Postoperative hyperglycaemia of diabetic patients undergoing cardiac surgery - a clinical audit

Previous studies have shown that hyperglycaemia is associated with postoperative complications in cardiac surgical patients. Conversely, well-controlled glucose levels are said to reduce major infectious complications in diabetic patients.

The purpose of this clinical audit was to evaluate the blood glucose levels of diabetic patients undergoing cardiac surgery and to determine the effectiveness of postoperative glycaemic control.

A group of 150 patients from a large Irish cardiac surgery centre was selected by convenience sampling. An audit tool was designed to capture the patients' blood glucose levels, treatment regimes and postoperative complications.

The findings showed major variations between 'high', 'good' and 'borderline' blood glucose levels in the pre- and postoperative phase. Although blood glucose testing practices seemed inconsistent, mean levels measured 'borderline'. Furthermore, the treatment regimes varied greatly and suggest a lack of consensus regarding the management of postoperative hyperglycaemia. A total of 52% (n = 78) patients developed 114 complications with a level of 21.4% (n = 32) postoperative wound infections.

The findings from this audit highlight the importance of regular blood glucose testing to enable early detection of hyperglycaemia and timely initiation of appropriate treatments regimes for diabetic patients undergoing cardiac surgery. Findings also show that hyperglycaemia derangement may make a difference in the recovery phase. While patients will benefit from lesser wound infections, hospitals might save costs involved with treating postoperative complications.

More consistent blood glucose testing might be achieved through the use of evidence-based protocols. However, the education of staff is as important as it develops knowledge on the complex metabolic interactions of diabetic patients undergoing cardiac surgery. While this means investing in staff education and policy development, costs for daily care and expensive treatments for complications will be saved as patient recovery will be speedier and less eventful.