Glucose intolerance during prolonged sevoflurane anaesthesia.

PURPOSE The effects of prolonged sevoflurane anaesthesia on insulin sensitivity were investigated by two successive intravenous glucose tolerance tests (IVGTT) in eight patients who underwent prolonged surgery. METHODS The first IVGTT was administered (25 g glucose as 20% dextrose in water iv) over two minutes 35 min after initiation of surgery. Arterial blood samples were obtained at 0, 5, 10, 30, 60, and 120 min after glucose administration for blood glucose and plasma insulin determination. A second IVGTT was performed six hours following the initiation of surgery. RESULTS The disappearance rate of glucose (k-value) for the first IVGTT was 0.887 +/- 0.436 (mean +/- SD) %.min-1, and 0.784 +/- 0.289 for the second IVGTT. Both k-values are lower than the normal value. The maximum insulin response to glucose (delta IRI-delta BS-1) of the second IVGTT was lower than the first IVGTT (0.124 +/- 0.092 vs 0.071 +/- 0.056, P < 0.05). The total insulin output of the first IVGTT was higher than the second IVGTT (1.161 +/- 830 vs 568 +/- 389 microU.min.ml-1, P < 0.05). CONCLUSION Glucose intolerance is enhanced by diminished insulin output in response to blood glucose elevation during prolonged anaesthesia and surgery.