Impact of intraoperative hyperglycaemia on renal dysfunction after off-pump coronary artery bypass

Cardiac Surgery-Associated Acute Kidney Injury

AKI is a common and serious complication of cardiac surgery that has a significant impact on patient morbidity and mortality. The Kidney Disease Improving Global Outcomes definition of AKI is widely used to classify and identify AKI associated with cardiac surgery (cardiac surgery-associated AKI [CSA-AKI]) on the basis of changes in serum creatinine and/or urine output. There are various preoperative, intraoperative, and postoperative risk factors for the development of CSA-AKI which should be recognized and addressed as early as possible to expedite its diagnosis, reduce its occurrence, and prevent or ameliorate its devastating complications. Crucial issues are the inaccuracy of serum creatinine as a surrogate parameter of kidney function in the perioperative setting of cardiothoracic surgery and the necessity to discover more representative markers of the pathophysiology of AKI. However, except for the tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 ratio, other diagnostic biomarkers with an acceptable sensitivity and specificity are still lacking. This article provides a comprehensive review of various aspects of CSA-AKI, including pathogenesis, risk factors, diagnosis, biomarkers, classification, prevention, and treatment management.

The prognosis of patients with postoperative hyperglycemia after Stanford type A aortic dissection surgery and construction of prediction model for postoperative hyperglycemia

Objective

The mortality of type A aortic dissection (TAAD) is extremely high. The effect of postoperative hyperglycemia (PHG) on the prognosis of TAAD surgery is unclear. This study aims to investigate the prognosis of patients with PHG after TAAD surgery and construct prediction model for PHG.

Methods

Patients underwent TAAD surgery from January 2016 to December 2020 in Xiangya Hospital were collected. A total of 203 patients were included and patients were divided into non PHG group and PHG group. The occurrence of postoperative delirium, cardiac complications, spinal cord complication, cerebral complications, acute kidney injury (AKI), hepatic dysfunction, hypoxemia, and in-hospital mortality were compared between two groups. Data from MIMIC-IV database were further applied to validate the relationship between PHG and clinical outcomes. The prediction model for PHG was then constructed using Extreme Gradient Boosting (XGBoost) analysis. The predictive value of selected features was further validated using patient data from MIMIC-IV database. Finally, the 28-days survival rate of patient with PHG was analyzed using data from MIMIC-IV database.

Results

There were 86 patients developed PHG. The incidences of postoperative AKI, hepatic dysfunction, and in-hospital mortality were significant higher in PHG group. The ventilation time after surgery was significant longer in PHG group. Data from MIMIC-IV database validated these results. Neutrophil, platelet, lactic acid, weight, and lymphocyte were selected as features for prediction model. The values of AUC in training and testing set were 0.8697 and 0.8286 respectively. Then, five features were applied to construct another prediction model using data from MIMIC-IV database and the value of AUC in the new model was 0.8185. Finally, 28-days survival rate of patients with PHG was significantly lower and PHG was an independent risk factor for 28-days mortality after TAAD surgery.

Conclusion

PHG was significantly associated with the occurrence of AKI, hepatic dysfunction, increased ventilation time, and in-hospital mortality after TAAD surgery. The feature combination of neutrophil, platelet, lactic acid, weight, and lymphocyte could effectively predict PHG. The 28-days survival rate of patients with PHG was significantly lower. Moreover, PHG was an independent risk factor for 28-days mortality after TAAD surgery.

Strategies for post–cardiac surgery acute kidney injury prevention: A network meta-analysis of randomized controlled trials

Objects

Cardiac surgery is associated with acute kidney injury (AKI). However, the effects of various pharmacological and non-pharmacological strategies for AKI prevention have not been thoroughly investigated, and their effectiveness in preventing AKI-related adverse outcomes has not been systematically evaluated.

Methods

Studies from PubMed, Embase, and Medline and registered trials from published through December 2021 that evaluated strategies for preventing post–cardiac surgery AKI were identified. The effectiveness of these strategies was assessed through a network meta-analysis (NMA). The secondary outcomes were prevention of dialysis-requiring AKI, mortality, intensive care unit (ICU) length of stay (LOS), and hospital LOS. The interventions were ranked using the P-score method. Confidence in the results of the NMA was assessed using the Confidence in NMA (CINeMA) framework.

Results

A total of 161 trials (involving 46,619 participants) and 53 strategies were identified. Eight pharmacological strategies {natriuretic peptides [odds ratio (OR): 0.30, 95% confidence interval (CI): 0.19–0.47], nitroprusside [OR: 0.29, 95% CI: 0.12–0.68], fenoldopam [OR: 0.36, 95% CI: 0.17–0.76], tolvaptan [OR: 0.35, 95% CI: 0.14–0.90], N-acetyl cysteine with carvedilol [OR: 0.37, 95% CI: 0.16–0.85], dexmedetomidine [OR: 0.49, 95% CI: 0.32–0.76;], levosimendan [OR: 0.56, 95% CI: 0.37–0.84], and erythropoietin [OR: 0.62, 95% CI: 0.41–0.94]} and one non-pharmacological intervention (remote ischemic preconditioning, OR: 0.76, 95% CI: 0.63–0.92) were associated with a lower incidence of post–cardiac surgery AKI with moderate to low confidence. Among these nine strategies, five (fenoldopam, erythropoietin, natriuretic peptides, levosimendan, and remote ischemic preconditioning) were associated with a shorter ICU LOS, and two (natriuretic peptides [OR: 0.30, 95% CI: 0.15–0.60] and levosimendan [OR: 0.68, 95% CI: 0.49–0.95]) were associated with a lower incidence of dialysis-requiring AKI. Natriuretic peptides were also associated with a lower risk of mortality (OR: 0.50, 95% CI: 0.29–0.86). The results of a sensitivity analysis support the robustness and effectiveness of natriuretic peptides and dexmedetomidine.

Conclusion

Nine potentially effective strategies were identified. Natriuretic peptide therapy was the most effective pharmacological strategy, and remote ischemic preconditioning was the only effective non-pharmacological strategy. Preventive strategies might also help prevent AKI-related adverse outcomes. Additional studies are required to explore the optimal dosages and protocols for potentially effective AKI prevention strategies.

The effect of dexmedetomidine on intraoperative blood glucose homeostasis: secondary analysis of a randomized controlled trial

Purpose

To investigate the effect of dexmedetomidine on intraoperative blood glucose hemostasis in elderly patients undergoing non-cardiac major surgery.

Methods

This was secondary analysis of a randomized controlled trial. Patients in dexmedetomidine group received a loading dose dexmedetomidine (0.6 μg/kg in 10 min before anaesthesia induction) followed by a continuous infusion (0.5 μg/kg/hr) till 1 h before the end of surgery. Patients in control group received volume-matched normal saline at the same time interval. Primary outcome was the incidence of intraoperative hyperglycemia (blood glucose higher than 10 mmol/L).

Results

303 patients in dexmedetomidine group and 306 patients in control group were analysed. The incidence of intraoperative hyperglycemia showed no statistical significance between dexmedetomidine group and control group (27.4% vs. 22.5%, RR = 1.22, 95%CI 0.92–1.60, P = 0.167). Median value of glycemic variation in dexmedetomidine group (2.5, IQR 1.4–3.7, mmol) was slightly lower than that in control group (2.6, IQR 1.5–4.0, mmol), P = 0.034. In multivariable logistic analysis, history of diabetes (OR 3.007, 95%CI 1.826–4.950, P < 0.001), higher baseline blood glucose (OR 1.353, 95%CI 1.174–1.560, P < 0.001) and prolonged surgery time (OR 1.197, 95%CI 1.083–1.324, P < 0.001) were independent risk factors of hyperglycaemia.

Conclusions

Dexmedetomidine presented no effect on intraoperative hyperglycemia in elderly patients undergoing major non-cardiac surgery.

Trial registration

Present study was registered at Chinese Clinical Trial Registry on December 1, 2015 (www.chictr.org.cn, registration number ChiCTR-IPR-15007654).

The association between intraoperative hyperglycemia and cerebrovascular markers

BACKGROUND AND PURPOSE: Hyperglycemia can lead to an increased rate of apoptosis of microglial cells and to damaged neurons. The relation between hyperglycemia and cerebrovascular markers on MRI is unknown. Our aim was to study the association between intraoperative hyperglycemia and cerebrovascular markers. METHODS: In this further analysis of a subgroup investigation of the BIOCOG study, 65 older non-demented patients (median 72 years) were studied who underwent elective surgery of ≥ 60 minutes. Intraoperative blood glucose maximum was determined retrospectively in each patient. In these patients, preoperatively and at 3 months follow-up a MRI scan was performed and white matter hyperintensity (WMH) volume and shape, infarcts, and perfusion parameters were determined. Multivariable logistic regression analyses were performed to determine associations between preoperative cerebrovascular markers and occurrence of intraoperative hyperglycemia. Linear regression analyses were performed to assess the relation between intraoperative hyperglycemia and pre- to postoperative changes in WMH volume. Associations between intraoperative hyperglycemia and postoperative WMH volume at 3 months follow-up were also assessed by linear regression analyses. RESULTS: Eighteen patients showed intraoperative hyperglycemia (glucose maximum ≥ 150 mg/dL). A preoperative more smooth shape of periventricular and confluent WMH was related to the occurrence of intraoperative hyperglycemia [convexity: OR 33.318 (95 % CI (1.002 - 1107.950); p = 0.050]. Other preoperative cerebrovascular markers were not related to the occurrence of intraoperative hyperglycemia. Intraoperative hyperglycemia showed no relation with pre- to postoperative changes in WMH volume nor with postoperative WMH volume at 3 months follow-up. CONCLUSIONS: We found that a preoperative more smooth shape of periventricular and confluent WMH was related to the occurrence of intraoperative hyperglycemia. These findings may suggest that a similar underlying mechanism leads to a certain pattern of vascular brain abnormalities and an increased risk of hyperglycemia.

Intraoperative hyperglycemia in patients with an elevated preoperative C-reactive protein level may increase the risk of acute kidney injury after cardiac surgery

PURPOSE

The effect of hyperglycemia on acute kidney injury (AKI) in patients undergoing cardiac surgery is unclear and may involve as yet unexplored factors. We hypothesized differential effects of intraoperative hyperglycemia on AKI after cardiac surgery depending on baseline inflammatory status, as reflected by the C-reactive protein (CRP) level.

METHODS

This retrospective study included patients who underwent cardiac surgery seen at our hospital from 2008 to 2018. Patients were classified into four groups according to their preoperative CRP level (≥ 1 or < 1 mg/dl) and their intraoperative time-weighted average glucose concentration (> 140 or ≤ 140 mg/dl): low CRP and normoglycemia, low CRP and hyperglycemia, high CRP and normoglycemia, and high CRP and hyperglycemia. The data were analyzed by multivariable logistic regression analysis.

RESULTS

The data of 3625 patients were analyzed. The logistic regression showed that patients in the high CRP and hyperglycemia group had a significantly higher risk of AKI than patients in the low CRP and normoglycemia group [odds ratio (OR), 1.58; 95% confidence interval (CI) 1.10-2.27], low CRP with hyperglycemia group (OR, 1.69; 95% CI 1.16-2.47) and high CRP with normoglycemia group (OR, 1.50; 95% CI 1.01-2.23).

CONCLUSIONS

Intraoperative hyperglycemia in patients with an elevated preoperative CRP level was significantly related to an increased risk of AKI after cardiac surgery. Individualized perioperative glycemic control may therefore be necessary in these patients.

Acute kidney injury in solitary kidney patients after partial nephrectomy: incidence, risk factors and prediction

Background

To analyze the incidence and risk factors of acute kidney injury (AKI) after partial nephrectomy (PN) in patients with solitary kidney, and to build AKI prediction models using logistic regression and machine learning (ML) approaches.

Methods

Clinical data of 87 solitary kidney patients with renal mass who received PN from January 2003 to March 2019 were collected. The diagnosis of AKI was based on KDIGO criteria. Logistic regression analysis and ML method were used to build prediction models.

Results

AKI developed in 52 (59.8%) patients. The logistic regression model had three variables: ischemia time (P=0.003), surgery time (P=0.001) and preoperative fasted blood glucose level (FBG) (P=0.049). The area under curve (AUC) was 0.826, with the specificity and sensitivity of optimal threshold value 82.9% and 69.2%. The ML model had the following variables: ischemia time, surgery time, age, FBG, mean arterial pressure (MAP), colloid, crystalloid, etc. XGBoost model has the best prediction performance. The AUC was 0.749, lower than that of the logistic regression model with no statistical difference (P=0.258), with the specificity and sensitivity 62.9% and 84.6%, respectively.

Conclusions

The incidence of AKI after PN in patients with a solitary kidney was relatively high, it was associated with longer ischemia time, surgery time and higher FBG level, etc. The performance of ML model had no significant difference with logistic regression model. Prospective studies with larger sample sizes are awaited to test and verify our research findings.

Acute Kidney Injury Associated with Cardiac Surgery: a Comprehensive Literature Review

Objective

To comprehensively understand cardiac surgeryassociated acute kidney injury (CSA-AKI) and methods of prevention of such complication in cardiac surgery patients.

Methods

A comprehensive literature search was performed using the electronic database to identify articles describing acute kidney injury (AKI) in patients that undergone cardiac surgery. There was neither time limit nor language limit on the search. The results were narratively summarized.

Results

All the relevant articles have been extracted; results have been summarized in each related section. CSA-AKI is a serious postoperative complication and it can contribute to a significant increase in perioperative morbidity and mortality rates. Optimization of factors that can reduce CSA-AKI, therefore, contributes to a better postoperative outcome.

Conclusion

Several factors can significantly increase the rate of AKI; identification and minimization of such factors can lead to lower rates of CSA-AKI and lower perioperative morbidity and mortality rates.

Impacto do controle glicêmico intensivo na lesão renal aguda: ensaio clínico randomizado

Resumo Objetivo Avaliar o impacto do controle glicêmico intensivo na redução da incidência de lesão renal aguda em pacientes adultos submetidos à cirurgia cardíaca. Métodos Ensaio clínico randomizado que avaliou 95 pacientes submetidos a duas estratégias de controle glicêmico. Os pacientes foram randomizados para o grupo intervenção (GI), com a meta de manutenção da glicemia pós-operatória entre 90 e 110 mg/dl. Nos pacientes alocados no grupo convencional (GC) o objetivo era a manutenção da glicemia entre 140 e 180 mg/dl. O ajuste da dose de insulina foi baseado em medições de glicose no sangue arterial não diluído, em intervalos de uma hora por meio de um sistema de monitoramento de glicose e beta-cetona no sangue. Resultados A incidência de LRA foi de 53,7% (KDIGO estágios 1, 2 ou 3). Não houve diferença significante entre os grupos quanto ao desfecho primário (p=0,294). Entretanto, observou-se maior frequência de recuperação da função renal (p=0,010), na alta da UTI (p=0,028) e alta hospitalar (p=0,048) entre os pacientes submetidos ao controle glicêmico convencional. A utilização do controle glicêmico intensivo esteve associada com maior tempo de permanência na UTI (p=0,031). O número de episódios de hipoglicemia foi semelhante nos dois grupos (1,6 ± 0,9 vs. 1,3 ± 0,6, p=0,731), demonstrando a segurança das estratégias utilizadas. Conclusão Não se observou o impacto do controle glicêmico intensivo na redução da incidência de lesão renal aguda. Em contrapartida, os pacientes tratados no GC apresentaram maior frequência de recuperação da função renal.

Acute kidney injury after cardiac surgery: prevalence, impact and management challenges

Acute kidney injury (AKI) is a major medical problem that is of particular concern after cardiac surgery. Perioperative AKI is independently associated with an increase in short-term morbidity, costs of treatment, and long-term mortality. In this review, we explore the definition of cardiac surgery-associated acute kidney injury (CSA-AKI) and identify diverse mechanisms and risk factors contributing to the renal insult. Current theories of the pathophysiology of CSA-AKI and description of its clinical course will be addressed in this review. Data on the most promising renal protective strategies in cardiac surgery, from well-designed studies, will be scrutinized. Furthermore, diagnostic tools such as novel biomarkers of AKI and their potential utility will be discussed.

Practice Guidelines for Enteral Nutrition Management in Dysglycemic Critically Ill Patients: A Relook for Indian Scenario

Background and aim

Intensive-care practices and settings differ for India in comparison to other countries. While guidelines are available to direct the use of enteral nutrition (EN), there are no recommendations specific to nutritional management of EN in dysglycemic patients, specific to patients in Indian critical care settings. Advisory board meetings were arranged to develop the practice guidelines specific to the Indian context, for the use of EN in dysglycemic critically ill patients and to overcome challenges in this field.

Materials and methods

Two advisory board meetings were organized to review various existing guidelines, meta-analyses, randomized controlled trials (RCTs), controlled trials and review articles, for their contextual relevance and strength. Three rounds of Delphi voting were done to arrive at consensus on certain recommendations. A systematic grading of practice guidelines by the advisory board was done based on strength of the consensus voting and reviewed supporting evidences.

Results

Based on the literature review, the recommendations for developing the practice guidelines were made as per the grading criteria agreed upon by the advisory board. The recommendations were to address challenges regarding prediction and assessment of dysglycemia (DG), acceptable glycemic targets in such settings, general nutritional aspects pertaining to DG nutrition, and nutrition in various superspecialty cases in critical care settings, where DG is commonly encountered.

Conclusion

This paper summarizes the optimum EN practices for managing DG in critically ill patients. The practical solutions to overcome the challenges in this field are presented as practice guidelines at the end of each section. These guidelines are expected to provide guidance for EN management in dysglycemic critically ill patients. These guidelines also outline the model glycemic control task force and its roles in nutrition care as well as an intensive care unit DG nutrition protocol.

How to cite this article

Mehta Y, Mithal A, Kulkarni A, Reddy BR, Sharma J, Dixit S, et al. Practice Guidelines for Enteral Nutrition Management in Dysglycemic Critically Ill Patients: A Relook for Indian Scenario. Indian J Crit Care Med 2019;23(12):594–603.

Risk Factors of Intraoperative Dysglycemia in Elderly Surgical Patients

BACKGROUNDː Dysglycemia is associated with adverse outcome including increased morbidity and mortality in surgical patients. Acute insulin resistance due to the surgical stress response is seen as a major cause of so-called stress hyperglycemia. However, understanding of factors determining blood glucose (BG) during surgery is limited. Therefore, we investigated risk factors contributing to intraoperative dysglycemia. METHODSː In this subgroup investigation of the BIOCOG study, we analyzed 87 patients of ≥ 65 years with tight intraoperative BG measurement every 20 min during elective surgery. Dysglycemia was defined as at least one intraoperative BG measurement outside the recommended target range of 80-150 mg/dL. Additionally, all postoperative BG measurements in the ICU were obtained. Multivariable logistic regression analysis adjusted for age, sex, American Society of Anesthesiologists (ASA) status, diabetes, type and duration of surgery, minimum Hemoglobin (Hb) and mean intraoperative norepinephrine use was performed to identify risk factors of intraoperative dysglycemia. RESULTSː 46 (52.9%) out of 87 patients developed intraoperative dysglycemia. 31.8% of all intraoperative BG measurements were detected outside the target range. Diabetes [OR 9.263 (95% CI 2.492, 34.433); p=0.001] and duration of surgery [OR 1.005 (1.000, 1.010); p=0.036] were independently associated with the development of intraoperative dysglycemia. Patients who experienced intraoperative dysglycemia had significantly elevated postoperative mean (p<0.001) and maximum BG levels (p=0.001). Length of ICU (p=0.007) as well as hospital stay (p=0.012) were longer in patients with dysglycemia. CONCLUSIONSː Diabetes and duration of surgery were confirmed as independent risk factors for intraoperative dysglycemia, which was associated with adverse outcome. These patients, therefore, might require intensified glycemic control. Increased awareness and management of intraoperative dysglycemia is warranted.

Wider intraoperative glycemic fluctuation increases risk of acute kidney injury after pediatric cardiac surgery

OBJECTIVE

The association between poor intraoperative glycemic control and postoperative acute kidney injury (AKI) in adult cardiac surgery has been observed, but data in the pediatrics remain unknown. We performed a hypothesis that intraoperative hyperglycemia and/or wider glycemic fluctuation were associated with the incidence of postoperative AKI in pediatric cardiac surgery.

METHODS

A retrospective study was performed in pediatrics who underwent cardiac surgery from 2013 to 2016. Perioperative glycemic data up to 48 hours after surgery were collected and analyzed. Patients with AKI were matched 1:1 with patients without AKI by a propensity score. Variables of demographic data, preoperative renal function and glycemic level, perioperative cardiac condition were matched.

RESULTS

The incidence of AKI was 11.5% (118/1026), with 53.4% (63/118), 30.5% (36/118), and 16.1% (19/118) categorized as AKIN stages I, II, and III, respectively. Children who experienced AKI were younger and cyanotic, underwent more complex surgeries, had higher peak intraoperative glucose levels, wider intraoperative glycemic fluctuation, greater inotropic scores and more transfusions, and poor outcomes (all p < .05). After matching, the AKI group had significantly wider intraoperative glycemic fluctuation (p < .05). Logistic regression showed intraoperative glycemic fluctuation was one of the risk factors for AKI (p = .033) and degree of AKI severity stage increased when the glycemic fluctuation increased (p < .01).

CONCLUSIONS

Wider intraoperative glycemic fluctuation, but not hyperglycemia, was associated with an increased incidence of postoperative AKI after pediatric cardiac surgery.

Evaluation of preoperative oral carbohydrate administration on insulin resistance in off-pump coronary artery bypass patients: A randomised trial

BACKGROUND

In fasting cardiac surgery patients, preoperative carbohydrate (CHO) drink intake attenuated insulin resistance and improved cardiac metabolism, although its beneficial effects were not evident after cardiac surgery possibly due to cardiopulmonary bypass-related extreme systemic inflammation.

OBJECTIVE

We aimed to evaluate whether preoperative CHO intake affected insulin resistance and free-fatty acid (FFA) concentrations in off-pump coronary revascularisation.

DESIGN

A randomised controlled trial.

SETTING

Primary care in a university hospital in Korea from January 2015 to July 2016.

PATIENTS

Sixty patients who underwent elective multi-vessel off-pump coronary revascularisation were randomised into two groups. Three patients were excluded from analysis and 57 patients completed study.

INTERVENTION

The CHO group received oral CHO (400 ml) the prior evening and 2 to 3 h before surgery, and the control group was fasted from food and water according to standard protocol.

MAIN OUTCOME MEASURES

Insulin resistance was assessed twice, after anaesthetic induction and after surgery via short insulin tolerance test. FFA, C-reactive protein and creatine kinase-myocardial band concentrations were determined serially for 48 h after surgery.

RESULTS

Insulin sensitivity was greater (P = 0.002) and plasma FFA concentrations were lower (P = 0.001) after anaesthetic induction in the CHO group compared with the Control group, although there were no intergroup differences after surgery. The postoperative peak creatine kinase-myocardial band concentration was significantly lower in the CHO group compared with the Control group [8.8 (5.4 to 18.2) vs. 6.4 (3.5 to 9.7) ng ml, P = 0.031].

CONCLUSION

A preoperative CHO supplement significantly reduced insulin resistance and FFA concentrations compared with fasting at the beginning of the surgery, but these benefits were lost after off-pump coronary revascularisation. Despite their transient nature, these beneficial effects resulted in less myocardial injury, mandating further studies focused on the impact of preoperative CHO on myocardial ischaemia and cardiac function after coronary revascularisation.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT 02330263.

Association Between Perioperative Hyperglycemia or Glucose Variability and Postoperative Acute Kidney Injury After Liver Transplantation: A Retrospective Observational Study

BACKGROUND

Glucose control can be difficult in the intraoperative and immediate postoperative period of liver transplantation. Hyperglycemia and glucose variability have been associated with acute kidney injury (AKI) in critically ill patients. We performed a retrospective study to test the hypothesis that perioperative glucose levels represented by time-weighted average glucose levels and glucose variability are independently associated with the incidence of postoperative AKI in patients undergoing liver transplantation.

METHODS

On the basis of blood glucose levels during liver transplantation and the initial 48 hours postoperatively, adult liver transplant recipients were classified into 4 groups according to their time-weighted average glucose: normoglycemia (80-200 mg/dL), mild hyperglycemia (200-250 mg/dL), moderate hyperglycemia (250-300 mg/dL), and severe hyperglycemia (>300 mg/dL) group. Patients were also classified into quartiles depending on their glucose variability, defined as the standard deviation of glucose measurements. The primary outcome was postoperative AKI.

RESULTS

AKI after liver transplantation was more common in the patients with greater perioperative glucose variability (first versus third quartile; OR, 2.47 [95%CI, 1.22-5.00], P = .012; first versus fourth quartile; OR, 2.16 [95% CI, 1.05-4.42], P = .035).

CONCLUSIONS

Our study suggests that increased perioperative glucose variability, but not hyperglycemia, is independently associated with increased risk of postoperative AKI in liver transplantation recipients.

Acute Kidney Injury After Pediatric Cardiac Surgery: A Secondary Analysis of the Safe Pediatric Euglycemia After Cardiac Surgery Trial

OBJECTIVES

To understand the effect of tight glycemic control on cardiac surgery-associated acute kidney injury.

DESIGN

Secondary analysis of data from the Safe Pediatric Euglycemia after Cardiac Surgery trial of tight glycemic control versus standard care.

SETTING

Pediatric cardiac ICUs at University of Michigan, C.S. Mott Children's Hospital, and Boston Children's Hospital.

PATIENTS

Children 0-36 months old undergoing congenital cardiac surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cardiac surgery-associated acute kidney injury was assigned using the Acute Kidney Injury Network criteria with the modification that a greater than 0.1 mg/dL increase in serum creatinine was required to assign cardiac surgery-associated acute kidney injury. We explored associations between cardiac surgery-associated acute kidney injury and tight glycemic control and clinical outcomes. Of 799 patients studied, cardiac surgery-associated acute kidney injury occurred in 289 patients (36%), most of whom had stage II or III disease (72%). Cardiac surgery-associated acute kidney injury rates were similar between treatment groups (36% vs 36%; p = 0.99). Multivariable modeling showed that patients with cardiac surgery-associated acute kidney injury were younger (p = 0.002), underwent more complex surgery (p = 0.005), and had longer cardiopulmonary bypass times (p = 0.002). Cardiac surgery-associated acute kidney injury was associated with longer mechanical ventilation and ICU and hospital stays and increased mortality. Patients at University of Michigan had higher rates of cardiac surgery-associated acute kidney injury compared with Boston Children's Hospital patients (66% vs 15%; p < 0.001), but University of Michigan patients with cardiac surgery-associated acute kidney injury had shorter time to extubation and ICU and hospital stays compared with Boston Children's Hospital patients.

CONCLUSIONS

Tight glycemic control did not reduce the cardiac surgery-associated acute kidney injury rate in this trial cohort. We observed significant differences in cardiac surgery-associated acute kidney injury rates between the two study sites, and there was a differential effect of cardiac surgery-associated acute kidney injury on clinical outcomes by site. These findings warrant further investigation to identify causal variation in perioperative practices that affect cardiac surgery-associated acute kidney injury epidemiology.

Procalcitonin cannot be used as a biomarker of infection in heart surgery patients with acute kidney injury

PURPOSE

We intended to assess how acute kidney injuy impacts on procalcitonin levels in cardiac surgery patients, with or without infection, and whether procalcitonin might be used as a biomarker of infection in acute kidney injuy.

MATERIAL AND METHODS

A case-control study was designed which included patients that had had cardiac surgery between January 2011 and January 2015. Every patient developing severe sepsis or septic shock (n = 122; 5.5%) was enrolled. In addition, consecutive cardiac surgery patients during 2013 developing systemic inflammatory response syndrome (n = 318) were enrolled. Those recruited 440 patients were divided into 2 groups, according to renal function.

RESULTS

Median procalcitonin levels were significantly higher during the 10 postoperative days in the acute kidney injury patients. Regression analysis showed that postoperatory day, creatinine, white blood cells and infection were significantly (P < .0001) associated to serum procalcitonin level. In patients with creatinine ≥2, median procalcitonin levels were similar in infected and non-infected patients. Only when creatinine was less than 2 mg/L, the median procalcitonin levels were significantly higher in patients with infection, as compared to those with no infection.

CONCLUSIONS

In acute kidney injuy patients, high procalcitonin levels are a marker of acute kidney injuy but will not be able to differentiate infected from non-infected patients.

Hyperglycemia and Acute Kidney Injury During the Perioperative Period

Hyperglycemia and acute kidney injury (AKI) are frequently observed during the perioperative period. Substantial evidence indicates that hyperglycemia increases the prevalence of AKI as a surgical complication. Patients who develop hyperglycemia and AKI during the perioperative period are at significantly elevated risk for poor outcomes such as major adverse cardiac events and all-cause mortality. Early observational and interventional trials demonstrated that the use of intensive insulin therapy to achieve strict glycemic control resulted in remarkable reductions of AKI in surgical populations. However, more recent interventional trials and meta-analyses have produced contradictory evidence questioning the renal benefits of strict glycemic control. Although the exact mechanisms through which hyperglycemia increases the risk of AKI have not been elucidated, multiple pathophysiologic pathways have been proposed. Hypoglycemia and glycemic variability may also play a significant role in the development of AKI. In this literature review, the complex relationship between hyperglycemia and AKI as well as its impact on clinical outcomes during the perioperative period is explored.

Renal tubular damage may contribute more to acute hyperglycemia induced kidney injury in non-diabetic conscious rats

AIMS

Growing evidences suggest that acute hyperglycemia is strongly related to kidney injury. Our study aimed to investigate the effects of acute hyperglycemia on kidney glomerular and tubular impairment in non-diabetic conscious rats.

METHODS

Non-diabetic conscious rats were randomly subjected to 6h of saline (control group) or high glucose (acute hyperglycemia group) infusion. Blood glucose was maintained at 16.0-18.0 mmol/L in acute hyperglycemia group. Renal structure and function alterations, systemic/renal inflammation and oxidative stress markers were assessed, and apoptosis markers of renal inherent cells were evaluated.

RESULTS

Acute hyperglycemia caused significant injury to structure of glomerular filtration barrier, tubular epithelial cells and peritubular vascular endothelial cells. It increased urinary microalbumin (68.01 ± 27.09 μg/24h vs 33.81 ± 13.81 μg/24h , P=0.014), β2-microglobulin, Cystatin C, urinary and serous neutrophil gelatinase-associated lipocalin levels (P < 0.05). Acute hyperglycemia decreased megalin and cubilin expression, activated systemic and renal oxidative stress as well as inflammation and promoted renal inherent cell apoptosis.

CONCLUSIONS

Acute hyperglycemia causes significant injury to kidney function and structure. Compared with damages of glomerular filtration barrier, renal tubular injury may contribute more to acute hyperglycemia induced proteinuria. Activation of inflammation especially renal inflammation, oxidative stress and enhanced apoptosis may be the underlying mechanisms.

Predictive roles of intraoperative blood glucose for post-transplant outcomes in liver transplantation

Diabetogenic traits in patients undergoing liver transplantation (LT) are exacerbated intraoperatively by exogenous causes, such as surgical stress, steroids, blood transfusions, and catecholamines, which lead to intraoperative hyperglycemia. In contrast to the strict glucose control performed in the intensive care unit, no systematic protocol has been developed for glucose management during LT. Intraoperative blood glucose concentrations typically exceed 200 mg/dL in LT, and extreme hyperglycemia (> 300 mg/dL) is common during the neohepatic phase. Only a few retrospective studies have examined the relationship between intraoperative hyperglycemia and post-transplant complications, with reports of infectious complications or mortality. However, no prospective studies have been conducted regarding the influence of intraoperative hyperglycemia in LT on post-transplant outcome. In addition to absolute blood glucose values, the temporal patterns in blood glucose levels during LT may serve as prognostic features. Persistent neohepatic hyperglycemia (without a decline) throughout LT is a useful indicator of early graft dysfunction. Moreover, intraoperative variability in glucose levels may predict the need for reoperation for hemorrhage after LT. Thus, there is an urgent need for guidelines for glucose control in these patients, as well as prospective studies on the impact of glucose control on various post-transplant complications. This report highlights some of the recent studies related to perioperative blood glucose management focused on LT and liver disease.