Computerized intensive insulin dosing can mitigate hypoglycemia and achieve tight glycemic control when glucose measurement is performed frequently and on time

The effectiveness of a computerized IV infusion protocol to treat hyperglycemia in burn patients

Tight glucose control (TGC) in critical care settings is becoming increasingly the standard of care. However, TGC comes with the risk of hypoglycemia, as highlighted by some recent studies. Our aim was to establish TGC in burn patients without increasing rates of hypoglycemia. The authors used a computer-driven glucose control program (CGS) to achieve this goal. The computer program calculates insulin drip rates by using a multiplier that changes according to blood glucose (BG) values as well as trends and keeps a record of BG data and insulin infusion rates for future quality control analysis. CGS is also a useful adjunct in transitioning patients from an IV insulin drip to subcutaneous insulin. A retrospective review of the glucose control program database was performed to obtain information on length of time to goal glucose levels (set at 100-150 mg/dl), glucose level trends, and incidence of hypoglycemia when using the computer program. Over 18 months, we used CGS on 94 critical and noncritical burn patients. Mean time to target BG was 5.1 hours. Glucose levels of 100 to 150 mg/dl were maintained 63.3% of the time, and values within the wider range of 70 to 150 mg/dl were maintained 80.8% of the time. The incidence of hypoglycemia, defined as BG level below 70 mg/dl, was only 1.66% and was treated without any adverse sequelae. Hyperglycemic episodes were directly correlated with surgical interventions during which time the CGS was not utilized in the operating room. CGS offers a safe and effective means of rapidly achieving and maintaining glucose targets in burn patients. Further analysis of the data needs to be conducted to determine whether the BG targets used in our study offer a morbidity benefit to burn patients.

Guidelines for the use of an insulin infusion for the management of hyperglycemia in critically ill patients

OBJECTIVE

To evaluate the literature and identify important aspects of insulin therapy that facilitate safe and effective infusion therapy for a defined glycemic end point.

METHODS

Where available, the literature was evaluated using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology to assess the impact of insulin infusions on outcome for general intensive care unit patients and those in specific subsets of neurologic injury, traumatic injury, and cardiovascular surgery. Elements that contribute to safe and effective insulin infusion therapy were determined through literature review and expert opinion. The majority of the literature supporting the use of insulin infusion therapy for critically ill patients lacks adequate strength to support more than weak recommendations, termed suggestions, such that the difference between desirable and undesirable effect of a given intervention is not always clear.

RECOMMENDATIONS

The article is focused on a suggested glycemic control end point such that a blood glucose ≥ 150 mg/dL triggers interventions to maintain blood glucose below that level and absolutely <180 mg/dL. There is a slight reduction in mortality with this treatment end point for general intensive care unit patients and reductions in morbidity for perioperative patients, postoperative cardiac surgery patients, post-traumatic injury patients, and neurologic injury patients. We suggest that the insulin regimen and monitoring system be designed to avoid and detect hypoglycemia (blood glucose ≤ 70 mg/dL) and to minimize glycemic variability.Important processes of care for insulin therapy include use of a reliable insulin infusion protocol, frequent blood glucose monitoring, and avoidance of finger-stick glucose testing through the use of arterial or venous glucose samples. The essential components of an insulin infusion system include use of a validated insulin titration program, availability of appropriate staffing resources, accurate monitoring technology, and standardized approaches to infusion preparation, provision of consistent carbohydrate calories and nutritional support, and dextrose replacement for hypoglycemia prevention and treatment. Quality improvement of glycemic management programs should include analysis of hypoglycemia rates, run charts of glucose values <150 and 180 mg/dL. The literature is inadequate to support recommendations regarding glycemic control in pediatric patients.

CONCLUSIONS

While the benefits of tight glycemic control have not been definitive, there are patients who will receive insulin infusion therapy, and the suggestions in this article provide the structure for safe and effective use of this therapy.

Monitoring in the intensive care

In critical care, the monitoring is essential to the daily care of ICU patients, as the optimization of patient's hemodynamic, ventilation, temperature, nutrition, and metabolism is the key to improve patients' survival. Indeed, the decisive endpoint is the supply of oxygen to tissues according to their metabolic needs in order to fuel mitochondrial respiration and, therefore, life. In this sense, both oxygenation and perfusion must be monitored in the implementation of any resuscitation strategy. The emerging concept has been the enhancement of macrocirculation through sequential optimization of heart function and then judging the adequacy of perfusion/oxygenation on specific parameters in a strategy which was aptly coined “goal directed therapy.” On the other hand, the maintenance of normal temperature is critical and should be regularly monitored. Regarding respiratory monitoring of ventilated ICU patients, it includes serial assessment of gas exchange, of respiratory system mechanics, and of patients' readiness for liberation from invasive positive pressure ventilation. Also, the monitoring of nutritional and metabolic care should allow controlling nutrients delivery, adequation between energy needs and delivery, and blood glucose. The present paper will describe the physiological basis, interpretation of, and clinical use of the major endpoints of perfusion/oxygenation adequacy and of temperature, respiratory, nutritional, and metabolic monitorings.

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.

Glucose measurement of intensive care unit patient plasma samples using a fixed-wavelength mid-infrared spectroscopy system

OBJECTIVE

Glycemic control is a rapidly developing field in intensive care medicine with the aim of reducing mortality, morbidity, and cost. Current intensive care unit (ICU) glucose measurement technologies are susceptible to interference from medications, volume expanders, and other substances present in critically ill patients. We hypothesized that a fixed-wavelength mid-infrared (mid-IR) spectroscopy system would be accurate for measuring glucose levels of ICU patients.

RESEARCH DESIGN AND METHODS

This is a prospective investigation of plasma samples from two different institutions treating a heterogeneous population of ICU patients. The first 292 samples were collected from 86 patients admitted to Stamford Hospital, and the next 352 samples were collected from 75 patients from three ICUs at the University of Maryland. Plasma samples were measured on a Fourier-transform infrared or a proprietary spectrometer, with a glucose prediction algorithm to correct for spectral interference, which were compared with reference measurements taken using a YSI 2300 glucose analyzer.

RESULTS

Glucose values ranged from 24 to 343 mg/dl. Numerous medications and injury/disease states were observed in the patient populations, with metoprolol, fentanyl, and multiple organ failure the most prevalent. Despite these interferents, there was a high correlation (r ≥ 0.94) and low standard error (≤12.8 mg/dl) between the predicted glucose values and those of the YSI 2300 STAT Plus reference instrument in the three studies. A total of 95.1% of the 644 values in the three studies met International Organization for Standardization 15197 criteria.

CONCLUSION

These results suggest that a fixed-wavelength mid-IR spectrometer can measure glucose accurately in the plasma of ICU patients.

Computer decision support software safely improves glycemic control in the burn intensive care unit: a randomized controlled clinical study

The optimal method for glycemic control in the critically burned patient is unknown. The purpose of this randomized controlled study was to determine the safety and efficacy of computer decision support software (CDSS) to control serum glucose concentration in a burn intensive care unit. Eighteen adult burn/trauma patients receiving continuous insulin infusion were initially randomized to receive glucose management by a traditional paper protocol or a computer protocol (CP) for 72 hours and then crossed over to the alternate method for an additional 72 hours. Time in target glucose range (range: 80-110 mg/dl) was higher in the CP group (47 ± 17% vs 41 ± 16.6%; P ≤ .05); time over target range was not significantly reduced in the CP group (49 ± 17.8% vs 54 ± 17.1%; P = .08); and no difference was noted in time under target range of 80 mg/dl (CP: 4.5 ± 2.8%, paper protocol: 4.8 ± 3.3%; P = .8), less than 60 mg/dl (P = .7), and less than 40 mg/dl (P = 1.0). Severe hypoglycemic events (<40 mg/dl) did not differ from the CP group compared with historical controls for patients receiving no insulin (P = .6). More glucose measurements were performed in the CP group (P = .0003), and nursing staff compliance with CP recommendations was greater (P < .0001). Glycemic control using CDSS is safe and effective for the critically burned patient. Time in target range improved without increase in hypoglycemic events. CDSS enhanced consistency in practice, providing standardization among nursing staff.

The evaluation of the ability of closed-loop glycemic control device to maintain the blood glucose concentration in intensive care unit patients

OBJECTIVES

Reduction in the variability of blood glucose concentration might be an important aspect of blood glucose management. A closed-loop glycemic control device (STG-22; NIKKISO, Tokyo, Japan) has been developed to maintain blood glucose levels within the target range through automatic infusion of insulin and glucose. We hypothesized that the STG-22 system could provide optimal blood glucose management without causing hypoglycemic events in patients admitted to intensive care units. In this study, we investigated the feasibility of glycemic control with the STG-22 system. Furthermore, we evaluated the variability in blood glucose concentration associated with the use of the STG-22 system.

DESIGN

Retrospective analysis.

SETTING

A five-bed medical/surgical intensive care unit in a university hospital.

PATIENTS

Two hundred eight patients admitted to the intensive care unit between August 2006 and July 2009.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We calculated the mean and sd of blood glucose concentrations in each patient during intensive insulin therapy (target range, 90-110 mg/dL) administered using STG-22. In addition, to evaluate the blood glucose control achieved using STG-22, the durations for which the blood glucose level was maintained at 70-110 mg/dL, 110-150 mg/dL, 150-180 mg/dL, and>180 mg/dL were calculated. The average operation time of STG-22 was 33.9±42.4 hrs. The blood glucose level was maintained at 70-110 mg/dL for 49.5% of the study period; the corresponding values for 110-150 mg/dL, 150-180 mg/dL, and>180 mg/dL were 31.4%, 7.0%, and 6.9%, respectively. No hypoglycemic events occurred. The sd of blood glucose levels was 19.9±10.9 mg/dL. After a level of 150 mg/dL was achieved, the sd of blood glucose was 12.6±3.1 mg/dL.

CONCLUSIONS

STG-22 can help maintain optimal blood glucose levels without causing hypoglycemia in patients admitted to the intensive care unit. In addition, the use of this device might help decrease the variability in blood glucose concentration. Further randomized clinical trials are required to elucidate whether the low glucose variability maintained using STG-22 can contribute to improving the outcomes of patients admitted to the intensive care unit.

Bioinformatics assistance of metabolic and nutrition management in the ICU

PURPOSE OF REVIEW

To review the domains in which computerized information systems have proven beneficial in facilitating the metabolic and nutritional management

RECENT FINDINGS

In glucose control, computerized insulin algorithms have proven safer and more efficient than manual systems, reducing workload, time to target glycemia and numbers of hypoglycemic and hyperglycemic events. By rendering the nutritional variables visible through specific customization, computers do improve daily monitoring of energy balance and adherence to guidelines, particularly for substrate delivery. Nurse-centered systems have shown to be the most successful to enable routine workflow based on protocol-based care.

SUMMARY

Computers are needed to analyze the increasing amount of data collected from critically ill patients from monitoring systems, laboratories and other sources. Studies have shown that computerized information systems do facilitate glucose control, helping reducing hypoglycemic events. They also improve nutritional monitoring (energy delivery and balance, protein and fat delivery), and quality of nutrition. They reduce nurse workload associated with the multiple balance calculations and ease visualization of events out of planned targets. Though integrated systems are expensive, they improve work efficiency.

Automated near-continuous glucose monitoring measured in plasma using mid-infrared spectroscopy

OBJECTIVE

There are increasing calls for a precise, automated system to enable tight glycemic control and to avoid hypoglycemia in an intensive care unit setting. OptiScan Biomedical has developed a glucose monitor based on mid-infrared spectroscopy that withdraws blood samples (120 µl) and measures plasma glucose. The goal of this study was to validate the performance of the OptiScan Model 5000 over a wide range of glycemic levels in patients.

RESEARCH DESIGN AND METHODS

Sixty people with type 1 (n = 18) or type 2 (n = 42) diabetes who were otherwise healthy were connected to OptiScanners. Their blood glucose concentrations were kept in a euglycemic, hypoglycemic (<75 mg/dl), and hyperglycemic (>180 mg/dl) range by intravenous administrations of insulin and glucose. OptiScanner venous blood samples were automatically withdrawn every 15 minutes. Reference measurements were done using the YSI 2300 glucose analyzer.

RESULTS

The aggregate data points (1155 paired readings) were within International Organization for Standardization standards, with 98.6% of the glucose values within ±20% above 75 mg/dl and ±15 mg/dl below this value. A Clarke error grid analysis showed a total of 1139 points (98.6%) in zone A. Points outside of A exceeded the A zone boundary by an average of 4.3%. The r(2) was 0.99. The total coefficient for variance was 6.4%.

CONCLUSIONS

These results show that the OptiScanner is highly accurate in healthy patients with diabetes across a wide range of glucose values. Mid-infrared spectroscopy may become the method of choice for highly accurate, high frequency, automated glucose measurements and may thus enable better glycemic control in critically ill patients.

Year in review 2009: Critical Care--metabolism

Novel insights into the metabolic alterations of critical illness were published in Critical Care in 2009. The association between early hypoglycaemia/high glycemic variability and poor outcome was confirmed. Improvements in the understanding of the pathophysiological mechanisms of stress hyperglycemia and potential progress in the bedside management of glucose control were presented. With regard to enteral nutrition, some alterations of gastrointestinal physiology were better delineated. The relationship between the achievement of nutritional goals and outcomes was further investigated. Finally, understanding of some critical-illness-related endocrine and neuromuscular disorders improved through new experimental and clinical findings.

Tight glycemic control: what do we really know, and what should we expect?

Tight glycemic control has engendered large numbers of investigations, with conflicting results. The world has largely embraced intensive insulin as a practice, but applies this therapy with great variability in the manner of glucose control and measurement. The present commentary reviews what we actually know with certainty from this vast sea of literature, and what we can expect looking forward.

Incidence of hypoglycemia with tight glycemic control protocols: a comparative study

BACKGROUND

Comparison of hypoglycemia incidence among tight glycemic control (TGC) protocols is a crucial aspect that has not been done in previous trials. This study compared the incidence of hypoglycemia using three TGC protocols in critically ill patients.

METHODOLOGY

This was a prospective study of 420 patients over 18 months. Patients were divided into three groups by TGC protocol: A (modified Leuven protocol), B (Georgia Hospital Association protocol, target blood glucose [BG] 80-110 mg/dL), and C (modified Georgia Hospital Association protocol, target BG 90-140 mg/dL). End points included differences in the incidence of first-degree hypoglycemia (BG <or= 60 mg/dL), second-degree hypoglycemia (BG <or= 40 mg/dL), and hyperglycemia (BG >or= 180 mg/dL).

RESULTS

A total of 34,497 BG samples were analyzed: group A, 11,202 (32.47%); group B, 9,627 (27.91%); and group C, 13,668 (39.62%). First-degree hypoglycemia was more frequent in group A (348 episodes [3.11%]) compared to group B (209 episodes [2.17%] [odds ratio (OR) 1.45, 95% confidence interval (CI) 1.25-1.172, P = 0.001]) and group C (266 episodes [1.95%] [OR 1.66, 95% CI 1.37-1.89, P = 0.001]). Second-degree hypoglycemia was more frequent in group A (131 episodes [1.17%]) compared to group B (62 episodes [0.64%] [OR 1.83, 95% CI 1.22-1.72, P = 0.001]) and group C (58 episodes [0.42%] [OR 2.77, 95% CI 2.04-3.79, P = 0.001]). No significant difference was found when groups B and C were compared (P = 0.10 and P = 0.06, respectively). Hyperglycemia was significantly more common in group A (2,175 episodes [19.42%]) compared to group B (1,333 episodes [13.83%] [OR 1.49, 95% CI 1.39-1.62, P = 0.001], but there was no significant difference compared to group C (2,560 episodes [18.73%] [P = 0.17]).

CONCLUSIONS

TGC protocols vary in their risk of inducing hypoglycemia. Whether this translates into differences in clinical outcomes such as mortality and adverse effects is still to be determined by future studies.