INTRAVENOUS LACTATE PREVENTS CEREBRAL-DYSFUNCTION DURING HYPOGLYCEMIAIN INSULIN-DEPENDENT DIABETES-MELLITUS

1, Intravenous lactate prevents cerebral dysfunction during hypoglycae mia in healthy volunteers, This study examines whether this also occur s in insulin-dependent diabetes, Changes in four-choice reaction time, auditory brain stem response, and P-300 latency were used as measures of cerebral function. 2, Ten subjects were studied twice at least 4 w eeks apart, Blood glucose was maintained between 5 and 8 mmol/l for 1 h before starting a 60 m-unit min(-1) m(-2) stepped hyperinsulinaemic clamp, achieving blood glucose concentrations of 4.5, 3.3 and 2.5 mmol /l, At one visit, 40 mu mol min(-1) kg(-1) sodium lactate was infused, and at the other, normal saline, Cerebral function was measured at ea ch blood glucose concentration. 3, Blood lactate rose to 3.32 +/- 0.06 mmol/l during lactate infusion compared with 0.9 +/- 0.03 mmol/l duri ng saline infusion, Compared with the results at 4.5 mmol/l there were no significant changes at 3.3 mmol/l in any measure of cerebral funct ion at either visit, At 2.5 mmol/l a significant increase in reaction time and P-300 latency occurred with saline [mean change 33.1 +/- 8.6 ms (P < 0.01) and 30.1 +/- 9.2 ms (P < 0.01) respectively] but not lac tate [mean change -5.9 +/- 3.7 ms (P > 0.05) and -6 +/- 7.6 ms (P > 0. 05) respectively]. No significant changes occurred in auditory brain s tem response, The catecholamine response to hypoglycaemia was attenuat ed by lactate (P < 0.05 for adrenaline and noradrenaline). 4, Thus int ravenous lactate prevents cerebral dysfunction during hypoglycaemia in insulin-dependent diabetes.