Effects of glucose-insulin-potassium (GIK) on myocardial blood flow and metabolism in canine endotoxin shock.
Glucose-insulin-potassium (GIK) has beneficial effects during endotoxin shock, possibly through improvement of myocardial function, but the mechanism is not clear. We have studied the effects of GIK on left ventricular function, coronary flow, and oxygen consumption in controls and dogs treated with endotoxin (1.5 mg/kg-1). The animals were anaesthetized (etomidate 4 mg/kg-1/hr-1) and ventilated (N2O:O2 = 2:1). We have measured left ventricular pressure, left ventricular end-diastolic pressure (LVEDP) and LVdP/dt, systemic blood pressure, cardiac output (CO; thermodilution), coronary blood flow (CBF; radioactive microspheres), and oxygen content and lactate in arterial and coronary sinus blood. Endotoxin caused a rapid fall of CO and blood pressure with a temporary recovery followed by gradual circulatory collapse. GIK infusion (50% glucose, 2 g/kg-1 bw, 8 mmol KCl, and 3 U insulin/kg-1 bw) increased CO (56%), CBF (61%), blood pressure (21%), LVEDP (77%), and LVdP/dt (28%), and systemic vascular resistance decreased (23%). Stroke work (80%) and tension time index (42%) decreased during shock, but GIK temporarily improved these variables. The ratio of stroke work, respectively tension time index to oxygen consumption, suggests that myocardial efficiency decreased during shock and improved after GIK. Endotoxin decreased the ratio of endo- to epicardial flow. GIK did not change this ratio. However, for the same endo to epi ratio, increased CBF implies increased flow to endocardium.
D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D004285:Dogs; D005947:Glucose / Q000627:therapeutic use*; D006352:Heart Ventricles; D006439:Hemodynamics / Q000187:drug effects; D007328:Insulin / Q000627:therapeutic use*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D011188:Potassium / Q000627:therapeutic use*; D012772:Shock, Septic / Q000188:drug therapy* / Q000503:physiopathology; D013997:Time Factors
D007328:Insulin; C030396:glucose-insulin-potassium cardioplegic solution; D005947:Glucose; D011188:Potassium