Venous versus arterialised venous blood for assessment of blood glucose levels during glucose clamping: comparison in healthy men.

Abstract

The aim of this study was to investigate the influence of the arteriovenous (A-V) gradient in blood glucose concentrations at low and high insulin levels on the determination of glucose requirements during glucose clamping in 9 healthy, insulin sensitive, male volunteers. In a random order two clamps were performed, once using arterialised venous blood (A Clamp, mean pO2 = 11.5 +/- 0.36 kPa, 86 +/- 2.7 mmHg), and once using venous blood (V clamp, mean pO2 = 7.9 +/- 0.21 kPa, 59 +/- 1.6 mmHg). Insulin levels were maintained at 48 +/- 2.4 mU/l from 0-180 min and at 1054 +/- 114 mU/l from 180-360 min. Elevation of insulin levels caused a significant rise of the A-V gradient: from 0.3 +/- 0.1 to 0.5 +/- 0.1 mmol/l (p < 0.05) and from 0.2 +/- 0.1 to 0.3 +/- 0.1 mmol/l (p < 0.05) during the A and V clamps, respectively. Despite these A-V glucose gradients no significant differences were found for the glucose requirements during the last 30 min of each period of insulin infusion between the A and V clamps: 43.70 +/- 3.4 vs 44.8 +/- 2.8 mumol.kg-1.min-1 during the low insulin level and 77.3 +/- 5.0 vs 76.2 +/- 3.4 mumol.kg-1.min-1 during the high insulin level. We conclude that the A-V glucose gradient, even at high insulin levels, does not influence the assessment of glucose requirements to a measurable extent, allowing the use of the simpler technique of taking venous rather than arterialised venous blood for the measurements of glucose levels during glucose clamping.