Intensive Insulin Therapy in Postoperative Intensive Care Unit Patients

Low-value clinical practices in injury care: A scoping review and expert consultation survey

BACKGROUND

Tests and treatments that are not supported by evidence and could expose patients to unnecessary harm, referred to here as low-value clinical practices, consume up to 30% of health care resources. Choosing Wisely and other organizations have published lists of clinical practices to be avoided. However, few apply to injury and most are based uniquely on expert consensus. We aimed to identify low-value clinical practices in acute injury care.

METHODS

We conducted a scoping review targeting articles, reviews and guidelines that identified low-value clinical practices specific to injury populations. Thirty-six experts rated clinical practices on a five-point Likert scale from clearly low value to clearly beneficial. Clinical practices reported as low value by at least one level I, II, or III study and considered clearly or potentially low-value by at least 75% of experts were retained as candidates for low-value injury care.

RESULTS

Of 50,695 citations, 815 studies were included and led to the identification of 150 clinical practices. Of these, 63 were considered candidates for low-value injury care; 33 in the emergency room, 9 in trauma surgery, 15 in the intensive care unit, and 5 in orthopedics. We also identified 87 "gray zone" practices, which did not meet our criteria for low-value care.

CONCLUSION

We identified 63 low-value clinical practices in acute injury care that are supported by empirical evidence and expert opinion. Conditional on future research, they represent potential targets for guidelines, overuse metrics and de-implementation interventions. We also identified 87 "gray zone" practices, which may be interesting targets for value-based decision-making. Our study represents an important step toward the deimplementation of low-value clinical practices in injury care.

LEVEL OF EVIDENCE

Systematic Review, Level IV.

Sepsis and Septic Shock Strategies

Three therapeutic principles most substantially improve organ dysfunction and survival in sepsis: early, appropriate antimicrobial therapy; restoration of adequate cellular perfusion; timely source control. The new definitions of sepsis and septic shock reflect the inadequate sensitivity, specify, and lack of prognostication of systemic inflammatory response syndrome criteria. Sequential (sepsis-related) organ failure assessment more effectively prognosticates in sepsis and critical illness. Inadequate cellular perfusion accelerates injury and reestablishing perfusion limits injury. Multiple organ systems are affected by sepsis and septic shock and an evidence-based multipronged approach to systems-based therapy in critical illness results in improve outcomes.

Perioperative glycemic control

Perioperative hyperglycemia has potential significant adverse consequences of increased mortality and morbidity including surgical site infection, renal insufficiency and anemia requiring transfusion. Both diabetic and non-diabetic patients are affected adversely by perioperative hyperglycemia. However, these two subgroups do not necessarily benefit equally from perioperative glycemic control. Moreover, ideal target glucose range as well as the appropriate patient population(s) for whom glycemic control offers the most benefit have yet to be fully elucidated. However, there are clear potential adverse consequences of tight control such as hypoglycemia.

Increasing blood glucose variability is a precursor of sepsis and mortality in burned patients

High glycemic variability, rather than a mean glucose level, is an important factor associated with sepsis and hospital mortality in critically ill patients. In this retrospective study we analyze the blood glucose data of 172 nondiabetic patients 18-60 yrs old with second and third-degree burns of total body surface area greater than 30% and 5%, respectively, admitted to ICU in 2004-2008. The analysis identified significant association of increasing daily glucose excursion (DELTA) accompanied by evident episodes of hyperglycemia (>11 mmol/l) and hypoglycemia (<2.8 mmol/l), with sepsis and forthcoming death, even when the mean daily glucose was within a range of acceptable glycemia. No association was found in sepsis complication and hospital mortality with doses of intravenous insulin and glucose infusion. A strong increase in DELTA before sepsis and death is treated as fluctuation amplification near the onset of dynamical instability.

Ionized calcium concentration and outcome in critical illness

OBJECTIVE

To assess the association of abnormalities of ionized calcium levels with mortality in a heterogeneous cohort of critically ill patients.

DESIGN

Retrospective, combined clinical and biochemical study.

SETTING

Four combined medical/surgical intensive care units.

PATIENTS

Cohort of 7,024 adult critically ill patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We studied 177,578 ionized calcium measurements, from 7024 patients, with a mean value of 1.11 mmol/L (ionized calcium measured every 4.5 hrs on average). The unadjusted lowest and highest ionized calcium reported during intensive care unit stay were significantly different between intensive care unit survivors and nonsurvivors (p < .001). If hypocalcemia occurred at least once during the intensive care unit stay, the probability of intensive care unit mortality increased by 46%, 108%, and 150% for ionized calcium levels <1.15, 0.90, and 0.80 mmol/L, respectively. If hypercalcemia occurred at least once during the intensive care unit stay, the probability of intensive care unit mortality increased by 100%, 162%, and 190% for ionized calcium levels >1.25, 1.35, and 1.45 mmol/L, respectively. Similar trends were seen for hospital mortality. However, from multivariate logistic regression analysis, only an ionized calcium <0.8 mmol/L or an ionized calcium >1.4 mmol/L were independently associated with intensive care unit and hospital mortality.

CONCLUSIONS

Within a broad range of values, ionized calcium concentration has no independent association with hospital or intensive care unit mortality. Only extreme abnormalities of ionized calcium concentrations are independent predictors of mortality.

Glycemic control and infections in patients with diabetes undergoing noncardiac surgery

OBJECTIVE

Examine the relationship between perioperative glucose control and postoperative infections in a nationwide sample of diabetic patients undergoing a wide variety of surgical procedures.

SUMMARY OF BACKGROUND DATA

Perioperative glucose control has been linked to postoperative infections after selected surgical procedures.

METHODS

Retrospective analysis of surgical outcomes data from 1999 to 2004 on 55,408 patients with diabetes undergoing a variety of noncardiac operations contained in the Veterans Heath Administration National Surgical Quality Improvement Program database, supplemented with the Veterans Heath Administration Decision Support Services hemoglobin A1c (HbA(₁c)) and serum glucose data. Multivariate Poisson regression model of postoperative infection including demographics, comorbidities, functional status, preoperative laboratories, surgical data, and glucose control (diabetes medications, serum glucose, HbA(₁c), mean serum glucose within 24 hours after surgery).

RESULTS

The most common procedures were herniorrhaphy (10%), carotid endarterectomy (6.6%), and open colectomy (5.6%). Mean (SD) preoperative HbA1c concentration was 7.9% (2.3); 51% of patients had preoperative serum glucose concentrations more than 150 mg/dL; and 72% of patients had a mean 24 hour postoperative glucose concentration at least 150 mg/dL. The overall postoperative infection rate was 8.0%. Higher rates of postoperative infection were associated with mean 24 hour postoperative serum glucose concentrations of 150 to 250 mg/dL (incidence rate ratio 1.22, 95% confidence interval, 1.04-1.43; P = 0.01) and more than 250 mg/dL (incidence rate ratio: 1.43; 95% confidence interval, 1.19-1.71; P < 0.001). Preoperative HbA1c and glucose concentrations were not associated with increased infection rates.

CONCLUSIONS

In a large nationwide sample of diabetic patients undergoing a variety of noncardiac surgical procedures, glucose control in the first 24 hours after surgery was poor, and mean serum glucose concentrations of 150 mg/dL and higher during this time period were associated with increased rates of postoperative infectious complications.

The interaction of chronic and acute glycemia with mortality in critically ill patients with diabetes

OBJECTIVES

The relationship between hyperglycemia and mortality is altered by the presence of diabetes mellitus. Biological adjustment to preexisting hyperglycemia might explain this phenomenon. We tested whether the degree of preexisting hyperglycemia would modulate the association between glycemia and outcome during critical illness in patients with diabetes mellitus.

DESIGN

Retrospective observational study.

SETTING

Two tertiary intensive care units.

PATIENTS

Four hundred fifteen critically ill diabetic patients with HbA1c levels measured within 3 months of intensive care unit admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 9,946 blood glucose measurements in this study cohort (glucose measured 6.7 times per day; every 3.6 hrs on average). The median preadmission HbA1c level was 7.0%. There was no significant difference in HbA1c levels (p = .17) or time-weighted average of blood glucose concentrations (p = .49) between survivors and nonsurvivors. The time-weighted average of blood glucose concentrations during intensive care unit stay for nonsurvivors was lower than that of survivors when the HbA1c was >6.8%. In multivariate analysis, we found that there was a significant interaction between HbA1c and the time-weighted glucose level, indicating that the relationship between HbA1c and mortality changed according to the levels of time-weighted average of blood glucose concentrations (p = .008). As a consequence, in patients with higher (>7%) preadmission levels of HbA1c, the higher the time-weighted acute glucose concentration during intensive care unit stay (>10 mmol/L), the lower the hospital mortality compared with the lower HbA1c cohort (<7%).

CONCLUSIONS

In patients with diabetes mellitus admitted to intensive care units, there was a significant interaction between preexisting hyperglycemia and the association between acute glycemia and mortality. These observations generate the hypothesis that glucose levels that are considered safe and desirable in other patients might be undesirable in diabetic patients with chronic hyperglycemia. Further studies are required to confirm or refute our findings.

Hypoglycemia and outcome in critically ill patients

OBJECTIVE

To determine whether mild or moderate hypoglycemia that occurs in critically ill patients is independently associated with an increased risk of death.

PATIENTS AND METHODS

Of patients admitted to 2 hospital intensive care units (ICUs) in Melbourne and Sydney, Australia, from January 1, 2000, to October 14, 2004, we analyzed all those who had at least 1 episode of hypoglycemia (glucose concentration, <81 mg/dL). The independent association between hypoglycemia and outcome was statistically assessed.

RESULTS

Of 4946 patients admitted to the ICUs, a cohort of 1109 had at least 1 episode of hypoglycemia (blood glucose level, <81 mg/dL). Of these 1109 patients (22.4% of all admissions to the intensive care unit), hospital mortality was 36.6% compared with 19.7% in the 3837 nonhypoglycemic control patients (P<.001). Even patients with a minimum blood glucose concentration between 72 and 81 mg/dL had a greater unadjusted mortality rate than did control patients (25.9% vs 19.7%; unadjusted odds ratio, 1.42; 95% confidence interval, 1.12-1.80; P=.004.) Mortality increased significantly with increasing severity of hypoglycemia (P<.001). After adjustment for insulin therapy, hypoglycemia was independently associated with increased risk of death, cardiovascular death, and death due to infectious disease.

CONCLUSION

In critically ill patients, an association exists between even mild or moderate hypoglycemia and mortality. Even after adjustment for insulin therapy or timing of hypoglycemic episode, the more severe the hypoglycemia, the greater the risk of death.

How to weigh the current evidence for clinical practice

This article presents a template for judging trials of tight glucose control in critically ill patients. It reviews threats to both internal validity and generalisability using examples from the current literature. When judging internal validity, it is important to consider factors specific to trials of glucose control (particularly the methods of glucose control, measurement and reporting) in addition to factors common to all randomised controlled trials (such as treatment allocation, losses to follow-up and protocol violations). Judging generalisability requires the identification of differences between the trial population and the population for whom the intervention is being considered. These may relate to the setting, the patients or the practical delivery of tight glucose control or other interventions. Once identified, a judgement must be made for each difference of whether it is likely to modify the effect of tight glucose control.

Scientific principles and clinical implications of perioperative glucose regulation and control

Development of hyperglycemia after major operations is very common and is modulated by many factors. These factors include perioperative metabolic state, intraoperative management of the patient, and neuroendocrine stress response to surgery. Acute insulin resistance also develops perioperatively and contributes significantly to hyperglycemia. Hyperglycemia is associated with poor outcomes in critically ill and postsurgical patients. A majority of the investigations use the term "hyperglycemia" very loosely and use varying thresholds for initiating treatment. Initial studies demonstrated improved outcomes in critically ill, postsurgical patients who received intensive glycemic control (IGC) (target serum glucose <110 mg/dL). These results were quickly extrapolated to other clinical areas, and IGC was enthusiastically recommended in the perioperative period. However, there are few studies investigating the value of intraoperative glycemic control. Moreover, recent prospective trials have not been able to show the benefit of IGC; neither an appropriate therapeutic glycemic target nor the true efficacy of perioperative glycemic control has been fully determined. Practitioners should also appreciate technical nuances of various glucose measurement techniques. IGC increases the risk of hypoglycemia significantly, which is not inconsequential in critically ill patients. Until further specific data are accumulated, it is prudent to maintain glucose levels <180 mg/dL in the perioperative period, and glycemic control should always be accompanied by close glucose monitoring.

Hyperglycemia-related mortality in critically ill patients varies with admission diagnosis

OBJECTIVES

Hyperglycemia during critical illness is common and is associated with increased mortality. Intensive insulin therapy has improved outcomes in some, but not all, intervention trials. It is unclear whether the benefits of treatment differ among specific patient populations. The purpose of the study was to determine the association between hyperglycemia and risk- adjusted mortality in critically ill patients and in separate groups stratified by admission diagnosis. A secondary purpose was to determine whether mortality risk from hyperglycemia varies with intensive care unit type, length of stay, or diagnosed diabetes.

DESIGN

Retrospective cohort study.

SETTING

One hundred seventy-three U.S. medical, surgical, and cardiac intensive care units.

PATIENTS

Two hundred fifty-nine thousand and forty admissions from October 2002 to September 2005; unadjusted mortality rate, 11.2%.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A two-level logistic regression model determined the relationship between glycemia and mortality. Age, diagnosis, comorbidities, and laboratory variables were used to calculate a predicted mortality rate, which was then analyzed with mean glucose to determine the association of hyperglycemia with hospital mortality. Hyperglycemia was associated with increased mortality independent of illness severity. Compared with normoglycemic individuals (70-110 mg/dL), adjusted odds of mortality (odds ratio, [95% confidence interval]) for mean glucose 111-145, 146-199, 200-300, and >300 mg/dL was 1.31 (1.26-1.36), 1.82 (1.74-1.90), 2.13 (2.03-2.25), and 2.85 (2.58-3.14), respectively. Furthermore, the adjusted odds of mortality related to hyperglycemia varied with admission diagnosis, demonstrating a clear association in some patients (acute myocardial infarction, arrhythmia, unstable angina, pulmonary embolism) and little or no association in others. Hyperglycemia was associated with increased mortality independent of intensive care unit type, length of stay, and diabetes.

CONCLUSIONS

The association between hyperglycemia and mortality implicates hyperglycemia as a potentially harmful and correctable abnormality in critically ill patients. The finding that hyperglycemia-related risk varied with admission diagnosis suggests differences in the interaction between specific medical conditions and injury from hyperglycemia. The design and interpretation of future trials should consider the primary disease states of patients and the balance of medical conditions in the intensive care unit studied.

Reducing glycemic variability in intensive care unit patients: a new therapeutic target?

Acute hyperglycemia is common in critically ill patients. Strict control of blood glucose (BG) concentration has been considered important because hyperglycemia is associated independently with increased intensive care unit mortality. After intensive insulin therapy was reported to reduce mortality in selected surgical critically ill patients, lowering of BG levels was recommended as a means of improving patient outcomes. However, a large multicenter multination study has found that intensive insulin therapy increased mortality significantly. A difference in variability of BG control may be one possible explanation why the effect of intensive insulin therapy varied from beneficial to harmful. Several studies have confirmed significant associations between variability of BG levels and patient outcomes. Decreasing the variability of the BG concentration may be an important dimension of glucose management. If reducing swings in the BG concentration is a major biologic mechanism behind the putative benefits of glucose control, it may not be necessary to pursue lower glucose levels with their attendant risk of hypoglycemia.

Glycemic control in the burn intensive care unit: focus on the role of anemia in glucose measurement

Glycemic control with intensive insulin therapy (IIT) has received widespread adoption secondary to findings of improved clinical outcomes and survival in the burn population. Severe burn as a model for trauma is characterized by a hypermetabolic state, hyperglycemia, and insulin resistance. In this article, we review the findings of a burn center research facility in terms of understanding glucose management. The conferred benefits from IIT, our findings of poor outcomes associated with glycemic variability, advantages from preserved diurnal variation of glucose and insulin, and impacts of glucometer error and hematocrit correction factor are discussed. We conclude with direction for further study and the need for a reliable continuous glucose monitoring system. Such efforts will further the endeavor for achieving adequate glycemic control in order to assess the efficacy of target ranges and use of IIT.

Perioperative and critical illness dysglycemia--controlling the iceberg

Patients with dysglycemia related to known or unrecognized diabetes, stress hyperglycemia, or hypoglycemia in the presence or absence of exogenous insulin routinely require care during the perioperative period or critical illness. Recent single and multicenter studies, a large multinational study, and three meta-analyses evaluated the safety of routine tight glycemic control (80-110 mg/dl) in critically ill adults. Results led to a call for more modest treatment goals (initiation of insulin at a blood glucose >180 mg/dl with a goal of approximately 150 mg/dl). In this symposium, an international group of multidisciplinary experts discusses the role of tight glycemic control, glucose measurement technique and its accuracy, glucose variability, hypoglycemia, and innovative methods to facilitate glucose homeostasis in this heterogeneous patient population.

The GRADE system for rating clinical guidelines

Brian Kavanagh critiques the GRADE system of grading guidelines, arguing that even though it has evolved through the Evidence-Based Medicine movement, there is no evidence that GRADE itself is reliable.

Early blood glucose control and mortality in critically ill patients in Australia

OBJECTIVE

To measure temporal trends in blood glucose (BG) control and describe their association with hospital mortality in a cohort of critically ill patients from Australia.

DESIGN

Interrogation of prospectively collected data from the Australia New Zealand Intensive Care Society Adult Patient Database.

SETTING

Twenty-four intensive care units (ICU) across Australia.

PATIENTS AND PARTICIPANTS

A cohort of 66,184 adult ICU admissions for >or=24 hours from January 1, 2000, to December 31, 2005.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Highest and lowest BG values within 24 hours of ICU admission, standard demographic, clinical, and physiologic data, and hospital mortality. Medical, mechanically ventilated surgical, cardiac surgical, and septic subgroups were evaluated. Average BG was evaluated as a continuous variable and by quartiles (low [<5.6 mmol/L], near normal [5.6-8.69 mmol/L], high [8.69-11.79 mmol/L], and highest [>11.79 mmol/L]). There were 132,368 BG values, with a mean (95% confidence intervals) value 8.69 mmol/L (8.66-8.73). There was no trend in BG for the entire cohort (p = 0.66) over the study period; yet, BG increased after 2002 (0.17 mmol/L, p < 0.0001). The mechanically ventilated surgical and cardiac surgical subgroups had decreasing trends in BG (p < 0.001), whereas the septic subgroup had an increasing BG trend (p < 0.001). BG in the low, high, and highest quartiles, compared with the near-normal quartile, were consistently associated with higher hospital mortality in crude (odds ratio 1.31, 1.58, and 2.00) and multivariable analysis (odds ratio 1.29, 1.07, and 1.10), respectively. This association was similarly shown for the mechanically ventilated surgical and cardiac surgical subgroups.

CONCLUSIONS

In a large cohort of ICU patients from Australia, there was no significant change in early glycemic control from 2000 to 2005. There were differences in selected subgroups. Average BG decreased in surgical subgroups, whereas it increased in septic patients. Both high and early low BG values were independently associated with hospital mortality.

Glucose control in the intensive care unit

OBJECTIVE

Hyperglycemia, be it secondary to diabetes, impaired glucose tolerance, impaired fasting glucose, or stress-induced is common in the critically ill. Hyperglycemia and glucose variability in intensive care unit (ICU) patients has some experts calling for routine administration of intensive insulin therapy to normalize glucose levels in hyperglycemic patients. Others, however, have raised concerns over the optimal glucose level, the accuracy of measurements, the resources required to attain tight glycemic control (TGC), and the impact of TGC across the heterogeneous ICU population in patients with diabetes, previously undiagnosed diabetes or stress-induced hyperglycemia. Increased variability in glucose levels during critical illness and the therapeutic intervention thereof have recently been reported to have a deleterious impact on survival, particularly in nondiabetic hyperglycemic patients. The incidence of hypoglycemia (<40 mg/dL or 2.2 mmol) associated with TGC is reported to be as high as 18.7%, by Van den Berghe in a medical ICU, although application of various approaches and computer-based algorithms may improve this. The impact of hypoglycemia, particularly in patients with septic shock and those with neurologic compromise, warrants further evaluation. This review briefly discusses the epidemiology of hyperglycemia in the acutely ill and glucose metabolism in the critically ill. It comments on present limitations in glucose monitoring, outlines current glucose management approaches in the critically ill, and the transition from the ICU to the intermediate care unit or ward. It closes with comment on future developments in glycemic care of the critically ill.

METHODS

The awareness of the potential deleterious impact of hyperglycemia was heightened after Van den Berghe et al presented their prospective trial in 2001. Therefore, source data were obtained from PubMed and Cochrane Analysis searches of the medical literature, with emphasis on the time period after 2000. Recent meta-analyses were reviewed, expert editorial opinion collated, and the Web site of the Normoglycemia in Intensive Care Evaluation and Survival Using Glucose Algorithm Regulation Trial investigated.

SUMMARY AND CONCLUSIONS

Hyperglycemia develops commonly in the critically ill and impacts outcome in patients with diabetes but, even more so, in patients with stress-induced hyperglycemia. Despite calls for TGC by various experts and regulatory agencies, supporting data remain somewhat incomplete and conflicting. A recently completed large international study, Normoglycemia in Intensive Care Evaluation and Survival Using Glucose Algorithm Regulation, should provide information to further guide best practice. This concise review interprets the current state of adult glycemic management guidelines to provide a template for care as new information becomes available.

Intensive versus conventional insulin therapy: a randomized controlled trial in medical and surgical critically ill patients

OBJECTIVE

The role of intensive insulin therapy in medical surgical intensive care patients remains unclear. The objective of this study was to examine the effect of intensive insulin therapy on mortality in medical surgical intensive care unit patients.

DESIGN

Randomized controlled trial.

SETTINGS

Tertiary care intensive care unit.

PATIENTS

Medical surgical intensive care unit patients with admission blood glucose of > 6.1 mmol/L or 110 mg/dL.

INTERVENTION

A total of 523 patients were randomly assigned to receive intensive insulin therapy (target blood glucose 4.4-6.1 mmol/L or 80-110 mg/dL) or conventional insulin therapy (target blood glucose 10-11.1 mmol/L or 180-200 mg/dL).

MEASUREMENTS AND MAIN OUTCOMES

The primary end point was intensive care unit mortality. Secondary end points included hospital mortality, intensive care unit and hospital length of stay, mechanical ventilation duration, the need for renal replacement therapy and packed red blood cells transfusion, and the rates of intensive care unit acquired infections as well as the rate of hypoglycemia (defined as blood glucose < or = 2.2 mmol/L or 40 mg/dL). There was no significant difference in intensive care unit mortality between the intensive insulin therapy and conventional insulin therapy groups (13.5% vs. 17.1%, p = 0.30). After adjustment for baseline characteristics, intensive insulin therapy was not associated with mortality difference (adjusted hazard ratio 1.09, 95% confidence interval 0.70-1.72). Hypoglycemia occurred more frequently with intensive insulin therapy (28.6% vs. 3.1% of patients; p < 0.0001 or 6.8/100 treatment days vs. 0.4/100 treatment days; p < 0.0001). There was no difference between the intensive insulin therapy and conventional insulin therapy in any of the other secondary end points.

CONCLUSIONS

Intensive insulin therapy was not associated with improved survival among medical surgical intensive care unit patients and was associated with increased occurrence of hypoglycemia. Based on these results, we do not advocate universal application of intensive insulin therapy in intensive care unit patients.

TRIAL REGISTRATION

Current Controlled Trials registry (ISRCTN07413772) http://www.controlled-trials.com/ISRCTN07413772/07413772; 2005.

Hyperglycemia and the outcome of pediatric cardiac surgery patients requiring peritoneal dialysis

OBJECTIVE

To study the nature of the association between glycemia and ICU mortality in pediatric cardiac surgery patients treated with peritoneal dialysis (PD).

MATERIALS AND METHODS

Retrospective observational study in the ICU of a tertiary hospital involving forty pediatric cardiac surgery patients treated with PD. We selected patients requiring PD, extracted glucose measurements and nutritional intake data during ICU stay and calculated mean and maximum blood glucose values i) during ICU stay; ii) during dependence on PD; and iii) during independence from PD. We statistically assessed the relationship between glycemia-related variables and ICU mortality.

MEASUREMENTS AND RESULTS

Twenty-two patients treated with PD died (mortality 55%). In the PD cohort, 9725 blood glucose measurements were performed (every 3.3 hours on average). The mean glycemia during dependence on PD was significantly higher in non-survivors than survivors (p<0.0001), but not during independence from PD (p=0.49). The area under the receiver operator characteristic curve for the mean glycemia during dependence on PD was significantly greater than that obtained during independence from PD. Even after adjustment for severity of illness using multivariate logistic analysis, the mean glycemia and calorie intake during PD were significant and independent predictors of ICU mortality.

CONCLUSIONS

A higher mean blood glucose concentration during PD, but not during PD-free periods was associated with greater ICU mortality. Mean glycemia and calorie intake during PD were significant and independent predictors of ICU mortality.

Intensive care management of the patient with cystic fibrosis

Cystic fibrosis was previously thought to be a disease of childhood. With a better understanding of this condition along with improvements in therapy, patients with cystic fibrosis are now living well into adulthood. The aim of this article is to familiarize the intensive care unit physician with cystic fibrosis care, to discuss complications associated with cystic fibrosis specifically related to the intensive care unit, and to detail the current recommendations for the clinical management of the patient with cystic fibrosis. With advancing disease, the most severely affected organs are the lungs. Obstruction, infection, and inflammation contribute to the decline of pulmonary function, ultimately leading to death. Some patients may be eligible for lung transplantation, but choosing wisely will affect posttransplant survival. Because other organs are affected by the genetic defect and associated treatments, serious complications related to the liver, pancreas, intestines, and kidneys must be considered by the intensivist faced with a patient with cystic fibrosis. As practitioners, the fact that not all patients will survive and help our patients and families gracefully through the end-of-life process should be accepted.

Pro/con debate: Is intensive insulin therapy targeting tight blood glucose control of benefit in critically ill patients?

You have decided to develop a protocol for insulin therapy in your intensive care unit (ICU). You wonder about the merit of using intensive insulin therapy (IIT) to maintain tight blood glucose control in your patients.

Blood glucose control in critical care patients - a review of the literature

The role of hyperglycaemia in critical illness, and its corresponding treatment, has been an area of controversy, fuelled by conflicting research findings. The aims of this study were to critically evaluate the literature and present an historical review of the sequence of published papers relating to blood glucose control in critical care. Their subsequent impact together with the implications for patient care is discussed. This article is based on a systematic review of papers relating to glycaemic control in critical care patients. The review was conducted using the MedLine, CINAHL and EMBASE databases using key search terms (details of the search terms can be found after the conclusion of the paper) for the period 1950-2006. The searches resulted in 4863 papers being screened for relevance to the historic progression of glycaemic management in critical care patients, by title and then abstract. Of these, 209 were accessed, and their reference lists were snowballed for further papers. Papers that were repeatedly quoted throughout the literature and were therefore considered important in the historical development of accepted critical care practice were finally subjected to rigorous appraisal. These totalled 91 papers and included 18 randomized controlled trials, an additional 28 research papers, 25 editorials and 20 reviews. This critical evaluation of published work indicates that the evidence for the benefit of this therapy may not be as compelling as previously indicated, and its widespread use may have been premature. From a nursing perspective, this demonstrates the importance of maintaining a questioning attitude to new therapies and reviewing best practice in the light of evolving evidence.

Why is there such a difference in outcome between Australian intensive care units and others?

PURPOSE OF REVIEW

The aim of this article is to assess the data on clinical outcomes for critically ill patients admitted to Australian and New Zealand intensive care units in comparison to information available for similar patients in other counties

RECENT FINDINGS

Australia and New Zealand have been collecting standardized data intensive care unit admissions for over a decade. The Australian and New Zealand Intensive Care Society Database Management Committee has developed a high quality database of close to 600 000 adult intensive care unit admissions. Although comparisons suffer from significant methodological, case-mix and process differences, which make their findings easily subject to criticism, interrogation of this database and of data from clusters of intensive care units within this system consistently yields patient outcomes, which are better than outcomes reported from other nations or international studies for similar patients. In addition, Australia and New Zealand has now achieved the highest rate of patient enrollment in an investigator-initiated multicentre randomized controlled trials.

SUMMARY

Although comparisons in outcome between Australia and New Zealand intensive care units and other units worldwide may not have sufficient scientific rigour to truly reflect better national outcomes, many features of Australian and New Zealand units are unique and worthy of consideration by other national systems as they consider their strategic national goals for the next decade.

Hypoglycemia in the intensive care unit

PURPOSE OF REVIEW

To review recent articles and evaluate hypoglycemia as a major complication of intensive insulin therapy in anticipation of emerging data from current clinical studies.

RECENT FINDINGS

Following the 2001 landmark Leuven study demonstrating that intensive insulin therapy in the surgical intensive care unit reduces mortality, many studies have evaluated aspects of intensive insulin therapy with respect to improved clinical outcome and the impact of hypoglycemia. Specific risk factors for hypoglycemia in the intensive care unit with intensive insulin therapy are diabetes, octreotide therapy, nutrition support, continuous venovenous hemofiltration with bicarbonate replacement fluid, sepsis and need for inotropic support. In prospective studies with a comparator group, the incidence of hypoglycemia in intensive care unit patients treated with intensive insulin therapy is up to 25%, corresponding to a relative risk of 5.0. In studies without a comparator group, however, the incidence is less than 7%.

SUMMARY

Hypoglycemia is associated with adverse outcome in intensive care unit patients. It remains unclear whether intensive insulin therapy-induced hypoglycemia per se is responsible for this adverse outcome. The threat of hypoglycemia is a barrier to intensive insulin therapy in critical care, supporting the need for frequent glucose monitoring, readily available concentrated intravenous dextrose infusions, better training of nurses and technological advances in glucose-sensing and insulin-dosing algorithms.

The medical emergency team and rapid response system: finding, treating, and preventing hypoglycemia

Administrative and quality improvement processes that occurred in response to one patient's series of critical hypoglycemic events ultimately contributed to systematic improvements in patient safety.

Glycaemic control in critically ill patients with cardiovascular disease

PURPOSE OF REVIEW

The role of hyperglycaemia in the pathogenesis of myocardial damage during cardiac surgery or patients with acute coronary syndromes has been the subject of increasing interest over the past few years. Several further trials and meta-analyses investigating the role of insulin treatment, either aimed at tight control of blood glucose concentration or as part of a regimen including glucose and potassium, have been reported recently and are the subject of this review.

RECENT FINDINGS

Good control of blood glucose has been demonstrated to improve outcomes for diabetic patients undergoing cardiac surgery and following acute myocardial infarction. In surgical intensive care patients, tight glucose control improved mortality--a finding that is awaiting confirmation in multicentre studies. The use of glucose-insulin-potassium regimens does not improve outcomes in patients with acute myocardial infarction who have undergone reperfusion therapy, but may be beneficial during cardiac surgery.

SUMMARY

Tight control of blood glucose has been shown to be beneficial in several patient groups. The optimal target glucose concentration and glucose and insulin regimens remain to be confirmed or determined in each clinical situation.

Sugar, soap and statins--an unlikely recipe for the critically ill

The eagerly awaited SOAP (Sepsis Occurrence in Acutely ill Patients) study is published and its observational data provide much of interest, not least in generating further hypotheses on improving treatment in this challenging group. Glycaemic control in the critically ill is once more the focus of attention, and we discuss three studies in this area. Not least among these reports is that from the van den Bergh group, who provide further data on their intensive insulin protocol in a more heterogeneous group, namely medical intensive care unit patients. Finally, we discuss another good reason to take statins.

Preventing ventilator-associated pneumonia in adults: sowing seeds of change

Ventilator-associated pneumonia (VAP), a major cause of ICU infection, results in high morbidity, mortality, and health-care costs. Multiple risk factors for VAP involve complex host factors and ubiquitous pathogens that require several different types of prevention strategies. Prevention efforts should focus on reducing bacterial colonization, and limiting aspiration, antibiotic exposure, and use of invasive devices. Although evidence-based prevention guidelines are available, they are lengthy, often ignored, and not implemented. New insights into the barriers to implementation of effective prevention programs are emerging. This article provides highlights from recent guidelines and publications discussing VAP prevention strategies and examines barriers to their implementation. Prevention and implementation of cost-effective strategies to reduce risk and improve patient outcomes should be prioritized. Clearly, prevention programs should be population specific and may vary among hospitals, but a multidisciplinary prevention team led by a "champion" is recommended to help set priorities, benchmarking goals, analyze data, and sow the seeds of change for risk reduction.

Hyperglycaemia in critically ill patients: marker or mediator of mortality?

Acute hyperglycaemia has been associated with complications, prolonged intensive care unit and hospital stay, and increased mortality. We made an inventory of the prevalence and prognostic value of hyperglycaemia, and of the effects of glucose control in different groups of critically ill patients. The prevalence of hyperglycaemia in critically ill patients, using stringent criteria, approaches 100%. An unambiguous negative correlation between hyperglycaemia and mortality has been described in various groups of critically ill patients. Although the available evidence remains inconsistent, there appears to be a favourable effect of glucose regulation. This effect on morbidity and mortality depends on patient characteristics. To be able to compare results of future studies involving glucose regulation, better definitions of hyperglycaemia (and consequently of normoglycaemia) and patient populations are needed.