Blood glucose management in the patient undergoing cardiac surgery: A review

Continuous Glucose Monitoring Using the Dexcom G6 in Cardiac Surgery During the Postoperative Period

OBJECTIVE

Cardiac surgery is associated with hyperglycemia, which in turn is associated with adverse postsurgical outcomes such as wound infections, acute renal failure, and mortality. This pilot study seeks to determine if Dexcom G6Pro continuous glucose monitor (Dexcom G6Pro CGM) is accurate during the postoperative cardiac surgery period when fluid shifts, systemic inflammatory response syndrome, and vasoactive medications are frequently encountered, compared to standard glucose monitoring techniques.

METHODS

This study received institutional review board approval. In this prospective study, correlation between clinical and Dexcom glucose readings was evaluated. Clinical glucose (blood gas, metabolic panel, and point of care) data set included 1428 readings from 29 patients, while the Dexcom G6Pro CGM data included 45 645 data points following placement to upper arm. Additionally, average clinical measurements of day and overnight temperatures and hemodynamics were evaluated. Clinical and Dexcom data were restricted to being at least 1 hour after prior clinical reading Matching Dexcom G6Pro CGM data were required within 5 minutes of clinical measure. Data included only if taken at least 2 hours after Dexcom G6Pro CGM insertion (warm-up time) and analyzed only following intensive care unit (ICU) admission. Finally, a data set excluding the first 24 hours after ICU admission was created to explore stability of the device. Patients remained on Dexcom G6Pro CGM until discharge or 10 days postoperatively.

RESULTS

The population was 71% male, 14% with known diabetes; 66% required intravenous insulin infusion. The Clarke error grid plot of all measures post-ICU admission showed 53.5% in zone A, 45.9% in zone B, and 0.6% (n = 5) in zones D or E. The restricted dataset that excluded the first 24 hours post-ICU admission showed 55.9% in zone A, 43.9% in zone B, and 0.2% in zone D. Mean absolute relative difference between clinical and Dexcom G6Pro CGM measures was 20.6% and 21.6% in the entire post-ICU admission data set, and the data set excluding the first 24 hours after ICU admission, respectively. In the subanalysis of the 12 patients who did not have more than a 5-minute tap in the operating room, a consensus error grid, demonstrated that after ICU admission, percentage in zone A was 53.9%, zone B 45.4%, and zone C 0.7%. Similar percentages were obtained removing the first 24 hours post-ICU admission. These numbers are very similar to the entire cohort. A consensus error grid created post-ICU admission demonstrated: (zone A) 54%, (zone B) 45%, (zone C) 0.9%, and the following for the dataset created excluding the first 24 hours: (zone A) 56%, (zone B) 44%, (zone C) 0.4%, which demonstrated very close agreement with the original Clarke error grid. No adverse events were reported.

CONCLUSIONS

Almost 100% of Dexcom G6Pro CGM and clinical data matching points fell within areas considered as giving clinically correct decisions (zone A) and clinically uncritical decisions (zone B). However, the relatively high mean absolute relative difference precludes its use for both monitoring and treatment in the clinical context. As technology evolves, interstitial glucose monitoring may become an important tool to limit iatrogenic anemia and mitigate glycemic fluctuations.

Myocardial protection in cardiac surgery: a comprehensive review of current therapies and future cardioprotective strategies

Cardiac surgery with cardiopulmonary bypass results in global myocardial ischemia-reperfusion injury, leading to significant postoperative morbidity and mortality. Although cardioplegia is the cornerstone of intraoperative cardioprotection, a number of additional strategies have been identified. The concept of preconditioning and postconditioning, despite its limited direct clinical application, provided an essential contribution to the understanding of myocardial injury and organ protection. Therefore, physicians can use different tools to limit perioperative myocardial injury. These include the choice of anesthetic agents, remote ischemic preconditioning, tight glycemic control, optimization of respiratory parameters during the aortic unclamping phase to limit reperfusion injury, appropriate choice of monitoring to optimize hemodynamic parameters and limit perioperative use of catecholamines, and early reintroduction of cardioprotective agents in the postoperative period. Appropriate management before, during, and after cardiopulmonary bypass will help to decrease myocardial damage. This review aimed to highlight the current advancements in cardioprotection and their potential applications during cardiac surgery.

Phytochemical Profile, Antioxidant, Antimicrobial, and Antidiabetic Activities of Ajuga iva (L.)

In Morocco, many applications in ethnomedicine on Ajuga iva (L.) have been recognized as able to treat various pathologies such as diabetes, stress, and microbial infections. The objective of this work is to carry out phytochemical, biological, and pharmacological investigations on the extracts of Ajuga iva leaves in order to confirm its therapeutic effects. The phytochemical screening carried out on the different extracts of Ajuga iva showed its richness in primary (lipids and proteins) and secondary metabolites (flavonoids, tannins, reducing compounds, oses, and holoside. The best contents of polyphenols, flavonoids, and tannins evaluated by spectrophotometric methods were found in the hydroethanolic extract (69.850 ± 2.783 mg EAG/g DE, 17.127 ± 0.474 mg EQ/g DE, 5.566 ± 0.000 mg EQC/g DE), respectively. Analysis of the chemical composition of the aqueous extract by LC/UV/MS revealed 32 polyphenolic compounds including ferulic acid (19.06%), quercetin (10.19%), coumaric acid (9.63%), and apigenin-7-(2-O-apiosylglucoside) (6.8%). The antioxidant activity of Ajuga iva extracts was evaluated by three methods (DPPH*, FRAP, CAT). The hydroethanolic extract recorded the strongest reducing power: DPPH* (IC₅₀ = 59.92 ± 0.7 µg/mL), FRAP (EC₅₀ = 196.85 ± 1.54 (µg/mL), and CAT (199.21 ± 0.37 mg EAG/gE). A strong correlation between phenolic compounds and antioxidant activities was confirmed by the determination of Pearson's coefficient. The antimicrobial activity of Ajuga iva studied by the microtiter method revealed potent antifungal and antibacterial qualities against Candida parapsilosis and Staphylococcus aureus BLACT. An in vivo oral glucose tolerance test (OGTT) using normal rats revealed that the antihyperglycemic action of the aqueous extract significantly reduced postprandial hyperglycaemia at (30 min, p < 0.01) and area under the curve (AUC glucose), p < 0.01. Similarly, the aqueous extract, tested on pancreatic α-amylase enzyme activity in vitro and in vivo significantly inhibited pancreatic α-amylase activity with IC₅₀ = 1.52 ± 0.03 mg/mL. In conclusion, the extract from Ajuga iva could be a good source of bioactive molecules, which exhibit potent antioxidant and antimicrobial activity, as well as strong antidiabetic activity, for applications in the pharmaceutical industry.

[Position statement: surgery and diabetes mellitus (Update 2023)]

This position statement reflects the perspective of the Austrian Diabetes Association concerning the perioperative management of people with diabetes mellitus based on the available scientific evidence. The paper covers necessary preoperative examinations from an internal/diabetological point of view as well as the perioperative metabolic control by means of oral antihyperglycemic and/or insulin therapy.

Implementing a Diabetic Algorithm for Ophthalmology Surgery Patients: A Quality Improvement Initiative

Introduction

The objective of this quality improvement, interventional study regarding patients with diabetes undergoing diabetic ophthalmology outpatient surgery aimed to develop, implement, and evaluate a new diabetic algorithm to improve safety, operating room efficiency, and decrease supply cost.

Methods

A multidisciplinary study team was assembled, including ophthalmologists, endocrinologists, anesthesiologists, management, and nurses to review the current diabetic protocol. From August 2016 to July 2017, 13 patient safety concerns or incident reports were reviewed that identified two serious cases of hypoglycemia. Using the concerns data, frontline perspectives, and reviewing best practice guidelines, a new diabetic algorithm was developed and trialed for 24 months. The new algorithm limited the use of an existing preoperative insulin protocol and reduced the number of nurses required. The number of adverse events, nursing setup process steps, setup time, and preoperative insulin infusion protocols used were collected. An evaluation of the supply costs was performed.

Results

After implementing the new diabetic algorithm, zero safety incidents were reported, and a 97.5% reduction in the use of preoperative insulin protocol resulted. Nursing staff perceived that the new diabetic algorithm was easier to configure, 23 minutes faster to set up, and required one nursing staff member. Supply cost was reduced by $30.63 (Canadian Dollars, CAD) per patient.

Conclusion

Perioperative glucose irregularities may threaten patient safety and surgical outcomes. Healthcare professionals must improve patient safety, decrease healthcare expenditure, and prevent unnecessary delays. Multidisciplinary frontline staff experiential knowledge aided in the recognition of potential problems and comprehensive solutions to optimize patient care.

Enhanced Recovery After Cardiac Surgery

The aims of "Fast track" cardiac anesthesia including shortening time to tracheal extubation and to hospital discharge in selected patients. The evidence is weak and recommendations are mostly based on observational, nonrandomized data and expert opinion. The majority of outcomes studied include: time to tracheal extubation, hospital/ICU length of stay, procedure-related financial costs, and the type/amount of opioids used in the peri-operative period. There should be a shift in focus to generating higher quality evidence supporting the use of enhanced recovery protocols in cardiac surgical patients and finding ways to tailor enhanced recovery principles to all cardiac surgical patients. Research should focus on the quality of care for individual patients and the delivery of health care to the public.

Multiobjective optimization challenges in perioperative anesthesia: A review

Physicians use perioperative decision-support tools to mitigate risks and maximize benefits to achieve the most successful outcome for patients. Contemporary risk-assessment practices augment surgeons' judgement and experience with decision-support algorithms driven by big data and machine learning. These algorithms accurately assess risk for a wide range of postoperative complications by parsing large datasets and performing complex calculations that would be cumbersome for busy clinicians. Even with these advancements, large gaps in perioperative risk assessment remain; decision-support algorithms often cannot account for risk-reduction therapies applied during a patient's perioperative course and do not quantify tradeoffs between competing goals of care (eg, balancing postoperative pain control with the risk of respiratory depression or balancing intraoperative volume resuscitation with the risk for complications from pulmonary edema). Multiobjective optimization solutions have been applied to similar problems successfully but have not yet been applied to perioperative decision support. Given the large volume of data available via electronic medical records, including intraoperative data, it is now feasible to successfully apply multiobjective optimization in perioperative care. Clinical application of multiobjective optimization would require semiautomated pipelines for analytics and reporting model outputs and a careful development and validation process. Under these circumstances, multiobjective optimization has the potential to support personalized, patient-centered, shared decision-making with precision and balance.

Covid-19 and Diabetes: A Complex Bidirectional Relationship

Covid-19 is a recently-emerged infectious disease caused by the novel severe acute respiratory syndrome coronavirus SARS-CoV2. SARS-CoV2 differs from previous coronavirus infections (SARS and MERS) due to its high infectivity (reproduction value, R0, typically 2-4) and pre- or asymptomatic transmission, properties that have contributed to the current global Covid-19 pandemic. Identified risk factors for disease severity and death from SARS-Cov2 infection include older age, male sex, diabetes, obesity and hypertension. The reasons for these associations are still largely obscure. Evidence is also emerging that SARS-CoV2 infection exacerbates the underlying pathophysiology of hyperglycemia in people with diabetes. Here, we discuss potential mechanisms through which diabetes may affect the risk of more severe outcomes in Covid-19 and, additionally, how diabetic emergencies and longer term pathology may be aggravated by infection with the virus. We consider roles for the immune system, the observed phenomenon of microangiopathy in severe Covid-19 infection and the potential for direct viral toxicity on metabolically-relevant tissues including pancreatic beta cells and targets of insulin action.

Continuous subcutaneous insulin infusion reduces the risk of postoperative infection

BACKGROUND

Perioperative hyperglycemia was associated with postoperative infection, and proper management of perioperative glucose has become critical in improving the prognosis of patients.

METHODS

A total of 1015 diabetic patients who underwent surgery and received insulin treatment for their hyperglycemia in our hospital were retrospectively reviewed. According to propensity matching, we obtained 253 pairs of patients from the group which received continuous subcutaneous insulin infusion (CSII) therapy (CSII group) and the group which received insulin injection therapy (non-CSII group). Perioperative glucose levels and corresponding outcomes were compared between the two groups.

RESULTS

Compared with the non-CSII group, the CSII group had lower fasting and mean glucose levels, lower incidence of fever (operation day: 18.6% vs 10.2%; P = .014; first postoperative day: 55.1% vs 34.7%; P < .001), a positive rate of postoperative secretion culture (6.3% vs 1.2%; P = .004), and a shorter time of antibiotics use (total antibiotics use: P = .002; postoperative antibiotics use: P < .001) and hospital stays (P < .001). However, there was no difference in the total medical expenditure between the two groups (P = .499). Further analysis showed that CSII therapy was superior to multiple daily insulin injection (MDI) therapy in its effect on infection and other postoperative outcomes when 64 pairs of patients from the CSII group and MDI group were compared.

CONCLUSIONS

CSII therapy provides better perioperative glucose control and a lower risk of postoperative infection without increasing the total medical expenditure.

[Position statement: surgery and diabetes mellitus (Update 2019)]

This position statement reflects the opinion of the Austrian Diabetes Association concerning the perioperative management of patients with diabetes mellitus based on the available scientific evidence. The paper covers necessary preoperative examinations from an internal/diabetological point of view as well as the perioperative metabolic control by means of oral antidiabetics and/or insulin therapy.

Risk factors and impact of postoperative hyperglycemia in nondiabetic patients after cardiac surgery: A prospective study

Cardiac surgery induces a significant inflammatory hypermetabolic stress response, resulting in postoperative hyperglycemia in both preoperatively diabetic and nondiabetic patients. Such postoperative hyperglycemia has been associated with adverse outcomes in surgery and postsurgical recovery. Yet, while diabetes is a known risk factor for postoperative hyperglycemia, predictors of postoperative hyperglycemia among nondiabetics in the local Southeast Asian population remain unknown.We aim to investigate the predictors and outcomes associated with hyperglycemia after cardiac surgery among nondiabetics in the local Southeast Asian population. We analyzed data from 1602 nondiabetic adult patients undergoing elective cardiac surgery, from 2008 to 2010 at the 2 main heart centers in Singapore.Nondiabetic patients who developed postoperative hyperglycemia tended to be women, older, more obese, and hypertensive. Higher body mass index (BMI), age, aortic cross-clamp time, and blood transfusion were identified as independent risk factors of postoperative hyperglycemia. Postoperative hyperglycemia was also significantly associated with postoperative cardiac arrhythmias (26.9% vs 15.0%, P < .001), acute kidney injury (30.0% vs 20.1%, P < .001), longer intensive care unit (ICU) stay (46.7 ± 104.1 vs 37.2 ± 76.6 hours, P = .044) and longer hospitalization (11.5 ± 12.2 vs 9.6 ± 8.0 days, P < .001).Our study identified aortic cross-clamp time and blood transfusion as independent risk factors of postoperative hyperglycemia after cardiac surgery in nondiabetics. Similar to other studies, higher BMI and age were independent risk factors for postoperative hyperglycemia. Postoperative hyperglycemia was also associated with adverse perioperative outcomes and should thereby be avoided by treating modifiable risk factors identified in this study including reducing blood transfusion and aortic cross-clamp time. Our findings contribute to early risk stratification of nondiabetic patients who are at increased risk of postoperative hyperglycemia.

Effects of Isolated Impaired Fasting Glucose on Brain Injury During Cardiac Surgery Under Cardiopulmonary Bypass

Objective: To evaluate the effects of isolated impaired fasting glucose (IIFG) on brain injury in patients undergoing cardiopulmonary bypass (CPB) surgery. Methods: Patients with rheumatic heart valve disease who underwent elective mitral valve replacement were included and divided into control and IIFG groups. Pre-, intra-, and postoperative blood glucose levels, serum insulin levels, insulin resistance index (HOMA-IR), lactic acid levels, and neuron-specific enolase (NSE) and S100B levels were measured. The cerebral oxygen extraction ratio (OER) was calculated. Cognitive function was assessed via the Mini-Mental State Examination (MMSE). Results: HOMA-IR levels were higher in the IIFG group than the control group 30 min after the beginning of CPB, at the termination of CPB, and 2 h after the termination of CPB. Cerebral OER and lactic acid increased intraoperatively in both groups, especially in the IIFG group. NSE and S100B levels were higher in the IIFG group than in the control group at the termination of CPB, 2 h after the termination of CPB, and at 24 h postoperatively. The MMSE scores did not significantly differ between the two groups. Delirium occurred in two patients in the IIFG group, and one in the control group. No other signs and symptoms of brain injuries were detected in either group. Conclusions: The increased postoperative NSE and S100B levels in the IIFG group compared with controls may be associated with severe insulin resistance and stress hyperglycemia. However, the IIFG group did not have clinical manifestations of brain injuries, including cognitive impairment.

Deep sternal infections after in situ bilateral internal thoracic artery grafting for left ventricular myocardial revascularization: predictors and influence on 20-year outcomes

Background

The incidence and potential factors influencing deep sternal wound infection (DSWI) in a cohort of patients undergoing coronary artery bypass grafting (CABG) using skeletonized bilateral internal thoracic artery (BITA) was explored. Furthermore, we studied influence of DSWI on long-term survival, major adverse cardiac events (MACEs) and repeat coronary revascularization (RCR).

Methods

The study cohort consisted of 1,325 consecutive patients who were divided in two groups: patients experiencing DSWI (n=33, group 1) and those who did not have sternal infection (n=1,292, group 2). A logistic regression model was employed to find predictors of DSWI whereas Cox regression and a competing risk models were carried out to test predictors of late death, MACE and RCR, respectively. Follow up was 100% complete and ranged from 1 to 245 months. Median follow-up was 103 months (IQR, 61 to 189 months). Cumulative follow-up was 16,430 patient years.

Results

The incidence of DSWI was 2.4%. Multivariable logistic regression analysis found any single independent predictor of DSWI. However, the association of peripheral vascular disease (PVD) and diabetes increased the risk by 1.4 and 1.6 times. When DM was associated with obesity the risk increased by 2.1 and 2.6 times compared to the single factors, respectively. Obese female patients were at a 1.6-fold higher risk when compared to the association of DM with obesity. DSWI was not an independent predictor of long-term survival (HR, 2.31; 95% CI: 0.59-9.12), RCR (SHR, 2.89; 95% CI: 0.65-10.12), or MACE (SHR, 1.98; 95% CI: 0.44-8.56).

Conclusions

With an accurate patient selection (i.e., exclusion of obese diabetic females) and strict DM control BITA represents a first choice for most of CABG patients, even at high risk for DSWI. The occurrence of DSWI does not influence long-term survival and late outcomes. Our findings should be confirmed by further larger research.

Evaluation of a novel in-line point-of-care blood gas analyser

Point-of-care testing is becoming increasingly relevant to the practice of anaesthesia and critical care medicine, especially in terms of minimisation of sample volumes and decreased time to decision making. We performed a prospective observational study to evaluate a novel, in-line blood gas analysis device against a conventional benchtop model, and assessed it while placing the enrolled patients under extreme physiological conditions, specifically deep hypothermic circulatory arrest. Eight patients were studied, and had between seven and 11 samples analysed for seven variables (pH, pCO2 , pO2 , HCO3 (-) , base excess [BE], K(+) and haematocrit [Hct]), using the device during the process of cooling to 20 °C on cardiopulmonary bypass, and subsequent rewarming to normothermia. After Passing-Bablok analysis, the variables were evaluated for bias, limits of agreement and percentage error at above and below 30 °C. Of the measured variables, only pH (percentage error 2.4%) and potassium (19.8%) demonstrated acceptable (< 30%) percentage error over the full range of temperatures measured. Carbon dioxide, when stratified by temperature, was acceptable (< 30 °C percentage error 24.6%, > 30 °C percentage error 9.9%), but the overall percentage error of the dataset (45.8%) was excessively high. Bicarbonate and haematocrit both had an acceptable percentage error above 30 °C (25.2% and 18.5%, respectively), but similar to carbon dioxide, percentage error for the full range of temperatures exceeded 30%. These data differ from previous work examining this device, and highlights the difference between derived measures using different apparatuses when exposed to extreme physiological conditions.

Continuous glucose monitoring identifies relationship between optimized glycemic control and post-discharge acute care facility needs

Objective

Hyperglycemia is an independent risk factor in hospitalized patients for adverse outcomes, even if patients are not diabetic. We used continuous glucose monitoring to evaluate whether glycemic control (hyperglycemia) in the first 72 h after an intensive care admission was associated with the need for admission to a post discharge long-term medical facility.

Results

We enrolled 59 coronary artery bypass grafting patients. Poor glycemic control was defined as greater than 33% of continuous glucose monitoring values < 70 and > 180 mg/dL (group 1); and then these patients were reevaluated with a less strict definition of poor glycemic control with greater than 25% of continuous glucose values < 70 and > 180 mg/dL (group 2). In group 1 4/10 (40.0%) whose glucose was not well controlled went to an extended care post discharge facility as opposed to 6/49 (12.2%) that were well controlled. In reevaluation as group 2, 5/14 (35.7%) whose glucose was not well controlled went to an extended care post discharge facility as opposed to 5/45 (11.1%) who were well controlled. Admission to a post discharge facility was increased in patients with poor glycemic control p = 0.045 and p = 0.042 for group 1 and group 2, and with odds ratios of 4.8 (95% CI 1.0–22.5) and 4.4 (95% CI 1.0–19.4), respectively.

Diabetes-Specific Formulae Versus Standard Formulae as Enteral Nutrition to Treat Hyperglycemia in Critically Ill Patients: Protocol for a Randomized Controlled Feasibility Trial

Background

During critical illness, hyperglycemia is prevalent and is associated with adverse outcomes. While treating hyperglycemia with insulin reduces morbidity and mortality, it increases glycemic variability and hypoglycemia risk, both of which have been associated with an increase in mortality. Therefore, other interventions which improve glycemic control, without these complications should be explored. Nutrition forms part of standard care, but the carbohydrate load of these formulations has the potential to exacerbate hyperglycemia. Specific diabetic-formulae with a lesser proportion of carbohydrate are available, and these formulae are postulated to limit glycemic excursions and reduce patients’ requirements for exogenous insulin.

Objective

The primary outcome of this prospective, blinded, single center, randomized controlled trial is to determine whether a diabetes-specific formula reduces exogenous insulin administration. Key secondary outcomes include the feasibility of study processes as well as glycemic variability.

Methods

Critically ill patients will be eligible if insulin is administered whilst receiving exclusively liquid enteral nutrition. Participants will be randomized to receive a control formula, or a diabetes-specific, low glycemic index, low in carbohydrate study formula. Additionally, a third group of patients will receive a second diabetes-specific, low glycemic index study formula, as part of a sub-study to evaluate its effect on biomarkers. This intervention group (n=12) will form part of recruitment to a nested cohort study with blood and urine samples collected at randomization and 48 hours later for the first 12 participants in each group with a secondary objective of exploring the metabolic implications of a change in nutrition formula. Data on relevant medication and infusions, nutrition provision and glucose control will be collected to a maximum of 48 hours post randomization. Baseline patient characteristics and anthropometric measures will be recorded. A 28-day phone follow-up will explore weight and appetite changes as well as blood glucose control pre and post intensive care unit (ICU) discharge.

Results

Recruitment commenced in February 2015 with an estimated completion date for data collection by May 2018. Results are expected to be available late 2018.

Conclusions

This feasibility study of the effect of diabetes-specific formulae on the administration of insulin in critically ill patients and will inform the design of a larger, multi-center trial.

Trial Registration

Australian New Zealand Clinical Trial Registry (ANZCTR):12614000166673; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12614000166673 (Archived by WebCite at http://www.webcitation.org/6xs0phrVu)

Does the Type of Cardioplegia Solution Affect Intraoperative Glucose Levels? A Propensity-Matched Analysis

Myocardial protection during cardiac surgery is a multifaceted process that is structured to limit injury and preserve function. Evolving techniques use solutions with varying constituents that enter the systemic circulation and alter intrinsic systemic concentrations. This study compared two distinct cardioplegia solutions on affecting intraoperative glucose levels. Data were abstracted from a multi-institutional perfusion registry, including a total of 1,188 propensity-matched cases performed from January through October 2016, at 17 cardiac surgical centers across the United States in which both del Nido and 4:1 cardioplegia were used during the study period. Covariate data included insulin administration, crystalloid cardioplegia volume, diabetes history, glucose at operating room entry, and nine additional variables. Primary and secondary endpoints were the highest intraoperative glucose level and maximum glucose in excess of 180 mg/dL. Mixed-effects multivariable linear and logistic regression models were used to assess the primary and secondary endpoints, respectively, allowing for statistical control of center and surgeon effects. Greater median crystalloid cardioplegia volume was given in the del Nido group (n = 594) 1,040 mL [interquartile range (IQR) = {800, 1,339}] compared with the 4:1 group (n = 594) 466 mL [IQR = {360, 660}] in the 4:1 group (p < .001) despite these groups being statistically indistinguishable in terms of bypass and cross-clamp times as well as seven other patient covariates. More patients required intraoperative insulin drip in the 4:1 group compared with del Nido (65.7% vs. 56.2%, p < .001). Multivariable linear mixed-effects analysis yielded an estimated maximum intraoperative glucose for the del Nido group of 177.8 mg/dL compared with that of the 4:1 group, 183.5 mg/dL-a statistically significant reduction of 5.7 mg/dL (p = .03). Multivariable logistic mixed-effects analysis showed a statistically nonsignificant reduction in the likelihood of crossing the 180 mg/dL threshold for del Nido compared with 4:1 (odds ratio [OR] = .79, p = .214). After controlling for known confounding variables, intraoperative maximum glucose levels for the del Nido group were 5.7 mg/dL lower than that of the 4:1 group; there was limited evidence suggesting a difference between methods in the likelihood of exceeding the threshold of 180 mg/dL intraoperatively. Further research is warranted to examine the differential effects of cardioplegia solution on intraoperative glucose levels.

Effect of glycaemic control on complications following cardiac surgery: literature review

Introduction

No uniform consensus in the UK or Europe exists, for glycaemic management of patients with Diabetes or pre-diabetes undergoing cardiac surgery.

Objective

[i] Determine the relationship between glycaemic control and cardiac surgical outcomes; [ii] Compare current vs gold standard management of patients with Diabetes or pre-diabetes undergoing cardiac surgery.

Methods

Searches of MEDLINE, NHS Evidence and Web of Science databases were completed. Articles were limited to those in English, German and French. No date limit was enforced.13,232 articles were identified on initial literature review, and 50 relevant papers included in this review.

Results

No national standards for glycaemic control prior to cardiac surgery were identified. Upto 30% of cardiac surgical patients have undiagnosed Diabetes. Cardiac surgical patients without Diabetes with pre-operative hyperglycaemia have a 1 year mortality double that of patients with normoglyacemia, and equivalent to patients already diagnosed with Diabetes. Pre- and peri-operative hyperglycaemia is associated with worse outcomes. Evidence regarding tight glycaemic control vs moderate glycaemic control is conflicting. Tight control may be more effective in patients without Diabetes with pre−/peri-operative hyperglycaemia, and moderate control appears more effective in patients with pre-existing Diabetes. Patients with well controlled Diabetes may achieve comparable outcomes to patients without Diabetes with similar glycaemic control.

Conclusions

Pre / peri-operative hyperglycaemia is associated with worse outcomes in both patients with, and without Diabetes undergoing CABG. This review supports the pre-operative screening, and optimisation of glycaemic control in patients undergoing cardiac surgery. Optimal glycaemic management remains unclear and clear guidelines are needed.

Continuous Glucose Monitoring in the Cardiac ICU: Current Use and Future Directions

Perioperative glucose control is highly important, particularly for patients undergoing cardiac surgery. Variable glucose levels before, during and after cardiac surgery lead to increased post-operative complications and patient mortality. [1] Current methods for intensive monitoring and treating hyperglycemia in the Intensive Care Unit (ICU) usually involve hourly glucose monitoring and continuous intravenous insulin infusions. With the advent of more accurate subcutaneous glucose monitoring systems, the role of improved glucose control with newer systems deserves consideration for widespread adoption.

Decision Support Tool to Improve Glucose Control Compliance After Cardiac Surgery

Hyperglycemia control is associated with improved outcomes in patients undergoing cardiac surgery. The Surgical Care Improvement Project metric (SCIP-inf-4) was introduced as a performance measure in surgical patients and included hyperglycemia control. Compliance with the SCIP-inf-4 metric remains suboptimal. A novel real-time decision support tool (DST) with guaranteed feedback that is based on the existing electronic medical record system was developed at a tertiary academic center. Implementation of the DST increased the compliance rate with the SCIP-inf-4 from 87.3% to 96.5%. Changes in tested clinical outcomes were not observed with improved metric compliance. This new framework can serve as a backbone for development of quality control processes for other metrics. Further and, ideally, multicenter studies are required to test if implementation of electronic DSTs will translate into improved resource utilization and outcomes for patients.

Determinants of prolonged intensive care unit stay in patients after cardiac surgery: a prospective observational study

BACKGROUND

Prolonged intensive care unit (ICU) stay of patients after cardiac surgery has a major impact on overall cost and resource utilization. The aim of this study was to identify perioperative factors which prolong stay in ICU.

METHODS

All adult patients from a single, specialized cardiac center who were admitted to the ICU after cardiac surgery during a 2-month period were included. Demographic and clinical characteristics, comorbidities, preoperative use of drugs, intraoperative variables, and postoperative course were recorded. Hemodynamic and blood gas measurements were recorded at four time intervals during the first 24 postoperative hours. Routine hematologic and biochemical laboratory results were recorded preoperatively and in the first postoperative hours.

RESULTS

During the study period 145 adult patients underwent cardiac surgery: 65 (45%) underwent coronary artery bypass graft surgery, 38 (26%) valve surgery, 26 (18%) combined surgery and 16 (11%) other types of cardiac operation. Seventy nine (54%) patients had an ICU stay of less than 24 hours. Random forests analysis identified four variables that had a major impact on the length of stay (LOS) in ICU; these variables were subsequently entered in a logistic regression model: preoperative hemoglobin [odds ratio (OR) =0.68], duration of aortic clamping (OR =1.01) and ratio of arterial oxygen partial pressure to inspired oxygen fraction (PaO₂/FiO₂) (OR =0.99) and blood glucose during the first four postoperative hours (OR =1.02). ROC curve analysis showed an AUC =0.79, P<0.001, 95% CI: 0.71-0.86.

CONCLUSIONS

Low preoperative hemoglobin, prolonged aortic clamping time and low PaO₂/FiO₂ ratio and blood glucose measured within the first postoperative hours, were strongly related with prolonged LOS in ICU.

[Position statement: surgery and diabetes mellitus]

This position statement reflects the opinion of the Austrian Diabetes Association concerning the perioperative management of patients with diabetes mellitus based on the available scientific evidence. The paper covers necessary preoperative examinations from an internal/diabetological point of view as well as the perioperative metabolic control by means of oral antidiabetics and/or insulin therapy.

Intensive Glycemic Control in Cardiac Surgery

Hyperglycemia has been found to be associated with increased morbidity and mortality in surgical patients, yet, the optimal glucose management strategy during the perioperative setting remains undetermined. While much has been published about hyperglycemia and cardiac surgery, most studies have used widely varying definitions of hyperglycemia, methods of insulin administration, and the timing of therapy. This has only allowed investigators to make general conclusions in this challenging clinical scenario. This review will introduce the basic pathophysiology of hyperglycemia in the cardiac surgery setting, describe the main clinical consequences of operative hyperglycemia, and take the reader through the published material of intensive and conservative glucose management. Overall, it seems that intensive control has modest benefits with adverse effects often outweighing these advantages. However, some studies have indicated differing results for certain patient subgroups, such as non-diabetics with acute operative hyperglycemia. Future studies should focus on distinguishing which patient populations, if any, would optimally benefit from intensive insulin therapy.