Abstract and Introduction
Background: Intraoperative glycemic variability is associated with increased risks of mortality and morbidity and an increased incidence of hyperglycemia after cardiac surgery. Accordingly, clinicians tend to use a tight glucose control to maintain perioperative blood glucose levels and therefore the need to develop a less laborious automated glucose control system is important especially in diabetic patients at a higher risk of developing complications.
Methods: Patients, aged between 40 and 75 years old, undergoing open heart surgery were randomized to either an automated protocol (experimental) or to the conventional technique at our institution (control).
Results: We showed that the percentage of patients maintained between 7.8–10 mmol.l−1 was not statistically different between the two groups, however, through an additional analysis, we showed that the proportion of patients whose glucose levels maintained between a safety level of 6.7–10 mmol.l−1 was significantly higher in the experimental group compared to control group, 14 (26.7%) vs 5 (17.2%) P = 0.025. In addition, the percentage of patients who had at least one intraoperative hyperglycemic event was significantly higher in the control group compared to the experimental group, 17 (58.6%) vs 5 (16.7%), P < 0.001 with no hypoglycemic events in the experimental group compared to two events in the control group. We also showed that longer surgeries can benefit more from using the automated glucose control system, particularly surgeries lasting more than 210 min.
Conclusion: We concluded that the automated glucose control pump in diabetic patients undergoing open heart surgeries maintained most of the patients within a predefined glucose range with a very low incidence of hyperglycemic events and no incidence of hypoglycemic events.
Trial registration: Registered with clinicaltrials.gov (NCT #NCT03314272, Principal investigator Roland Kaddoum, date of registration: 19/10/2017).
Decades ago, glucose control became an important treatment goal in hospitalised patients. The notion of tight glycemic control became more prominent in 2001 when a landmark study by Van Den Berghe demonstrated a significant decrease in mortality when maintaining blood glucose between 4.4 and 5.6 mmol.l−1 in intensive care unit patients.
It has been found that the incidence of hyperglycemia after cardiac surgery is very high (stress induced hyperglycemia), and it occurs almost universally after cardiac surgeries, regardless of whether a person is diabetic or not. The mechanisms by which hyperglycemia affect outcomes could be related to suppressive effects on immune function and an associated increased risk of infection, endothelial damage, hepatocyte mitochondrial damage, and potentiation of tissue ischemia due to acidosis or inflammation.[3–5]
Knowing that hyperglycemia, hypoglycemia, and increased glycemic variability have been associated with increased risk of mortality and morbidity, many centers established protocols for glycemic control. However, normoglycemia is not easy to establish, and barriers to widespread adoption of tight glucose control were many including an increased risk of severe hypoglycemia, a difficulty in achieving normoglycemia, as well as an increase in the resources and the workload for medical staff.[6,7] Because of these issues and uncertainty about the balance of risks and benefits, tight glucose control is used infrequently by clinicians.[8,9]
Development of a closed loop glucose control system that automatically infuses insulin based on an automated algorithm that integrates a continuous glucose signal, could help overcome these obstacles and permit strict glycemic control without increasing the workload for the medical staff. This is the first study to examine the effectiveness of a closed loop glucose control system on intra- and post- operative glucose levels in patients undergoing open heart surgeries. Our hypothesis is that the automated protocol will allow a higher percentage of diabetic patients undergoing open heart surgery to remain in the glycemic corridor of 7.8–10 mmol.l−1 as compared to the conventional technique while avoiding hypoglycemic and hyperglycemic episodes.
BMC Anesthesiol. 2022;22(184) © 2022 BioMed Central, Ltd.