Tight perioperative glycemic control using an artificial endocrine pancreas

Toward Automation: The Road Traveled and Road Ahead for Integrating Automated Insulin Delivery into Inpatient Care

The introduction of automated insulin delivery (AID) systems represents a significant advancement in diabetes care, offering substantial benefits in outpatient settings. Although clinical studies suggest that these systems can also help improve glycemic control in acutely ill patients, several barriers remain for the actual implementation and use of these technologies in clinical practice. Three main contexts for inpatient use are addressed, including: (a) continuation of personal AID systems, (b) initiation of AID during hospitalization, and (c) initiation of AID systems at discharge. A research road map with immediate to long-term actions is presented. Initially, it calls for clinical studies assessing in-hospital efficacy, safety, and utility, addressing specific patient needs and health care operational impacts. Midterm, it focuses on practical integration, simplifying AID use, ensuring electronic health record compatibility, clarifying regulatory uncertainties, and supporting health care professionals and patients. Long-term goals include system optimizations and policy advocacy for in-hospital AID use.

Usefulness of an interprofessional work manual for perioperative glucose control of an artificial pancreas

BACKGROUND

A closed-loop bedside-type artificial pancreas for perioperative glucose control has previously been introduced. However, artificial pancreas therapy was often interrupted due to continuous blood sampling failure. We developed an interprofessional work manual to reduce the interruption time of artificial pancreatic therapy for perioperative blood glucose control due to continuous blood sampling failure. This study aimed to investigate the usefulness of this manual.

METHODS

The manual consisted of the following sections: (1) the roles of the professionals in the preparation and management of the artificial pancreas, (2) how to address continuous blood sampling failure, and (3) checkpoints for interprofessional transfer of the artificial pancreas. We compared the results before the introduction of the manual and 2 years after the introduction of the manual.

RESULTS

There were 35 and 37 patients in the Before and After groups, respectively. There were no significant differences in patient backgrounds between the two groups, although there was significantly less blood loss in the After group (1164 vs. 366 mL; p < 0.001). The mean artificial pancreas therapy and artificial pancreas therapy interruption times were 847 min and 20 min, respectively. Artificial pancreas therapy interruption time (34 vs. 8 min; p = 0.078) and time per interruption (24 vs. 4 min; p < 0.001) were significantly shorter in the After group than in the Before group.

CONCLUSIONS

The interprofessional working manual was useful in reducing the artificial pancreatic therapy interruption time for perioperative glucose control.

Effects of an artificial pancreas on postoperative inflammation in patients with esophageal cancer

PURPOSES

Subtotal esophagectomy for esophageal cancer (EC) is associated with high morbidity rates. Tight glycemic control using an artificial pancreas (AP) is one of the promising strategies to reduce postoperative inflammation and morbidities. However, the effects of tight glycemic control using AP in patients with EC are yet to be fully elucidated.

METHOD

This study reviewed 96 patients with EC who underwent subtotal esophagectomy. The postoperative inflammation parameters and morbidity rates were compared between patients who used the AP (n = 27) or not (control group, n = 69). AP is a closed-loop system that comprises a continuous glucose monitor and an insulin pump.

RESULTS

The numbers of white blood cells (WBC) and Neutrophils (Neut) were noted to be lower in the AP group than in the control group, but with no significant difference. The ratio in which the number of WBC, Neut, and CRP on each postoperative day (POD) was divided by those tested preoperatively was used to standardize the results. The ratio of WBC and Neut on 1POD was significantly lower in the AP group than in the control group. The rate of surgical site infection was lower in the AP group than in the control group.

CONCLUSION

AP significantly decreased WBC and Neut on 1POD; this suggests the beneficial effects of AP in alleviating postoperative inflammation.

Surgical Site Infections and Inflammatory Reaction After Cardiac Surgery; Bedside Artificial Pancreas Versus Conventional Insulin Therapy: A Propensity Score-Matched Analysis

OBJECTIVES

Perioperative hyperglycemia is associated with poor postoperative recovery, including compromised immune function and increased risk of infection. A closed-loop glycemic control system (artificial pancreas) has demonstrated strict safe perioperative glycemic control without hypoglycemia risk. The authors hypothesized that the artificial pancreas would reduce surgical site infections (SSIs) and postoperative inflammatory reactions. This study aimed to assess the effect of the artificial pancreas on SSIs and C-reactive protein (CRP) levels after cardiac surgery.

DESIGN

A single-center retrospective, propensity score-matched analysis.

SETTING

A university hospital.

PARTICIPANTS

In total, 295 patients who underwent cardiovascular surgery with cardiopulmonary bypass were included.

INTERVENTIONS

Patients were divided into two groups: artificial pancreas (target blood glucose: 120-150 mg/dL) and intravenous insulin infusion (conventional insulin therapy, target blood glucose: <200 mg/dL).

MEASUREMENTS AND MAIN RESULTS

The differences in the incidence of SSIs and CRP levels between the two groups were assessed. After 1:1 propensity score matching based on their covariates, 101 matched patients were selected from each group. The incidence of SSIs was reduced by 3%, 5% (conventional insulin therapy), and 2% (artificial pancreas), but the reduction was not statistically significant (p = 0.45). The postoperative maximum CRP level was significantly lower in the artificial pancreas group than in the conventional insulin therapy group, mean (standard deviation)14.53 (5.64) mg/dL v 16.57 (5.58) mg/dL; p = 0.01.

CONCLUSIONS

The artificial pancreas did not demonstrate a significant reduction in the incidence of SSIs. However, the artificial pancreas was safe and suppressed postoperative inflammation compared with conventional insulin therapy.

Managing hyperglycemia during the COVID-19 pandemic: Improving outcomes using new technologies in intensive care

Hyperglycemia is a significant risk for mortality in COVID-19 infections and is most dramatically noted in critically ill patients. Hyperglycemia and/or diabetes are noted in approximately 30%-40% of patients admitted with COVID-19 infections. Previous studies have shown a marked increase in mortality related to increased glucose concentrations and reduction with improved glucose control. In vivo and in vitro studies reveal the mechanisms by which hyperglycemia increases virulence and how glucose control and insulin reduce it. Optimal glucose control in intensive care is limited by manual sampling of glucose and intravenous insulin adjustment, as well as increased nursing workload and the need of protective equipment. Tools for safe and effective automation of glucose control in intensive care are discussed. A suitable closed loop device could save the lives of thousands of hospitalized hyperglycemic individuals infected with COVID-19 while protecting medical professionals from infection risk.

Impact of using a perioperative artificial endocrine pancreas in pancreatic resection

AIM

Pancreatectomy causes both hyperglycemia, secondary to surgical stress, and pancreatic diabetes, which leads to difficult-to-control postoperative blood glucose levels. We investigated whether using an artificial pancreas perioperatively to provide appropriate blood glucose control could reduce postoperative complications following pancreatectomy.

METHODS

We retrospectively enrolled 52 patients who underwent pancreatectomy at Tokushima University Hospital from 2015 to 2019. The most recent 26/52 patients received perioperative blood glucose control using an artificial pancreas. Postoperative blood glucose control with manual insulin injections based on a sliding scale was performed in the earlier 26 patients (controls). We compared surgical outcomes between the artificial pancreas group and the control group.

RESULTS

There was no significant difference in patients' white blood cell or neutrophil counts, prognostic nutritional index, neutrophil-lymphocyte ratio, and C-reactive protein-to-albumin ratio on postoperative day 1; however, lymphocyte counts were higher in the artificial pancreas group. The number of serious complications of Clavien-Dindo grade >IIIa was significantly lower in the artificial pancreas group (P < .05).

CONCLUSIONS

Using an artificial pancreas for perioperative blood glucose control in patients undergoing pancreatectomy decreased the number of serious complications through proper management of blood glucose levels without hypoglycemia, and may influence peripheral lymphocytes.

Artificial endocrine pancreas with a closed-loop system effectively suppresses the accelerated hyperglycemic status after reperfusion during aortic surgery

OBJECTIVES

To control intraoperative hyperglycemia in patients who underwent aortic surgery using STG-55^® artificial endocrine pancreas and clarify the effectiveness of this device.

METHODS

Blood glucose control using the STG-55^® was performed in 18 patients (15 men and 3 women; age, 66 ± 10 years) who required hypothermic circulatory arrest (STG-55^® group). Seventeen patients (10 men and 7 women; age, 71 ± 8 years) whose blood glucose was controlled using the conventional method were included in the control group. Glucose concentration was controlled with the aim of maintaining it at 150 mg/dl.

RESULTS

In both groups, the blood glucose concentrations did not significantly change during the interruption of systemic perfusion; however, a sharp increase was noted immediately after reperfusion. Although the hyperglycemic status persisted after reperfusion in the control group, it was effectively suppressed in the STG-55^® group (STG^® vs. control group at 50 min after reperfusion: 180 ± 35 vs. 212 ± 47 mg/dl, p = 0.026) and blood glucose concentration reached the target value of 150 mg/dl at 100 min after reperfusion (STG^® vs. control group: 153 ± 29 vs. 215 ± 43 mg/dl, p = 0.0008). The total administered insulin dose was 175 ± 81 U and 5 ± 3 U in the STG^® and control groups, respectively (p < 0.0001).

CONCLUSIONS

To treat the accelerated hyperglycemic status in aortic surgery requiring circulatory arrest, strict glycemic control using an artificial endocrine pancreas might be beneficial.

Impact of newly developed, next-generation artificial endocrine pancreas

BACKGROUND

Recent studies have shown that strict perioperative blood glucose management may reduce mortality and morbidity in critically ill adult patients. The purpose of this study was to assess the accuracy and efficacy of the intraoperative application of a newly developed, next-generation artificial endocrine pancreas (STG-55, Nikkiso Co., Ltd., Tokyo, Japan).

METHODS

Twenty patients scheduled to undergo surgery were enrolled in this study. The STG-55 is designed to be more user-friendly than its conventional counterpart (STG-22) while maintaining the latter's fundamental functions, such as a closed-loop system using algorithms for insulin and glucose infusion. After anesthetic induction, a 20G intravenous catheter was inserted into a peripheral forearm vein and connected to a continuous blood glucose monitor. The resultant 105 scores for paired blood glucose values were compared by Bland-Altman analysis.

RESULTS

Stable blood glucose values were maintained automatically, and there were no complications related to use of the STG-55. A close correlation (r=0.96) was observed between continuous glucose measurements using the STG-55 and conventional intermittent glucose measurements. The difficulty of manipulation using this system was decreased by improved preparation procedures.

CONCLUSION

The glycemic control system using the STG-55 could provide an alternative way to achieve effective and safe perioperative glycemic control.

Comparison between a novel and conventional artificial pancreas for perioperative glycemic control using a closed-loop system

This clinical study aimed to compare a novel and conventional artificial pancreas (AP) used in surgical patients for perioperative glycemic control, with respect to usability, blood glucose measurements, and glycemic control characteristics. From July in 2010 to March in 2015, 177 patients underwent perioperative glycemic control using a novel AP. Among them, 166 patients were eligible for inclusion in this study. Intensive insulin therapy (IIT) targeting a blood glucose range of 80-110 mg/dL was implemented in 82 patients (49 %), and the remaining 84 patients (51 %) received a less-intensive regime of insulin therapy. Data were collected prospectively and were reviewed or analyzed retrospectively. A comparison study of 324 patients undergoing IIT for glycemic control using a novel (n = 82) or conventional AP (n = 242) was conducted retrospectively. All patients had no hypoglycemia. The comparison study revealed no significant differences in perioperative mean blood glucose level, achievement rates for target blood glucose range, and variability in blood glucose level achieved with IIT between the novel AP and conventional AP groups. The usability, performance with respect to blood glucose measurement, and glycemic control characteristics of IIT were comparable between novel and conventional AP systems. However, the novel AP was easier to manipulate than the conventional AP due to its smaller size, lower weight, and shorter time for preparation. In the near future, this novel AP system might be accepted worldwide as a safe and useful device for use in perioperative glycemic control.

Comparison of subcutaneous and intravenous continuous glucose monitoring accuracy in an operating room and an intensive care unit

Although we have used an intravenous continuous glucose monitor for blood glucose management, a previous study reported that a subcutaneous continuous glucose monitor was also reliable for use in critically ill patients. The aim of this study was to compare the subcutaneous and intravenous continuous glucose monitors. This was an observational trial (UMIN-CTR, ID:000013338). We included patients who were admitted to our intensive care units (ICU) after hepato-biliary pancreatic surgery. Continuous blood glucose measurement was performed from the beginning of the operation to ICU discharge using the intravenous continuous monitor STG-55 (Nikkiso, Tokyo, Japan) and the subcutaneous continuous monitor iPro2 (Medtronic Japan, Tokyo, Japan). The STG-55 measured the glucose level in real time, and the iPro2 measured this every 5 min. We compared glucose levels obtained using the two devices every 5 min using a Bland-Altman plot and a regression analyses. A total of 3592 comparative samples in 15 cases were analyzed. The mean glucose level measured using the STG-55 was 139 ± 21 mg/dl, and that measured using the iPro2 was 144 ± 31 mg/dl. A linear regression line had the equation of the form y = 0.225x + 106. The coefficient of determination was 0.11, and the F-test significance level was set as p < 0.01. The mean of the differences was -5.2 mg/dl, with a 95 % agreement limit of -67 to + 57 mg/dL. The percent error was 44 %. In conclusion, the current study suggests that subcutaneous and intravenous continuous glucose monitoring was not highly correlated during either surgery or ICU stay.

Tight glycemic control and cardiovascular effects in type 2 diabetic patients

Diabetes Mellitus (DM) with poor glycemic control is one of the leading causes for cardiovascular mortality in diabetic patients. Tight glycemic control with glycosylated haemoglobin of <7 gms% is recommended as a routine and < 6.5 gms% is recommended for young and newly diagnosed diabetics. Treatment goal aims at achieving near normal blood glucose level, and directed at management of other co morbid conditions such as obesity, hypertension and dyslipidemia. Oral hypoglycemic agents are the preferred drugs, alone or in combination. Preference for glitazones is declining due to the increasing evidences of associated adverse events. Gliptins appear as promising agents with lesser tendency to cause hypoglycemia, but their long term safety and efficacy is yet to be established. We emphasize the role of preventive measures in prediabetics and in established DM, treatment should be individualized and customized to minimize hypoglycemic effects and to retain quality of life.

Are closed-loop systems for intensive insulin therapy ready for prime time in the ICU?

PURPOSE OF REVIEW

Recent findings suggest that the effects of tight glycemic control (TGC) performing intensive insulin therapy (IIT) in medical and surgical ICU have had conflicting results. The purpose of this review is to summarize the current evidence in humans how closed-loop systems for IIT are ready for prime time in the ICU.

RECENT FINDINGS

Current evidence suggests that maintaining normoglycemia postoperatively can improve the outcome and reduce the mortality and morbidity of critically ill patients by TGC performing IIT according to the large randomized trials. However, trials examining the effects of TGC have had conflicting results. Systematic reviews and meta-analyses have also led to differing conclusions. The main reason these clinical trials and meta-analyses were negative results for TGC was because of the high incidence of hypoglycemia. This could not be prevented as there is no reliable technique currently able to avoid this condition during IIT. The development of accurate, continuous blood glucose monitoring devices, and closed-loop systems for computer-assisted blood glucose control in the ICU, will probably help avoid hypoglycemia in these situations.

SUMMARY

The challenge in the hospital setting demonstrated that a closed-loop glycemic control system is expected to the achievement of TGC with no occurrence of hypoglycemia induced by IIT after surgery. Closed-loop glycemic control systems for IIT are now ready for prime time in the ICU.

Perioperative intensive insulin therapy using an artificial endocrine pancreas with closed-loop glycemic control system: the effects of no hypoglycemia

BACKGROUND

We examined whether perioperative intensive insulin therapy (IIT) using an artificial pancreas (AP) with a closed-loop glycemic control system can be used to prevent hypoglycemia in surgical patients.

METHODS

Between 2006 and 2012, perioperative glycemic control using an AP was performed in 427 patients undergoing general surgery. A total of 305 patients undergoing IIT using an AP in the target blood glucose range of 80 to 110 mg/dL were enrolled in the study. Data were collected prospectively and were reviewed or analyzed retrospectively.

RESULTS

No patients had hypoglycemia. Perioperative mean blood glucose level and achievement rates in target blood glucose range of 80 to 110 mg/dL were 100.5 ± 11.9 mg/dL and 88.1% ± 16.0%, respectively. For the 3 primary operative methods, including hepatic, pancreatic, and esophageal resections, there were no significant differences in glycemic control stability between the types of surgery.

CONCLUSION

Perioperative IIT using an AP with a closed-loop glycemic control system can be used to prevent hypoglycemia and maintain stable glycemic control with less variability of blood glucose concentration.

Development of perioperative glycemic control using an artificial endocrine pancreas

It is well known that tight glycemic control (TGC) in patients with diabetes mellitus is the most important to reduce complications, such as nephropathy, neuropathy, and retinopathy. Also, surgical stress induced hyperglycemia leading to glucose toxicity is the main cause of infectious complications after surgery. Recently perioperative TGC has been proven an effective method to reduce postoperative infectious complications and accelerate enhanced recovery after surgery (ERAS), with the main purpose of short staying hospital. However, conventional TGC with open-loop glycemic control system is likely to induce not only occurrence of hypoglycemia but also unstable glycemic control. To solve these problems, we have involved introduction of novel glycemic control using an artificial pancreas (AP) with closed-loop glycemic control system since 2006. To date, this novel perioperative glycemic control was performed in more than 400 surgical patients. As a result, we established stable and safe TGC using an AP to improve surgical outcomes without hypoglycemia. In this paper, we report current scientific evidence focusing on perioperative glycemic control using an AP.

Correlation between high blood IL-6 level, hyperglycemia, and glucose control in septic patients

Introduction

The aim of the present study was to investigate the relationship between the blood IL-6 level, the blood glucose level, and glucose control in septic patients.

Methods

This retrospective observational study in a general ICU of a university hospital included a total of 153 patients with sepsis, severe sepsis, or septic shock who were admitted to the ICU between 2005 and 2010, stayed in the ICU for 7 days or longer, and did not receive steroid therapy prior to or after ICU admission. The severity of stress hyperglycemia, status of glucose control, and correlation between those two factors in these patients were investigated using the blood IL-6 level as an index of hypercytokinemia.

Results

A significant positive correlation between blood IL-6 level and blood glucose level on ICU admission was observed in the overall study population (n = 153; r = 0.24, P = 0.01), and was stronger in the nondiabetic subgroup (n = 112; r = 0.42, P < 0.01). The rate of successful glucose control (blood glucose level < 150 mg/dl maintained for 6 days or longer) decreased with increase in blood IL-6 level on ICU admission (P < 0.01). The blood IL-6 level after ICU admission remained significantly higher and the 60-day survival rate was significantly lower in the failed glucose control group than in the successful glucose control group (P < 0.01 and P < 0.01, respectively).

Conclusions

High blood IL-6 level was correlated with hyperglycemia and with difficulties in glucose control in septic patients. These results suggest the possibility that hypercytokinemia might be involved in the development of hyperglycemia in sepsis, and thereby might affect the success of glucose control.

Surgery for a gastroenteropancreatic neuroendocrine tumor (GEPNET) in multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominantly inherited endocrine tumor syndrome characterized by tumor development in various endocrine organs such as the parathyroid, endocrine pancreas, anterior pituitary and adrenal cortex. The first extensive database for Asian patients with MEN1 was established by the MEN Consortium of Japan. Although the clinical features of Japanese patients with MEN1 are similar to those from Western countries, there are several characteristic differences between them. In particular, gastroenteropancreatic neuroendocrine tumor (GEPNET) is seen in approximately 60 % of patients with MEN1 in Japan. Although its development is the strongest prognostic factor in patients with MEN1, the characteristics of MEN1-associated GEPNET still remain unclear. This is especially true for the differences in clinical features of GEPNET with and without MEN1. Improved long-term survival is obtained by curative surgery for patients with MEN1-associated GEPNET. The current surgical indications are expanding even in patients with hepatic metastases because of the improved surgical outcome. This article reviews the clinical characteristics in these patients with a particular focus on surgery, diagnosis, surgical indications, surgical method, and surgical outcome.

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.

Management of hyperglycemia during the perioperative period

Hyperglycemia is frequently encountered in the inpatient setting and is distinctly associated with poor clinical outcomes. Recent literature suggests an association between stringent glycemic control and increased mortality, thus keeping optimal glycemic targets a relevant subject of debate. In the surgical population, hyperglycemia with or without diabetes mellitus may be unrecognized. Factors contributing to hyperglycemia in the hospital include critical illness, use of certain drugs, use of enteral or parenteral nutrition, and variability in oral or nutritional intake as can occur when patients are prepared for procedures or surgery. A sensible approach to managing hyperglycemia in this population includes preoperative recognition of diabetes mellitus and risks for inpatient hyperglycemia. Judicious control of glycemia during the pre-, intra-, and postoperative time periods with avoidance of hypoglycemia mandates the need for a strategy for patient management that extend to time of discharge. We review the consequences of uncontrolled perioperative hyperglycemia, discuss current clinical guidelines and recent controversies, and provide practical tools for glycemic control in the surgical population.

Perioperative glycemic management in 2011: paradigm shifts

PURPOSE OF REVIEW

The publication of Van den Berghe's landmark study in 2001 supported the use of intensive insulin therapy (IIT) to target normoglycemia in the critically ill and triggered a new era in glycemic management in the perioperative period and in the ICU. In 2009, the normoglycemia in intensive care evaluation-survival using glucose algorithm regulation (NICE-SUGAR) trial demonstrated increased mortality and incidence of hypoglycemia in patients managed with IIT, resulting in a shift toward higher blood glucose targets in this patient population. This review distills clinically pertinent principles from the related literature published in the months since the NICE-SUGAR trial.

RECENT FINDINGS

A target blood glucose level in the acute care setting supported by many of the pertinent societies and frequently quoted in the literature is 140-180 mg/dl. Hyperglycemia, hypoglycemia, and glucose variability are detrimental. Accurate and efficient glucose monitoring devices are essential. Insulin infusion protocols (IIPs) employed to achieve desired blood glucose targets must be individualized and validated for the ICU and institution in which they are being implemented.

SUMMARY

Appropriate glycemic management in the acute care setting can be achieved by targeting a reasonable blood glucose range and employing specific and institutionally validated IIPs.

Anti-inflammatory effects of perioperative intensive insulin therapy during cardiac surgery with cardiopulmonary bypass

PURPOSE

Recent studies have reported that controlling blood glucose with insulin can suppress systemic inflammation. In the present study, we evaluated how perioperative intensive insulin therapy (IIT) influences the inflammatory response in an artificial pancreas during cardiac surgery with cardiopulmonary bypass.

METHODS

We randomly divided the patients undergoing cardiac surgery with cardiopulmonary bypass into two groups: an IIT group (n = 13) and a conventional treatment (CT) group (n = 12). For the IIT group, blood glucose control was initiated with an artificial pancreas at initiation of surgery. Blood glucose was maintained at 100 mg/dl until 24 h postoperatively. Blood samples were collected to determine changes in serum cytokine levels over time.

RESULTS

Patients' characteristics did not differ significantly between groups. Blood glucose levels were significantly higher in the CT group after surgery. Serum levels of tumor necrosis factor-α, interleukin-6, and high-mobility group box 1 were higher in the CT group than in the IIT group.

CONCLUSIONS

Use of IIT in the artificial pancreas during the perioperative period significantly decreased the inflammatory response. Moreover, we did not find evidence of hypoglycemia in those treated with IIT. This suggests that use of IIT in an artificial pancreas can be safe and effective for critically ill patients.

Progressive artificial endocrine pancreas: The era of novel perioperative blood glucose control for surgery

Strict glycemic control needs to be maintained in critically ill surgical patients to reduce the mortality and morbidity due to hyperglycemia and associated infection. However, conventional intensive insulin therapy (IIT), which consists of intermittent blood glucose measurement and manually controlled infusions of insulin, tends to induce hypoglycemia and glucose variability. Many randomized clinical trials have been conducted to improve the efficacy of IIT, although some of these were stopped owing to frequent hypoglycemia. In pursuing safe and strict glycemic control for critically ill surgical patients, we found that a closed-loop glycemic control system was able to maintain appropriate blood glucose levels without hypoglycemia in more than 400 clinical cases. Considering the need for the perioperative and intensive care environment, a well-established artificial pancreas was modified into a new closed-loop glycemic control system, called the progressive artificial pancreas. The new device is slim in shape and shows clinical compatibility with the conventional artificial pancreas. We herein review this new closed-loop glycemic control system and the expectations for its future application in critically ill surgical patients.

Pancreatogenic diabetes after pancreatic resection

The loss of pancreatic parenchyma resulting from pancreatic resection causes an extreme disruption of glucose homeostasis known as pancreatogenic diabetes. This form of glucose intolerance is different from the other forms of diabetes mellitus in that affected individuals suffer frequent episodes of iatrogenic hypoglycemia. The development of sophisticated surgical procedures, improved postoperative care, and the capacity for early diagnosis of disease has prolonged life expectancy after pancreatic resection. For this reason, pancreatogenic diabetes is now attracting attention as the primary factor influencing quality of life in patients who have undergone this procedure. The incidence of new-onset diabetes mellitus after pancreatic resection increases as the follow-up period after surgery becomes longer and is related to the progression of underlying disease, the type of surgery, and the extent of resection. The pathophysiology of pancreatogenic diabetes is related to pancreatic hormone deficiency and the altered responses of the liver and peripheral organs to lower than normal hormone levels. Hyperglycemia occurs when the amount of insulin produced or administered is insufficient because of unsuppressed hepatic glucose production secondary to a deficiency in pancreatic polypeptide. In contrast, patients lapse into hypoglycemia when insulin is barely excessive because of enhanced peripheral insulin sensitivity and glucagon deficiency. Nutritional state, pancreatic exocrine function and intestinal function also affect glycemic control. Insulin replacement is considered to be the main treatment option for insulin dependent pancreatogenic diabetes. Pancreatic polypeptide replacement and islet autotransplantation have potential as new approaches to treating patients with pancreatogenic diabetes after pancreatic resection. and IAP.

Continuous monitoring of glucose levels in the hepatic vein and systemic circulation during the Pringle maneuver in beagles

Intraoperative continuous glucose monitoring revealed that liver ischemia/reperfusion causes a rapid and profound transition in glucose concentration. We hypothesized that the washout of the glucose stored in the liver leads to a rapid transition in blood glucose concentration. Six female beagles were studied. A portosystemic shunt was established, and the glucose levels in the jugular, hepatic, and portal veins were continuously monitored. All beagles were stabilized for 30 min, and, subsequently, the hepatic artery and portal vein were clamped (the Pringle maneuver). After 30 min of warm hepatic ischemia, the clamp was removed in order to initiate hepatic reperfusion. The endpoint of the experiment was 60 min after the onset of reperfusion. The glucose levels in the abovementioned veins were recorded continuously. The glucose level in the hepatic vein increased 10 min after the start of the Pringle maneuver and was significantly higher than that in the jugular vein and portal vein just before unclamping. The glucose level in the hepatic vein peaked at 2 min after unclamping and that in the portal and jugular veins started to increase after reperfusion. The glucose level in the hepatic vein was significantly higher than that in the jugular and portal veins between 9 min after clamping and 8 min after reperfusion. In conclusion, our study among beagles showed that glucose release from the hepatic vein and sinusoid leads to a rapid elevation in systemic blood glucose levels after liver ischemia/reperfusion. This knowledge might help in the development of new strategies for blood glucose management during hepatectomy.

Preliminary study on glucose control with an artificial pancreas in postoperative sepsis patients

BACKGROUND

Glucose control is essential to avoid hypoglycemia in postoperative patients.

AIM

To conduct a preliminary examination to evaluate the feasibility of the use of an artificial pancreas for glucose control as well as the accuracy of assessment by the artificial pancreas of the insulin dose required.

SUBJECTS AND METHODS

Glucose control using an artificial pancreas was undertaken in 8 postoperative sepsis patients. The blood glucose level was set at 80-150 mg/dl. Blood glucose levels over time, insulin dose requirements, and occurrence of hypoglycemia (≤40 mg/dl) were recorded for each patient. The patients were divided into 2 groups based on the total insulin dose they received over the 7 days (HG, n = 4: consisting of patients who required a higher insulin dose; LG, n = 4: patients who required a lower insulin dose). The data of the 2 groups were analyzed retrospectively.

RESULTS

The blood glucose level before glucose control was 203.3 ± 9.9 mg/dl and could be controlled in all patients to within the target range. No hypoglycemia events were recorded for any of the patients. The insulin dose in the HG and LG groups was 21,824.8 ± 6,030.4 and 6,254.5 ± 3,402.3 mU/kg (p < 0.05).

CONCLUSIONS

Accurate glucose control could be achieved with the artificial pancreas.

The evaluation of the ability of closed-loop glycemic control device to maintain the blood glucose concentration in intensive care unit patients

OBJECTIVES

Reduction in the variability of blood glucose concentration might be an important aspect of blood glucose management. A closed-loop glycemic control device (STG-22; NIKKISO, Tokyo, Japan) has been developed to maintain blood glucose levels within the target range through automatic infusion of insulin and glucose. We hypothesized that the STG-22 system could provide optimal blood glucose management without causing hypoglycemic events in patients admitted to intensive care units. In this study, we investigated the feasibility of glycemic control with the STG-22 system. Furthermore, we evaluated the variability in blood glucose concentration associated with the use of the STG-22 system.

DESIGN

Retrospective analysis.

SETTING

A five-bed medical/surgical intensive care unit in a university hospital.

PATIENTS

Two hundred eight patients admitted to the intensive care unit between August 2006 and July 2009.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We calculated the mean and sd of blood glucose concentrations in each patient during intensive insulin therapy (target range, 90-110 mg/dL) administered using STG-22. In addition, to evaluate the blood glucose control achieved using STG-22, the durations for which the blood glucose level was maintained at 70-110 mg/dL, 110-150 mg/dL, 150-180 mg/dL, and>180 mg/dL were calculated. The average operation time of STG-22 was 33.9±42.4 hrs. The blood glucose level was maintained at 70-110 mg/dL for 49.5% of the study period; the corresponding values for 110-150 mg/dL, 150-180 mg/dL, and>180 mg/dL were 31.4%, 7.0%, and 6.9%, respectively. No hypoglycemic events occurred. The sd of blood glucose levels was 19.9±10.9 mg/dL. After a level of 150 mg/dL was achieved, the sd of blood glucose was 12.6±3.1 mg/dL.

CONCLUSIONS

STG-22 can help maintain optimal blood glucose levels without causing hypoglycemia in patients admitted to the intensive care unit. In addition, the use of this device might help decrease the variability in blood glucose concentration. Further randomized clinical trials are required to elucidate whether the low glucose variability maintained using STG-22 can contribute to improving the outcomes of patients admitted to the intensive care unit.

Intensive insulin therapy during cardiovascular surgery

Recent evidence in the fields of surgery, emergency and critical care medicine indicates that strict glycemic control results in lower mortality. Hyperglycemia occurs frequently in patients with and without diabetes during cardiovascular surgery, especially during cardiopulmonary bypass. However, strict glucose control is difficult to achieve during cardiovascular procedures. To establish effective intensive insulin therapy during cardiovascular surgery, we conduct continuous blood glucose monitoring and employ automatic control by using an artificial endocrine pancreas (the STG-22, Nikkiso, Tokyo, Japan). In this review, we will outline the present status and problems of conventional glycemic control for perioperative cardiovascular surgery and introduce the new perioperative blood glucose management method that we are testing now. We will also discuss the importance of perioperative glycemic control for cardiovascular surgery as well as future prospects.

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 of infection 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.