Best practice & research. Clinical anaesthesiology
-
Best Pract Res Clin Anaesthesiol · Dec 2009
ReviewHyperglycaemia as part of the stress response: the underlying mechanisms.
Stress hyperglycaemia is a distinctive clinical feature of critical illness. Stress mediators, namely stress hormones, cytokines and the central nervous system, interfere with normal carbohydrate metabolism, especially in the liver and skeletal muscle. Central insulin resistance, defined as increased hepatic gluconeogenesis and glucose output despite abundant endogenous insulin levels, appears pivotal to the occurrence of stress hyperglycaemia. ⋯ Still, exogenous insulin administration normalises blood glucose levels in this setting. Insulin treatment may counteract hepatic insulin resistance during acute critical illness. During prolonged critical illness, therapeutic insulin effects seem mediated by increased skeletal muscle glucose uptake and use.
-
Best Pract Res Clin Anaesthesiol · Dec 2009
ReviewClinical benefits of tight glycaemic control: focus on the perioperative setting.
The benefits of tight glycaemic control (TGC) were first shown in cardiac surgical patients with diabetes. These concepts migrated to other surgical and medical specialties through intensive care units caring for a variety of patients with a variety of disease states Although some disagreement and controversy surrounds the use of TGC in the medical population, the benefits of this therapy ir the diabetes cardiac surgery population is unblemished. Perioperative hyperglycaemia has been shown to be associated with adverse surgical outcomes in several different patient populations TGC for 3 full postoperative days or more mitigates these risks Although this has been definitively proven in the diabetes coronary artery bypass graft (CABG) population, evidence for beneficia effects of TGC in other surgical populations remains elusive at this point in time. In this article, we explore the risks of hyper- and hypoglycaemia in the surgical patient; safety and efficacy of insulin protocols in the surgical population, target range goals and dura tion of therapy; the beneficial effects of TGC on decreasing mortality, reducing infectious complications, length of stay and other complications; define target surgical populations tha benefit from TGC; analyse current controversies as they relate to surgical populations; and describe questions that remain for the future of TGC.
-
Best Pract Res Clin Anaesthesiol · Dec 2009
ReviewClinical benefits of tight glycaemic control: focus on the intensive care unit.
While stress hyperglycaemia has traditionally been regarded as an adaptive, beneficial response, it is clear that hyperglycaemia and hypoglycaemia are associated with increased risk of death in critically ill intensive care unit (ICU) patients. Recent studies on blood-glucose control failed to fully clarify whether this association is causal. Early proof-of-concept single-centre randomised controlled studies found that maintaining normoglycaemia by intensive insulin therapy, as compared with tolerating hyperglycaemia as an adaptive response, improved patient outcome. ⋯ Finally, the studies on tight blood-glucose control were done with vastly different nutritional and end-of-life strategies. The currently available studies do not allow to confidently recommend one optimal target for glucose in heterogeneous ICU patient groups and settings. Provided that adequate devices for blood-glucose measurement and insulin administration are available, together with an extensive experience of the nursing staff, blood-glucose levels should be controlled as close to normal as possible, without evoking unacceptable fluctuations and hypoglycaemia.
-
Best Pract Res Clin Anaesthesiol · Dec 2009
ReviewMolecular mechanisms behind clinical benefits of intensive insulin therapy during critical illness: glucose versus insulin.
High blood glucose levels have been associated with morbidity and poor outcome in critically ill patients, irrespective of underlying pathology. In a large, randomised, controlled study the use of insulin therapy to maintain normoglycaemia for at least a few days improved survival and reduced morbidity of patients who are in a surgical intensive care unit (ICU). ⋯ We first describe the molecular origin of hyperglycaemia and the impact of the therapy on insulin sensitivity. Next, the molecular basis of glucose toxicity in critical illness and the impact of intensive insulin therapy hereon are described, as well as other non-glucose-toxicity-related metabolic effects of intensive insulin therapy.
-
Best Pract Res Clin Anaesthesiol · Dec 2009
ReviewClinical benefits of tight glycaemic control: focus on the paediatric patient.
Hyperglycaemia and glucose variability occur frequently during critical illness or after major surgery in children and are associated with worse outcome. Association does not necessarily imply causality however, and the question whether tight glycaemic control (TGC) with insulin infusion improves morbidity and mortality can only be answered by randomised controlled trials (RCTs). ⋯ Before universal implementation in paediatric intensive care both long-term effects on outcome and development and issues regarding optimal levels of blood glucose control need to be cleared in multicentre prospective RCTs. Technological improvement might be helpful in optimising blood glucose control.