Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion.
Specific interventions included in the review
Studies of GIK therapy were eligible for inclusion. Studies in which other substances were given in addition to GIK were excluded. In the included studies GIK was administered either pre-operatively, peri-operatively, post-operatively or peri- and post-operatively. The duration of treatment ranged from a few seconds to around 18 hours. The total amounts of glucose, insulin and potassium administered differed greatly between studies. The control intervention appeared to be placebo.
Participants included in the review
Studies in cardiac surgery patients were eligible for inclusion. The patients in the included studies underwent coronary artery bypass grafting or heart valve replacement. A few studies specifically excluded patients with diabetes whereas one study included only patients with diabetes. Some studies included both patients with preserved and impaired ventricular function, while some included only those with preserved ventricular function. Five studies excluded patients on the basis of ejection fraction (EF), specifying a cut-off of less than 20, 40 or 50%. Two studies used age as an exclusion criterion, over 70 years and over 80 years, respectively. One study excluded women.
Outcomes assessed in the review
Studies that used recovery of contractile function as a primary outcome were eligible for inclusion. The measurements used in the included studies to assess recovery of function were cardiac index, dp/dt max and EF. Other outcomes reported included post-operative atrial fibrillation (AF) and post-operative requirement for inotropic support.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.