Intraoperative glycemic control procedures and the use of an artificial pancreas

Strict intraoperative glycemic control can significantly decrease the incidence of postoperative infection; however, anesthesiologists must carefully control blood glucose levels as well as properly manage the respiratory and cardiovascular systems. However, standard blood glucose measurement systems and insulin dosing algorithms, which are necessary for achieving strict glycemic control, have not yet been developed. An artificial pancreas (STG-22TM; Nikkiso Co., Tokyo, Japan) is considered a highly accurate blood glucose monitoring system capable of closed-loop control of blood glucose. The device has, however, many problems to be addressed since it is a large and expensive system with little versatility, and it requires a large amount of blood to be collected. Therefore, the development of less invasive and inexpensive systems with future technological progress is greatly anticipated.

Predicting the output error of the suboptimal state estimator to improve the performance of the MPC-based artificial pancreas

The error of single step-ahead output prediction is the information traditionally used to correct the state estimate while exploiting the new measurement of the system output.However,its dynamics and statistical properties can be further studied and exploited in other ways.It is known that in the case of suboptimal state estimation,this output prediction error forms a correlated sequence,hence it can be effectively predicted in real time.Such a suboptimal scenario is typical in applications where the process noise model is not known or it is uncertain.Therefore,the paper deals with the problems of analytical and empirical modeling,identification,and prediction of the output error of the suboptimal state estimator for the sake of improving the output prediction accuracy and ultimately the performance of the model predictive control.The improvements are validated on an empirical model of type 1 diabetes within an in-silico experiment focused on glycemia prediction and implementation of the MPC-based artificial pancreas.

Perioperative insulin therapy using a closed-loop artificial endocrine pancreas after hepatic resection

Postoperative hyperglycemia is common in critically ill patients, even in those without a prior history of diabetes mellitus. It is well known that hyperglycemia induced by surgical stress often results in dysregulation of liver metabolism and immune function, impairing postoperative recovery. Current evidence suggests that maintaining normoglycemia postoperatively improves surgical outcome and reduces the mortality and morbidity of critically ill patients. On the basis of these observations, several large randomized controlled studies were designed to evaluate the benefit of postoperative tight glycemic control with intensive insulin therapy. However, intensive insulin therapy carries the risk of hypoglycemia, which is linked to serious neurological events. Recently, we demonstrated that perioperative tight glycemic control in surgical patients could be achieved safely using a closed-loop glycemic control system and that this decreased both the incidence of infection at the site of the surgical incision, without the appearance of hypoglycemia, and actual hospital costs. Here, we review the benefits and requirements of perioperative intensive insulin therapy using a dosed-loop artificial endocrine pancreas system in hepatectomized patients. This novel intensive insulin therapy is safe and effectively improves surgical outcome after hepatic resection.

What is artificial endocrine pancreas? Mechanism and history

The artificial endocrine pancreas is a feedback control instrument that regulates insulin delivery on a minute-by-minute basis according to measured blood glucose levels. Only one type of bedsidetype artificial endocrine pancreas is now available in Japan: STG-22 (Nikkiso Co. Ltd., Japan). In the insulin infusion algorithm, insulin is infused on the basis ofits proportional and derivative actions, to blood glucose concentrations with a constant time delay. The bedside-type artificial endocrine pancreas has been proven to be useful not only as a therapeutic tool for diabetes mellitus, but also as an elegant research tool for investigating the pathophysiology of the disease, by using the euglycemic hyperinsulinemic glucose clamp technique. The wearable type of closed-loop system has been developed recently. The breakthrough is the establishment of a needle-type glucose sensor. The development of closed-loop glycemic control systems that enable long-term physiological regulation has focused on implantable devices. Much effort has been expended to realize these devices.

Tight glycemic control using an artificial endocrine pancreas may play an important role in preventing infection after pancreatic resection

It is well known that perioperative hyperglycemia is the main cause of infectious complications after surgery.To improve perioperative glycemic control,we wish to highlight and comment on an interesting paper published recently by the Annals of Surgery entitled:"Early postoperative hyperglycemia is associated with postoperative complications after pancreatoduodenectomy(PD)" by Eshuis et al.The authors concluded that early postoperative glucose levels more than 140 mg/dL was significantly associated with complications after PD.Since we recommend that perioperative tight glycemic control(TGC) is an effective method to prevent postoperative complications including surgical site infection after distal,proximal,and total pancreatic resection,we support strongly this conclusion drawn in this article.However,if early postoperative glucose control in patients undergoing PD was administrated by conventional method such as sliding scale approach as described in this article,it is difficult to maintain TGC.Therefore,we introduce a novel perioperative glycemic control using an artificial endocrine pancreas against pancreatogenic diabetes after pancreatic resection including PD.

Evaluation of hybrid closed-loop insulin delivery system in type 1 diabetes in real-world clinical practice:One-year observational study

BACKGROUND In 2016,the Food and Drug Administration approved the first hybrid closed-loop(HCL)insulin delivery system for adults with type 1 diabetes(T1D).There is limited information on the impact of using HCL systems on patient-reported outcomes(PROs)in patients with T1D in real-world clinical practice.In this independent study,we evaluated glycemic parameters and PROs over one year of continuous use of Medtronic’s 670G HCL in real-world clinical practice.AIM To assess the effects of hybrid closed loop system on glycemic control and quality of life in adults with T1D.METHODS We evaluated 71 patients with T1D(mean age:45.5±12.1 years;59%females;body weight:83.8±18.7 kg,body mass index:28.7±5.6 kg/m2,A1C:7.6%±0.8%)who were treated with HCL at Joslin Clinic from 2017 to 2019.We measured A1C and percent of glucose time-in-range(%TIR)at baseline and 12 months.We measured percent time in auto mode(%TiAM)for the last two weeks preceding the final visit and assessed PROs through several validated quality-of-life surveys related to general health and diabetes management.RESULTS At 12 mo,A1C decreased by 0.3%±0.1%(P=0.001)and%TIR increased by 8.1%±2.5%(P=0.002).The average%TiAM was only 64.3%±32.8%and was not associated with A1C,%TIR or PROs.PROs,provided at baseline and at the end of the study,showed that the physical functioning submodule of 36Item Short-Form Health Survey increased significantly by 22.9%(P<0.001).Hypoglycemia fear survey/worry scale decreased significantly by 24.9%(P<0.000);Problem Areas In Diabetes reduced significantly by-17.2%(P=0.002).The emotional burden submodules of dietary diversity score reduced significantly by-44.7%(P=0.001).Furthermore,analysis of Clarke questionnaire showed no increase in awareness of hypoglycemic episodes.WHO-5 showed no improvements in subject’s wellbeing among participants after starting the 670G HCL system.Finally,analysis of Pittsburgh Sleep Quality Index showed no difference in sleep quality,sleep latency,or duration of sleep from baseline to 12 mo.CONCLUSION The use of HCL in real-world clinical practice for one year was associated with significant improvements in A1C,%TIR,physical functioning,hypoglycemia fear,emotional distress,and emotional burden related to diabetes management.However,these changes were not associated with time in auto mode.

Relationship between perioperative glycemic control and postoperative infections

Perioperative hyperglycemia in critically ill surgery patients increases the risk of postoperative infection (POI), which is a common, and often costly, surgical complication. Hyperglycemia is associated with abnormalities in leukocyte function, including granulocyte adherence, impaired phagocytosis, delayed chemotaxis, and depressed bactericidal capacity. These leukocyte deficiencies are the cause ofinfection and improve with tight glycemic control, which leads to fewer POIs in critically ill surgical patients. Tight glycemic control, such as intensive insulin therapy, has a risk of hypoglycemia. In addition, the optimal targeted blood glucose range to reduce POI remains unknown. Since 2006, we have investigated tight perioperative blood glucose control using a closed-loop artificial endocrine pancreas system, to reduce POI and to avoid hypoglycemia. In this Topic Highlight, we review the relationship between perioperative glycemic control and POI, including the use of the artificial pancreas.