c-peptide and Tachycardia

The purpose of this study was to evaluate intraoperative glucose control.. Prospective unblinded study.. Tertiary care center.. Diabetic (n = 17) and nondiabetic (n = 23) patients undergoing elective cardiac surgery.. Diabetics received a modified insulin regimen consisting of a fixed rate infusion of regular insulin, 10 U/m2/h, and a variable infusion of D10W, adjusted to maintain glucose between 101 to 140 mg/dL.. Baseline glucose was higher in diabetics versus nondiabetics (mean +/- standard error of the mean: 203 +/- 27 v 117 +/- 3 mg/dL, p < 0.005). After baseline, insulin levels were increased in diabetics to 410 to 568 microU/mL. Corresponding insulin levels in nondiabetics were 12 to 40 microU/mL. Compared with baseline, glucose was decreased by 10% +/- 29% in diabetics during hypothermic cardiopulmonary bypass and increased by 21% +/- 30% in nondiabetics (p < 0.005). After discontinuation of bypass, glucose was lower in diabetics (137 +/- 12 mg/dL) versus nondiabetics (162 +/- 8 mg/dL, p < 0.005). Nine diabetics had adequate intraoperative glycemic control during hypothermic bypass (glucose 123 +/- 8 mg/dL, insulin 550 +/- 68 microU/mL, glucose infusion rate 1.87 +/- 0.29 mg/kg/min), 6 approached adequate control near the end of surgery (glucose 147 +/- 8 mg/dL, insulin 483 +/- 86 microU/mL, glucose infusion rate 0.35 +/- 0.05 mg/kg/min), and 2 never achieved control. Diabetics with elevated initial glucose >300 mg/dL did not achieve adequate glycemic control. Four diabetics (3 with renal failure) required injection of 50% dextrose after bypass for hypoglycemia.. Adequate glycemic control can be achieved in most diabetics during cardiac surgery using a modified insulin clamp technique provided initial glucose is <300 mg/dL.

Topics: Aged; Aged, 80 and over; Biomarkers; Blood Glucose; C-Peptide; Cardiac Surgical Procedures; Cardiopulmonary Bypass; Diabetes Mellitus; Female; Human Growth Hormone; Humans; Hydrocortisone; Hypoglycemic Agents; Infusions, Intravenous; Insulin; Insulin Resistance; Intraoperative Complications; Lactic Acid; Male; Middle Aged; Prospective Studies; Tachycardia; Tumor Necrosis Factor-alpha

Oral glucose administration increased plasma noradrenaline concentration significantly in seven normal subjects (p less than 0.02), whereas in six young short-term Type 1 diabetic patients without complications plasma noradrenaline did not change. Basal plasma noradrenaline did not differ between the two groups. In the first 3 h after oral glucose administration, the mean heart rate in eight normal subjects was increased 3.5% above basal levels (p less than 0.05). In contrast, no such increase was found in eight Type 1 diabetic patients after glucose administration. In two normal subjects thoroughly examined before and after oral glucose administration, we observed a significant correlation between heart rate and systolic blood pressure (p less than 0.001) but this was not seen in two diabetic patients in whom neither heart rate nor systolic blood pressure increased. Our findings indicate that sympathetic nervous activity and cardiovascular function is abnormal in early diabetes during an oral glucose load.

Topics: Adolescent; Adult; Blood Pressure; C-Peptide; Diabetes Mellitus, Type 1; Female; Glucose; Heart Rate; Humans; Male; Norepinephrine; Stimulation, Chemical; Sympathetic Nervous System; Tachycardia