Impact of perioperative glycemic control strategy on patient survival after coronary bypass surgery

Perioperative Glycemic Management in Cardiac Surgery: A Narrative Review

Diabetes and hyperglycemic events in cardiac surgical patients are associated with postoperative morbidity and mortality. The causes of dysglycemia, the abnormal fluctuations in blood glucose concentrations, in the perioperative period include surgical stress, surgical techniques, medications administered perioperatively, and patient factors. Both hyperglycemia and hypoglycemia lead to poor outcomes after cardiac surgery. While trying to control blood glucose concentration tightly for better postoperative outcomes, hypoglycemia is the main adverse event. Currently, there is no definite consensus on the optimum perioperative blood glucose concentration to be maintained in cardiac surgical patients. This review provides an overview of perioperative glucose homeostasis, the pathophysiology of dysglycemia, factors that affect glycemic control in cardiac surgery, and current practices for glycemic control in cardiac surgery.

Intensive Care Unit Hyperglycemia After Cardiac Surgery: Risk Factors and Clinical Outcomes

OBJECTIVES

Patients with hyperglycemia after cardiac surgery face increased morbidity and mortality due to postoperative complications. The main purpose of this study was to evaluate the incidence of postoperative hyperglycemia, the hyperglycemia risk factors, and its association with clinical outcomes in patients admitted to the cardiac surgery intensive care unit after cardiac surgery.

DESIGN

Prospective, observational study.

SETTING

Single-center hospital.

PARTICIPANTS

Two hundred ten consecutive postoperative cardiac surgery patients admitted to the cardiac surgery intensive care unit.

INTERVENTIONS

Patients' blood glucose levels were evaluated immediately after cardiac surgery and every 3 hours daily for 7 days or earlier upon discharge. Intravenous insulin was administered as per the institution's protocol. Perioperative predisposing risk factors for hyperglycemia and clinical outcomes were assessed.

MEASUREMENTS AND MAIN RESULTS

Postoperative hyperglycemia, defined as glucose level ≥180 mg/dL, occurred in 30% of cardiac surgery patients. Diabetes mellitus (odds ratio [OR] 6.73; 95% CI [3.2-14.3]; p < 0.001), white blood cell count (OR 1.28; 95% CI [1.1-1.4]; p < 0.001), and EuroSCORE II (OR 1.20; 95% CI [1.1-1.4]; p = 0.004) emerged as independent prognostic factors for hyperglycemia. Moreover, patients with glucose ≥180 mg/dL had higher rates of acute kidney injury (34.9% v 18.9%, p = 0.013), longer duration of mechanical ventilation (959 v 720 min, p = 0.019), and sedation (711 v 574 min, p = 0.034), and higher levels of intensive care unit (ICU)-acquired weakness (14% v 5.5%, p = 0.027) and rate of multiorgan failure (6.3% v 0.7%, p = 0.02) compared with patients with glucose levels <180 mg/dL.

CONCLUSIONS

In the intensive care unit, hyperglycemia occurs frequently in patients immediately after cardiac surgery. Diabetes, high EuroSCORE II, and preoperative leukocytosis are independent risk factors for postoperative hyperglycemia. Hyperglycemia is associated with worse clinical outcomes, including a higher rate of acute kidney injury and ICU-acquired weakness, greater duration of mechanical ventilation, and a higher rate of multiorgan failure.

Perioperative glycaemic control for people with diabetes undergoing surgery

BACKGROUND

People with diabetes mellitus are at increased risk of postoperative complications. Data from randomised clinical trials and meta-analyses point to a potential benefit of intensive glycaemic control, targeting near-normal blood glucose, in people with hyperglycaemia (with and without diabetes mellitus) being submitted for surgical procedures. However, there is limited evidence concerning this question in people with diabetes mellitus undergoing surgery.

OBJECTIVES

To assess the effects of perioperative glycaemic control for people with diabetes undergoing surgery.

SEARCH METHODS

For this update, we searched the databases CENTRAL, MEDLINE, LILACS, WHO ICTRP and ClinicalTrials.gov. The date of last search for all databases was 25 July 2022. We applied no language restrictions.

SELECTION CRITERIA

We included randomised controlled clinical trials (RCTs) that prespecified different targets of perioperative glycaemic control for participants with diabetes (intensive versus conventional or standard care).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the risk of bias. Our primary outcomes were all-cause mortality, hypoglycaemic events and infectious complications. Secondary outcomes were cardiovascular events, renal failure, length of hospital and intensive care unit (ICU) stay, health-related quality of life, socioeconomic effects, weight gain and mean blood glucose during the intervention. We summarised studies using meta-analysis with a random-effects model and calculated the risk ratio (RR) for dichotomous outcomes and the mean difference (MD) for continuous outcomes, using a 95% confidence interval (CI), or summarised outcomes with descriptive methods. We used the GRADE approach to evaluate the certainty of the evidence (CoE).

MAIN RESULTS

A total of eight additional studies were added to the 12 included studies in the previous review leading to 20 RCTs included in this update. A total of 2670 participants were randomised, of which 1320 were allocated to the intensive treatment group and 1350 to the comparison group. The duration of the intervention varied from during surgery to five days postoperative. No included trial had an overall low risk of bias. Intensive glycaemic control resulted in little or no difference in all-cause mortality compared to conventional glycaemic control (130/1263 (10.3%) and 117/1288 (9.1%) events, RR 1.08, 95% CI 0.88 to 1.33; I2 = 0%; 2551 participants, 18 studies; high CoE). Hypoglycaemic events, both severe and non-severe, were mainly experienced in the intensive glycaemic control group. Intensive glycaemic control may slightly increase hypoglycaemic events compared to conventional glycaemic control (141/1184 (11.9%) and 41/1226 (3.3%) events, RR 3.36, 95% CI 1.69 to 6.67; I2 = 64%; 2410 participants, 17 studies; low CoE), as well as those considered severe events (37/927 (4.0%) and 6/969 (0.6%), RR 4.73, 95% CI 2.12 to 10.55; I2 = 0%; 1896 participants, 11 studies; low CoE). Intensive glycaemic control, compared to conventional glycaemic control, may result in little to no difference in the rate of infectious complications (160/1228 (13.0%) versus 224/1225 (18.2%) events, RR 0.75, 95% CI 0.55 to 1.04; P = 0.09; I2 = 55%; 2453 participants, 18 studies; low CoE). Analysis of the predefined secondary outcomes revealed that intensive glycaemic control may result in a decrease in cardiovascular events compared to conventional glycaemic control (107/955 (11.2%) versus 125/978 (12.7%) events, RR 0.73, 95% CI 0.55 to 0.97; P = 0.03; I2 = 44%; 1454 participants, 12 studies; low CoE). Further, intensive glycaemic control resulted in little or no difference in renal failure events compared to conventional glycaemic control (137/1029 (13.3%) and 158/1057 (14.9%), RR 0.92, 95% CI 0.69 to 1.22; P = 0.56; I2 = 38%; 2086 participants, 14 studies; low CoE). We found little to no difference between intensive glycaemic control and conventional glycaemic control in length of ICU stay (MD -0.10 days, 95% CI -0.57 to 0.38; P = 0.69; I2 = 69%; 1687 participants, 11 studies; low CoE), and length of hospital stay (MD -0.79 days, 95% CI -1.79 to 0.21; P = 0.12; I2 = 77%; 1520 participants, 12 studies; very low CoE). Due to the differences within included studies, we did not pool data for the reduction of mean blood glucose. Intensive glycaemic control resulted in a mean lowering of blood glucose, ranging from 13.42 mg/dL to 91.30 mg/dL. One trial assessed health-related quality of life in 12/37 participants in the intensive glycaemic control group, and 13/44 participants in the conventional glycaemic control group; no important difference was shown in the measured physical health composite score of the short-form 12-item health survey (SF-12). One substudy reported a cost analysis of the population of an included study showing a higher total hospital cost in the conventional glycaemic control group, USD 42,052 (32,858 to 56,421) compared to the intensive glycaemic control group, USD 40,884 (31.216 to 49,992). It is important to point out that there is relevant heterogeneity between studies for several outcomes. We identified two ongoing trials. The results of these studies could add new information in future updates on this topic.

AUTHORS' CONCLUSIONS

High-certainty evidence indicates that perioperative intensive glycaemic control in people with diabetes undergoing surgery does not reduce all-cause mortality compared to conventional glycaemic control. There is low-certainty evidence that intensive glycaemic control may reduce the risk of cardiovascular events, but cause little to no difference to the risk of infectious complications after the intervention, while it may increase the risk of hypoglycaemia. There are no clear differences between the groups for the other outcomes. There are uncertainties among the intensive and conventional groups regarding the optimal glycaemic algorithm and target blood glucose concentrations. In addition, we found poor data on health-related quality of life, socio-economic effects and weight gain. It is also relevant to underline the heterogeneity among studies regarding clinical outcomes and methodological approaches. More studies are needed that consider these factors and provide a higher quality of evidence, especially for outcomes such as hypoglycaemia and infectious complications.

Hyperglycemia is associated with worse 3-year survival in older patients admitted to the intensive care unit after non-cardiac surgery: Post hoc analysis of a randomized trial

Objective

Hyperglycemia is common in critically ill patients after surgery and is associated with worse perioperative outcomes. Yet, the impact of postoperative hyperglycemia on long-term outcomes remains unclear. We therefore analyzed the association between early postoperative hyperglycemia and 3-year overall survival in older patients who were admitted to the intensive care unit after surgery.

Methods

This was a post hoc analysis of database obtained from a previous randomized trial and 3-year follow-up. The underlying trial enrolled 700 patients aged 65 years or older who were admitted to the intensive care unit after elective non-cardiac surgery. Early postoperative time-weighted average blood glucose was calculated and was divided into three levels, i.e., <8.0 mmol/L, from 8.0 to 10.0 mmol/L, and >10.0 mmol/L. The primary outcome was 3-year overall survival. The association between time-weighted average blood glucose level and 3-year overall survival was analyzed with Cox proportional hazard regression models. Subgroup analyses were also performed in patients with or without diabetes, and in patients following cancer or non-cancer surgery.

Results

A total of 677 patients (mean age 74 years, 60% male sex) were included in the final analysis. Within 3 years after surgery, deaths occurred in 22.1% (30/136) of patients with time-weighted average blood glucose <8.0 mmol/L, compared with 35.7% (81/227) of those from 8.0 to 10.0 mmol/L (unadjusted hazard ratio 1.75, 95% CI 1.15 to 2.67, P = 0.009), and 36.9% (116/314) of those >10.0 mmol/L (unadjusted hazard ratio 1.91, 95% CI 1.28 to 2.85, P = 0.002). After adjustment for confounding factors, the risk of 3-year mortality remained higher in patients with time-weighted average blood glucose from 8.0 to 10.0 mmol/L (adjusted hazard ratio 2.28, 95% CI 1.47 to 3.54, P < 0.001) and in those >10.0 mmol/L (adjusted hazard ratio 2.00, 95% CI 1.29 to 3.10, P = 0.002). Similar results were obtained in the subgroups of patients without diabetes and patients following cancer surgery.

Conclusion

For older patients admitted to the intensive care unit after elective non-cardiac surgery, high early blood glucose (time-weighted average blood glucose ≥ 8.0 mmol/L) was associated with poor 3-year overall survival. The impact of moderate glycemic control on long-term survival deserves further investigation.

Hospital-acquired complications in intensive care unit patients with diabetes: A before-and-after study of a conventional versus liberal glucose control protocol

BACKGROUND

Critically ill patients with diabetes mellitus (DM) are at increased risk of in-hospital complications and the optimal glycemic target for such patients remains unclear. A more liberal approach to glucose control has recently been suggested for patients with DM, but uncertainty remains regarding its impact on complications.

METHODS

We aimed to test the hypothesis that complications would be more common with a liberal glycemic target in ICU patients with DM. Thus, we compared hospital-acquired complications in the first 400 critically ill patients with DM included in a sequential before-and-after trial of liberal (glucose target: 10-14 mmol/L) vs conventional (glucose target: 6-10 mmol/L) glucose control.

RESULTS

Of the 400 patients studied, 165 (82.5%) patients in the liberal and 177 (88.5%) in the conventional-control group were coded for at least one hospital-acquired complication (P = 0.09). When comparing clinically relevant complications diagnosed between ICU admission and hospital discharge, we found no difference in the odds for infectious (adjusted odds ratio [aOR] for liberal-control: 1.15 [95% CI: 0.68-1.96], P = 0.60), cardiovascular (aOR 1.40 [95% CI: 0.63-3.12], P = 0.41) or neurological complications (aOR: 1.07 [95% CI: 0.61-1.86], P = 0.81), acute kidney injury (aOR 0.83 [95% CI: 0.43-1.58], P = 0.56) or hospital mortality (aOR: 1.09 [95% CI: 0.59-2.02], P = 0.77) between the liberal and the conventional-control group.

CONCLUSION

In this prospective before-and-after study, liberal glucose control was not associated with an increased risk of hospital-acquired infectious, cardiovascular, renal or neurological complications in critically ill patients with diabetes.

Postoperative tight glycemic control significantly reduces postoperative infection rates in patients undergoing surgery: a meta-analysis

BACKGROUND

The benefit results of postoperative tight glycemic control (TGC) were controversial and there was a lack of well-powered studies that support current guideline recommendations.

METHODS

The EMBASE, MEDLINE, and the Cochrane Library databases were searched utilizing the key words "Blood Glucose", "insulin" and "Postoperative Period" to retrieve all randomized controlled trials evaluating the benefits of postoperative TGC as compared to conventional glycemic control (CGC) in patients undergoing surgery.

RESULTS

Fifteen studies involving 5053 patients were identified. As compared to CGC group, there were lower risks of total postoperative infection (9.4% vs. 15.8%; RR 0.586, 95% CI 0.504 to 0.680, p <  0.001) and wound infection (4.6% vs. 7.2%; RR 0.620, 95% CI 0.422 to 0.910, p = 0.015) in TGC group. TGC also showed a lower risk of postoperative short-term mortality (3.8% vs. 5.4%; RR 0.692, 95% CI 0.527 to 0.909, p = 0.008), but sensitivity analyses showed that the result was mainly influenced by one study. The patients in the TGC group experienced a significant higher rate of postoperative hypoglycemia (22.3% vs. 11.0%; RR 3.145, 95% CI 1.928 to 5.131, p <  0.001) and severe hypoglycemia (2.8% vs. 0.7%; RR 3.821, 95% CI 1.796 to 8.127, p <  0.001) as compared to CGC group. TGC showed less length of ICU stay (SMD, - 0.428 days; 95% CI, - 0.833 to - 0.022 days; p = 0.039). However, TGC showed a neutral effect on neurological dysfunction (1.1% vs. 2.4%; RR 0.499, 95% CI 0.219 to 1.137, p = 0.098), acute renal failure (3.3% vs. 5.4%, RR 0.610, 95% CI 0.359 to 1.038, p = 0.068), duration of mechanical ventilation (p = 0.201) and length of hospitalization (p = 0.082).

CONCLUSIONS

TGC immediately after surgery significantly reduces total postoperative infection rates and short-term mortality. However, it might limit conclusion regarding the efficacy of TGC for short-term mortality in sensitivity analyses. The patients in the TGC group experienced a significant higher rate of postoperative hypoglycemia. This study may suggest that TGC should be administrated under close glucose monitoring in patients undergoing surgery, especially in those with high postoperative infection risk.

Perioperative Management of Hyperglycemia and Diabetes in Cardiac Surgery Patients

Perioperative hyperglycemia is common after cardiac surgery, reported in 60% to 90% of patients with diabetes and in approximately 60% of patients without history of diabetes. Many observational and prospective randomized trials in critically-ill cardiac surgery patients support a strong association between hyperglycemia and poor clinical outcome. Despite ongoing debate about the optimal glucose target, there is strong agreement that improved glycemic control reduces perioperative complications.

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.

Cardiothoracic Critical Care

High-value CCC is rapidly evolving to meet the demands of increased patient acuity and to incorporate advances in technology. The high-performing CCC system and culture should aim to learn quickly and continuously improve. CCC demands a proactive, interactive, precise, an expert team, and continuity.

Prospective Study of Postoperative Glycemic Control with a Standardized Insulin Infusion Protocol after Infrainguinal Bypass and Open Abdominal Aortic Aneurysm Repair

BACKGROUND

The aim of this study is to examine the effect of moderate postoperative glycemic control in diabetic and nondiabetic patients undergoing infrainguinal bypass (INFRA) or open abdominal aortic aneurysm (OAAA) repair.

METHODS

In a single center prospective study, we investigated postoperative glycemic control using a standardized insulin infusion protocol after elective INFRA bypass (n = 53, 62%) and OAAA repair (n = 33, 38%) between January 2013 and March 2015. The primary end point was optimal glycemic control, defined as having ≥85% of blood glucose values within the 80-150 mg/dL target range. Suboptimal glycemic control was defined as <85% of blood glucose values within the blood glucose target range. Secondary end points included in-hospital and 30-day surgical site infection (SSI) rates, composite adverse events, length of stay (LOS), and hospital cost.

RESULTS

Optimal glycemic control was achieved more commonly after OAAA repair than INFRA bypass (85% vs. 64%, P = 0.04). Moderate hypoglycemia (<70 mg/dL) was observed in 32 (37%) patients, while severe hypoglycemia (<50 mg/dL) was observed in 6 (7%) patients. SSI at 30 days was more common after INFRA bypass (n = 15, 29%) than OAAA repair (n = 2, 6%) (P = 0.01). In-hospital (6% vs. 6%, P = 1.0) and 30-day (24% vs. 22%, P = 1.0) SSI rates were similar for optimal versus suboptimal glycemic control patients after INFRA bypass. In-hospital (4% vs. 0%, P = 1.0) and 30-day (4% vs. 0%, P = 1.0) SSI rates were similar for optimal versus suboptimal glycemic control patients after OAAA repair. The percentage of blood glucose > 250 mg/dL was similar for patients with and without SSI (3% vs. 2%, P = 0.36). Adverse cardiac and pulmonary events after INFRA bypass were similar between groups (9% vs. 21%, P = 0.23; 0% vs. 5%, P = 0.36, respectively). Adverse cardiac and pulmonary events after OAAA repair were similar between groups (2% vs. 0%, P = 1.0; 4% vs. 0%, P = 1.0, respectively). Mean LOS was significantly lower in patients with optimal glycemic control after INFRA bypass (4.2 vs. 7.3 days, P = 0.02). Mean LOS was similar after OAAA repair for patients with optimal and suboptimal control (5.8 vs. 6.4 days, P = 0.46). Inpatient hospital costs after INFRA bypass were lower for the group with optimal (median $25,012, interquartile range [IQ] range $21,726-28,331) versus suboptimal glycemic control (median $28,944, IQ range 24,773-41,270, P = 0.02).

CONCLUSIONS

Postoperative hyperglycemia is common after INFRA bypass and OAAA repair and can be effectively ameliorated with an insulin infusion protocol. The protocol was low risk with reduced LOS and cost after INFRA bypass. Complications including SSI were not reduced in patients with optimal perioperative glycemic control.

Perioperative Hyperglycemia Management: An Update

An association between perioperative hyperglycemia and adverse outcomes has been established in surgical patients, 1 -3 with morbidity being reduced in those treated with insulin.5 -6 A practical treatment algorithm and literature summary is provided for surgical patients with diabetes and hyperglycemia.

Can the onset of heart failure be delayed by treating diabetic cardiomyopathy?

The pathophysiology of diabetic cardiomyopathy (DC) is not fully understood. This frequently undiagnosed complication of chronic hyperglycemia leads to heart failure (HF). However, it is suggested that an appropriate metabolic control of diabetes at an early stage of this deleterious disease, is able to inhibit the development and progression of DC to HF. Recently, it has been postulated that myocardial ischaemia plays an important role in the development of this pathology. Results of the antianginal pharmacological treatment and revascularization are unsatisfactory and reveal a gap in our knowledge and current approaches to treating DC. Most recent studies emphasize the ischaemic component of DC as a key target for therapeutic strategies, which could change its unfavorable history. More stress is put on an early diagnosis of coronary artery disease (CAD), promoting prompt revascularization. Choosing the accurate time of surgical revascularization, with the inclusion of the metabolic background, can ensure complete revascularization with better prognosis. This review will focus on the complexity of DC and summarize contemporary knowledge of treatment strategies for patients with diabetes and CAD.

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.

Long-term glycaemic control (HbA1c), not admission glucose, predicts hospital re-admission in diabetic patients

BACKGROUND

Diabetic patients are commonly hyperglycaemic on presentation. Admission hyperglycaemia is associated with adverse outcomes, particularly prolonged hospitalisation. Improving inpatient glycaemia may reduce length of hospital stay (LOS) in diabetic patients.

AIMS

To determine whether in-hospital recognition and treatment of admission hyperglycaemia in diabetic patients is associated with reduced LOS.

METHODS

Medical records were reviewed from 1 November 2011 to 31 May 2012 for 162 diabetic patients admitted with a blood glucose level (BGL) ≥11.1mmol/L. In-hospital outcomes were compared. Stepwise multiple regression was used to evaluate factors contributing to LOS.

RESULTS

Compared to the untreated individuals (n=67), hyperglycaemia treatment (n=95) was associated with a longer LOS (median eight vs. four days, p<0.01), higher HbA1c (9.0 vs. 7.3 per cent, p<0.01), more infections (50 vs. 25 per cent, p<0.01), and more patients with follow-up plans (35 vs. 10 per cent, p<0.01). Higher HbA1c was significantly related to more follow-up (ρs=0.30, n=110, p<0.01) with a trend to lower re-admission in those with follow-up plans (ρs=-1.41, n=162, p=0.07).

CONCLUSION

Recognition and treatment of admission hyperglycaemia in diabetic patients was associated with longer LOS than if untreated. Contributory factors to LOS include: illness severity, infections, and higher HbA1c. Although follow-up plans were few (27 per cent) for diabetic patients with hyperglycaemia, it was significantly more likely in those with higher HbA1c. Diabetic patients' complexities require timely multidisciplinary team involvement. Improved follow-up care, particularly for hospitalised diabetic patients identified to have chronically poor glycaemic control, may help prevent future diabetic patient re-admissions.

Association of time in blood glucose range with outcomes following cardiac surgery

Background

The importance of optimal postoperative glycemic control in cardiac patients remains unclear. Various glycemic targets have been prescribed to reduce wound infection and overall mortality rates.

Aim of the work: To assess glucose control, as determined by time in range (TIR), in patients with glycemic targets of 6.0 to 8.1 mmol/L, and to determine factors related to poor control.

Methods

This prospective descriptive study evaluated 227 consecutive patients, 100 with and 127 without diabetes, after cardiac surgery. Patients received insulin to target glucose concentrations of 6.0 to 8.1 mmol/L. Data analyzed included patient age, gender, race, Euro score, cardiopulmonary bypass time (CPB), aortic cross clamp time (ACC), length of ventilation, stay in the intensive care unit (ICU) and stay in the hospital. Patients were divided into two groups, those who maintained > 80% and < 80% TIR. Outcome variables were compared in diabetics and non-diabetics.

Results

Patients with >80% and <80% TIR were matched in age, sex, gender, and Euro score. Failure to maintain target glycemia was significantly more frequent in diabetics (p = 0.001), in patients with glycated hemoglobin (HbA1c) > 8% (p = 0.0001), and in patients taking dopamine (p = 0.04) and adrenaline (p = 0.05). Times of CPB and ACC, length of stay in the ICU and ventilation were significantly higher in patients with TIR <80% than >80%. Rates of hypoglycemia, acute kidney injury, and in-hospital mortality were similar in the two groups, although the incidence of wound infection was higher in patients with TIR <80%. Both diabetics and non-diabetics with low TIR had poorer outcomes, as shown by length of stay and POAF. No significant differences were found between the two ethnic groups (Arabs and Asians).

Conclusion

Patients with >80% TIR, whether or not diabetics, had better outcomes than those with <80% TIR, as determined by wound infection, lengths of ventilation and ICU stay. Additionally, they were not subject to frequent hypoglycemic events. Preoperatively high HbA1C is likely a good predictor of poor glycemic control.