22 adults underwent CABG or valvular replacement (Table 1). Patients with diabetes mellitus, clonidine treatment or requiring emergency surgery were excluded. Due to the nyctohemeral endocrine variations, all operations started at 8:00 am.
All patients were anesthetized by the same physician (J.J.L.) to ensure a consistent anesthetic approach. All cardiac medications were continued until the day before surgery.
Table 1—Demographic and Surgical Data (Mean±SD)
|Group 1 (n = 12)||Group 2 (n = 10)|
|Age (yr)||60±9||55± 14|
|Sex ratio (M/F)||9/3||8/2|
|Weight (kg)||74 ±14||74± 14|
|Height (cm)||169 ±9||168 ±7|
|CPB duration (min)||102 ±18||53 ±22*|
|Duration of aortic crossclamping (min)||53± 16||40 ±13*|
|Minimum rectal temperature (°C)||30.4 ±1.2||35.9 ±0.6*|
|Hematocrit before induction||0.42 ±0.04||0.44 ±0.05|
|Minimum hematocrit during CPB||0.25 ±0.05||0.28 ±0.03|
|Inotropic support after CPB||4||2|