Transition from intravenous insulin to subcutaneous long-acting insulin in critical care patients on enteral or parenteral nutrition.
The optimal initial dose of subcutaneous (SC) insulin after intravenous (IV) infusion is controversial, especially in patients receiving continuous enteral nutrition (EN) or total parenteral nutrition (TPN). The aim of this study was to evaluate the strategy used at our hospital intensive care unit (ICU) in patients switched from IV insulin to SC insulin glargine while receiving EN or TPN. A retrospective analysis was made of 27 patients on EN and 14 on TPN switched from IV infusion insulin to SC insulin. The initial dose of SC insulin was estimated as 50% of the daily IV insulin requirements, extrapolated from the previous 12h. A corrective dose of short-acting insulin (lispro) was used when necessary. Mean blood glucose (BG) level during SC insulin treatment was 136±35mg/dL in the EN group and 157±37mg/dL in the TPN group (p=0.01). In the TPN group, mean BG was >180mg/dL during the first three days after switching, and a 41% increase in the glargine dose was required to achieve the target BG. In the EN group, mean BG remained <180mg/dL throughout the days of transition and the dose of glargine remained unchanged. In the transition from IV to SC insulin therapy, initial insulin glargine dose estimated as 50% of daily IV insulin requirements is adequate for patients on EN, but inadequate in those given TPN.