Diabetes manifests as an elevated blood glucose level caused by a deficiency in insulin production, inadequate insulin secretion, or an increase in insulin resistance in the peripheral tissue. In 2005, an estimated 20.8 million people had diabetes and an estimated 6.2 million people had undiagnosed diabetes.1 This estimate may be significantly higher today. A recent survey conducted via telephone interviews of more than 620,000 adults estimated that 26 million Americans now have diabetes.2
The estimated 6.2 million people who have undiagnosed diabetes are likely to be in an uncontrolled hyperglycemic state. Even persons who are euglycemic may develop a hyperglycemic condition known as stress-induced hyperglycemia,3 which occurs when the release of catecholamine and cortisol causes increased glycogen levels and insulin resistance in peripheral tissue.4
Sustained elevated blood glucose levels can cause surgical complications, such as urinary tract infection, stroke, postoperative hemorrhage, and wound infection.5 Risk of wound infection is further complicated by poor wound healing. Factors such as chemotaxis of leukocytes and macrophages, a prolonged inflammatory phase, lower rate of collagen synthesis and granulation, and peripheral neuropathy contribute to deficient wound healing.
Patients who suffer a severe trauma injury are likely to stimulate stress-induced hyperglycemia. Furthermore, the level of hyperglycemia may indicate the severity of the injury. Members of a surgical team will benefit from understanding the correlation between hyperglycemia and trauma and also the potential challenges that may occur when treating affected patients.
HYPERGLYCEMIA AT ADMISSION
Hyperglycemia, defined as a glucose level higher than 200 mg/dL, is often discovered through routine chemistry panels of trauma victims at admission. Hyperglycemia on admission is an independent predictor of infection, hospital length of stay (HLOS), ICU length of stay (ILOS), and overall mortality.4-7 In trauma patients with hyperglycemia at admission, the primary site of infection is within the respiratory system.5,6,8
Hemoglobin A1C testing is needed to determine whether the hyperglycemia is a manifestation of a history of uncontrolled glucose or if the phenomenon is related to the injury. This laboratory test is not routinely performed at admission of surgical patients. Only a few studies have focused solely on the correlation between trauma and hyperglycemia at admission.5-7 One study of 738 trauma patients assessed the effect of mild hyperglycemia (glucose level higher than 135 mg/dL) and moderate hyperglycemia (glucose level higher than 200 mg/dL) on outcomes.5 The mild hyperglycemia group had a mortality rate of 15% versus 2% in a corresponding group of normoglycemic patients.5 An even greater difference was seen in the moderate hyperglycemic group (34%) compared with a corresponding normoglycemic group (3.7%).5 These results show that admission hyperglycemia is associated with increased morbidity and mortality in the critically ill general trauma population.
A significant number of trauma patients require immediate surgical intervention for stabilization. Bochiccio and colleagues conducted a study on surgical interventions for trauma victims and found that glucose level at admission is an accurate predictor of postoperative infection as well as HLOS, ILOS, and mortality.7 Data from these trials suggest admission hyperglycemia can be used as a screening tool to determine injury severity and the possibility of surgical complications.