Intensive insulin therapy confers a similar survival benefit in the burn intensive care unit to the surgical intensive care unit

Blood glucose control in the burn intensive care unit: A narrative review of literature

Burn survivors undergoing complex glycemic derangements in the acute period after burn are at significantly increased risk of worse outcomes. Although most critical care investigations recommend intensive glycemic control to prevent morbidity and mortality, conflicting recommendations exist. To date, no literature review has studied outcomes associated with intensive glucose control in the burn intensive care unit (ICU) population. This review addresses this gap to improve practice guidelines and support further research regarding glycemic control. This is a narrative review of literature utilizing PubMed for articles published at any time. Inclusion criteria were English studies describing glucose management in ICU adult burn patients. Studies involving pediatric patients, non-human subjects, care non-ICU care, case reports, editorials, and position pieces were excluded. Our literature search identified 2154 articles. Full text review of 61 articles identified eight meeting inclusion criteria. Two studies reported mortality benefit of intensive glucose control ( mg/dL) compared to controls ( mg/dL), while two studies showed no mortality differences. Three studies reported reduced infectious complications such as pneumonia, urinary tract infection, sepsis, and bacteremia. A majority of the studies (6/8) reported higher risk for hypoglycemia with tight glucose control, but few reported instances of adverse sequela associated with hypoglycemia. Intensive glucose control may provide benefit to burn patients, but complications associated with hypoglycemia must be considered. This review recommends an individualized patient-centered approach factoring comorbidities, burn injury characteristics, and risk factors when determining whether to employ intensive glucose control.

Anabolic and anticatabolic agents used in burn care: What is known and what is yet to be learned

Major thermal injury induces profound metabolic derangements secondary to an inflammatory "stress-induced" hormonal environment. Several pharmacological interventions have been tested in an effort to halt the hypermetabolic response to severe burns. Insulin, insulin growth factor 1, insulin growth factor binding protein 3, metformin, human growth hormone, thyroid hormones, testosterone, oxandrolone, and propranolol, among others, have been proposed to have anabolic or anticatabolic effects. The aim of this broad analysis of pharmacological interventions was to raise awareness of treatment options and to help establishing directions for future clinical research efforts. A PubMed search was conducted on the anabolic and anticatabolic agents used in burn care. One hundred and thirty-five human studies published between 1999 and 2017 were included in this review. The pharmacological properties, rationale for the treatments, efficacy considerations and side effect profiles are summarized in the article. Many of the drugs tested for investigational purposes in the severely thermally injured are not yet gold-standard therapies in spite of their potential benefit. Propranolol and oxandrolone have shown great promise but further evidence is still needed to clarify their potential use for anabolic and anticatabolic purposes.

Sweet and Sour: Impact of Early Glycemic Control on Outcomes in Necrotizing Soft-Tissue Infections

Background: Necrotizing soft-tissue infection (NSTI) is a devastating disease associated with high rates of morbidity and mortality. Hyperglycemia is associated with poor wound healing; however, there are no studies evaluating glycemic control outcomes in patients with NSTI. The objective of this study was to examine disease progression and death in patients with NSTI who achieved early glycemic control (EGC) compared with patients that did not. Methods: A retrospective chart review of patients with NSTI was conducted between November 2011 and August 2017. Early glycemic control was defined as a daily average blood glucose concentration ≤150 mg/dL for a minimum of two consecutive days from admission to hospital day three. The primary outcome of this study was a composite of ≤3 debridement procedures by hospital day 14 and survival to discharge. Secondary outcomes were the total number of debridement procedures, amputation, hospital length of stay (LOS), intensive care unit (ICU) LOS, number of hypoglycemic events throughout hospitalization, and discharge disposition. Results: One-hundred five patients were included in the analysis. There were 62% male patients, mean age of 55.3 years, mean weight of 106.9 kg, and 57.1% with diabetes mellitus (DM). The 54 (51.4%) patients with EGC were less likely to have DM (29.6% versus 86.3%; p < 0.001), had a lower median admission glucose concentration (120.5 [97-144] versus 198 [153-295.5] mg/dL; p < 0.001), and had lower median daily glucose values during the first 96 hours after admission (p < 0.001). There was no significant difference in the primary outcome (83.3%% versus 84.3%; p > 0.99) or incidence of hypoglycemia (14.8% versus 23.5%; p = 0.32). Patients with EGC were more likely to return home after discharge (44.4% versus 23.5%; p = 0.039). Conclusion: Overall, there was no difference in composite clinical outcomes between patients with EGC and those without, although more patients who achieved EGC were discharged home. Patients with DM were less likely to achieve EGC.

Burn injury outcomes in patients with pre-existing diabetic mellitus: Risk of hospital-acquired infections and inpatient mortality

BACKGROUND

Diabetes mellitus (DM) is a major cause of illness and death in the United States, and diabetic patients are at increased risk for burn injury. We therefore sought to examine the impact of pre-existing DM on the risk of inpatient mortality and hospital acquired infections (HAI) among burn patients.

METHODS

Adult patients (≥18 years old) admitted from 2004 to 2013 were analyzed. Weighted Kaplan-Meier survival curves - adjusting for patient demographics, burn mechanism, presence of inhalation injury, total body surface area, additional comorbidities, and differential lengths of stay - were used to estimate the 30-day and 60-day risk of mortality and HAIs.

RESULTS

A total of 5539 adult patients were admitted and included in this study during the study period. 655 (11.8%) had a pre-existing DM. The crude incidence of HAIs and in-hospital mortality for the whole burn cohort was 8.5% (n=378) and 4.4% (n=243), respectively. Diabetic patients were more likely to be older, female, have additional comorbidities, inhalational injury, and contact burns. After adjusting for patient and burn characteristics, the 60-day risk of HAI among patients with DM was significantly higher, compared to non-diabetic patients (RR 2.07, 95% CI 1.28, 6.79). However, no significant difference was seen in the 60-day risk of mortality (RR 1.34, 95% CI 0.44, 3.10).

CONCLUSIONS

Pre-existing DM significantly increases the risk of developing an HAI in patients following burn injury, but does not significantly impact the risk of inpatient mortality. Further understanding of the immune modulatory mechanism of burn injury and DM is imperative to better attenuate the acquisition of HAIs.

Critical care of burn patients. New approaches to old problems

Recent publications on treatment options in critically ill patients change beliefs and clinical behaviors. Many dogmas, which the modern management of critical illness relies on, have been questioned. These publications (consensus articles, reviews, meta-analysis and original papers) concern some fundamental issues of critical care: interventions in acute respiratory distress syndrome (ARDS), hemodynamic monitoring, glucose control and nutritional support and revise our views on many key points of critical care of burn patients.

Clinical impact of sample interference on intensive insulin therapy in severely burned patients: a pilot study

Severely burned patients benefit from intensive insulin therapy (IIT) for tight glycemic control (TGC). The authors evaluated the clinical impact of automatic correction of hematocrit and ascorbic acid interference for bedside glucose monitoring performance in critically ill burn patients. The performance of two point-of-care glucose monitoring systems (GMSs): 1) GMS1, an autocorrecting device, and 2) GMS2, a noncorrecting device were compared. Sixty remnant arterial blood samples were collected in a prospective observational study to evaluate hematocrit and ascorbic acid effects on GMS1 vs GMS2 accuracy paired against a plasma glucose reference. Next, we enrolled 12 patients in a pilot randomized controlled trial. Patients were randomized 1:1 to receive IIT targeting a TGC interval of 111 to 151 mg/dl and guided by either GMS1 or GMS2. GMS bias, mean insulin rate, and glycemic variability were calculated. In the prospective study, GMS1 results were similar to plasma glucose results (mean bias, -0.75 [4.0] mg/dl; n = 60; P = .214). GMS2 results significantly differed from paired plasma glucose results (mean bias, -5.66 [18.7] mg/dl; n = 60; P = .048). Ascorbic acid therapy elicited significant GMS2 performance bias (29.2 [27.2]; P < .001). Randomized controlled trial results reported lower mean bias (P < .001), glycemic variability (P < .05), mean insulin rate (P < .001), and frequency of hypoglycemia (P < .001) in the GMS1 group than in the GMS2 group. Anemia and high-dose ascorbic acid therapy negatively impact GMS accuracy and TGC in burn patients. Automatic correction of confounding factors improves glycemic control. Further studies are warranted to determine outcomes associated with accurate glucose monitoring during IIT.

The glucoregulatory benefits of glucagon-like peptide-1 (7-36) amide infusion during intensive insulin therapy in critically ill surgical patients: a pilot study

OBJECTIVES

Intensive insulin therapy for tight glycemic control in critically ill surgical patients has been shown to reduce mortality; however, intensive insulin therapy is associated with iatrogenic hypoglycemia and increased variability of blood glucose levels. The incretin glucagon-like peptide-1 (7-36) amide is both insulinotropic and insulinomimetic and has been suggested as an adjunct to improve glycemic control in critically ill patients. We hypothesized that the addition of continuous infusion of glucagon-like peptide-1 to intensive insulin therapy would result in better glucose control, reduced requirement of exogenous insulin administration, and fewer hypoglycemic events.

DESIGN

Prospective, randomized, double-blind, placebo-controlled clinical trial.

SETTING

Surgical or burn ICU.

PATIENTS

Eighteen patients who required intensive insulin therapy.

INTERVENTIONS

A 72-hour continuous infusion of either glucagon-like peptide-1 (1.5 pmol/kg/min) or normal saline plus intensive insulin therapy.

MEASUREMENTS AND MAIN RESULTS

The glucagon-like peptide-1 cohort (n = 9) and saline cohort (n = 9) were similar in age, Acute Physiology and Chronic Health Evaluation score, and history of diabetes. Blood glucose levels in the glucagon-like peptide-1 group were better controlled with much less variability. The coefficient of variation of blood glucose ranged from 7.2% to 30.4% in the glucagon-like peptide-1 group and from 19.8% to 56.8% in saline group. The mean blood glucose coefficient of variation for the glucagon-like peptide-1 and saline groups was 18.0% ± 2.7% and 30.3% ± 4.0% (p = 0.010), respectively. The 72-hour average insulin infusion rates were 3.37 ± 0.61 and 4.57 ± 1.18 U/hr (p = not significant). The incidents of hypoglycemia (≤ 2.78 mmol/L) in both groups were low (one in the glucagon-like peptide-1 group, three in the saline group).

CONCLUSIONS

Glucagon-like peptide-1 (7-36) amide is a safe and efficacious form of adjunct therapy in patients with hyperglycemia in the surgical ICU setting. Improved stability of blood glucose is a favorable outcome, which enhances the safety of intensive insulin therapy. Larger studies of this potentially valuable therapy for glycemic control in the ICU are justified.

Clinical review: Glucose control in severely burned patients - current best practice

Tight glucose control changed the way many burn centers practice burn ICU care. However, after the initial impressive data, various clinical trials followed that showed mixed results. The objective of the present review is to discuss recent studies in the area of burn and critical care, and to identify the current best practice for current burn care providers. We reviewed relevant publications from PubMed and selected high-impact publications on tight glycemic control in various patient populations with a focus on burn patients. We conclude that in burns there seems to be a signal that insulin administration to a target range of 130 to 150 mg/dl is beneficial in terms of morbidity and mortality without the risk of hypoglycemia.

Elderly patients may benefit from tight glucose control

BACKGROUND

While minimizing hyperglycemia in critically injured patients improves outcomes, it is debatable whether postinjury glucose control should aim for conventional glucose control levels (≤180 mg/dL) or tight glucose control levels (81-108 mg/dL). We queried our 17-year prospective database of patients at risk for postinjury multiple organ failure to examine the association between glucose levels and adverse outcomes.

METHODS

Acutely injured patients admitted to a Level I trauma center intensive care unit from 1992 to 2008 who were more than 15 years of age, had Injury Severity Scores >15, and who survived >48 hours were eligible for the study. Multiple logistic regression was used to determine the independent association of glucose control with adverse outcomes (death, ventilator-free days, intensive care unit-free days, and major infections), adjusted for Injury Severity Score, age, and red blood cell transfusion in the first 12 hours.

RESULTS

Overall, 2,231 patients were eligible, of whom 153 (6.9%) died. The mean age was 37.8 ± 0.4 years, and the median Injury Severity Score was 27 (interquartile range, 21-35). The majority (77%) of these patients maintained mean glucose within conventional glucose control levels and only 10% achieved mean glucose levels within tight glucose control levels. Nonsurvivors required greater doses of insulin to control glucose levels and had greater mean insulin to glucose ratios (t test; P = .025). After adjusting for confounders, mean glucose remained significantly associated with the studied adverse outcomes. Age significantly modified all these associations with older patients seeming to benefit more from tight glucose control levels than their younger counterparts.

CONCLUSION

Age is an effect modifier of the association between glucose levels and adverse outcomes. Future studies including larger samples of elderly trauma patients are needed to determine the ideal levels for glucose control in this growing population.

Early glycemic control in critically ill patients with burn injury

Glucose management in patients with burn injury is often difficult because of their hypermetabolic state with associated hyperglycemia, hyperinsulinemia, and insulin resistance. Recent studies suggest that time to glycemic control is associated with improved outcomes. The authors sought to determine the influence of early glycemic control on the outcomes of critically ill patients with burn injury. A retrospective analysis was performed at the Ohio State University Medical Center. Patients hospitalized with burn injury were enrolled if they were admitted to the intensive care unit between March 1, 2006, and February 28, 2009. Early glycemic control was defined as the achievement of a mean daily blood glucose of ≤150 mg/dl for at least two consecutive days by postburn day 3. Forty-six patients made up the study cohort with 26 achieving early glycemic control and 20 who did not. The two groups were similar at baseline with regard to age, pre-existing diabetes, APACHE II score and burn size and depth. There were no differences in number of surgical interventions, infectious complications, or length of stay between patients who achieved or failed early glycemic control. Failure of early glycemic control was, however, associated with significantly higher mortality both by univariate (35.0 vs 7.7%, P = .03) and multivariate analyses (hazard ratio 6.754 [1.16-39.24], P = .03) adjusting for age, TBSA, and inhalation injury. Failure to achieve early glycemic control in patients with burn injury is associated with an increased risk of mortality. However, further prospective controlled trials are needed to establish causality of this association.

Review of burn injury research for the year 2009

Research in burn care for the calendar year 2009 was robust and diverse with >1400 research articles published on a wide range of topics. In this review, the authors highlight some innovative and potentially impactful research related to the overall care of burn- injured patients. The authors grouped articles according to the following categories: critical care, infection, inhalation injury, epidemiology, psychology, wound characterization and treatment, nutrition and metabolism, pain and itch management, burn reconstruction, and rehabilitation. They found that the holistic nature of burn care is reflected in the diverse research performed in 2009 throughout the world and that this research has provided important evidence that has improved or will improve burn care overall.

[Perioperative mortality: retrospective cross-sectional study of surgical patients who died between 2004 and 2008 in a tertiary care hospital]

OBJECTIVE

Retrospective analysis of all surgical, early postoperative, and 1-week to detect risk factors.

MATERIAL AND METHODS

A database was established to record clinical, anesthetic, and surgical variables, grouped as preoperative, intraoperative and postoperative factors, and reflecting comorbidities and postoperative complications. Each patient's cause of death was also recorded. Factors influencing mortality during surgery, at 48 hours, and at 1 week were explored by comparing frequencies to detect correlations.

RESULTS

From 2004 to 2008, a total of 809 deaths occurred in the 82412 hospitalized surgical patients. Patients who died during surgery or within 48 hours were younger, had a higher ASA physical status classification, had more cardiovascular risk factors, were less likely to have a diagnosis of cancer, and had spent less time in hospital before the operation. Intraoperative complications, particularly bleeding and cardiac events, were more frequent in patients whose condition was more complex and who died during surgery; that pattern was similar but less marked in patients dying within 48 hours. The patients who died within 48 hours had a higher rate of postoperative hemodynamic complications; the patients who died during the week following surgery had higher rates of septic, neurologic, and respiratory complications.

CONCLUSIONS

Emergency surgery stands out as an important predictor of death during or after surgery; other significant risk factors are postoperative complications.

Randomized clinical trial to compare the effects of preoperative oral carbohydrate versus placebo on insulin resistance after colorectal surgery

Background

Preoperative oral carbohydrate (OCH) reduces postoperative insulin resistance (PIR). This randomized trial investigated whether this effect is related to insulin-induced activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB) signalling pathway.

Methods

Patients with colorectal cancer scheduled for elective open resection were randomly assigned to preoperative OCH, fasting or placebo. Preoperative general well-being, insulin resistance before and immediately after surgery, and postoperative expression of PI3K, PKB, protein tyrosine kinase (PTK) and glucose transporter 4 (GLUT4) in rectus abdominis muscle were evaluated.

Results

Patient and operative characteristics did not differ between groups. Subjective well-being was significantly better in OCH and placebo groups than in the fasting group, primarily because of reduced thirst (P = 0·005) and hunger (P = 0·041). PIR was significantly greater in fasting and placebo groups (P &lt; 0·010). By the end of surgery, muscle PTK activity as well as PI3K and PKB levels were significantly increased in the OCH group compared with values in fasting and placebo groups (P &lt; 0·050), but GLUT4 expression was unaffected.

Conclusion

PIR involves the PI3K/PKB signalling pathway. Preoperative OCH intake improves preoperative subjective feelings of hunger and thirst compared with fasting, while attenuating PIR by stimulation of the PI3K/PKB pathway. Registration number: NCT00755729 (http://www.clinicaltrials.gov).