Implementing Intensive Insulin Therapy: Development and Audit of the Bath Insulin Protocol

Cerebral metabolic effects of strict versus conventional glycaemic targets following severe traumatic brain injury

Background

Optimal glycaemic targets for patients with severe traumatic brain injury remain unclear. The primary objective of this microdialysis study was to compare cerebral metabolism with strict versus conventional glycaemic control.

Methods

We performed a prospective single-centre randomised controlled within-subject crossover study of 20 adult patients admitted to an academic neurointensive care unit with severe traumatic brain injury. Patients underwent randomised, consecutive 24-h periods of strict (4–7 mmol/L; 72–126 mg/dl) and conventional (<10 mmol/L; 180 mg/dl) glycaemic control with microdialysis measurements performed hourly. The first 12 h of each study period was designated as a ‘washout’ period, with the subsequent 12 h being the period of interest.

Results

Cerebral glucose was lower during strict glycaemia than with conventional control (mean 1.05 [95% CI 0.58–1.51] mmol/L versus 1.28 [0.81–1.74] mmol/L; P = 0.03), as was lactate (3.07 [2.44–3.70] versus 3.56 [2.81–4.30]; P < 0.001). There were no significant differences in pyruvate or the lactate/pyruvate ratio between treatment phases. Strict glycaemia increased the frequency of low cerebral glucose (< 0.8 mmol/L; OR 1.91 [95% CI 1.01–3.65]; P < 0.05); however, there were no differences in the frequency of critically low glucose (< 0.2 mmol/L) or critically elevated lactate/pyruvate ratio between phases.

Conclusions

Compared with conventional glycaemic targets, strict blood glucose control was associated with lower mean levels of cerebral glucose and an increased frequency of abnormally low glucose levels. These data support conventional glycaemic targets following traumatic brain injury.

Trial registration

ISRCTN, ISRCTN19146279. Retrospectively registered on 2 May 2014.

Electronic supplementary material

The online version of this article (10.1186/s13054-017-1933-5) contains supplementary material, which is available to authorized users.

Knowledge translation interventions for critically ill patients: a systematic review*

OBJECTIVE

We systematically reviewed ICU-based knowledge translation studies to assess the impact of knowledge translation interventions on processes and outcomes of care.

DATA SOURCES

We searched electronic databases (to July, 2010) without language restrictions and hand-searched reference lists of relevant studies and reviews.

STUDY SELECTION

Two reviewers independently identified randomized controlled trials and observational studies comparing any ICU-based knowledge translation intervention (e.g., protocols, guidelines, and audit and feedback) to management without a knowledge translation intervention. We focused on clinical topics that were addressed in greater than or equal to five studies.

DATA EXTRACTION

Pairs of reviewers abstracted data on the clinical topic, knowledge translation intervention(s), process of care measures, and patient outcomes. For each individual or combination of knowledge translation intervention(s) addressed in greater than or equal to three studies, we summarized each study using median risk ratio for dichotomous and standardized mean difference for continuous process measures. We used random-effects models. Anticipating a small number of randomized controlled trials, our primary meta-analyses included randomized controlled trials and observational studies. In separate sensitivity analyses, we excluded randomized controlled trials and collapsed protocols, guidelines, and bundles into one category of intervention. We conducted meta-analyses for clinical outcomes (ICU and hospital mortality, ventilator-associated pneumonia, duration of mechanical ventilation, and ICU length of stay) related to interventions that were associated with improvements in processes of care.

DATA SYNTHESIS

From 11,742 publications, we included 119 investigations (seven randomized controlled trials, 112 observational studies) on nine clinical topics. Interventions that included protocols with or without education improved continuous process measures (seven observational studies and one randomized controlled trial; standardized mean difference [95% CI]: 0.26 [0.1, 0.42]; p = 0.001 and four observational studies and one randomized controlled trial; 0.83 [0.37, 1.29]; p = 0.0004, respectively). Heterogeneity among studies within topics ranged from low to extreme. The exclusion of randomized controlled trials did not change our results. Single-intervention and lower-quality studies had higher standardized mean differences compared to multiple-intervention and higher-quality studies (p = 0.013 and 0.016, respectively). There were no associated improvements in clinical outcomes.

CONCLUSIONS

Knowledge translation interventions in the ICU that include protocols with or without education are associated with the greatest improvements in processes of critical care.

Assessing the performance of a continuous infusion for potassium supplementation in the critically ill

Hypokalaemia is a common problem in critically ill patients, which if untreated, can result in dysrhythmia or another adverse outcome. We assessed the safety and efficacy of a continuous infusion of potassium chloride versus an existing intermittent infusion regimen. In this open-label randomised parallel-arm active-controlled pilot study, critically ill adults with plasma potassium concentration between 2.5 and 3.8 mmol/l were randomised to receive either a continuous infusion or intermittent infusions of potassium chloride for establishment and maintenance of normokalaemia. The primary outcome was the mean difference in plasma potassium concentration over time between the two study arms as assessed by a linear mixed-effects model. Although a statistically significant difference was observed (0.22 mmol/l; 95% confidence interval 0.17, 0.27; P <0.0001), this did not reach the pre-determined level indicative of a treatment effect (0.5 mmol/l). The continuous group demonstrated less variance in (mean) plasma potassium as reflected in narrower confidence intervals in a prediction-by-time model. The incidence rate ratio of dysrhythmia, assessed by a mixed-effects Poisson model, was similar in each group (0.62; 95% confidence interval 0.32, 1.21; P=0.16). We recorded no adverse events directly attributable to infusion of potassium chloride in either study arm. Although titrated continuous infusion did not demonstrate a clinically important difference by comparison with intermittent infusions for the maintenance of normokalaemia, there was more consistent control of plasma potassium with no observed complications or adverse events. Therefore, this trial showed an acceptable efficacy and safety profile for the continuous infusion regimen, suggesting scope for further study.

Nurse-led implementation of a safe and effective intravenous insulin protocol in a medical intensive care unit

BACKGROUND

Recent evidence has linked tight glucose control to worsened clinical outcomes among adults in intensive care units.

OBJECTIVE

To evaluate the effectiveness and safety of a nurse-led intravenous insulin protocol designed to achieve conservative blood glucose control in patients in a medical intensive care unit.

METHODS

A nurse-led intravenous insulin protocol was developed, targeting blood glucose levels at 110 to 149 mg/dL. Hypoglycemia was defined as a blood glucose level less than 70 mg/dL. Patients admitted to the medical intensive care unit who required an insulin infusion were enrolled in the study. Blood glucose levels in those patients were compared with levels in 153 historical control patients admitted to the unit in the 12 months before the protocol was implemented who required an insulin infusion.

RESULTS

Ninety-six patients were enrolled and treated with the protocol. The protocol and control groups had similar characteristics at baseline. More measurements in the protocol group than in the control group (46.3% vs 36.1%, P<.001) were within the target glucose range (110-149 mg/dL). Hyperglycemia (blood glucose ≥200 mg/dL) occurred less often in the protocol group than in the control group (14.8% vs 20.1%, P=.003). Hypoglycemic events (blood glucose <70 mg/dL) also occurred less often in the protocol group (0.07% vs 0.83%, P<.001).

CONCLUSIONS

Implementation of a nurse-led, conservative intravenous insulin protocol in the medical intensive care unit is effective and safe and markedly reduces the rate of hypoglycemia.

Evaluating glycemic control algorithms by computer simulations

BACKGROUND

Numerous guidelines and algorithms exist to achieve glycemic control. Their strengths and weaknesses are difficult to assess without head-to-head comparison in time-consuming clinical trials. We hypothesized that computer simulations may be useful.

METHODS

Two open-label randomized clinical trials were replicated using computer simulations. One study compared performance of the enhanced model predictive control (eMPC) algorithm at two intensive care units in the United Kingdom and Belgium. The other study compared three glucose control algorithms-eMPC, Matias (the absolute glucose protocol), and Bath (the relative glucose change protocol)-in a single intensive care unit. Computer simulations utilized a virtual population of 56 critically ill subjects derived from routine data collected at four European surgical and medical intensive care units.

RESULTS

In agreement with the first clinical study, computer simulations reproduced the main finding and discriminated between the two intensive care units in terms of the sampling interval (1.3 h vs. 1.8 h, United Kingdom vs. Belgium; P < 0.01). Other glucose control metrics were comparable between simulations and clinical results. The principal outcome of the second study was also reproduced. The eMPC demonstrated better performance compared with the Matias and Bath algorithms as assessed by the time when plasma glucose was in the target range between 4.4 and 6.1 mmol/L (65% vs. 43% vs. 42% [P < 0.001], eMPC vs. Matias vs. Bath) without increasing the risk of severe hypoglycemia.

CONCLUSIONS

Computer simulations may provide resource-efficient means for preclinical evaluation of algorithms for glycemic control in the critically ill.

Analytic review: glucose controversies in the ICU

Hyperglycemia is common in critical illness and has been associated with increased morbidity and mortality. An era of tight glucose control began when intensive insulin therapy was shown to improve outcomes in a single-center randomized trial. More recently, with the publication of additional studies, questions have been raised regarding the efficacy and safety of intensive glycemic management. This article will review the biologic mechanisms that may help us understand why and how hyperglycemia and insulin are relevant in critical illness. We will then explore insights gleaned from available clinical trials. Finally, we will discuss specific areas of controversy that relate to the implementation of glycemic control in the intensive care unit, such as the ideal glucose target and the importance of hypoglycemia.

Close relationship between strict blood glucose control, including suppression of blood glucose variability, and mortality reduction in acutely ill patients with glucose intolerance investigated by means of a bedside-type artificial pancreas

The purpose of this study was to elucidate the relationship between strict control of blood glucose (BG) and mortality reduction with the use of an artificial pancreas (AP). Patients were evaluated in the (1) early phase (E phase: mean 3.3 ± 2.6 days after admission, n = 84) and in the (2) late phase (L phase: mean 9.9 ± 3.3 days, n = 88), and were classified into a (1) group with a higher daily mean BG level (BGm) (BGmXa: BGm above Xmg/dl) and a (2) group with a lower BGm (BGmXb: BGm below Xmg/dl). Each group was classified into a (1) subgroup with a higher daily standard deviation of the BG levels (BGsd) and a (2) subgroup with a lower BGsd. In the E phase, the (1) mortality of the BGm200a group was significantly higher than that of the BGm200b group (56 vs. 29%, p < 0.05), and (2) in the BGm200b group, the mortality of the subgroup with a BGsd above 14 mg/dl was significantly higher than that with a BGsd below 14 mg/dl (46 vs. 17%, p < 0.025). In the L phase, the mortality of the BGm175a group was significantly higher than that of the BGm175b group (50 vs. 28%, p < 0.05). In conclusion, (1) a higher BGm and (2) higher BGsd in the E phase were prognostic risk factors. Based on the findings, it was considered that the target for BG control should be set at (1) BGm below 200 mg/dl and BGsd below 14 mg/dl in the E phase, and (2) BGm below 175 mg/dl in the L phase.

Comparisons of different insulin infusion protocols: a review of recent literature

PURPOSE OF REVIEW

To provide an update on the currently available insulin infusion protocols for treatment of hyperglycemia in critically ill patients and to discuss the major differences and similarities among them.

RECENT FINDINGS

We identified a total of 26 protocols, 20 of which used manual blood-glucose calculations, and six that used computerized algorithms. The major differences and similarities among the insulin infusion protocols were in the following areas: patient characteristics, target glucose level, time to achieve target glucose level, incidence of hypoglycemia, rationale for adjusting the rates of insulin infusion, and methods of blood-glucose measurements. Several computerized protocols hold promise for safer achievement of glycemic targets.

SUMMARY

Insulin infusion is the most effective method for controlling hyperglycemia in critically ill patients. Clinicians should utilize a validated insulin infusion protocol that is well tolerated, and is most appropriate and practical for their institution based on the resources that are available.

How do nurses, midwives and health visitors contribute to protocol-based care? A synthesis of the UK literature

OBJECTIVES

To explore how nurses, midwives and health visitors contribute to the development, implementation and audit of protocol-based care. Protocol-based care refers to the use of documents that set standards for clinical care processes with the intent of reducing unacceptable variations in practice. Documents such as protocols, clinical guidelines and care pathways underpin evidence-based practice throughout the world.

METHODS

An interpretative review using the five-stage systematic literature review process. The data sources were the British Nursing Index, CINAHL, EMBASE, MEDLINE and Web of Science from onset to 2005. The Journal of Integrated Care Pathways was hand searched (1997-June 2006). Thirty three studies about protocol-based care in the United Kingdom were appraised using the Qualitative Assessment and Review Instrument (QARI version 2). The literature was synthesized inductively and deductively, using an official 12-step guide for development as a framework for the deductive synthesis.

RESULTS

Most papers were descriptive, offering practitioner knowledge and positive findings about a locally developed and owned protocol-based care. The majority were instigated in response to clinical need or service re-design. Development of protocol-based care was a non-linear, idiosyncratic process, with steps omitted, repeated or completed in a different order. The context and the multiple purposes of protocol-based care influenced the development process. Implementation and sustainability were rarely mentioned, or theorised as a change. The roles and activities of nurses were so understated as to be almost invisible. There were notable gaps in the literature about the resource use costs, the engagement of patients in the decision-making process, leadership and the impact of formalisation and new roles on inter-professional relations.

CONCLUSIONS

Documents that standardise clinical care are part of the history of nursing as well as contemporary evidence-based care and expanded roles. Considering the proliferation and contested nature of protocol-based care, the dearth of literature about the contribution, experience and outcomes for nurses, midwives and health visitors is noteworthy and requires further investigation.

Delay in blood glucose monitoring during an insulin infusion protocol is associated with increased risk of hypoglycemia in intensive care units

BACKGROUND

Hypoglycemia during insulin infusion therapy is a major problem. We investigated whether a delay in blood glucose (BG) monitoring during an insulin infusion protocol (IIP) in the intensive care unit (ICU) is associated with hypoglycemia.

METHODS

Data were collected for 50 consecutive patients treated with Brigham and Women's Hospital's IIP. Point-of-care BG values were obtained from the bedside paper flow sheets and the exact times of individual measurements were ascertained from an internet-based glucose meter download program. Data were carefully studied for protocol time violations, defined as a delay of >10 minutes after the recommended time for BG measurement.

RESULTS

A total of 2309 BG values were evaluated for time violation. A total of 1474 (63.9%) measurements had been obtained at the recommended time or earlier; 835 (36.1%) measurements had been obtained >10 minutes after the recommended time for measurement. There were a significantly higher proportion of BG values <80 mg/dL following the time violation as compared to no time violation (17.8% versus 11.6%; P < 0.001).

CONCLUSION

We conclude that the risk of hypoglycemia during insulin infusion therapy is higher after a delay in BG measurement.

Comparison of three protocols for tight glycemic control in cardiac surgery patients

OBJECTIVE

We performed a randomized trial to compare three insulin-titration protocols for tight glycemic control (TGC) in a surgical intensive care unit: an absolute glucose (Matias) protocol, a relative glucose change (Bath) protocol, and an enhanced model predictive control (eMPC) algorithm.

RESEARCH DESIGN AND METHODS

A total of 120 consecutive patients after cardiac surgery were randomly assigned to the three protocols with a target glycemia range from 4.4 to 6.1 mmol/l. Intravenous insulin was administered continuously or in combination with insulin boluses (Matias protocol). Blood glucose was measured in 1- to 4-h intervals as requested by the protocols.

RESULTS

The eMPC algorithm gave the best performance as assessed by time to target (8.8 +/- 2.2 vs. 10.9 +/- 1.0 vs. 12.3 +/- 1.9 h; eMPC vs. Matias vs. Bath, respectively; P < 0.05), average blood glucose after reaching the target (5.2 +/- 0.1 vs. 6.2 +/- 0.1 vs. 5.8 +/- 0.1 mmol/l; P < 0.01), time in target (62.8 +/- 4.4 vs. 48.4 +/- 3.28 vs. 55.5 +/- 3.2%; P < 0.05), time in hyperglycemia >8.3 mmol/l (1.3 +/- 1.2 vs. 12.8 +/- 2.2 vs. 6.5 +/- 2.0%; P < 0.05), and sampling interval (2.3 +/- 0.1 vs. 2.1 +/- 0.1 vs. 1.8 +/- 0.1 h; P < 0.05). However, time in hypoglycemia risk range (2.9-4.3 mmol/l) in the eMPC group was the longest (22.2 +/- 1.9 vs. 10.9 +/- 1.5 vs. 13.1 +/- 1.6; P < 0.05). No severe hypoglycemic episode (<2.3 mmol/l) occurred in the eMPC group compared with one in the Matias group and two in the Bath group.

CONCLUSIONS

The eMPC algorithm provided the best TGC without increasing the risk of severe hypoglycemia while requiring the fewest glucose measurements. Overall, all protocols were safe and effective in the maintenance of TGC in cardiac surgery patients.

Hyperglycemia during acute coronary syndrome: a nurse-managed insulin infusion protocol for stricter and safer control

BACKGROUND

Diabetic patients with acute coronary syndromes (ACS) might benefit from tight glycemic control by means of insulin infusion. Nurse-implemented insulin infusion protocols (IIP) are available but none validated in patients with ACS admitted to a coronary care unit (CCU).

AIMS

To assess feasibility, effectiveness and safety of a new nurse-managed IIP (Desio Diabetes Diagram, DDD) for intensive glucose control in patients with suspected ACS and known diabetes or blood glucose (BG) >200 mg/dL.

METHODS AND RESULTS

To reach and maintain a target BG level of 100-139 mg/dL we adopted a nomogram based on the percent changes in the insulin infusion rate according to the current BG value and the percent change from previous BG level. Ninety-one consecutive patients (53 men, mean age 69.7+/-11.2 years) were treated with DDD IIP. Baseline BG was 202.2+/-86.8 mg/dL. The median time to achieve the target was 3 h (Q1-Q3 2-5 h). Afterwards target BG levels were maintained for 70.4+/-15.9% of the time. During 5004 h of insulin infusion BG never fell below 40 mg/dL.

CONCLUSIONS

The nurse-managed DDD IIP was easily implemented in our CCU and permitted strict and safe glycemic control in hyperglycemic patients with ACS.

A systematic review on quality indicators for tight glycaemic control in critically ill patients: need for an unambiguous indicator reference subset

Introduction

The objectives of this study were to systematically identify and summarize quality indicators of tight glycaemic control in critically ill patients, and to inspect the applicability of their definitions.

Methods

We searched in MEDLINE^® for all studies evaluating a tight glycaemic control protocol and/or quality of glucose control that reported original data from a clinical trial or observational study on critically ill adult patients.

Results

Forty-nine studies met the inclusion criteria; 30 different indicators were extracted and categorized into four nonorthogonal categories: blood glucose zones (for example, 'hypoglycaemia'); blood glucose levels (for example, 'mean blood glucose level'); time intervals (for example, 'time to occurrence of an event'); and protocol characteristics (for example, 'blood glucose sampling frequency'). Hypoglycaemia-related indicators were used in 43 out of 49 studies, acting as a proxy for safety, but they employed many different definitions. Blood glucose level summaries were used in 41 out of 49 studies, reported as means and/or medians during the study period or at a certain time point (for example, the morning blood glucose level or blood glucose level upon starting insulin therapy). Time spent in the predefined blood glucose level range, time needed to reach the defined blood glucose level target, hyperglycaemia-related indicators and protocol-related indicators were other frequently used indicators. Most indicators differ in their definitions even when they are meant to measure the same underlying concept. More importantly, many definitions are not precise, prohibiting their applicability and hence the reproducibility and comparability of research results.

Conclusions

An unambiguous indicator reference subset is necessary. The result of this systematic review can be used as a starting point from which to develop a standard list of well defined indicators that are associated with clinical outcomes or that concur with clinicians' subjective views on the quality of the regulatory process.

A benchmark data set for model-based glycemic control in critical care

BACKGROUND

Hyperglycemia is prevalent in critical care. That tight control saves lives is becoming more clear, but the "how" and "for whom" in repeating the initial results remain elusive. Model-based methods can provide tight, patient-specific control, as well as providing significant insight into the etiology and evolution of this condition. However, it is still often difficult to compare results due to lack of a common benchmark. This article puts forward a benchmark data set for critical care glycemic control in a medical intensive care unit (ICU). Based on clinical patient data from SPecialized Relative Insulin and Nutrition Tables (SPRINT) studies, it provides a benchmark for comparing and analyzing performance in model-based glycemic control.

METHODS

Data from 20 of the first 150 postpilot patients treated under SPRINT are presented. All patients had longer than a 5-day length of stay (LoS) in the Christchurch ICU. The benchmark data set matches overall patient data and glycemic control results for the entire cohort and this particular LoS >5-day group. The mortality outcome (n =3, 15%) also matches SPRINT results for this patient group.

RESULTS

Data cover 20 patients and 6372 total patient hours with an average of 339.4 hours per patient. It includes insulin and nutrition inputs along with 4182 blood glucose measurements at an average of 224.3 measurements per patient, averaging a measurement approximately every 1.5 hours (16 per day). Data are available via download in a Microsoft Excel format. A series of cumulative distribution functions and tables are used to summarize data in this article.

CONCLUSION

Model-based methods can provide tighter, more adaptable "one method fits all" solutions using methods that enable patient-specific modeling and control. A benchmark data set will enable easier model and protocol development for groups lacking clinical data, as well as providing a benchmark to compare results of different protocols on a single (virtual) cohort based on real clinical data.

The impact of parameter identification methods on drug therapy control in an intensive care unit

This paper investigates the impact of fast parameter identification methods, which do not require any forward simulations, on model-based glucose control, using retrospective data in the Christchurch Hospital Intensive Care Unit. The integral-based identification method has been previously clinically validated and extensively applied in a number of biomedical applications; and is a crucial element in the presented model-based therapeutics approach. Common non-linear regression and gradient descent approaches are too computationally intense and not suitable for the glucose control applications presented. The main focus in this paper is on better characterizing and understanding the importance of the integral in the formulation and the effect it has on model-based drug therapy control. As a comparison, a potentially more natural derivative formulation which has the same computation speed advantages is investigated, and is shown to go unstable with respect to modelling error which is always present clinically. The integral method remains robust.

Tight glycaemic control: a prospective observational study of a computerised decision-supported intensive insulin therapy protocol

INTRODUCTION

A single centre has reported that implementation of an intensive insulin protocol, aiming for tight glycaemic control (blood glucose 4.4 to 6.1 mmol/l), resulted in significant reduction in mortality in longer stay medical and surgical critically ill patients. Our aim was to determine the degree to which tight glycaemic control can be maintained using an intensive insulin therapy protocol with computerized decision support and to identify factors that may be associated with the degree of control.

METHODS

At a general adult 22-bed intensive care unit, we implemented an intensive insulin therapy protocol in mechanically ventilated patients, aiming for a target glucose range of 4.4 to 6.1 mmol/l. The protocol was integrated into the computerized information management system by way of a decision support program. The time spent in each predefined blood glucose band was estimated, assuming a linear trend between measurements.

RESULTS

Fifty consecutive patients were investigated, involving analysis of 7,209 blood glucose samples, over 9,214 hours. The target tight glycaemic control band (4.4 to 6.1 mmol/l) was achieved for a median of 23.1% of the time that patients were receiving intensive insulin therapy. Nearly half of the time (median 48.5%), blood glucose was within the band 6.2 to 7.99 mmol/l. Univariate analysis revealed that body mass index (BMI), Acute Physiology and Chronic Health Evaluation (APACHE) II score and previous diabetes each explained approximately 10% of the variability in tight glycaemic control. BMI and APACHE II score explained most (27%) of the variability in tight glycaemic control in the multivariate analysis, after adjusting for age and previous diabetes.

CONCLUSION

Use of the computerized decision supported intensive insulin therapy protocol did result in achievement of tight glycaemic control for a substantial percentage of each patient's stay, although it did deliver 'normoglycaemia' (4.4 to about 8 mmol/l) for nearly 75% of the time. Tight glycaemic control was difficult to achieve in critically ill patients using this protocol. More sophisticated methods such as continuous blood glucose monitoring with automated insulin and glucose infusion adjustment may be a more effective way to achieve tight glycaemic control. Glycaemia in patients with high BMI and APACHE II scores may be more difficult to control using intensive insulin therapy protocols. Trial registration number 05/Q0505/1.

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.

Comparison of a nurse initiated insulin infusion protocol for intensive insulin therapy between adult surgical trauma, medical and coronary care intensive care patients

Background

Sustained hyperglycemia is a known risk factor for adverse outcomes in critically ill patients. The specific aim was to determine if a nurse initiated insulin infusion protocol (IIP) was effective in maintaining blood glucose values (BG) within a target goal of 100–150 mg/dL across different intensive care units (ICUs) and to describe glycemic control during the 48 hours after protocol discontinuation.

Methods

A descriptive, retrospective review of 366 patients having 28,192 blood glucose values in three intensive care units, Surgical Trauma Intensive Care Unit (STICU), Medical (MICU) and Coronary Care Unit (CCU) in a quaternary care hospital was conducted. Patients were > 15 years of age, admitted to STICU (n = 162), MICU (n = 110) or CCU (n = 94) over 8 months; October 2003-June 2004 and who had an initial blood glucose level > 150 mg/dL. We summarized the effectiveness and safety of a nurse initiated IIP, and compared these endpoints among STICU, MICU and CCU patients.

Results

The median blood glucose values (mg/dL) at initiation of insulin infusion protocol were lower in STICU (188; IQR, 162–217) than in MICU, (201; IQR, 170–268) and CCU (227; IQR, 178–313); p < 0.0001. Mean time to achieving a target glucose level (100–150 mg/dL) was similar between the three units: 4.6 hours in STICU, 4.7 hours in MICU and 4.9 hours in CCU (p = 0.27). Hypoglycemia (BG < 60 mg/dL) occurred in 7% of STICU, 5% of MICU, and 5% of CCU patients (p = 0.85). Protocol violations were uncommon in all three ICUs. Mean blood glucose 48 hours following IIP discontinuation was significantly different for each population: 142 mg/dL in STICU, 167 mg/dL in MICU, and 160 mg/dL in CCU (p < 0.0001).

Conclusion

The safety and effectiveness of nurse initiated IIP was similar across different ICUs in our hospital. Marked variability in glucose control after the protocol discontinuation suggests the need for further research regarding glucose control in patients transitioning out of the ICU.

Insulin infusion protocols for critically ill patients: a highlight of differences and similarities

OBJECTIVE

To discuss the major differences and similarities among the currently published insulin infusion protocols (IIPs) for critically ill patients.

METHODS

IIPs were identified by searching MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. The reference lists for all retrieved protocols were also reviewed to identify any IIPs that were not surfaced with use of our initial search strategies. The major differences and similarities among the IIPs were identified and examined. In addition, strategies for successful implementation of IIPs were outlined.

RESULTS

Our search strategies retrieved 17 IIPs. Currently, no published studies have compared one insulin protocol with another. The major differences or similarities among the published IIPs were in the following areas: patient characteristics, target glucose level, time to achieve target glucose level, incidence of hypoglycemia, rationale for adjusting the rates of insulin infusion, and methods of blood glucose measurements. Because of variations in the definition of hypoglycemia, methods of blood glucose measurement, and types of blood samples used, some comparisons across the protocols were difficult. Use of a multidisciplinary team and gaining administrative support are crucial for addressing issues and provision of necessary resources for implementing a protocol for "tight" glycemic control in critically ill patients.

CONCLUSION

Clinicians should evaluate the type of patients in their critical care units, the mean baseline glucose levels, and the available resources to determine the most appropriate and practical IIP for their institution.

Intensive insulin therapy in critical care: a review of 12 protocols

OBJECTIVE

To review performance characteristics of 12 insulin infusion protocols.

RESEARCH DESIGN AND METHODS

We systematically identify and compare 12 protocols and then apply the protocols to generate insulin recommendations in the management of a patient with hyperglycemia. The main focus involves a comparison of insulin doses and patterns of insulin administration.

RESULTS

There is great variability in protocols. Areas of variation include differences in initiation and titration of insulin, use of bolus dosing, requirements for calculation in adjustment of the insulin infusion, and method of insulin protocol adjustments. Insulin recommendations for a sample patient are calculated to highlight differences between protocols, including the patterns and ranges of insulin dose recommended (range 27-115 units [mean +/- SD 66.7 +/- 27.9]), amount recommended for glucose readings >200 mg/dl, and adjustments nearing target glucose.

CONCLUSIONS

The lack of consensus in the delivery of intravenous insulin infusions is reflected in the wide variability of practice noted in this survey. This mandates close attention to the choice of a protocol. One protocol may not suffice for all patients.

A review of the use of insulin protocols to maintain normoglycaemia in high dependency patients

AIM

This paper critically examines the evidence base for and issues involved in the introduction of an insulin protocol to maintain normoglycaemia in patients within a medical/surgical high dependency ward.

BACKGROUND

A growing body of evidence has linked hyperglycaemia to worsened clinical outcomes. This has led to intravenous insulin protocols becoming a new standard of care in intensive care units. However, the use and benefits of insulin protocols within high dependency units have not yet been addressed in the literature.

METHODS

The literature was examined for the 10-year period up to January 2005. The databases searched were MEDLINE, OVID, CINHAL, the British Nursing Index, the EBSCO collection, the COCHRANE library, the Department of Health, and guidelines within the Scottish Intercollegiate Guidelines Network and National Institute for Clinical Excellence using the key words insulin, protocol, hyperglycaemia, critical care, intensive care and high dependency.

RESULTS

The literature reports that both medical and surgical intensive care patients treated with intravenous insulin protocols to maintain normoglycaemia experienced significantly reduced mortality and morbidity. Resulting hypoglycaemic episodes were limited with no incidence of patient deterioration. A review of published intravenous insulin protocols used in intensive care settings revealed their safe and effective use in nurse to patient ratios similar to those present in high dependency units.

CONCLUSIONS

In the light of this evidence, it would seem safe and ethically correct to enable high dependency patients to benefit from this cheap intervention. An insulin protocol tailored for the glycaemic control of high dependency patients has been suggested, although it may have to be commenced in conjunction with other fluid and nutrition protocols to safeguard the risk of hypoglycaemic events. Further research into the safety and benefit of insulin protocols in high dependency populations is required.

RELEVANCE TO CLINICAL PRACTICE

The stress of critical illness often leads to hyperglycaemia, which is linked to worsened clinical outcomes. Both medical and surgical intensive care patients treated with intravenous insulin protocols to maintain normoglycaemia experienced significantly reduced mortality and morbidity. This paper identifies that, to date, no research into the benefits of glycaemic control in high dependency populations has been published. The case for the introduction of insulin protocols into high dependency units is therefore examined and an insulin protocol suggested.

A practical approach to hyperglycemia management in the intensive care unit: evaluation of an intensive insulin infusion protocol

STUDY OBJECTIVES

To evaluate the effectiveness and safety of maintaining a target blood glucose concentration of 91-130 mg/dl with a standardized, nurse-managed, intensive insulin infusion protocol outside a study setting, and to determine if a statistically significant favorable effect on morbidity and mortality was achieved.

DESIGN

Retrospective, observational, chart review.

SETTING

Medical and surgical intensive care units (ICUs) in a community teaching hospital.

PATIENTS

One hundred forty-three adult patients who received insulin infusions managed at the discretion of the physician over a 1-year period before initiation of the protocol (control group), and 70 patients who received insulin infusions over a 6-month period with infusion dosages titrated by using the protocol (protocol group).

MEASUREMENTS AND MAIN RESULTS

Episodes of hypoglycemia, time within target range, mean blood glucose concentration, frequency of measurement, length of ICU stay, duration of mechanical ventilation, and overall mortality were collected. Hypoglycemic episodes were not significantly different between the groups. Blood glucose concentrations were within target range in 34% of all measurements in the protocol group compared with 23% in the control group (p<0.001, relative risk [RR] 1.48, 95% confidence interval [CI] 1.38-1.58). Once target range was reached on one measurement, 43% of concentrations remained in target range in the protocol group compared with 29% in the control group (p<0.001, RR 1.47, 95% CI 1.38-1.56). Frequency of measurements was higher in the protocol group versus control group (p=0.01); however, clinical difference was minimal. Protocol group had lower overall mortality rate (27% [19/70] vs 32% [46/143], p=0.45), reduced mean ICU length of stay (16.7 +/- 10.6 vs 18.4 +/- 16.0 days, p=0.37), and less mechanical ventilation time (16.5 +/- 9.7 vs 17.0 +/- 15.0 days, p=0.79).

CONCLUSION

The nurse-managed insulin infusion protocol improved glycemic control with minimal hypoglycemic episodes compared with baseline practice. A trend toward decreased mortality, ICU length of stay, sand days of mechanical ventilation was observed. When compared with other published protocols, our insulin protocol displays comparable effectiveness with the use of less-frequent blood glucose measurements.

Achieving tight glycaemic control

The implementation of tight glycaemic control (TGC) is becoming accepted best practice within intensive care units throughout the world. It is recommended by the Surviving Sepsis Campaign and is included in the sepsis care bundle. The major impact of TGC is currently thought to be associated with reduced morbidity and mortality. The process of achieving TGC is, however, not without risk. In particular, the need for frequent, accurate blood glucose measurement and the possibility of prolonged, unrecognised hypoglycaemia are of concern. There is also the potential for patients who exhibit significant insulin resistance to require the administration of large amounts of insulin. The transfer of patients from the intensive care unit to the operating theatre or for computerised tomography during intensive insulin therapy is also hazardous. The purpose of this paper is to describe a series of nurse led pilot studies which aimed to introduce the process of TGC whilst maintaining patient safety. The results demonstrate the effectiveness of a staged approach and the achievement of TGC.

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.

Overview of glycemic control in critical care: relating performance and clinical results

BACKGROUND

Hyperglycemia is prevalent in critical care and tight control can save lives. Current ad-hoc clinical protocols require significant clinical effort and produce highly variable results. Model-based methods can provide tight, patient specific control, while addressing practical clinical difficulties and dynamic patient evolution. However, tight control remains elusive as there is not enough understanding of the relationship between control performance and clinical outcome.

METHODS

The general problem and performance criteria are defined. The clinical studies performed to date using both ad-hoctitration and model-based methods are reviewed. Studies reporting mortality outcome are analysed in terms of standardized mortality ratio (SMR) and a 95(th) percentile (+/-2sigma) standard error (SE(95%)) to enable better comparison across cohorts.

RESULTS

Model-based control trials lower blood glucose into a 72-110 mg/dL band within 10 hours, have target accuracy over 90%, produce fewer hypoglycemic episodes, and require no additional clinical intervention. Plotting SMR versus SE(95%) shows potentially high correlation (r=0.84) between ICU mortality and tightness of control.

SUMMARY

Model-based methods provide tighter, more adaptable one method fits all solutions, using methods that enable patient-specific modeling and control. Correlation between tightness of control and clinical outcome suggests that performance metrics, such as time in a relevant glycemic band, may provide better guidelines. Overall, compared to the current one size fits all sliding scale and ad-hoc regimens, patient-specific pharmacodynamic and pharmacokinetic model-based, or one method fits all control, utilizing computational and emerging sensor technologies, offers improved treatment and better potential outcomes when treating hyperglycemia in the highly dynamic critically ill patient.

Intensive insulin therapy in intensive care: an example of the struggle to implement evidence-based medicine

Schultz and colleagues discuss the factors hindering implementation of intensive insulin therapy.

Towards a feasible algorithm for tight glycaemic control in critically ill patients: a systematic review of the literature

Introduction

Tight glycaemic control is an important issue in the management of intensive care unit (ICU) patients. The glycaemic goals described by Van Den Berghe and colleagues in their landmark study of intensive insulin therapy appear difficult to achieve in a real life ICU setting. Most clinicians and nurses are concerned about a potentially increased frequency of severe hypoglycaemic episodes with more stringent glycaemic control. One of the steps we took before we implemented a glucose regulation protocol was to review published trials employing insulin/glucose algorithms in critically ill patients.

Methods

We conducted a search of the PubMed, Embase and Cochrane databases using the following terms: 'glucose', 'insulin', 'protocol', 'algorithm', 'nomogram', 'scheme', 'critically ill' and 'intensive care'. Our search was limited to clinical trials conducted in humans. The aim of the papers selected was required to be glycaemic control in critically ill patients; the blood glucose target was required to be 10 mmol/l or under (or use of a protocol that resulted in a mean blood glucose = 10 mmol/l). The studies were categorized according to patient type, desired range of blood glucose values, method of insulin administration, frequency of blood glucose control, time taken to achieve the desired range for glucose, proportion of patients with glucose in the desired range, mean blood glucose and frequency of hypoglycaemic episodes.

Results

A total of twenty-four reports satisfied our inclusion criteria. Most recent studies (nine) were conducted in an ICU; nine others were conducted in a perioperative setting and six were conducted in patients with acute myocardial infarction or stroke. Studies conducted before 2001 did not include normoglycaemia among their aims, which changed after publication of the study by Van Den Berghe and coworkers in 2001; glycaemic goals became tighter, with a target range between 4 and 8 mmol/l in most studies.

Conclusion

Studies using a dynamic scale protocol combining a tight glucose target and the last two blood glucose values to determine the insulin infusion rate yielded the best results in terms of glycaemic control and reported low frequencies of hypoglycaemic episodes.

A pilot study of the SPRINT protocol for tight glycemic control in critically Ill patients

BACKGROUND

Stress-induced hyperglycemia is prevalent in critical care, even in patients with no history of diabetes. Increased counter-regulatory hormone response increases gluconeogenesis and effective insulin resistance, which can be exacerbated by drug therapy. Control of blood glucose levels to the 4.0-6.1 mmol/L range has been shown to reduce mortality and improve clinical outcomes. The Specialized Relative Insulin and Nutrition Tables (SPRINT) protocol is a simple alternative intensive care unit protocol for modulating insulin and nutritional input to gain tight blood glucose control in the 4.0-6.1 mmol/L target band. The look-up tables, implemented in a wheel-based format, are used by nurses to determine glycemic control actions based on hourly or 2-hourly blood glucose measurements and nutrition and insulin administration rates.

METHODS

An 11 patient pilot study was conducted comprising 2,152 hours of blood glucose level control using the SPRINT protocol. The patient cohort average Acute Physiology and Chronic Health Evaluation II score was 22, which was higher than previous intensive insulin clinical studies.

RESULTS

Overall, 64% of measurements were in the 4.0-6.1 mmol/L band, 89% in the 4.0-7.0 mmol/L band, and 96% of all measurements in the 4.0-7.75 mmol/L band. The average value was 5.8 +/- 0.9 mmol/L. Only 1.4% of all measurements were below 4 mmol/L, with a minimum of 3.2 mmol/L. The maximum value recorded was 11.8 mmol/L.

CONCLUSIONS

Control of blood glucose level was achieved using a protocol implemented by the nursing staff without the need for physician intervention or interpretation, where control is defined as maximizing time within a desired band. The results led to a high level of support for the SPRINT protocol among clinical staff and acceptance of the frequent measurement requirement for effective control. The ease-of-use of the protocol resulted in minimal noncompliance by clinical staff.

Introducing intensive insulin therapy: the nursing perspective

Intensive insulin therapy (IIT) for the management of high blood glucose can reduce mortality and morbidity in the critically ill. However, there is little published literature on how to implement it successfully. The aim of this study is to chronicle the development and difficulties encountered in implementing an IIT protocol in a critical care unit in a district general hospital. A nurse-led protocol was developed. Qualitative audit was undertaken during development and implementation to identify potential problems with using the Bath Insulin Protocol. Regular feedback sessions were introduced to encourage change and further identify problem issues. Qualitative audit led to changes in practice for individual nurses and changes to other unit protocols. The main change for individual nurses was to measure blood glucose hourly using a bedside glucometer. The unit's feeding and drug dilution policies were identified as a potential cause of glucose instability and were modified. To implement IIT successfully, it is necessary to consider changing working practices and to identify other unit protocols which can cause glucose instability. The additional nursing workload must be considered and appropriate means of supporting staff identified.

A simple insulin-nutrition protocol for tight glycemic control in critical illness: development and protocol comparison

BACKGROUND

Hyperglycemia is prevalent in critical care, and tight control can significantly reduce mortality. However, current protocols have been considered taxing to administer and may require extra staff. In addition, increased insulin resistance and saturation effects limit the level of control possible using insulin alone. Thus, regulating both insulin and exogenous nutritional inputs is required to control blood glucose.

METHODS

A robust, easy-to-use protocol ["SPRINT" (Specialized Relative Insulin Nutrition Tables)] that employs both insulin and feed modulation is developed and analyzed using retrospective data from 19 patients with average Acute Physiology and Chronic Health Evaluation II score of 21.8. Results are compared with several published protocols in simulation, and verified in a proof-of-concept trial.

RESULTS

In simulation, 61.7% of measurements were in the 75-110 mg/dL band and 83.5% in the 75-140 mg/dL band. Results from the simulation of published protocols agreed with published results. Clinically, for two patients, 64% and 85% of measurements were between 75 and 110 mg/dL during the two proof-of-concept trials. Total enteral feeding was similar to, or exceeded, retrospective data.

CONCLUSIONS

Tight control was achieved in simulation using a protocol that is easy to implement in an intensive care unit. Similarly tight control was also maintained during the two proof-of-concept clinical trials. Measurement frequency of 1-2 h is seen to be critical to achieving and maintaining tight control. The overall SPRINT protocol is easy to use for clinical staff and effective in achieving and maintaining normoglycemia in critical illness.

Collaborative development of an insulin nomogram for intensive insulin therapy

A significant reduction in morbidity and mortality can be achieved by using intensive insulin therapy to achieve normoglycemia in the critically ill patient. Nurses hourly titrate insulin infusion rates using protocols, most often in chart form, to guide practice. Despite the reported development of several intensive insulin protocols, information about the accuracy, practicality, ease of calculation, and preferences of critical care nurses have not been studied. The purpose of this study was to test a newly developed nomogram to determine if it was clinically practical, easily understood, and more quickly and accurately used than existing protocols in chart form. Three cohorts of nurses (N = 153), with an average of 9 years experience in critical care, performed calculations of insulin doses on the basis of hypothetical patient data, using chart and nomogram protocols. Time, accuracy, preference, and feedback were examined over all 3 phases. No statistical significance was found between the chart and nomogram methods regarding time to complete the calculations nor was there any significant effect of experience on the time it took to complete the calculations or the accuracy of the resultant answers. Overall, the accuracy of the calculations improved with each revision of the nomogram. The nurses did not have a preference of one tool over another but gave extensive feedback that helped refine the nomogram. The resultant nomogram was shown to be easy to use, helpful in improving the accuracy of insulin dosage calculation, and judged to be practical by the nurses who would use the tool at the bedside.

Barriers to Glucose Control in the Intensive Care Unit

Despite published evidence supporting glycemic control in critically ill patients, achieving euglycemia remains a problem in the intensive care units (ICUs) of many institutions. Clinicians seeking to implement the findings of published evidence in their practice face many potential barriers that make euglycemia difficult to achieve in patients in the ICU. Developing a comprehensive understanding of the many barriers to ICU glucose control can aide clinicians in attempting to change practice and improve patient outcomes. Barriers to ICU glucose control include the role of different health professionals in glucose management, communication among health care professionals, guidelines, protocols, ICU culture, fear of hypoglycemia, glucose monitoring, education, systems analysis, health care resources, nutritional needs, and drug utilization. By ensuring compliance, changing ICU culture, developing guidelines and protocols, and incorporating a multidisciplinary approach, clinicians can achieve glycemic control in the critically ill population and improve patient outcomes.

Recommended guidelines for reviewing, reporting, and conducting research on post-resuscitation care: The Utstein style

The aim of this report is to establish recommendations for reviewing, reporting, and conducting research during the post-resuscitation period in hospital. It defines data that are needed for research and more specialised registries and therefore supplements the recently updated Utstein template for resuscitation registries. The updated Utstein template and the out-of-hospital "Chain of Survival" describe factors of importance for successful resuscitation up until return of spontaneous circulation (ROSC). Several factors in the in-hospital phase after ROSC are also likely to affect the ultimate outcome of the patient. Large differences in survival to hospital discharge for patients admitted alive are reported between hospitals. Therapeutic hypothermia has been demonstrated to improve the outcome, and other factors such as blood glucose, haemodynamics, ventilatory support, etc., might also influence the result. No generally accepted, scientifically based protocol exists for the post-resuscitation period in hospital, other than general brain-oriented intensive care. There is little published information on this in-hospital phase. This statement is the result of a scientific consensus development process started as a symposium by a task force at the Utstein Abbey, Norway, in September 2003. Suggested data are defined as core and supplementary and include the following categories: pre-arrest co-morbidity and functional status, cause of death, patients' quality of life, in-hospital system factors, investigations and treatment, and physiological data at various time points during the first three days after admission. It is hoped that the publication of these recommendations will encourage research into the in-hospital post-resuscitation phase, which we propose should be included in the chain-of-survival as a fifth ring. Following these recommendations should enable better understanding of the impact of different in-hospital treatment strategies on outcome.

Does hyperglycaemia precede the clinical onset of myocardial ischaemia?

Stress hyperglycaemia has been observed previously in a large proportion of patients with acute myocardial infarction. We report a patient who presented to our intensive care unit (ICU) on two occasions with acute hyperglycaemia preceding new onset myocardial ischaemia by several hours.

Sepsis strategies: an ICU package?

--Mortality of patients with severe sepsis remains at unacceptable levels and recent new strategies are not being widely embraced. --Five strategies are discussed within this article [low tidal volumes in acute lung injury/acute respiratory distress syndrome, early goal-directed therapy, drotrecogin alfa (activated), moderate dose corticosteroids and tight control of blood glucose]. --The critical care nurse plays a leading role in the detection, monitoring and treatment of patients with severe sepsis. --The role of the critical care nurse within the multidisciplinary team is explored. --Education, combination of strategies and the use of protocols are discussed.