Transition from intravenous insulin to subcutaneous long-acting insulin in critical care patients on enteral or parenteral nutrition.

BACKGROUND AND AIMS: 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. DESIGN AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

B-type natriuretic peptides for prediction and diagnosis of weaning failure from cardiac origin.

AIM: To evaluate and compare BNP and NT-proBNP concentrations to predict weaning failure from mechanical ventilation (MV) due to heart failure (HF) before a spontaneous breathing trial (SBT) and to identify HF as the cause of failure. METHODS: Prospective, observational study in a university hospital. The sample included 100 patients on MV for over 48 h who underwent an SBT. Echocardiography and sampling for natriuretic peptides were performed immediately before and at the end of SBT. HF was diagnosed by pulmonary artery occlusion pressure >18 mm Hg or signs of elevated filling pressures in echocardiography. RESULTS: Thirty-two patients failed the SBT, 12 due to HF and 20 due to respiratory failure (RF). Before SBT, BNP and NT-proBNP were higher in patients failing due to HF than RF or in successfully weaned patients. Cut-off values using ROC curve analyses to predict HF were 263 ng/L for BNP (p < 0.001) and 1,343 ng/L for NT-proBNP (p = 0.08). BNP and NT-proBNP increased significantly during SBT in patients failing due to HF. Increases in BNP and NT-proBNP of 48 and 21 ng/L, respectively, showed a diagnostic accuracy for HF of 88.9 and 83.3% (p < 0.001). BNP performed better than NT-proBNP for HF prediction (p = 0.01) and diagnosis (p = 0.009). CONCLUSION: B-type natriuretic peptides, particularly BNP, can predict weaning failure due to HF before an SBT; increases in natriuretic peptides during SBT are diagnostic of HF as the cause of weaning failure. BNP performs better than NT-proBNP in prediction and diagnosis of HF.