To improve blood glucose levels worsened by treatment with short-acting neutral insulin without buffer (A) switched from that with buffer (B) on CSII, we treated 7 IDDM patients by various devices with heparin in A solution or two needle sizes with A, or with short-acting acidified insulin (C) on CSII. After treatment with A, blood glucose levels increased significantly (P<0.01) becoming unstable in four patients, but were not significantly changed in three patients. Increased glucose levels were observed on Day 1 and peaked on Day 2 after treatment with A when a syringe was used for three days, the needles being changed daily. Addition of heparin Na to A solution improved the glucose levels, but heparin Ca solution did not. The effect of C was similar to that of B. Insulin precipitation was not observed in the tubes and needles. The results show that treatment with heparin Na of a short-acting neutral insulin solution without buffer or with short-acting acidified insulin is effective in patients worsened by CSII with short-acting neutral insulin without buffer, indicating that insulin absorption by the blood may be disturbed in the outlet of the needle under subcutaneous tissue by ions and fibrination on influence of material of the tube or syringe and intrinsic factors in the patients.
