Protocol-directed insulin infusion sliding scales improve perioperative hyperglycaemia in critical care

Perioperative hyperglycaemia is associated with poor outcomes in patients undergoing cardiac surgery. Frequent postoperative hyperglycaemia in cardiac surgery patients has led to the initiation of an insulin infusion sliding scale for quality improvement. A systematic review was conducted to determine whether a protocol-directed insulin infusion sliding scale is as safe and effective as a conventional practitioner-directed insulin infusion sliding scale, within target blood glucose ranges. A literature survey was conducted to identify reports on the effectiveness and safety of an insulin infusion protocol, using seven electronic databases from 2000 to 2012: MEDLINE, CINAHL, EMBASE, the Cochrane Library, the Joanna Briggs Institute Library and SIGLE. Data were extracted using pre-determined systematic review and meta-analysis criteria. Seven research studies met the inclusion criteria. There was an improvement in overall glycaemic control in five of these studies. The implementation of protocols led to the achievement of blood glucose concentration targets more rapidly and the maintenance of a specified target blood glucose range for a longer time, without any increased frequency of hyperglycaemia. Of the seven studies, four used controls and three had no controls. In terms of the meta-analysis carried out, four studies revealed a failure of patients reaching target blood glucose levels (P < 0.0005) in the control group compared with patients in the protocol group. The risk of hypoglycaemia was significantly reduced (P <0.00001) between studies. It can be concluded that the protocol-directed insulin infusion sliding scale is safe and improves blood glucose control when compared with the conventional practitioner-directed insulin infusion sliding scale. This study supports the adoption of a protocol-directed insulin infusion sliding scale as a standard of care for post-cardiac surgery patients.