[Optimal glucose dose in the preoperative fluid infusion].

We have measured blood concentrations of glucose, 3-hydroxybutyrate (3-OHBA), non-esterified fatty acid (NEFA) and lactate before and after glucose administration in 105 patients to determine the optimal glucose dose during the period of preoperative fasting state. The patients, scheduled for laparotomy in the afternoon, received fluid infusion containing an arbitrary glucose dose for 4 hours prior to surgery. The glucose dose showed a negative correlation with the ratio of 3-OHBA or NEFA prior to and after glucose administration (r = 0.40, r = 0.41 respectively, P < 0.05). There was no correlation between lactate ratio and glucose dose (r = 0.06). Glucose administration more than 0.4 g.kg-1 significantly suppressed 3-OHBA production (P < 0.05). Hyperglycemia (> 200 mg.dl-1) developed more often in the groups given 0.5 g.kg-1 or more glucose (P < 0.05), while significant hypoglycemia (< 60 mg.dl-1) occurred in the groups given less than 0.2 g.kg-1 of glucose (P < 0.05). This study demonstrates that preoperative infusion of glucose 0.4-0.5 g.kg-1 is useful to maintain the energy metabolism during the fasting state in patients scheduled for operation in the afternoon.

Cooling of extraction electrode of an ion source in long-pulse operation.

Experimental studies were made on the cooling of extraction electrodes of an ion source in the case of long-pulse operation. Copper electrodes with forced water cooling pipes were tested under the condition that an ion beam of 1 to 5 A at 30 keV was extracted for up to 10 s. The average heat loading to the grid are of the electrode was as high as 130 W/cm2. This high heat flux was obtained by a set of electrodes artificially arranged to produce poor beam optics, and hence the high heat loading. Temperature of the ground electrode was measured at two points by thermocouples buried and silver brazed in it, and was kept below 230 degrees C due to a large boiling heat transfer coefficient of the cooling water. No evidences of deformation or deterioration of the electrodes was observed after repetitious beam extraction. This heat loading was still a half of that on the grid of the ion source for the JT-60 NBI.