Diabetes Is Associated With Reduced Stress Hyperlactatemia in Cardiac Surgery

Association between intraoperative hyperglycemia/hyperlactatemia and acute kidney injury following on-pump cardiac surgery: a retrospective cohort study

Background

Despite the long-lasting notion about the substantial contribution of intraoperative un-stabilization of homeostasis factors on the incidence on acute kidney injury (AKI), the possible influence of intraoperative glucose or lactate management, as a modifiable factor, on the development of AKI remains inconclusive.

Objectives

To investigated the relationship between intraoperative hyperglycemia, hyperlactatemia, and postoperative AKI in cardiac surgery.

Methods

A retrospective cohort study was conducted among 4,435 adult patients who underwent on-pump cardiac surgery from July 2019 to March 2022. Intraoperative hyperglycemia and hyperlactatemia were defined as blood glucose levels >10 mmol/L and lactate levels >2 mmol/L, respectively. The primary outcome was the incidence of AKI. All statistical analyses, including t tests, Wilcoxon rank sum tests, chi-square tests, Fisher's exact test, Kolmogorov-Smirnov test, logistic regression models, subgroup analyses, collinearity analysis, and receiver operating characteristic analysis, were performed using the statistical software program R version 4.1.1.

Results

Among the 4,435 patients in the final analysis, a total of 734 (16.55%) patients developed AKI after on-pump cardiac surgery. All studied intraoperative metabolic disorders was associated with increased AKI risk, with most pronounced odds ratio (OR) noted for both hyperglycemia and hyperlactatemia were present intraoperatively [adjusted OR 3.69, 95% confidence intervals (CI) 2.68-5.13, p < 0.001]. Even when hyperglycemia or hyperlactatemia was present alone, the risk of postoperative AKI remained elevated (adjusted OR 1.97, 95% CI 1.50-2.60, p < 0.001).

Conclusion

The presence of intraoperative hyperglycemia and hyperlactatemia may be associated with postoperative acute kidney injury (AKI) in patients undergoing on-pump cardiac surgery. Proper and timely interventions for these metabolic disorders are crucially important in mitigating the risk of AKI.

Biochemical Changes in Cardiopulmonary Bypass in Cardiac Surgery: New Insights

Patients undergoing coronary revascularization with extracorporeal circulation or cardiopulmonary bypass (CPB) may develop several biochemical changes in the microcirculation that lead to a systemic inflammatory response. Surgical incision, post-CPB reperfusion injury and blood contact with non-endothelial membranes can activate inflammatory signaling pathways that lead to the production and activation of inflammatory cells, with cytokine production and oxidative stress. This inflammatory storm can cause damage to vital organs, especially the heart, and thus lead to complications in the postoperative period. In addition to the organic pathophysiology during and after the period of exposure to extracorporeal circulation, this review addresses new perspectives for intraoperative treatment and management that may lead to a reduction in this inflammatory storm and thereby improve the prognosis and possibly reduce the mortality of these patients.

Impact of the time-weighted average glucose concentration and diabetes on in-hospital mortality in critically ill patients older than 75 years : a retrospective cohort study

OBJECTIVE

To evaluate the effects of diabetes and hyperglycemia on in-hospital mortality in critically ill patients older than 75 years.

METHODS

This was a single-center retrospective cohort study of patients older than 75 years in the first intensive care unit stay. The patients were divided into four groups: time-weighted average glucose (TWAG) < 140 mg/dL without diabetes (group 1); TWAG ≥ 140 mg/dL without diabetes (group 2); TWAG < 180 mg/dL with diabetes (group 3); TWAG ≥ 180 mg/dL with diabetes (group 4). Clinical and laboratory data were analyzed.

RESULTS

A total of 6760 patients over 75 years of age were included, including 2089 patients previously diagnosed with diabetes. The patients in group 2 had the highest in-hospital mortality (27.4%). In the fully adjusted regression model, the risk of in-hospital mortality increased by 76% (OR = 1.76, 95% CI: 1.49-2.08) in group 2 as compared with group 1. Those from groups 3 and 4 exhibited risks equivalent to the risks of those in group 1; similar results were observed in the subgroup analysis. A J-shaped curve relationship and threshold effect were observed in patients without diabetes. For those with diabetes, a flatter curve pattern with a small slope was observed.

CONCLUSION

Stress hyperglycemia was more detrimental to short-term prognosis than diabetes status in these patients. Looser glucose control may be suitable for patients older than 75 years with diabetes but unnecessary for those without diabetes. Patients with diabetes may be more resistant to the detrimental effects of glucose variations.

Does the Same Hyperlactatemia Cut-Off in the Context of Acute Diseases Hold the Same Meaning in Diabetes Mellitus?

Background

Hyperlactatemia is defined by a lactate concentration of >2 mmol/L, and a lactate concentration of above >4 mmol/L is commonly used to define severe hyperlactatemia. It is a common disorder in critically ill patients and is associated with adverse prognosis. Diabetes mellitus(DM) can also be associated with increased lactate levels at baseline. In this study, we aimed to document the development of severe hyperlactatemia in acute situations among patients with and without DM, to analyze potential contributors to lactate elevation and their impact on mortality, and to analyze whether lactate concentrations of >4 mmol/L have equal prognostic significance in patients with and without DM.

Methodology

A retrospective, cross-sectional study was performed among patients admitted to our internal medicine wards in the context of acute disease with lactate concentrations of ​​≥2 mmol/L. Data were collected regarding age, sex, highest lactate concentrations, cause of hyperlactatemia, DM, and mortality. Statistical analysis was performed using SPSS version 23.

Results

In total, 151 patients with lactate levels of ≥2 mmol/L were analyzed. The mean age of the patients was 78.2 ± 14.9 years, and 55% of the patients were female. Overall, 55.6% of the patients had DM, as well as higher lactatemia of 6.3 ± 3.4 mmol/L (vs 5.1 ± 3.2 in non-DM patients, p = 0.003), with the majority reaching values of >4 mmol/L (vs 34.8% in non-DM patients). When potential contributors to the development of severe hyperlactatemia (lactate >4 mmol/L) were analyzed in DM patients, metformin consumption concomitantly with factors potentiating its accumulation, sepsis/septic shock, ischemia, and neoplasia were the most frequently identified contributors. In non-DM patients, the three former factors were also the most frequently reported. The 30-day mortality rate was 25.82%, with deceased patients also displaying a higher lactatemia of 6.5 ± 3.2 mmol/L (vs. 5.5 ± 3.3 mmol/L in patients who survived) (p = 0.037). In multivariate analysis, lactate values of >4 mmol/L were an independent predictor of mortality in the entire sample and in the subgroup without DM, but not in DM patients.

Conclusions

In our sample, patients with DM had higher lactate levels than non-DM patients. Our analysis raises the possibility that the same lactate values may not have equal capacity to assess prognosis in acute situations in patients with and without DM. Large-scale studies are needed to optimize cut-off points for lactatemia in patients with high baseline values, such as DM patients.

The relationship between admission glucose and lactate with critical illness amongst adult patients presenting to the emergency department

AIM

Our aim was to determine the relationship between glucose and lactate amongst adult patients admitted to hospital via the emergency department.

METHOD

We performed a cross-sectional observational study of 2541 patients admitted via the emergency department who had an admission glucose and lactate measurement available.

RESULTS

23% of the whole cohort had a diagnosis of diabetes. Glucose and lactate were predictors of the primary outcome of critical illness defined as composite of intensive care unit (ICU) admission or in-hospital death. In the multivariable analysis, lactate but not glucose remained an independent predictor of ICU/in hospital death in the group without diabetes. In the diabetes group, both glucose and lactate remained independent predictors of ICU admission/ in-hospital death.

CONCLUSIONS

Hyperglycaemia and hyperlactataemia are part of the metabolic response to critical illness. Lactate and a diagnosis of diabetes modify the relationship between glycaemia and critical illness.

Biomarker monitoring and long-acting insulin treatment in a stress model to facilitate personalized diabetic control

Diabetes is a chronic disease involving elevated blood glucose levels. Controlled insulin delivery is an ideal method to achieve glycemic control. However, glucose levels vary as a result of changes in the body's physiological conditions resulting from different daily events, such as meals, exercise and stress. It is essential to develop and to monitor appropriate biomarkers for these natural physiological perturbations in order to achieve a holistic understanding of metabolic changes in diabetic patients to facilitate optimal glucose management and make possible personalized medicine for this very debilitating disease. The novel aspects of the current research include the combination of the tail suspension stress animal model and microdialysis for stress biomarker monitoring. A tail suspension test was optimized and used as a stress inducer for different groups of model rats (normal, untreated diabetic and insulin-treated diabetic rats). The levels of multiple metabolic analytes in the subcutaneous tissue were monitored continuously using subcutaneous microdialysis analysis. Different analytes, including pH, glucose and lactate were monitored and analyzed. Another important and original aspect of the reported work is that revelation that the pH, lactate and glucose levels increased under the stress conditions and the changes tended to be more pronounced in diabetic rats (both untreated and long-acting insulin-treated) compared to normal rats. Long-acting insulin treatment was shown to shorten the duration of the pH and glucose changes in response to stress when compared to the untreated diabetic rats. An additional novel aspect of the research is that subcutaneous pH was shown to be a sensitive stress biomarker for diabetic rats as pH changes rapidly after stress initiation. This research provides insight into the importance of accurate glycemic control and diabetes management for individual patients through highlighting stress management and appropriate biomarker monitoring, especially the value of combining pH and lactate monitoring with typical glucose monitoring. This research will pave the way for individualized medicine for diabetic patients through helping to obtain a holistic understanding of the various important biomarkers, rather than solely depending on glucose monitoring to determine appropriate insulin dosing.

The prognostic value of peak arterial lactate levels within 72 h of lung transplantation in identifying patient outcome

Background

Lactic acidosis is often seen in lung transplantation (LTx). Postoperative lactate is frequently associated with poor outcome in postoperative and critically ill patients. Our aim was to evaluate the predictive value of postoperative peak lactate levels within 72 h of LTx for 30-day and late mortality.

Methods

We evaluated patients who underwent LTx from January 2015 to September 2017. All admitted patients were classified according to the peak lactate level (PL) within 72 h of surgery: PL <5 mmol/L (Group 1); PL =5–10 mmol/L (Group 2), and PL >10 mmol/L (Group 3). We performed logistic regression analysis and used Cox regression models to identify the peak lactate level as a predictive factor for 30-day and late mortality, respectively.

Results

Of 255 eligible patients, mean age 55.61±12.16, mean lactate 4.99±2.93 and 80% male, and 40% had hyperlactatemia (PL >5 mmol/L) after LTx. The 30-day mortality rate was 17.9%, 28.9% and 68.8% in the three groups, respectively (P<0.05). Multivariate regression analyses revealed postoperative PL as a notable predictor of 30-day mortality [odds ratio =2.62 (1.42–4.84), P=0.002] as well as for late mortality [hazard ratio =2.70 (1.13–6.42), P=0.025].

Conclusions

The postoperative peak lactate level within 72 h of surgery was an independent predictor for 30-day and late mortality in LTx patients.

The effect of hyperlactatemia timing on the outcomes after cardiac surgery

Background

Several studies linked postoperative hyperlactatemia to worse outcomes in adult patients undergoing cardiac surgery. However, data on the effect of timing of hyperlactatemia on outcomes are scarce. We sought to determine the prevalence of early hyperlactatemia (EHL) and its impact on clinical outcomes compared to late hyperlactatemia (LHL) in patients undergoing ACS procedures.

Results

We included 305 consecutive adult patients who underwent cardiac surgery procedures between July 2017 and Nov 2019 at a single institution. Lactate level was measured in the first 10 h after surgery and EHL was defined as lactate level > 3 mmol/L in the first hour after surgery. Logistic regression analysis was performed to determine predictors of EHL. Seventeen percent (n = 52) had EH while 83% (n = 253) did not. Patients with EHL had significantly longer cardiopulmonary bypass (P = 0.001) and cross-clamp (P = 0.001) times due to increased surgical complexity in this group. Early hyperlactatemia was associated with increased post-operative extracorporeal membrane oxygenation (ECMO) support (0% vs 5.7%, P < 0.001), longer intensive care unit stay (P = 0.004), and increased hospital mortality (0% vs. 3.8%, P = 0.009). Cardiopulmonary bypass time (OR 1.001; 95% CI 1.011–1.012, P = 0.02) and glucose level (OR 1.2; 95% CI 1.1–1.3, P = 0.003) were independently associated with increased rate of EHL. In contrast, diabetes mellitus (OR 0.26; 95% CI 0.12–0.55, P < 0.001) significantly attenuated the rate of EHL.

Conclusions

Early hyperlactatemia after cardiac surgery was associated with increased morbidity and mortality. Late hyperlactatemia was very common and had a self-limiting and benign course.

Prognostic impact of elevated lactate levels on mortality in critically ill patients with and without preadmission metformin treatment: a Danish registry-based cohort study

BACKGROUND

Lactate is a robust prognostic marker for the outcome of critically ill patients. Several small studies reported that metformin users have higher lactate levels at ICU admission without a concomitant increase in mortality. However, this has not been investigated in a larger cohort. We aimed to determine whether the association between lactate levels around ICU admission and mortality is different in metformin users compared to metformin nonusers.

METHODS

This cohort study included patients admitted to ICUs in northern Denmark between January 2010 and August 2017 with any circulating lactate measured around ICU admission, which was defined as 12 h before until 6 h after admission. The association between the mean of the lactate levels measured during this period and 30-day mortality was determined for metformin users and nonusers by modelling restricted cubic splines obtained from a Cox regression model.

RESULTS

Of 37,293 included patients, 3183 (9%) used metformin. The median (interquartile range) lactate level was 1.8 (1.2-3.2) in metformin users and 1.6 (1.0-2.7) mmol/L in metformin nonusers. Lactate levels were strongly associated with mortality for both metformin users and nonusers. However, the association of lactate with mortality was different for metformin users, with a lower mortality rate in metformin users than in nonusers when admitted with similar lactate levels. This was observed over the whole range of lactate levels, and consequently, the relation of lactate with mortality was shifted rightwards for metformin users.

CONCLUSION

In this large observational cohort of critically ill patients, early lactate levels were strongly associated with mortality. Irrespective of the degree of hyperlactataemia, similar lactate levels were associated with a lower mortality rate in metformin users compared with metformin nonusers. Therefore, lactate levels around ICU admission should be interpreted according to metformin use.